separate svgcanvas from svgedit

now you can use directlt svgcanvas. see readme.md

* configure workspaces
* move svgcanvas to packages folder
* move utils to common and paint to svgcanvas
* make svgcanvas a dependency of svgedit
* update deps
* workspaces requires npm 7 at least so the ci needs a new node version
* update github actions to V3
* update snapshots using custom svg exports
* remove unmaintained cypress snapshot plugin
* new github action to add coverage in PR
* Update onpushandpullrequest.yml
* svgcanvas v7.1.6

packages/svgcanvas/blur-event.js

@@ -0,0 +1,156 @@
+/**
+ * Tools for blur event.
+ * @module blur
+ * @license MIT
+ * @copyright 2011 Jeff Schiller
+ */
+
+let svgCanvas = null
+
+/**
+* @function module:blur.init
+* @param {module:blur.blurContext} blurContext
+* @returns {void}
+*/
+export const init = (canvas) => {
+  svgCanvas = canvas
+}
+
+/**
+* Sets the `stdDeviation` blur value on the selected element without being undoable.
+* @function module:svgcanvas.SvgCanvas#setBlurNoUndo
+* @param {Float} val - The new `stdDeviation` value
+* @returns {void}
+*/
+export const setBlurNoUndo = function (val) {
+  const selectedElements = svgCanvas.getSelectedElements()
+  if (!svgCanvas.getFilter()) {
+    svgCanvas.setBlur(val)
+    return
+  }
+  if (val === 0) {
+    // Don't change the StdDev, as that will hide the element.
+    // Instead, just remove the value for "filter"
+    svgCanvas.changeSelectedAttributeNoUndo('filter', '')
+    svgCanvas.setFilterHidden(true)
+  } else {
+    const elem = selectedElements[0]
+    if (svgCanvas.getFilterHidden()) {
+      svgCanvas.changeSelectedAttributeNoUndo('filter', 'url(#' + elem.id + '_blur)')
+    }
+    const filter = svgCanvas.getFilter()
+    svgCanvas.changeSelectedAttributeNoUndo('stdDeviation', val, [filter.firstChild])
+    svgCanvas.setBlurOffsets(filter, val)
+  }
+}
+
+/**
+*
+* @returns {void}
+*/
+function finishChange () {
+  const bCmd = svgCanvas.undoMgr.finishUndoableChange()
+  svgCanvas.getCurCommand().addSubCommand(bCmd)
+  svgCanvas.addCommandToHistory(svgCanvas.getCurCommand())
+  svgCanvas.setCurCommand(null)
+  svgCanvas.setFilter(null)
+}
+
+/**
+* Sets the `x`, `y`, `width`, `height` values of the filter element in order to
+* make the blur not be clipped. Removes them if not neeeded.
+* @function module:svgcanvas.SvgCanvas#setBlurOffsets
+* @param {Element} filterElem - The filter DOM element to update
+* @param {Float} stdDev - The standard deviation value on which to base the offset size
+* @returns {void}
+*/
+export const setBlurOffsets = function (filterElem, stdDev) {
+  if (stdDev > 3) {
+    // TODO: Create algorithm here where size is based on expected blur
+    svgCanvas.assignAttributes(filterElem, {
+      x: '-50%',
+      y: '-50%',
+      width: '200%',
+      height: '200%'
+    }, 100)
+  } else {
+    filterElem.removeAttribute('x')
+    filterElem.removeAttribute('y')
+    filterElem.removeAttribute('width')
+    filterElem.removeAttribute('height')
+  }
+}
+
+/**
+* Adds/updates the blur filter to the selected element.
+* @function module:svgcanvas.SvgCanvas#setBlur
+* @param {Float} val - Float with the new `stdDeviation` blur value
+* @param {boolean} complete - Whether or not the action should be completed (to add to the undo manager)
+* @returns {void}
+*/
+export const setBlur = function (val, complete) {
+  const {
+    InsertElementCommand, ChangeElementCommand, BatchCommand
+  } = svgCanvas.history
+
+  const selectedElements = svgCanvas.getSelectedElements()
+  if (svgCanvas.getCurCommand()) {
+    finishChange()
+    return
+  }
+
+  // Looks for associated blur, creates one if not found
+  const elem = selectedElements[0]
+  const elemId = elem.id
+  svgCanvas.setFilter(svgCanvas.getElement(elemId + '_blur'))
+
+  val -= 0
+
+  const batchCmd = new BatchCommand()
+
+  // Blur found!
+  if (svgCanvas.getFilter()) {
+    if (val === 0) {
+      svgCanvas.setFilter(null)
+    }
+  } else {
+    // Not found, so create
+    const newblur = svgCanvas.addSVGElementsFromJson({
+      element: 'feGaussianBlur',
+      attr: {
+        in: 'SourceGraphic',
+        stdDeviation: val
+      }
+    })
+
+    svgCanvas.setFilter(svgCanvas.addSVGElementsFromJson({
+      element: 'filter',
+      attr: {
+        id: elemId + '_blur'
+      }
+    }))
+    svgCanvas.getFilter().append(newblur)
+    svgCanvas.findDefs().append(svgCanvas.getFilter())
+
+    batchCmd.addSubCommand(new InsertElementCommand(svgCanvas.getFilter()))
+  }
+
+  const changes = { filter: elem.getAttribute('filter') }
+
+  if (val === 0) {
+    elem.removeAttribute('filter')
+    batchCmd.addSubCommand(new ChangeElementCommand(elem, changes))
+    return
+  }
+
+  svgCanvas.changeSelectedAttribute('filter', 'url(#' + elemId + '_blur)')
+  batchCmd.addSubCommand(new ChangeElementCommand(elem, changes))
+  svgCanvas.setBlurOffsets(svgCanvas.getFilter(), val)
+  const filter = svgCanvas.getFilter()
+  svgCanvas.setCurCommand(batchCmd)
+  svgCanvas.undoMgr.beginUndoableChange('stdDeviation', [filter ? filter.firstChild : null])
+  if (complete) {
+    svgCanvas.setBlurNoUndo(val)
+    finishChange()
+  }
+}

packages/svgcanvas/clear.js

@@ -0,0 +1,43 @@
+/**
+ * Tools for clear.
+ * @module clear
+ * @license MIT
+ * @copyright 2011 Jeff Schiller
+ */
+import { NS } from './namespaces.js'
+
+let svgCanvas = null
+
+/**
+* @function module:clear.init
+* @param {module:clear.SvgCanvas#init} clearContext
+* @returns {void}
+*/
+export const init = (canvas) => {
+  svgCanvas = canvas
+}
+
+export const clearSvgContentElementInit = () => {
+  const curConfig = svgCanvas.getCurConfig()
+  const { dimensions } = curConfig
+  const el = svgCanvas.getSvgContent()
+  // empty
+  while (el.firstChild) { el.removeChild(el.firstChild) }
+
+  // TODO: Clear out all other attributes first?
+  const pel = svgCanvas.getSvgRoot()
+  el.setAttribute('id', 'svgcontent')
+  el.setAttribute('width', dimensions[0])
+  el.setAttribute('height', dimensions[1])
+  el.setAttribute('x', dimensions[0])
+  el.setAttribute('y', dimensions[1])
+  el.setAttribute('overflow', curConfig.show_outside_canvas ? 'visible' : 'hidden')
+  el.setAttribute('xmlns', NS.SVG)
+  el.setAttribute('xmlns:se', NS.SE)
+  el.setAttribute('xmlns:xlink', NS.XLINK)
+  pel.appendChild(el)
+
+  // TODO: make this string optional and set by the client
+  const comment = svgCanvas.getDOMDocument().createComment(' Created with SVG-edit - https://github.com/SVG-Edit/svgedit')
+  svgCanvas.getSvgContent().append(comment)
+}

packages/svgcanvas/coords.js

@@ -0,0 +1,298 @@
+/**
+ * Manipulating coordinates.
+ * @module coords
+ * @license MIT
+ */
+
+import {
+  snapToGrid, assignAttributes, getBBox, getRefElem, findDefs
+} from './utilities.js'
+import {
+  transformPoint, transformListToTransform, matrixMultiply, transformBox
+} from './math.js'
+
+// this is how we map paths to our preferred relative segment types
+const pathMap = [
+  0, 'z', 'M', 'm', 'L', 'l', 'C', 'c', 'Q', 'q', 'A', 'a',
+  'H', 'h', 'V', 'v', 'S', 's', 'T', 't'
+]
+
+/**
+ * @interface module:coords.EditorContext
+ */
+/**
+ * @function module:coords.EditorContext#getGridSnapping
+ * @returns {boolean}
+ */
+/**
+ * @function module:coords.EditorContext#getSvgRoot
+ * @returns {SVGSVGElement}
+*/
+
+let svgCanvas = null
+
+/**
+* @function module:coords.init
+* @param {module:svgcanvas.SvgCanvas#event:pointsAdded} editorContext
+* @returns {void}
+*/
+export const init = (canvas) => {
+  svgCanvas = canvas
+}
+
+/**
+ * Applies coordinate changes to an element based on the given matrix.
+ * @name module:coords.remapElement
+ * @type {module:path.EditorContext#remapElement}
+*/
+export const remapElement = (selected, changes, m) => {
+  const remap = (x, y) => transformPoint(x, y, m)
+  const scalew = (w) => m.a * w
+  const scaleh = (h) => m.d * h
+  const doSnapping = svgCanvas.getGridSnapping() && selected.parentNode.parentNode.localName === 'svg'
+  const finishUp = () => {
+    if (doSnapping) {
+      Object.entries(changes).forEach(([o, value]) => {
+        changes[o] = snapToGrid(value)
+      })
+    }
+    assignAttributes(selected, changes, 1000, true)
+  }
+  const box = getBBox(selected);
+
+  ['fill', 'stroke'].forEach((type) => {
+    const attrVal = selected.getAttribute(type)
+    if (attrVal?.startsWith('url(') && (m.a < 0 || m.d < 0)) {
+      const grad = getRefElem(attrVal)
+      const newgrad = grad.cloneNode(true)
+      if (m.a < 0) {
+        // flip x
+        const x1 = newgrad.getAttribute('x1')
+        const x2 = newgrad.getAttribute('x2')
+        newgrad.setAttribute('x1', -(x1 - 1))
+        newgrad.setAttribute('x2', -(x2 - 1))
+      }
+
+      if (m.d < 0) {
+        // flip y
+        const y1 = newgrad.getAttribute('y1')
+        const y2 = newgrad.getAttribute('y2')
+        newgrad.setAttribute('y1', -(y1 - 1))
+        newgrad.setAttribute('y2', -(y2 - 1))
+      }
+      newgrad.id = svgCanvas.getCurrentDrawing().getNextId()
+      findDefs().append(newgrad)
+      selected.setAttribute(type, 'url(#' + newgrad.id + ')')
+    }
+  })
+
+  const elName = selected.tagName
+  if (elName === 'g' || elName === 'text' || elName === 'tspan' || elName === 'use') {
+    // if it was a translate, then just update x,y
+    if (m.a === 1 && m.b === 0 && m.c === 0 && m.d === 1 && (m.e !== 0 || m.f !== 0)) {
+      // [T][M] = [M][T']
+      // therefore [T'] = [M_inv][T][M]
+      const existing = transformListToTransform(selected).matrix
+      const tNew = matrixMultiply(existing.inverse(), m, existing)
+      changes.x = Number.parseFloat(changes.x) + tNew.e
+      changes.y = Number.parseFloat(changes.y) + tNew.f
+    } else {
+      // we just absorb all matrices into the element and don't do any remapping
+      const chlist = selected.transform.baseVal
+      const mt = svgCanvas.getSvgRoot().createSVGTransform()
+      mt.setMatrix(matrixMultiply(transformListToTransform(chlist).matrix, m))
+      chlist.clear()
+      chlist.appendItem(mt)
+    }
+  }
+
+  // now we have a set of changes and an applied reduced transform list
+  // we apply the changes directly to the DOM
+  switch (elName) {
+    case 'foreignObject':
+    case 'rect':
+    case 'image': {
+    // Allow images to be inverted (give them matrix when flipped)
+      if (elName === 'image' && (m.a < 0 || m.d < 0)) {
+      // Convert to matrix
+        const chlist = selected.transform.baseVal
+        const mt = svgCanvas.getSvgRoot().createSVGTransform()
+        mt.setMatrix(matrixMultiply(transformListToTransform(chlist).matrix, m))
+        chlist.clear()
+        chlist.appendItem(mt)
+      } else {
+        const pt1 = remap(changes.x, changes.y)
+        changes.width = scalew(changes.width)
+        changes.height = scaleh(changes.height)
+        changes.x = pt1.x + Math.min(0, changes.width)
+        changes.y = pt1.y + Math.min(0, changes.height)
+        changes.width = Math.abs(changes.width)
+        changes.height = Math.abs(changes.height)
+      }
+      finishUp()
+      break
+    } case 'ellipse': {
+      const c = remap(changes.cx, changes.cy)
+      changes.cx = c.x
+      changes.cy = c.y
+      changes.rx = scalew(changes.rx)
+      changes.ry = scaleh(changes.ry)
+      changes.rx = Math.abs(changes.rx)
+      changes.ry = Math.abs(changes.ry)
+      finishUp()
+      break
+    } case 'circle': {
+      const c = remap(changes.cx, changes.cy)
+      changes.cx = c.x
+      changes.cy = c.y
+      // take the minimum of the new selected box's dimensions for the new circle radius
+      const tbox = transformBox(box.x, box.y, box.width, box.height, m)
+      const w = tbox.tr.x - tbox.tl.x; const h = tbox.bl.y - tbox.tl.y
+      changes.r = Math.min(w / 2, h / 2)
+
+      if (changes.r) { changes.r = Math.abs(changes.r) }
+      finishUp()
+      break
+    } case 'line': {
+      const pt1 = remap(changes.x1, changes.y1)
+      const pt2 = remap(changes.x2, changes.y2)
+      changes.x1 = pt1.x
+      changes.y1 = pt1.y
+      changes.x2 = pt2.x
+      changes.y2 = pt2.y
+    } // Fallthrough
+    case 'text':
+    case 'tspan':
+    case 'use': {
+      finishUp()
+      break
+    } case 'g': {
+      const dataStorage = svgCanvas.getDataStorage()
+      const gsvg = dataStorage.get(selected, 'gsvg')
+      if (gsvg) {
+        assignAttributes(gsvg, changes, 1000, true)
+      }
+      break
+    } case 'polyline':
+    case 'polygon': {
+      changes.points.forEach((pt) => {
+        const { x, y } = remap(pt.x, pt.y)
+        pt.x = x
+        pt.y = y
+      })
+
+      // const len = changes.points.length;
+      let pstr = ''
+      changes.points.forEach((pt) => {
+        pstr += pt.x + ',' + pt.y + ' '
+      })
+      selected.setAttribute('points', pstr)
+      break
+    } case 'path': {
+      const segList = selected.pathSegList
+      let len = segList.numberOfItems
+      changes.d = []
+      for (let i = 0; i < len; ++i) {
+        const seg = segList.getItem(i)
+        changes.d[i] = {
+          type: seg.pathSegType,
+          x: seg.x,
+          y: seg.y,
+          x1: seg.x1,
+          y1: seg.y1,
+          x2: seg.x2,
+          y2: seg.y2,
+          r1: seg.r1,
+          r2: seg.r2,
+          angle: seg.angle,
+          largeArcFlag: seg.largeArcFlag,
+          sweepFlag: seg.sweepFlag
+        }
+      }
+
+      len = changes.d.length
+      const firstseg = changes.d[0]
+      let currentpt
+      if (len > 0) {
+        currentpt = remap(firstseg.x, firstseg.y)
+        changes.d[0].x = currentpt.x
+        changes.d[0].y = currentpt.y
+      }
+      for (let i = 1; i < len; ++i) {
+        const seg = changes.d[i]
+        const { type } = seg
+        // if absolute or first segment, we want to remap x, y, x1, y1, x2, y2
+        // if relative, we want to scalew, scaleh
+        if (type % 2 === 0) { // absolute
+          const thisx = (seg.x !== undefined) ? seg.x : currentpt.x // for V commands
+          const thisy = (seg.y !== undefined) ? seg.y : currentpt.y // for H commands
+          const pt = remap(thisx, thisy)
+          const pt1 = remap(seg.x1, seg.y1)
+          const pt2 = remap(seg.x2, seg.y2)
+          seg.x = pt.x
+          seg.y = pt.y
+          seg.x1 = pt1.x
+          seg.y1 = pt1.y
+          seg.x2 = pt2.x
+          seg.y2 = pt2.y
+          seg.r1 = scalew(seg.r1)
+          seg.r2 = scaleh(seg.r2)
+        } else { // relative
+          seg.x = scalew(seg.x)
+          seg.y = scaleh(seg.y)
+          seg.x1 = scalew(seg.x1)
+          seg.y1 = scaleh(seg.y1)
+          seg.x2 = scalew(seg.x2)
+          seg.y2 = scaleh(seg.y2)
+          seg.r1 = scalew(seg.r1)
+          seg.r2 = scaleh(seg.r2)
+        }
+      } // for each segment
+
+      let dstr = ''
+      changes.d.forEach((seg) => {
+        const { type } = seg
+        dstr += pathMap[type]
+        switch (type) {
+          case 13: // relative horizontal line (h)
+          case 12: // absolute horizontal line (H)
+            dstr += seg.x + ' '
+            break
+          case 15: // relative vertical line (v)
+          case 14: // absolute vertical line (V)
+            dstr += seg.y + ' '
+            break
+          case 3: // relative move (m)
+          case 5: // relative line (l)
+          case 19: // relative smooth quad (t)
+          case 2: // absolute move (M)
+          case 4: // absolute line (L)
+          case 18: // absolute smooth quad (T)
+            dstr += seg.x + ',' + seg.y + ' '
+            break
+          case 7: // relative cubic (c)
+          case 6: // absolute cubic (C)
+            dstr += seg.x1 + ',' + seg.y1 + ' ' + seg.x2 + ',' + seg.y2 + ' ' +
+              seg.x + ',' + seg.y + ' '
+            break
+          case 9: // relative quad (q)
+          case 8: // absolute quad (Q)
+            dstr += seg.x1 + ',' + seg.y1 + ' ' + seg.x + ',' + seg.y + ' '
+            break
+          case 11: // relative elliptical arc (a)
+          case 10: // absolute elliptical arc (A)
+            dstr += seg.r1 + ',' + seg.r2 + ' ' + seg.angle + ' ' + Number(seg.largeArcFlag) +
+              ' ' + Number(seg.sweepFlag) + ' ' + seg.x + ',' + seg.y + ' '
+            break
+          case 17: // relative smooth cubic (s)
+          case 16: // absolute smooth cubic (S)
+            dstr += seg.x2 + ',' + seg.y2 + ' ' + seg.x + ',' + seg.y + ' '
+            break
+        }
+      })
+
+      selected.setAttribute('d', dstr)
+      break
+    }
+  }
+}

packages/svgcanvas/copy-elem.js

@@ -0,0 +1,45 @@
+import { preventClickDefault } from './utilities.js'
+
+/**
+ * Create a clone of an element, updating its ID and its children's IDs when needed.
+ * @function module:utilities.copyElem
+ * @param {Element} el - DOM element to clone
+ * @param {module:utilities.GetNextID} getNextId - The getter of the next unique ID.
+ * @returns {Element} The cloned element
+ */
+export const copyElem = function (el, getNextId) {
+  // manually create a copy of the element
+  const newEl = document.createElementNS(el.namespaceURI, el.nodeName)
+  Object.values(el.attributes).forEach((attr) => {
+    newEl.setAttributeNS(attr.namespaceURI, attr.nodeName, attr.value)
+  })
+  // set the copied element's new id
+  newEl.removeAttribute('id')
+  newEl.id = getNextId()
+
+  // now create copies of all children
+  el.childNodes.forEach(function (child) {
+    switch (child.nodeType) {
+      case 1: // element node
+        newEl.append(copyElem(child, getNextId))
+        break
+      case 3: // text node
+        newEl.textContent = child.nodeValue
+        break
+      default:
+        break
+    }
+  })
+
+  if (el.dataset.gsvg) {
+    newEl.dataset.gsvg = newEl.firstChild
+  } else if (el.dataset.symbol) {
+    const ref = el.dataset.symbol
+    newEl.dataset.ref = ref
+    newEl.dataset.symbol = ref
+  } else if (newEl.tagName === 'image') {
+    preventClickDefault(newEl)
+  }
+
+  return newEl
+}

packages/svgcanvas/dataStorage.js

@@ -0,0 +1,28 @@
+/** A storage solution aimed at replacing jQuerys data function.
+* Implementation Note: Elements are stored in a (WeakMap)[https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/WeakMap].
+* This makes sure the data is garbage collected when the node is removed.
+*/
+const dataStorage = {
+  _storage: new WeakMap(),
+  put: function (element, key, obj) {
+    if (!this._storage.has(element)) {
+      this._storage.set(element, new Map())
+    }
+    this._storage.get(element).set(key, obj)
+  },
+  get: function (element, key) {
+    return this._storage.get(element)?.get(key)
+  },
+  has: function (element, key) {
+    return this._storage.has(element) && this._storage.get(element).has(key)
+  },
+  remove: function (element, key) {
+    const ret = this._storage.get(element).delete(key)
+    if (this._storage.get(element).size === 0) {
+      this._storage.delete(element)
+    }
+    return ret
+  }
+}
+
+export default dataStorage

packages/svgcanvas/demos/canvas.html

@@ -0,0 +1,68 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <meta charset="utf-8" />
+    <title>Minimal demo of SvgCanvas</title>
+    <style> #svgroot { overflow: hidden; } </style>
+  </head>
+
+  <body>
+    <h1>Minimal demo of SvgCanvas</h1>
+
+    <div id="editorContainer"></div>
+
+    <div>
+      [<button onclick="canvas.setMode('select')">Select</button>
+      <button onclick="canvas.setMode('circle')">Circle</button>
+      <button onclick="canvas.setMode('rect')">Rect</button>
+      <button onclick="canvas.setMode('text')">Text</button>]
+      <button onclick="fill('#ff0000')">Fill Red</button>
+      <button onclick="canvas.deleteSelectedElements()">Delete Selected</button>
+      <button onclick="canvas.clear(); canvas.updateCanvas(width, height);">Clear All</button>
+      <button onclick="alert(canvas.getSvgString())">Get SVG</button>
+    </div>
+    <!-- Not visible, but useful -->
+    <input id="text" style="width:0;height:0;opacity: 0"/>
+    <script type="module">
+/* globals canvas */
+import SvgCanvas from '@svgedit/svgcanvas'
+
+const container = document.querySelector('#editorContainer')
+const { width, height } = { width: 500, height: 300 }
+window.width = width
+window.height = height
+
+const hiddenTextTagId = 'text'
+
+const config = {
+  initFill: { color: 'FFFFFF', opacity: 1 },
+  initStroke: { color: '000000', opacity: 1, width: 1 },
+  text: { stroke_width: 0, font_size: 24, font_family: 'serif' },
+  initOpacity: 1,
+  imgPath: '/src/editor/images',
+  dimensions: [ width, height ],
+  baseUnit: 'px'
+}
+
+window.canvas = new SvgCanvas(container, config)
+canvas.updateCanvas(width, height)
+
+window.fill = function (colour) {
+  canvas.getSelectedElements().forEach((el) => {
+    el.setAttribute('fill', colour)
+  })
+}
+
+const hiddenTextTag = window.canvas.$id(hiddenTextTagId)
+window.canvas.textActions.setInputElem(hiddenTextTag)
+
+const addListenerMulti = (element, eventNames, listener) => {
+  eventNames.split(' ').forEach((eventName) => element.addEventListener(eventName, listener, false))
+}
+
+addListenerMulti(hiddenTextTag, 'keyup input', (evt) => {
+  window.canvas.setTextContent(evt.currentTarget.value)
+})
+    </script>
+  </body>
+</html>

packages/svgcanvas/history.js

@@ -0,0 +1,619 @@
+/* eslint-disable no-console */
+/**
+ * For command history tracking and undo functionality.
+ * @module history
+ * @license MIT
+ * @copyright 2010 Jeff Schiller
+ */
+
+import { getHref, setHref, getRotationAngle, getBBox } from './utilities.js'
+
+/**
+* Group: Undo/Redo history management.
+*/
+export const HistoryEventTypes = {
+  BEFORE_APPLY: 'before_apply',
+  AFTER_APPLY: 'after_apply',
+  BEFORE_UNAPPLY: 'before_unapply',
+  AFTER_UNAPPLY: 'after_unapply'
+}
+
+/**
+* Base class for commands.
+*/
+export class Command {
+  /**
+  * @returns {string}
+  */
+  getText () {
+    return this.text
+  }
+
+  /**
+   * @param {module:history.HistoryEventHandler} handler
+   * @param {callback} applyFunction
+   * @returns {void}
+  */
+  apply (handler, applyFunction) {
+    handler && handler.handleHistoryEvent(HistoryEventTypes.BEFORE_APPLY, this)
+    applyFunction(handler)
+    handler && handler.handleHistoryEvent(HistoryEventTypes.AFTER_APPLY, this)
+  }
+
+  /**
+   * @param {module:history.HistoryEventHandler} handler
+   * @param {callback} unapplyFunction
+   * @returns {void}
+  */
+  unapply (handler, unapplyFunction) {
+    handler && handler.handleHistoryEvent(HistoryEventTypes.BEFORE_UNAPPLY, this)
+    unapplyFunction()
+    handler && handler.handleHistoryEvent(HistoryEventTypes.AFTER_UNAPPLY, this)
+  }
+
+  /**
+   * @returns {Element[]} Array with element associated with this command
+   * This function needs to be surcharged if multiple elements are returned.
+  */
+  elements () {
+    return [this.elem]
+  }
+
+  /**
+    * @returns {string} String with element associated with this command
+  */
+  type () {
+    return this.constructor.name
+  }
+}
+
+// Todo: Figure out why the interface members aren't showing
+//   up (with or without modules applied), despite our apparently following
+//   http://usejsdoc.org/tags-interface.html#virtual-comments
+
+/**
+ * An interface that all command objects must implement.
+ * @interface module:history.HistoryCommand
+*/
+/**
+ * Applies.
+ *
+ * @function module:history.HistoryCommand#apply
+ * @param {module:history.HistoryEventHandler} handler
+ * @fires module:history~Command#event:history
+ * @returns {void|true}
+ */
+/**
+ *
+ * Unapplies.
+ * @function module:history.HistoryCommand#unapply
+ * @param {module:history.HistoryEventHandler} handler
+ * @fires module:history~Command#event:history
+ * @returns {void|true}
+ */
+/**
+ * Returns the elements.
+ * @function module:history.HistoryCommand#elements
+ * @returns {Element[]}
+ */
+/**
+ * Gets the text.
+ * @function module:history.HistoryCommand#getText
+ * @returns {string}
+ */
+/**
+ * Gives the type.
+ * @function module:history.HistoryCommand.type
+ * @returns {string}
+ */
+
+/**
+ * @event module:history~Command#event:history
+ * @type {module:history.HistoryCommand}
+ */
+
+/**
+ * An interface for objects that will handle history events.
+ * @interface module:history.HistoryEventHandler
+ */
+/**
+ *
+ * @function module:history.HistoryEventHandler#handleHistoryEvent
+ * @param {string} eventType One of the HistoryEvent types
+ * @param {module:history~Command#event:history} command
+ * @listens module:history~Command#event:history
+ * @returns {void}
+ *
+ */
+
+/**
+ * History command for an element that had its DOM position changed.
+ * @implements {module:history.HistoryCommand}
+*/
+export class MoveElementCommand extends Command {
+  /**
+  * @param {Element} elem - The DOM element that was moved
+  * @param {Element} oldNextSibling - The element's next sibling before it was moved
+  * @param {Element} oldParent - The element's parent before it was moved
+  * @param {string} [text] - An optional string visible to user related to this change
+  */
+  constructor (elem, oldNextSibling, oldParent, text) {
+    super()
+    this.elem = elem
+    this.text = text ? ('Move ' + elem.tagName + ' to ' + text) : ('Move ' + elem.tagName)
+    this.oldNextSibling = oldNextSibling
+    this.oldParent = oldParent
+    this.newNextSibling = elem.nextSibling
+    this.newParent = elem.parentNode
+  }
+
+  /**
+   * Re-positions the element.
+   * @param {module:history.HistoryEventHandler} handler
+   * @fires module:history~Command#event:history
+   * @returns {void}
+  */
+  apply (handler) {
+    super.apply(handler, () => {
+      this.elem = this.newParent.insertBefore(this.elem, this.newNextSibling)
+    })
+  }
+
+  /**
+   * Positions the element back to its original location.
+   * @param {module:history.HistoryEventHandler} handler
+   * @fires module:history~Command#event:history
+   * @returns {void}
+  */
+  unapply (handler) {
+    super.unapply(handler, () => {
+      this.elem = this.oldParent.insertBefore(this.elem, this.oldNextSibling)
+    })
+  }
+}
+
+/**
+* History command for an element that was added to the DOM.
+* @implements {module:history.HistoryCommand}
+*/
+export class InsertElementCommand extends Command {
+  /**
+   * @param {Element} elem - The newly added DOM element
+   * @param {string} text - An optional string visible to user related to this change
+  */
+  constructor (elem, text) {
+    super()
+    this.elem = elem
+    this.text = text || ('Create ' + elem.tagName)
+    this.parent = elem.parentNode
+    this.nextSibling = this.elem.nextSibling
+  }
+
+  /**
+  * Re-inserts the new element.
+  * @param {module:history.HistoryEventHandler} handler
+  * @fires module:history~Command#event:history
+  * @returns {void}
+  */
+  apply (handler) {
+    super.apply(handler, () => {
+      this.elem = this.parent.insertBefore(this.elem, this.nextSibling)
+    })
+  }
+
+  /**
+  * Removes the element.
+  * @param {module:history.HistoryEventHandler} handler
+  * @fires module:history~Command#event:history
+  * @returns {void}
+  */
+  unapply (handler) {
+    super.unapply(handler, () => {
+      this.parent = this.elem.parentNode
+      this.elem.remove()
+    })
+  }
+}
+
+/**
+* History command for an element removed from the DOM.
+* @implements {module:history.HistoryCommand}
+*/
+export class RemoveElementCommand extends Command {
+  /**
+  * @param {Element} elem - The removed DOM element
+  * @param {Node} oldNextSibling - The DOM element's nextSibling when it was in the DOM
+  * @param {Element} oldParent - The DOM element's parent
+  * @param {string} [text] - An optional string visible to user related to this change
+  */
+  constructor (elem, oldNextSibling, oldParent, text) {
+    super()
+    this.elem = elem
+    this.text = text || ('Delete ' + elem.tagName)
+    this.nextSibling = oldNextSibling
+    this.parent = oldParent
+  }
+
+  /**
+  * Re-removes the new element.
+  * @param {module:history.HistoryEventHandler} handler
+  * @fires module:history~Command#event:history
+  * @returns {void}
+  */
+  apply (handler) {
+    super.apply(handler, () => {
+      this.parent = this.elem.parentNode
+      this.elem.remove()
+    })
+  }
+
+  /**
+  * Re-adds the new element.
+  * @param {module:history.HistoryEventHandler} handler
+  * @fires module:history~Command#event:history
+  * @returns {void}
+  */
+  unapply (handler) {
+    super.unapply(handler, () => {
+      if (!this.nextSibling) {
+        console.error('Reference element was lost')
+      }
+      this.parent.insertBefore(this.elem, this.nextSibling) // Don't use `before` or `prepend` as `this.nextSibling` may be `null`
+    })
+  }
+}
+
+/**
+* @typedef {"#text"|"#href"|string} module:history.CommandAttributeName
+*/
+/**
+* @typedef {PlainObject<module:history.CommandAttributeName, string>} module:history.CommandAttributes
+*/
+
+/**
+* History command to make a change to an element.
+* Usually an attribute change, but can also be textcontent.
+* @implements {module:history.HistoryCommand}
+*/
+export class ChangeElementCommand extends Command {
+  /**
+  * @param {Element} elem - The DOM element that was changed
+  * @param {module:history.CommandAttributes} attrs - Attributes to be changed with the values they had *before* the change
+  * @param {string} text - An optional string visible to user related to this change
+   */
+  constructor (elem, attrs, text) {
+    super()
+    this.elem = elem
+    this.text = text ? ('Change ' + elem.tagName + ' ' + text) : ('Change ' + elem.tagName)
+    this.newValues = {}
+    this.oldValues = attrs
+    for (const attr in attrs) {
+      if (attr === '#text') {
+        this.newValues[attr] = (elem) ? elem.textContent : ''
+      } else if (attr === '#href') {
+        this.newValues[attr] = getHref(elem)
+      } else {
+        this.newValues[attr] = elem.getAttribute(attr)
+      }
+    }
+  }
+
+  /**
+  * Performs the stored change action.
+  * @param {module:history.HistoryEventHandler} handler
+  * @fires module:history~Command#event:history
+  * @returns {void}
+  */
+  apply (handler) {
+    super.apply(handler, () => {
+      let bChangedTransform = false
+      Object.entries(this.newValues).forEach(([attr, value]) => {
+        if (value) {
+          if (attr === '#text') {
+            this.elem.textContent = value
+          } else if (attr === '#href') {
+            setHref(this.elem, value)
+          } else {
+            this.elem.setAttribute(attr, value)
+          }
+        } else if (attr === '#text') {
+          this.elem.textContent = ''
+        } else {
+          this.elem.setAttribute(attr, '')
+          this.elem.removeAttribute(attr)
+        }
+
+        if (attr === 'transform') { bChangedTransform = true }
+      })
+
+      // relocate rotational transform, if necessary
+      if (!bChangedTransform) {
+        const angle = getRotationAngle(this.elem)
+        if (angle) {
+          const bbox = getBBox(this.elem)
+          const cx = bbox.x + bbox.width / 2
+          const cy = bbox.y + bbox.height / 2
+          const rotate = ['rotate(', angle, ' ', cx, ',', cy, ')'].join('')
+          if (rotate !== this.elem.getAttribute('transform')) {
+            this.elem.setAttribute('transform', rotate)
+          }
+        }
+      }
+    })
+  }
+
+  /**
+  * Reverses the stored change action.
+  * @param {module:history.HistoryEventHandler} handler
+  * @fires module:history~Command#event:history
+  * @returns {void}
+  */
+  unapply (handler) {
+    super.unapply(handler, () => {
+      let bChangedTransform = false
+      Object.entries(this.oldValues).forEach(([attr, value]) => {
+        if (value) {
+          if (attr === '#text') {
+            this.elem.textContent = value
+          } else if (attr === '#href') {
+            setHref(this.elem, value)
+          } else {
+            this.elem.setAttribute(attr, value)
+          }
+        } else if (attr === '#text') {
+          this.elem.textContent = ''
+        } else {
+          this.elem.removeAttribute(attr)
+        }
+        if (attr === 'transform') { bChangedTransform = true }
+      })
+      // relocate rotational transform, if necessary
+      if (!bChangedTransform) {
+        const angle = getRotationAngle(this.elem)
+        if (angle) {
+          const bbox = getBBox(this.elem)
+          const cx = bbox.x + bbox.width / 2
+          const cy = bbox.y + bbox.height / 2
+          const rotate = ['rotate(', angle, ' ', cx, ',', cy, ')'].join('')
+          if (rotate !== this.elem.getAttribute('transform')) {
+            this.elem.setAttribute('transform', rotate)
+          }
+        }
+      }
+    })
+  }
+}
+
+// TODO: create a 'typing' command object that tracks changes in text
+// if a new Typing command is created and the top command on the stack is also a Typing
+// and they both affect the same element, then collapse the two commands into one
+
+/**
+* History command that can contain/execute multiple other commands.
+* @implements {module:history.HistoryCommand}
+*/
+export class BatchCommand extends Command {
+  /**
+  * @param {string} [text] - An optional string visible to user related to this change
+  */
+  constructor (text) {
+    super()
+    this.text = text || 'Batch Command'
+    this.stack = []
+  }
+
+  /**
+  * Runs "apply" on all subcommands.
+  * @param {module:history.HistoryEventHandler} handler
+  * @fires module:history~Command#event:history
+  * @returns {void}
+  */
+  apply (handler) {
+    super.apply(handler, () => {
+      this.stack.forEach((stackItem) => {
+        console.assert(stackItem, 'stack item should not be null')
+        stackItem && stackItem.apply(handler)
+      })
+    })
+  }
+
+  /**
+  * Runs "unapply" on all subcommands.
+  * @param {module:history.HistoryEventHandler} handler
+  * @fires module:history~Command#event:history
+  * @returns {void}
+  */
+  unapply (handler) {
+    super.unapply(handler, () => {
+      this.stack.reverse().forEach((stackItem) => {
+        console.assert(stackItem, 'stack item should not be null')
+        stackItem && stackItem.unapply(handler)
+      })
+    })
+  }
+
+  /**
+  * Iterate through all our subcommands.
+  * @returns {Element[]} All the elements we are changing
+  */
+  elements () {
+    const elems = []
+    let cmd = this.stack.length
+    while (cmd--) {
+      if (!this.stack[cmd]) continue
+      const thisElems = this.stack[cmd].elements()
+      let elem = thisElems.length
+      while (elem--) {
+        if (!elems.includes(thisElems[elem])) { elems.push(thisElems[elem]) }
+      }
+    }
+    return elems
+  }
+
+  /**
+  * Adds a given command to the history stack.
+  * @param {Command} cmd - The undo command object to add
+  * @returns {void}
+  */
+  addSubCommand (cmd) {
+    console.assert(cmd !== null, 'cmd should not be null')
+    this.stack.push(cmd)
+  }
+
+  /**
+  * @returns {boolean} Indicates whether or not the batch command is empty
+  */
+  isEmpty () {
+    return !this.stack.length
+  }
+}
+
+/**
+*
+*/
+export class UndoManager {
+  /**
+  * @param {module:history.HistoryEventHandler} historyEventHandler
+  */
+  constructor (historyEventHandler) {
+    this.handler_ = historyEventHandler || null
+    this.undoStackPointer = 0
+    this.undoStack = []
+
+    // this is the stack that stores the original values, the elements and
+    // the attribute name for begin/finish
+    this.undoChangeStackPointer = -1
+    this.undoableChangeStack = []
+  }
+
+  /**
+  * Resets the undo stack, effectively clearing the undo/redo history.
+  * @returns {void}
+  */
+  resetUndoStack () {
+    this.undoStack = []
+    this.undoStackPointer = 0
+  }
+
+  /**
+  * @returns {Integer} Current size of the undo history stack
+  */
+  getUndoStackSize () {
+    return this.undoStackPointer
+  }
+
+  /**
+  * @returns {Integer} Current size of the redo history stack
+  */
+  getRedoStackSize () {
+    return this.undoStack.length - this.undoStackPointer
+  }
+
+  /**
+  * @returns {string} String associated with the next undo command
+  */
+  getNextUndoCommandText () {
+    return this.undoStackPointer > 0 ? this.undoStack[this.undoStackPointer - 1].getText() : ''
+  }
+
+  /**
+  * @returns {string} String associated with the next redo command
+  */
+  getNextRedoCommandText () {
+    return this.undoStackPointer < this.undoStack.length ? this.undoStack[this.undoStackPointer].getText() : ''
+  }
+
+  /**
+  * Performs an undo step.
+  * @returns {void}
+  */
+  undo () {
+    if (this.undoStackPointer > 0) {
+      const cmd = this.undoStack[--this.undoStackPointer]
+      cmd.unapply(this.handler_)
+    }
+  }
+
+  /**
+  * Performs a redo step.
+  * @returns {void}
+  */
+  redo () {
+    if (this.undoStackPointer < this.undoStack.length && this.undoStack.length > 0) {
+      const cmd = this.undoStack[this.undoStackPointer++]
+      cmd.apply(this.handler_)
+    }
+  }
+
+  /**
+  * Adds a command object to the undo history stack.
+  * @param {Command} cmd - The command object to add
+  * @returns {void}
+  */
+  addCommandToHistory (cmd) {
+    // TODO: we MUST compress consecutive text changes to the same element
+    // (right now each keystroke is saved as a separate command that includes the
+    // entire text contents of the text element)
+    // TODO: consider limiting the history that we store here (need to do some slicing)
+
+    // if our stack pointer is not at the end, then we have to remove
+    // all commands after the pointer and insert the new command
+    if (this.undoStackPointer < this.undoStack.length && this.undoStack.length > 0) {
+      this.undoStack = this.undoStack.splice(0, this.undoStackPointer)
+    }
+    this.undoStack.push(cmd)
+    this.undoStackPointer = this.undoStack.length
+  }
+
+  /**
+  * This function tells the canvas to remember the old values of the
+  * `attrName` attribute for each element sent in.  The elements and values
+  * are stored on a stack, so the next call to `finishUndoableChange()` will
+  * pop the elements and old values off the stack, gets the current values
+  * from the DOM and uses all of these to construct the undo-able command.
+  * @param {string} attrName - The name of the attribute being changed
+  * @param {Element[]} elems - Array of DOM elements being changed
+  * @returns {void}
+  */
+  beginUndoableChange (attrName, elems) {
+    const p = ++this.undoChangeStackPointer
+    let i = elems.length
+    const oldValues = new Array(i); const elements = new Array(i)
+    while (i--) {
+      const elem = elems[i]
+      if (!elem) { continue }
+      elements[i] = elem
+      oldValues[i] = elem.getAttribute(attrName)
+    }
+    this.undoableChangeStack[p] = {
+      attrName,
+      oldValues,
+      elements
+    }
+  }
+
+  /**
+  * This function returns a `BatchCommand` object which summarizes the
+  * change since `beginUndoableChange` was called.  The command can then
+  * be added to the command history.
+  * @returns {BatchCommand} Batch command object with resulting changes
+  */
+  finishUndoableChange () {
+    const p = this.undoChangeStackPointer--
+    const changeset = this.undoableChangeStack[p]
+    const { attrName } = changeset
+    const batchCmd = new BatchCommand('Change ' + attrName)
+    let i = changeset.elements.length
+    while (i--) {
+      const elem = changeset.elements[i]
+      if (!elem) { continue }
+      const changes = {}
+      changes[attrName] = changeset.oldValues[i]
+      if (changes[attrName] !== elem.getAttribute(attrName)) {
+        batchCmd.addSubCommand(new ChangeElementCommand(elem, changes, attrName))
+      }
+    }
+    this.undoableChangeStack[p] = null
+    return batchCmd
+  }
+}

packages/svgcanvas/historyrecording.js

@@ -0,0 +1,161 @@
+/**
+ * HistoryRecordingService component of history.
+ * @module history
+ * @license MIT
+ * @copyright 2016 Flint O'Brien
+ */
+
+import {
+  BatchCommand, MoveElementCommand, InsertElementCommand, RemoveElementCommand,
+  ChangeElementCommand
+} from './history.js'
+
+/**
+ * History recording service.
+ *
+ * A self-contained service interface for recording history. Once injected, no other dependencies
+ * or globals are required (example: UndoManager, command types, etc.). Easy to mock for unit tests.
+ * Built on top of history classes in history.js.
+ *
+ * There is a simple start/end interface for batch commands.
+ *
+ * HistoryRecordingService.NO_HISTORY is a singleton that can be passed in to functions
+ * that record history. This helps when the caller requires that no history be recorded.
+ *
+ * The following will record history: insert, batch, insert.
+ * @example
+ * hrService = new HistoryRecordingService(this.undoMgr);
+ * hrService.insertElement(elem, text); // add simple command to history.
+ * hrService.startBatchCommand('create two elements');
+ * hrService.changeElement(elem, attrs, text); // add to batchCommand
+ * hrService.changeElement(elem, attrs2, text); // add to batchCommand
+ * hrService.endBatchCommand(); // add batch command with two change commands to history.
+ * hrService.insertElement(elem, text); // add simple command to history.
+ *
+ * @example
+ * // Note that all functions return this, so commands can be chained, like so:
+ * hrService
+ *   .startBatchCommand('create two elements')
+ *   .insertElement(elem, text)
+ *   .changeElement(elem, attrs, text)
+ *   .endBatchCommand();
+ *
+ * @memberof module:history
+ */
+class HistoryRecordingService {
+  /**
+  * @param {history.UndoManager|null} undoManager - The undo manager.
+  *     A value of `null` is valid for cases where no history recording is required.
+  *     See singleton: {@link module:history.HistoryRecordingService.HistoryRecordingService.NO_HISTORY}
+  */
+  constructor (undoManager) {
+    this.undoManager_ = undoManager
+    this.currentBatchCommand_ = null
+    this.batchCommandStack_ = []
+  }
+
+  /**
+   * Start a batch command so multiple commands can recorded as a single history command.
+   * Requires a corresponding call to endBatchCommand. Start and end commands can be nested.
+   *
+   * @param {string} text - Optional string describing the batch command.
+   * @returns {module:history.HistoryRecordingService}
+   */
+  startBatchCommand (text) {
+    if (!this.undoManager_) { return this }
+    this.currentBatchCommand_ = new BatchCommand(text)
+    this.batchCommandStack_.push(this.currentBatchCommand_)
+    return this
+  }
+
+  /**
+   * End a batch command and add it to the history or a parent batch command.
+   * @returns {module:history.HistoryRecordingService}
+   */
+  endBatchCommand () {
+    if (!this.undoManager_) { return this }
+    if (this.currentBatchCommand_) {
+      const batchCommand = this.currentBatchCommand_
+      this.batchCommandStack_.pop()
+      const { length: len } = this.batchCommandStack_
+      this.currentBatchCommand_ = len ? this.batchCommandStack_[len - 1] : null
+      this.addCommand_(batchCommand)
+    }
+    return this
+  }
+
+  /**
+   * Add a `MoveElementCommand` to the history or current batch command.
+   * @param {Element} elem - The DOM element that was moved
+   * @param {Element} oldNextSibling - The element's next sibling before it was moved
+   * @param {Element} oldParent - The element's parent before it was moved
+   * @param {string} [text] - An optional string visible to user related to this change
+   * @returns {module:history.HistoryRecordingService}
+   */
+  moveElement (elem, oldNextSibling, oldParent, text) {
+    if (!this.undoManager_) { return this }
+    this.addCommand_(new MoveElementCommand(elem, oldNextSibling, oldParent, text))
+    return this
+  }
+
+  /**
+   * Add an `InsertElementCommand` to the history or current batch command.
+   * @param {Element} elem - The DOM element that was added
+   * @param {string} [text] - An optional string visible to user related to this change
+   * @returns {module:history.HistoryRecordingService}
+   */
+  insertElement (elem, text) {
+    if (!this.undoManager_) { return this }
+    this.addCommand_(new InsertElementCommand(elem, text))
+    return this
+  }
+
+  /**
+   * Add a `RemoveElementCommand` to the history or current batch command.
+   * @param {Element} elem - The DOM element that was removed
+   * @param {Element} oldNextSibling - The element's next sibling before it was removed
+   * @param {Element} oldParent - The element's parent before it was removed
+   * @param {string} [text] - An optional string visible to user related to this change
+   * @returns {module:history.HistoryRecordingService}
+   */
+  removeElement (elem, oldNextSibling, oldParent, text) {
+    if (!this.undoManager_) { return this }
+    this.addCommand_(new RemoveElementCommand(elem, oldNextSibling, oldParent, text))
+    return this
+  }
+
+  /**
+   * Add a `ChangeElementCommand` to the history or current batch command.
+   * @param {Element} elem - The DOM element that was changed
+   * @param {module:history.CommandAttributes} attrs - An object with the attributes to be changed and the values they had *before* the change
+   * @param {string} [text] - An optional string visible to user related to this change
+   * @returns {module:history.HistoryRecordingService}
+   */
+  changeElement (elem, attrs, text) {
+    if (!this.undoManager_) { return this }
+    this.addCommand_(new ChangeElementCommand(elem, attrs, text))
+    return this
+  }
+
+  /**
+   * Private function to add a command to the history or current batch command.
+   * @private
+   * @param {Command} cmd
+   * @returns {module:history.HistoryRecordingService|void}
+   */
+  addCommand_ (cmd) {
+    if (!this.undoManager_) { return this }
+    if (this.currentBatchCommand_) {
+      this.currentBatchCommand_.addSubCommand(cmd)
+    } else {
+      this.undoManager_.addCommandToHistory(cmd)
+    }
+    return undefined
+  }
+}
+/**
+ * @memberof module:history.HistoryRecordingService
+ * @property {module:history.HistoryRecordingService} NO_HISTORY - Singleton that can be passed to functions that record history, but the caller requires that no history be recorded.
+ */
+HistoryRecordingService.NO_HISTORY = new HistoryRecordingService()
+export default HistoryRecordingService

packages/svgcanvas/json.js

@@ -0,0 +1,110 @@
+/**
+ * Tools for SVG handle on JSON format.
+ * @module svgcanvas
+ * @license MIT
+ *
+ * @copyright 2010 Alexis Deveria, 2010 Jeff Schiller
+ */
+import { getElement, assignAttributes, cleanupElement } from './utilities.js'
+import { NS } from './namespaces.js'
+
+let svgCanvas = null
+let svgdoc_ = null
+
+/**
+ * @function module:json.jsonContext#getSelectedElements
+ * @returns {Element[]} the array with selected DOM elements
+*/
+/**
+ * @function module:json.jsonContext#getDOMDocument
+ * @returns {HTMLDocument}
+*/
+
+/**
+* @function module:json.init
+* @param {module:json.jsonContext} jsonContext
+* @returns {void}
+*/
+export const init = (canvas) => {
+  svgCanvas = canvas
+  svgdoc_ = canvas.getDOMDocument()
+}
+/**
+* @function module:json.getJsonFromSvgElements Iterate element and return json format
+* @param {ArgumentsArray} data - element
+* @returns {svgRootElement}
+*/
+export const getJsonFromSvgElements = (data) => {
+  // Text node
+  if (data.nodeType === 3) return data.nodeValue
+
+  const retval = {
+    element: data.tagName,
+    // namespace: nsMap[data.namespaceURI],
+    attr: {},
+    children: []
+  }
+
+  // Iterate attributes
+  for (let i = 0, attr; (attr = data.attributes[i]); i++) {
+    retval.attr[attr.name] = attr.value
+  }
+
+  // Iterate children
+  for (let i = 0, node; (node = data.childNodes[i]); i++) {
+    retval.children[i] = getJsonFromSvgElements(node)
+  }
+
+  return retval
+}
+
+/**
+* This should really be an intersection implementing all rather than a union.
+* @name module:json.addSVGElementsFromJson
+* @type {module:utilities.EditorContext#addSVGElementsFromJson|module:path.EditorContext#addSVGElementsFromJson}
+*/
+
+export const addSVGElementsFromJson = (data) => {
+  if (typeof data === 'string') return svgdoc_.createTextNode(data)
+
+  let shape = getElement(data.attr.id)
+  // if shape is a path but we need to create a rect/ellipse, then remove the path
+  const currentLayer = svgCanvas.getDrawing().getCurrentLayer()
+  if (shape && data.element !== shape.tagName) {
+    shape.remove()
+    shape = null
+  }
+  if (!shape) {
+    const ns = data.namespace || NS.SVG
+    shape = svgdoc_.createElementNS(ns, data.element)
+    if (currentLayer) {
+      (svgCanvas.getCurrentGroup() || currentLayer).append(shape)
+    }
+  }
+  const curShape = svgCanvas.getCurShape()
+  if (data.curStyles) {
+    assignAttributes(shape, {
+      fill: curShape.fill,
+      stroke: curShape.stroke,
+      'stroke-width': curShape.strokeWidth,
+      'stroke-dasharray': curShape.stroke_dasharray,
+      'stroke-linejoin': curShape.stroke_linejoin,
+      'stroke-linecap': curShape.stroke_linecap,
+      'stroke-opacity': curShape.stroke_opacity,
+      'fill-opacity': curShape.fill_opacity,
+      opacity: curShape.opacity / 2,
+      style: 'pointer-events:inherit'
+    }, 100)
+  }
+  assignAttributes(shape, data.attr, 100)
+  cleanupElement(shape)
+
+  // Children
+  if (data.children) {
+    data.children.forEach((child) => {
+      shape.append(addSVGElementsFromJson(child))
+    })
+  }
+
+  return shape
+}

packages/svgcanvas/layer.js

@@ -0,0 +1,228 @@
+/**
+ * Provides tools for the layer concept.
+ * @module layer
+ * @license MIT
+ *
+ * @copyright 2011 Jeff Schiller, 2016 Flint O'Brien
+ */
+
+import { NS } from './namespaces.js'
+import { toXml, walkTree } from './utilities.js'
+
+/**
+ * This class encapsulates the concept of a layer in the drawing. It can be constructed with
+ * an existing group element or, with three parameters, will create a new layer group element.
+ *
+ * @example
+ * const l1 = new Layer('name', group); // Use the existing group for this layer.
+ * const l2 = new Layer('name', group, svgElem); // Create a new group and add it to the DOM after group.
+ * const l3 = new Layer('name', null, svgElem); // Create a new group and add it to the DOM as the last layer.
+ * @memberof module:layer
+ */
+class Layer {
+  /**
+  * @param {string} name - Layer name
+  * @param {SVGGElement|null} group - An existing SVG group element or null.
+  *     If group and no svgElem, use group for this layer.
+  *     If group and svgElem, create a new group element and insert it in the DOM after group.
+  *     If no group and svgElem, create a new group element and insert it in the DOM as the last layer.
+  * @param {SVGGElement} [svgElem] - The SVG DOM element. If defined, use this to add
+  *     a new layer to the document.
+  */
+  constructor (name, group, svgElem) {
+    this.name_ = name
+    this.group_ = svgElem ? null : group
+
+    if (svgElem) {
+      // Create a group element with title and add it to the DOM.
+      const svgdoc = svgElem.ownerDocument
+      this.group_ = svgdoc.createElementNS(NS.SVG, 'g')
+      const layerTitle = svgdoc.createElementNS(NS.SVG, 'title')
+      layerTitle.textContent = name
+      this.group_.append(layerTitle)
+      if (group) {
+        group.insertAdjacentElement('afterend', this.group_)
+      } else {
+        svgElem.append(this.group_)
+      }
+    }
+
+    addLayerClass(this.group_)
+    walkTree(this.group_, function (e) {
+      e.setAttribute('style', 'pointer-events:inherit')
+    })
+
+    this.group_.setAttribute('style', svgElem ? 'pointer-events:all' : 'pointer-events:none')
+  }
+
+  /**
+   * Get the layer's name.
+   * @returns {string} The layer name
+   */
+  getName () {
+    return this.name_
+  }
+
+  /**
+   * Get the group element for this layer.
+   * @returns {SVGGElement} The layer SVG group
+   */
+  getGroup () {
+    return this.group_
+  }
+
+  /**
+   * Active this layer so it takes pointer events.
+   * @returns {void}
+   */
+  activate () {
+    this.group_.setAttribute('style', 'pointer-events:all')
+  }
+
+  /**
+   * Deactive this layer so it does NOT take pointer events.
+   * @returns {void}
+   */
+  deactivate () {
+    this.group_.setAttribute('style', 'pointer-events:none')
+  }
+
+  /**
+   * Set this layer visible or hidden based on 'visible' parameter.
+   * @param {boolean} visible - If true, make visible; otherwise, hide it.
+   * @returns {void}
+   */
+  setVisible (visible) {
+    const expected = visible === undefined || visible ? 'inline' : 'none'
+    const oldDisplay = this.group_.getAttribute('display')
+    if (oldDisplay !== expected) {
+      this.group_.setAttribute('display', expected)
+    }
+  }
+
+  /**
+   * Is this layer visible?
+   * @returns {boolean} True if visible.
+   */
+  isVisible () {
+    return this.group_.getAttribute('display') !== 'none'
+  }
+
+  /**
+   * Get layer opacity.
+   * @returns {Float} Opacity value.
+   */
+  getOpacity () {
+    const opacity = this.group_.getAttribute('opacity')
+    if (!opacity) {
+      return 1
+    }
+    return Number.parseFloat(opacity)
+  }
+
+  /**
+   * Sets the opacity of this layer. If opacity is not a value between 0.0 and 1.0,
+   * nothing happens.
+   * @param {Float} opacity - A float value in the range 0.0-1.0
+   * @returns {void}
+   */
+  setOpacity (opacity) {
+    if (typeof opacity === 'number' && opacity >= 0.0 && opacity <= 1.0) {
+      this.group_.setAttribute('opacity', opacity)
+    }
+  }
+
+  /**
+   * Append children to this layer.
+   * @param {SVGGElement} children - The children to append to this layer.
+   * @returns {void}
+   */
+  appendChildren (children) {
+    for (const child of children) {
+      this.group_.append(child)
+    }
+  }
+
+  /**
+  * @returns {SVGTitleElement|null}
+  */
+  getTitleElement () {
+    const len = this.group_.childNodes.length
+    for (let i = 0; i < len; ++i) {
+      const child = this.group_.childNodes.item(i)
+      if (child?.tagName === 'title') {
+        return child
+      }
+    }
+    return null
+  }
+
+  /**
+   * Set the name of this layer.
+   * @param {string} name - The new name.
+   * @param {module:history.HistoryRecordingService} hrService - History recording service
+   * @returns {string|null} The new name if changed; otherwise, null.
+   */
+  setName (name, hrService) {
+    const previousName = this.name_
+    name = toXml(name)
+    // now change the underlying title element contents
+    const title = this.getTitleElement()
+    if (title) {
+      while (title.firstChild) { title.removeChild(title.firstChild) }
+      title.textContent = name
+      this.name_ = name
+      if (hrService) {
+        hrService.changeElement(title, { '#text': previousName })
+      }
+      return this.name_
+    }
+    return null
+  }
+
+  /**
+   * Remove this layer's group from the DOM. No more functions on group can be called after this.
+   * @returns {SVGGElement} The layer SVG group that was just removed.
+   */
+  removeGroup () {
+    const group = this.group_
+    this.group_.remove()
+    this.group_ = undefined
+    return group
+  }
+
+  /**
+   * Test whether an element is a layer or not.
+   * @param {SVGGElement} elem - The SVGGElement to test.
+   * @returns {boolean} True if the element is a layer
+   */
+  static isLayer (elem) {
+    return elem && elem.tagName === 'g' && Layer.CLASS_REGEX.test(elem.getAttribute('class'))
+  }
+}
+/**
+ * @property {string} CLASS_NAME - class attribute assigned to all layer groups.
+ */
+Layer.CLASS_NAME = 'layer'
+
+/**
+ * @property {RegExp} CLASS_REGEX - Used to test presence of class Layer.CLASS_NAME
+ */
+Layer.CLASS_REGEX = new RegExp('(\\s|^)' + Layer.CLASS_NAME + '(\\s|$)')
+
+/**
+ * Add class `Layer.CLASS_NAME` to the element (usually `class='layer'`).
+ *
+ * @param {SVGGElement} elem - The SVG element to update
+ * @returns {void}
+ */
+function addLayerClass (elem) {
+  const classes = elem.getAttribute('class')
+  if (!classes || !classes.length) {
+    elem.setAttribute('class', Layer.CLASS_NAME)
+  } else if (!Layer.CLASS_REGEX.test(classes)) {
+    elem.setAttribute('class', classes + ' ' + Layer.CLASS_NAME)
+  }
+}
+
+export default Layer

packages/svgcanvas/math.js

@@ -0,0 +1,221 @@
+/**
+ * Mathematical utilities.
+ * @module math
+ * @license MIT
+ *
+ * @copyright 2010 Alexis Deveria, 2010 Jeff Schiller
+ */
+
+/**
+* @typedef {PlainObject} module:math.AngleCoord45
+* @property {Float} x - The angle-snapped x value
+* @property {Float} y - The angle-snapped y value
+* @property {Integer} a - The angle at which to snap
+*/
+
+/**
+* @typedef {PlainObject} module:math.XYObject
+* @property {Float} x
+* @property {Float} y
+*/
+
+import { NS } from './namespaces.js'
+
+// Constants
+const NEAR_ZERO = 1e-14
+
+// Throw away SVGSVGElement used for creating matrices/transforms.
+const svg = document.createElementNS(NS.SVG, 'svg')
+
+/**
+ * A (hopefully) quicker function to transform a point by a matrix
+ * (this function avoids any DOM calls and just does the math).
+ * @function module:math.transformPoint
+ * @param {Float} x - Float representing the x coordinate
+ * @param {Float} y - Float representing the y coordinate
+ * @param {SVGMatrix} m - Matrix object to transform the point with
+ * @returns {module:math.XYObject} An x, y object representing the transformed point
+*/
+export const transformPoint = function (x, y, m) {
+  return { x: m.a * x + m.c * y + m.e, y: m.b * x + m.d * y + m.f }
+}
+
+/**
+ * Helper function to check if the matrix performs no actual transform
+ * (i.e. exists for identity purposes).
+ * @function module:math.isIdentity
+ * @param {SVGMatrix} m - The matrix object to check
+ * @returns {boolean} Indicates whether or not the matrix is 1,0,0,1,0,0
+*/
+export const isIdentity = function (m) {
+  return (m.a === 1 && m.b === 0 && m.c === 0 && m.d === 1 && m.e === 0 && m.f === 0)
+}
+
+/**
+ * This function tries to return a `SVGMatrix` that is the multiplication `m1 * m2`.
+ * We also round to zero when it's near zero.
+ * @function module:math.matrixMultiply
+ * @param {...SVGMatrix} args - Matrix objects to multiply
+ * @returns {SVGMatrix} The matrix object resulting from the calculation
+*/
+export const matrixMultiply = function (...args) {
+  const m = args.reduceRight((prev, m1) => {
+    return m1.multiply(prev)
+  })
+
+  if (Math.abs(m.a) < NEAR_ZERO) { m.a = 0 }
+  if (Math.abs(m.b) < NEAR_ZERO) { m.b = 0 }
+  if (Math.abs(m.c) < NEAR_ZERO) { m.c = 0 }
+  if (Math.abs(m.d) < NEAR_ZERO) { m.d = 0 }
+  if (Math.abs(m.e) < NEAR_ZERO) { m.e = 0 }
+  if (Math.abs(m.f) < NEAR_ZERO) { m.f = 0 }
+
+  return m
+}
+
+/**
+ * See if the given transformlist includes a non-indentity matrix transform.
+ * @function module:math.hasMatrixTransform
+ * @param {SVGTransformList} [tlist] - The transformlist to check
+ * @returns {boolean} Whether or not a matrix transform was found
+*/
+export const hasMatrixTransform = function (tlist) {
+  if (!tlist) { return false }
+  let num = tlist.numberOfItems
+  while (num--) {
+    const xform = tlist.getItem(num)
+    if (xform.type === 1 && !isIdentity(xform.matrix)) { return true }
+  }
+  return false
+}
+
+/**
+* @typedef {PlainObject} module:math.TransformedBox An object with the following values
+* @property {module:math.XYObject} tl - The top left coordinate
+* @property {module:math.XYObject} tr - The top right coordinate
+* @property {module:math.XYObject} bl - The bottom left coordinate
+* @property {module:math.XYObject} br - The bottom right coordinate
+* @property {PlainObject} aabox - Object with the following values:
+* @property {Float} aabox.x - Float with the axis-aligned x coordinate
+* @property {Float} aabox.y - Float with the axis-aligned y coordinate
+* @property {Float} aabox.width - Float with the axis-aligned width coordinate
+* @property {Float} aabox.height - Float with the axis-aligned height coordinate
+*/
+
+/**
+ * Transforms a rectangle based on the given matrix.
+ * @function module:math.transformBox
+ * @param {Float} l - Float with the box's left coordinate
+ * @param {Float} t - Float with the box's top coordinate
+ * @param {Float} w - Float with the box width
+ * @param {Float} h - Float with the box height
+ * @param {SVGMatrix} m - Matrix object to transform the box by
+ * @returns {module:math.TransformedBox}
+*/
+export const transformBox = function (l, t, w, h, m) {
+  const tl = transformPoint(l, t, m)
+  const tr = transformPoint((l + w), t, m)
+  const bl = transformPoint(l, (t + h), m)
+  const br = transformPoint((l + w), (t + h), m)
+
+  const minx = Math.min(tl.x, tr.x, bl.x, br.x)
+  const maxx = Math.max(tl.x, tr.x, bl.x, br.x)
+  const miny = Math.min(tl.y, tr.y, bl.y, br.y)
+  const maxy = Math.max(tl.y, tr.y, bl.y, br.y)
+
+  return {
+    tl,
+    tr,
+    bl,
+    br,
+    aabox: {
+      x: minx,
+      y: miny,
+      width: (maxx - minx),
+      height: (maxy - miny)
+    }
+  }
+}
+
+/**
+ * This returns a single matrix Transform for a given Transform List
+ * (this is the equivalent of `SVGTransformList.consolidate()` but unlike
+ * that method, this one does not modify the actual `SVGTransformList`).
+ * This function is very liberal with its `min`, `max` arguments.
+ * @function module:math.transformListToTransform
+ * @param {SVGTransformList} tlist - The transformlist object
+ * @param {Integer} [min=0] - Optional integer indicating start transform position
+ * @param {Integer} [max] - Optional integer indicating end transform position;
+ *   defaults to one less than the tlist's `numberOfItems`
+ * @returns {SVGTransform} A single matrix transform object
+*/
+export const transformListToTransform = function (tlist, min, max) {
+  if (!tlist) {
+    // Or should tlist = null have been prevented before this?
+    return svg.createSVGTransformFromMatrix(svg.createSVGMatrix())
+  }
+  min = min || 0
+  max = max || (tlist.numberOfItems - 1)
+  min = Number.parseInt(min)
+  max = Number.parseInt(max)
+  if (min > max) { const temp = max; max = min; min = temp }
+  let m = svg.createSVGMatrix()
+  for (let i = min; i <= max; ++i) {
+    // if our indices are out of range, just use a harmless identity matrix
+    const mtom = (i >= 0 && i < tlist.numberOfItems
+      ? tlist.getItem(i).matrix
+      : svg.createSVGMatrix())
+    m = matrixMultiply(m, mtom)
+  }
+  return svg.createSVGTransformFromMatrix(m)
+}
+
+/**
+ * Get the matrix object for a given element.
+ * @function module:math.getMatrix
+ * @param {Element} elem - The DOM element to check
+ * @returns {SVGMatrix} The matrix object associated with the element's transformlist
+*/
+export const getMatrix = (elem) => {
+  const tlist = elem.transform.baseVal
+  return transformListToTransform(tlist).matrix
+}
+
+/**
+ * Returns a 45 degree angle coordinate associated with the two given
+ * coordinates.
+ * @function module:math.snapToAngle
+ * @param {Integer} x1 - First coordinate's x value
+ * @param {Integer} y1 - First coordinate's y value
+ * @param {Integer} x2 - Second coordinate's x value
+ * @param {Integer} y2 - Second coordinate's y value
+ * @returns {module:math.AngleCoord45}
+*/
+export const snapToAngle = (x1, y1, x2, y2) => {
+  const snap = Math.PI / 4 // 45 degrees
+  const dx = x2 - x1
+  const dy = y2 - y1
+  const angle = Math.atan2(dy, dx)
+  const dist = Math.sqrt(dx * dx + dy * dy)
+  const snapangle = Math.round(angle / snap) * snap
+
+  return {
+    x: x1 + dist * Math.cos(snapangle),
+    y: y1 + dist * Math.sin(snapangle),
+    a: snapangle
+  }
+}
+
+/**
+ * Check if two rectangles (BBoxes objects) intersect each other.
+ * @function module:math.rectsIntersect
+ * @param {SVGRect} r1 - The first BBox-like object
+ * @param {SVGRect} r2 - The second BBox-like object
+ * @returns {boolean} True if rectangles intersect
+ */
+export const rectsIntersect = (r1, r2) => {
+  return r2.x < (r1.x + r1.width) &&
+    (r2.x + r2.width) > r1.x &&
+    r2.y < (r1.y + r1.height) &&
+    (r2.y + r2.height) > r1.y
+}

packages/svgcanvas/namespaces.js

@@ -0,0 +1,40 @@
+/**
+ * Namespaces or tools therefor.
+ * @module namespaces
+ * @license MIT
+*/
+
+/**
+* Common namepaces constants in alpha order.
+* @enum {string}
+* @type {PlainObject}
+* @memberof module:namespaces
+*/
+export const NS = {
+  HTML: 'http://www.w3.org/1999/xhtml',
+  MATH: 'http://www.w3.org/1998/Math/MathML',
+  SE: 'http://svg-edit.googlecode.com',
+  SVG: 'http://www.w3.org/2000/svg',
+  XLINK: 'http://www.w3.org/1999/xlink',
+  OI: 'http://www.optimistik.fr/namespace/svg/OIdata',
+  XML: 'http://www.w3.org/XML/1998/namespace',
+  XMLNS: 'http://www.w3.org/2000/xmlns/' // see http://www.w3.org/TR/REC-xml-names/#xmlReserved
+  // SODIPODI: 'http://sodipodi.sourceforge.net/DTD/sodipodi-0.dtd',
+  // INKSCAPE: 'http://www.inkscape.org/namespaces/inkscape',
+  // RDF: 'http://www.w3.org/1999/02/22-rdf-syntax-ns#',
+  // OSB: 'http://www.openswatchbook.org/uri/2009/osb',
+  // CC: 'http://creativecommons.org/ns#',
+  // DC: 'http://purl.org/dc/elements/1.1/'
+}
+
+/**
+* @function module:namespaces.getReverseNS
+* @returns {string} The NS with key values switched and lowercase
+*/
+export const getReverseNS = function () {
+  const reverseNS = {}
+  Object.entries(NS).forEach(([name, URI]) => {
+    reverseNS[URI] = name.toLowerCase()
+  })
+  return reverseNS
+}

packages/svgcanvas/package-lock.json

@@ -0,0 +1,13 @@
+{
+    "name": "@svgedit/svgcanvas",
+    "version": "7.1.5",
+    "lockfileVersion": 2,
+    "requires": true,
+    "packages": {
+        "": {
+            "name": "@svgedit/svgcanvas",
+            "version": "7.1.5",
+            "license": "MIT"
+        }
+    }
+}

packages/svgcanvas/package.json

@@ -0,0 +1,56 @@
+{
+    "name": "@svgedit/svgcanvas",
+    "version": "7.1.6",
+    "description": "SVG Canvas",
+    "main": "dist/svgcanvas.js",
+    "author": "Narendra Sisodiya",
+    "publishConfig": {
+        "access": "public"
+    },
+    "bugs": {
+        "url": "https://github.com/SVG-Edit/svgedit/issues"
+    },
+    "repository": {
+        "type": "git",
+        "url": "git+https://github.com/SVG-Edit/svgedit.git"
+    },
+    "homepage": "https://github.com/SVG-Edit/svgedit#readme",
+    "contributors": [
+        "Pavol Rusnak",
+        "Jeff Schiller",
+        "Vidar Hokstad",
+        "Alexis Deveria",
+        "Brett Zamir",
+        "Fabien Jacq",
+        "OptimistikSAS"
+    ],
+    "keywords": [
+        "svg-editor",
+        "javascript",
+        "svg-edit",
+        "svg",
+        "svgcanvas"
+    ],
+    "license": "MIT",
+    "browserslist": [
+        "defaults",
+        "not IE 11",
+        "not OperaMini all"
+    ],
+    "standard": {
+        "ignore": ["dist"],
+        "globals": [
+            "cy",
+            "assert"
+        ],
+        "env": [
+            "mocha",
+            "browser"
+        ]
+    },
+    "scripts": {
+        "build": "rollup -c",
+        "prebuild": "standard . && npm i",
+        "prepublishOnly": "npm run build"
+    }
+}

packages/svgcanvas/paint.js

@@ -0,0 +1,88 @@
+/**
+ *
+ */
+export default class Paint {
+  /**
+   * @param {module:jGraduate.jGraduatePaintOptions} [opt]
+  */
+  constructor (opt) {
+    const options = opt || {}
+    this.alpha = isNaN(options.alpha) ? 100 : options.alpha
+    // copy paint object
+    if (options.copy) {
+      /**
+       * @name module:jGraduate~Paint#type
+       * @type {"none"|"solidColor"|"linearGradient"|"radialGradient"}
+       */
+      this.type = options.copy.type
+      /**
+       * Represents opacity (0-100).
+       * @name module:jGraduate~Paint#alpha
+       * @type {Float}
+       */
+      this.alpha = options.copy.alpha
+      /**
+       * Represents #RRGGBB hex of color.
+       * @name module:jGraduate~Paint#solidColor
+       * @type {string}
+       */
+      this.solidColor = null
+      /**
+       * @name module:jGraduate~Paint#linearGradient
+       * @type {SVGLinearGradientElement}
+       */
+      this.linearGradient = null
+      /**
+       * @name module:jGraduate~Paint#radialGradient
+       * @type {SVGRadialGradientElement}
+       */
+      this.radialGradient = null
+
+      switch (this.type) {
+        case 'none':
+          break
+        case 'solidColor':
+          this.solidColor = options.copy.solidColor
+          break
+        case 'linearGradient':
+          this.linearGradient = options.copy.linearGradient.cloneNode(true)
+          break
+        case 'radialGradient':
+          this.radialGradient = options.copy.radialGradient.cloneNode(true)
+          break
+      }
+    // create linear gradient paint
+    } else if (options.linearGradient) {
+      this.type = 'linearGradient'
+      this.solidColor = null
+      this.radialGradient = null
+      if (options.linearGradient.hasAttribute('xlink:href')) {
+        const xhref = document.getElementById(options.linearGradient.getAttribute('xlink:href').substr(1))
+        this.linearGradient = xhref.cloneNode(true)
+      } else {
+        this.linearGradient = options.linearGradient.cloneNode(true)
+      }
+    // create linear gradient paint
+    } else if (options.radialGradient) {
+      this.type = 'radialGradient'
+      this.solidColor = null
+      this.linearGradient = null
+      if (options.radialGradient.hasAttribute('xlink:href')) {
+        const xhref = document.getElementById(options.radialGradient.getAttribute('xlink:href').substr(1))
+        this.radialGradient = xhref.cloneNode(true)
+      } else {
+        this.radialGradient = options.radialGradient.cloneNode(true)
+      }
+    // create solid color paint
+    } else if (options.solidColor) {
+      this.type = 'solidColor'
+      this.solidColor = options.solidColor
+    // create empty paint
+    } else {
+      this.type = 'none'
+      this.solidColor = null
+      this.linearGradient = null
+      this.radialGradient = null
+    }
+  }
+}

packages/svgcanvas/paste-elem.js

@@ -0,0 +1,127 @@
+import {
+  getStrokedBBoxDefaultVisible
+} from './utilities.js'
+import * as hstry from './history.js'
+
+const {
+  InsertElementCommand, BatchCommand
+} = hstry
+
+let svgCanvas = null
+
+/**
+* @function module:paste-elem.init
+* @param {module:paste-elem.pasteContext} pasteContext
+* @returns {void}
+*/
+export const init = (canvas) => {
+  svgCanvas = canvas
+}
+
+/**
+* @function module:svgcanvas.SvgCanvas#pasteElements
+* @param {"in_place"|"point"|void} type
+* @param {Integer|void} x Expected if type is "point"
+* @param {Integer|void} y Expected if type is "point"
+* @fires module:svgcanvas.SvgCanvas#event:changed
+* @fires module:svgcanvas.SvgCanvas#event:ext_IDsUpdated
+* @returns {void}
+*/
+export const pasteElementsMethod = function (type, x, y) {
+  let clipb = JSON.parse(sessionStorage.getItem(svgCanvas.getClipboardID()))
+  if (!clipb) return
+  let len = clipb.length
+  if (!len) return
+
+  const pasted = []
+  const batchCmd = new BatchCommand('Paste elements')
+  // const drawing = getCurrentDrawing();
+  /**
+* @typedef {PlainObject<string, string>} module:svgcanvas.ChangedIDs
+*/
+  /**
+* @type {module:svgcanvas.ChangedIDs}
+*/
+  const changedIDs = {}
+
+  // Recursively replace IDs and record the changes
+  /**
+*
+* @param {module:svgcanvas.SVGAsJSON} elem
+* @returns {void}
+*/
+  function checkIDs (elem) {
+    if (elem.attr?.id) {
+      changedIDs[elem.attr.id] = svgCanvas.getNextId()
+      elem.attr.id = changedIDs[elem.attr.id]
+    }
+    if (elem.children) elem.children.forEach((child) => checkIDs(child))
+  }
+  clipb.forEach((elem) => checkIDs(elem))
+
+  // Give extensions like the connector extension a chance to reflect new IDs and remove invalid elements
+  /**
+* Triggered when `pasteElements` is called from a paste action (context menu or key).
+* @event module:svgcanvas.SvgCanvas#event:ext_IDsUpdated
+* @type {PlainObject}
+* @property {module:svgcanvas.SVGAsJSON[]} elems
+* @property {module:svgcanvas.ChangedIDs} changes Maps past ID (on attribute) to current ID
+*/
+  svgCanvas.runExtensions(
+    'IDsUpdated',
+    /** @type {module:svgcanvas.SvgCanvas#event:ext_IDsUpdated} */
+    { elems: clipb, changes: changedIDs },
+    true
+  ).forEach(function (extChanges) {
+    if (!extChanges || !('remove' in extChanges)) return
+
+    extChanges.remove.forEach(function (removeID) {
+      clipb = clipb.filter(function (clipBoardItem) {
+        return clipBoardItem.attr.id !== removeID
+      })
+    })
+  })
+
+  // Move elements to lastClickPoint
+  while (len--) {
+    const elem = clipb[len]
+    if (!elem) { continue }
+
+    const copy = svgCanvas.addSVGElementsFromJson(elem)
+    pasted.push(copy)
+    batchCmd.addSubCommand(new InsertElementCommand(copy))
+
+    svgCanvas.restoreRefElements(copy)
+  }
+
+  svgCanvas.selectOnly(pasted)
+
+  if (type !== 'in_place') {
+    let ctrX; let ctrY
+
+    if (!type) {
+      ctrX = svgCanvas.getLastClickPoint('x')
+      ctrY = svgCanvas.getLastClickPoint('y')
+    } else if (type === 'point') {
+      ctrX = x
+      ctrY = y
+    }
+
+    const bbox = getStrokedBBoxDefaultVisible(pasted)
+    const cx = ctrX - (bbox.x + bbox.width / 2)
+    const cy = ctrY - (bbox.y + bbox.height / 2)
+    const dx = []
+    const dy = []
+
+    pasted.forEach(function (_item) {
+      dx.push(cx)
+      dy.push(cy)
+    })
+
+    const cmd = svgCanvas.moveSelectedElements(dx, dy, false)
+    if (cmd) batchCmd.addSubCommand(cmd)
+  }
+
+  svgCanvas.addCommandToHistory(batchCmd)
+  svgCanvas.call('changed', pasted)
+}

packages/svgcanvas/path.js

@@ -0,0 +1,781 @@
+/**
+ * Path functionality.
+ * @module path
+ * @license MIT
+ *
+ * @copyright 2011 Alexis Deveria, 2011 Jeff Schiller
+ */
+
+import { shortFloat } from './units.js'
+import { transformPoint } from './math.js'
+import {
+  getRotationAngle, getBBox,
+  getRefElem, findDefs,
+  getBBox as utilsGetBBox
+} from './utilities.js'
+import {
+  init as pathMethodInit, ptObjToArrMethod, getGripPtMethod,
+  getPointFromGripMethod, addPointGripMethod, getGripContainerMethod, addCtrlGripMethod,
+  getCtrlLineMethod, getPointGripMethod, getControlPointsMethod, replacePathSegMethod,
+  getSegSelectorMethod, Path
+} from './path-method.js'
+import {
+  init as pathActionsInit, pathActionsMethod
+} from './path-actions.js'
+
+const segData = {
+  2: ['x', 'y'], // PATHSEG_MOVETO_ABS
+  4: ['x', 'y'], // PATHSEG_LINETO_ABS
+  6: ['x', 'y', 'x1', 'y1', 'x2', 'y2'], // PATHSEG_CURVETO_CUBIC_ABS
+  8: ['x', 'y', 'x1', 'y1'], // PATHSEG_CURVETO_QUADRATIC_ABS
+  10: ['x', 'y', 'r1', 'r2', 'angle', 'largeArcFlag', 'sweepFlag'], // PATHSEG_ARC_ABS
+  12: ['x'], // PATHSEG_LINETO_HORIZONTAL_ABS
+  14: ['y'], // PATHSEG_LINETO_VERTICAL_ABS
+  16: ['x', 'y', 'x2', 'y2'], // PATHSEG_CURVETO_CUBIC_SMOOTH_ABS
+  18: ['x', 'y'] // PATHSEG_CURVETO_QUADRATIC_SMOOTH_ABS
+}
+
+let svgCanvas
+/**
+ * @tutorial LocaleDocs
+ * @typedef {module:locale.LocaleStrings|PlainObject} module:path.uiStrings
+ * @property {PlainObject<string, string>} ui
+*/
+
+const uiStrings = {}
+/**
+* @function module:path.setUiStrings
+* @param {module:path.uiStrings} strs
+* @returns {void}
+*/
+export const setUiStrings = (strs) => {
+  Object.assign(uiStrings, strs.ui)
+}
+
+let pathFuncs = []
+
+let linkControlPts = true
+
+// Stores references to paths via IDs.
+// TODO: Make this cross-document happy.
+let pathData = {}
+
+/**
+* @function module:path.setLinkControlPoints
+* @param {boolean} lcp
+* @returns {void}
+*/
+export const setLinkControlPoints = (lcp) => {
+  linkControlPts = lcp
+}
+
+/**
+ * @name module:path.path
+ * @type {null|module:path.Path}
+ * @memberof module:path
+*/
+export let path = null
+
+/**
+* @external MouseEvent
+*/
+
+/**
+* Object with the following keys/values.
+* @typedef {PlainObject} module:path.SVGElementJSON
+* @property {string} element - Tag name of the SVG element to create
+* @property {PlainObject<string, string>} attr - Has key-value attributes to assign to the new element.
+*   An `id` should be set so that {@link module:utilities.EditorContext#addSVGElementsFromJson} can later re-identify the element for modification or replacement.
+* @property {boolean} [curStyles=false] - Indicates whether current style attributes should be applied first
+* @property {module:path.SVGElementJSON[]} [children] - Data objects to be added recursively as children
+* @property {string} [namespace="http://www.w3.org/2000/svg"] - Indicate a (non-SVG) namespace
+*/
+/**
+ * @interface module:path.EditorContext
+ * @property {module:select.SelectorManager} selectorManager
+ * @property {module:svgcanvas.SvgCanvas} canvas
+ */
+/**
+ * @function module:path.EditorContext#call
+ * @param {"selected"|"changed"} ev - String with the event name
+ * @param {module:svgcanvas.SvgCanvas#event:selected|module:svgcanvas.SvgCanvas#event:changed} arg - Argument to pass through to the callback function.
+ *  If the event is "changed", an array of `Element`s is passed; if "selected", a single-item array of `Element` is passed.
+ * @returns {void}
+ */
+/**
+ * Note: This doesn't round to an integer necessarily.
+ * @function module:path.EditorContext#round
+ * @param {Float} val
+ * @returns {Float} Rounded value to nearest value based on `zoom`
+ */
+/**
+ * @function module:path.EditorContext#clearSelection
+ * @param {boolean} [noCall] - When `true`, does not call the "selected" handler
+ * @returns {void}
+*/
+/**
+ * @function module:path.EditorContext#addToSelection
+ * @param {Element[]} elemsToAdd - An array of DOM elements to add to the selection
+ * @param {boolean} showGrips - Indicates whether the resize grips should be shown
+ * @returns {void}
+*/
+/**
+ * @function module:path.EditorContext#addCommandToHistory
+ * @param {Command} cmd
+ * @returns {void}
+ */
+/**
+ * @function module:path.EditorContext#remapElement
+ * @param {Element} selected - DOM element to be changed
+ * @param {PlainObject<string, string>} changes - Object with changes to be remapped
+ * @param {SVGMatrix} m - Matrix object to use for remapping coordinates
+ * @returns {void}
+ */
+/**
+ * @function module:path.EditorContext#addSVGElementsFromJson
+ * @param {module:path.SVGElementJSON} data
+ * @returns {Element} The new element
+*/
+/**
+ * @function module:path.EditorContext#getGridSnapping
+ * @returns {boolean}
+ */
+/**
+ * @function module:path.EditorContext#getOpacity
+ * @returns {Float}
+ */
+/**
+ * @function module:path.EditorContext#getSelectedElements
+ * @returns {Element[]} the array with selected DOM elements
+*/
+/**
+ * @function module:path.EditorContext#getContainer
+ * @returns {Element}
+ */
+/**
+ * @function module:path.EditorContext#setStarted
+ * @param {boolean} s
+ * @returns {void}
+ */
+/**
+ * @function module:path.EditorContext#getRubberBox
+ * @returns {SVGRectElement}
+*/
+/**
+ * @function module:path.EditorContext#setRubberBox
+ * @param {SVGRectElement} rb
+ * @returns {SVGRectElement} Same as parameter passed in
+ */
+/**
+ * @function module:path.EditorContext#addPtsToSelection
+ * @param {PlainObject} cfg
+ * @param {boolean} cfg.closedSubpath
+ * @param {SVGCircleElement[]} cfg.grips
+ * @returns {void}
+ */
+/**
+ * @function module:path.EditorContext#endChanges
+ * @param {PlainObject} cfg
+ * @param {string} cfg.cmd
+ * @param {Element} cfg.elem
+ * @returns {void}
+*/
+/**
+ * @function module:path.EditorContext#getZoom
+ * @returns {Float} The current zoom level
+ */
+/**
+ * Returns the last created DOM element ID string.
+ * @function module:path.EditorContext#getId
+ * @returns {string}
+ */
+/**
+ * Creates and returns a unique ID string for a DOM element.
+ * @function module:path.EditorContext#getNextId
+ * @returns {string}
+*/
+/**
+ * Gets the desired element from a mouse event.
+ * @function module:path.EditorContext#getMouseTarget
+ * @param {external:MouseEvent} evt - Event object from the mouse event
+ * @returns {Element} DOM element we want
+ */
+/**
+ * @function module:path.EditorContext#getCurrentMode
+ * @returns {string}
+ */
+/**
+ * @function module:path.EditorContext#setCurrentMode
+ * @param {string} cm The mode
+ * @returns {string} The same mode as passed in
+*/
+/**
+ * @function module:path.EditorContext#setDrawnPath
+ * @param {SVGPathElement|null} dp
+ * @returns {SVGPathElement|null} The same value as passed in
+ */
+/**
+ * @function module:path.EditorContext#getSvgRoot
+ * @returns {SVGSVGElement}
+*/
+
+/**
+* @function module:path.init
+* @param {module:path.EditorContext} editorContext
+* @returns {void}
+*/
+export const init = (canvas) => {
+  svgCanvas = canvas
+  svgCanvas.replacePathSeg = replacePathSegMethod
+  svgCanvas.addPointGrip = addPointGripMethod
+  svgCanvas.removePath_ = removePath_
+  svgCanvas.getPath_ = getPath_
+  svgCanvas.addCtrlGrip = addCtrlGripMethod
+  svgCanvas.getCtrlLine = getCtrlLineMethod
+  svgCanvas.getGripPt = getGripPt
+  svgCanvas.getPointFromGrip = getPointFromGripMethod
+  svgCanvas.setLinkControlPoints = setLinkControlPoints
+  svgCanvas.reorientGrads = reorientGrads
+  svgCanvas.getSegData = () => { return segData }
+  svgCanvas.getUIStrings = () => { return uiStrings }
+  svgCanvas.getPathObj = () => { return path }
+  svgCanvas.setPathObj = (obj) => { path = obj }
+  svgCanvas.getPathFuncs = () => { return pathFuncs }
+  svgCanvas.getLinkControlPts = () => { return linkControlPts }
+  pathFuncs = [0, 'ClosePath']
+  const pathFuncsStrs = [
+    'Moveto', 'Lineto', 'CurvetoCubic', 'CurvetoQuadratic', 'Arc',
+    'LinetoHorizontal', 'LinetoVertical', 'CurvetoCubicSmooth', 'CurvetoQuadraticSmooth'
+  ]
+  pathFuncsStrs.forEach((s) => {
+    pathFuncs.push(s + 'Abs')
+    pathFuncs.push(s + 'Rel')
+  })
+  pathActionsInit(svgCanvas)
+  pathMethodInit(svgCanvas)
+}
+
+/* eslint-disable max-len */
+/**
+* @function module:path.ptObjToArr
+* @todo See if this should just live in `replacePathSeg`
+* @param {string} type
+* @param {SVGPathSegMovetoAbs|SVGPathSegLinetoAbs|SVGPathSegCurvetoCubicAbs|SVGPathSegCurvetoQuadraticAbs|SVGPathSegArcAbs|SVGPathSegLinetoHorizontalAbs|SVGPathSegLinetoVerticalAbs|SVGPathSegCurvetoCubicSmoothAbs|SVGPathSegCurvetoQuadraticSmoothAbs} segItem
+* @returns {ArgumentsArray}
+*/
+/* eslint-enable max-len */
+export const ptObjToArr = ptObjToArrMethod
+
+/**
+* @function module:path.getGripPt
+* @param {Segment} seg
+* @param {module:math.XYObject} altPt
+* @returns {module:math.XYObject}
+*/
+export const getGripPt = getGripPtMethod
+
+/**
+* @function module:path.getPointFromGrip
+* @param {module:math.XYObject} pt
+* @param {module:path.Path} pth
+* @returns {module:math.XYObject}
+*/
+export const getPointFromGrip = getPointFromGripMethod
+
+/**
+* Requires prior call to `setUiStrings` if `xlink:title`
+*    to be set on the grip.
+* @function module:path.addPointGrip
+* @param {Integer} index
+* @param {Integer} x
+* @param {Integer} y
+* @returns {SVGCircleElement}
+*/
+export const addPointGrip = addPointGripMethod
+
+/**
+* @function module:path.getGripContainer
+* @returns {Element}
+*/
+export const getGripContainer = getGripContainerMethod
+
+/**
+* Requires prior call to `setUiStrings` if `xlink:title`
+*    to be set on the grip.
+* @function module:path.addCtrlGrip
+* @param {string} id
+* @returns {SVGCircleElement}
+*/
+export const addCtrlGrip = addCtrlGripMethod
+
+/**
+* @function module:path.getCtrlLine
+* @param {string} id
+* @returns {SVGLineElement}
+*/
+export const getCtrlLine = getCtrlLineMethod
+
+/**
+* @function module:path.getPointGrip
+* @param {Segment} seg
+* @param {boolean} update
+* @returns {SVGCircleElement}
+*/
+export const getPointGrip = getPointGripMethod
+
+/**
+* @function module:path.getControlPoints
+* @param {Segment} seg
+* @returns {PlainObject<string, SVGLineElement|SVGCircleElement>}
+*/
+export const getControlPoints = getControlPointsMethod
+
+/**
+* This replaces the segment at the given index. Type is given as number.
+* @function module:path.replacePathSeg
+* @param {Integer} type Possible values set during {@link module:path.init}
+* @param {Integer} index
+* @param {ArgumentsArray} pts
+* @param {SVGPathElement} elem
+* @returns {void}
+*/
+export const replacePathSeg = replacePathSegMethod
+
+/**
+* @function module:path.getSegSelector
+* @param {Segment} seg
+* @param {boolean} update
+* @returns {SVGPathElement}
+*/
+export const getSegSelector = getSegSelectorMethod
+
+/**
+ * @typedef {PlainObject} Point
+ * @property {Integer} x The x value
+ * @property {Integer} y The y value
+ */
+
+/**
+* Takes three points and creates a smoother line based on them.
+* @function module:path.smoothControlPoints
+* @param {Point} ct1 - Object with x and y values (first control point)
+* @param {Point} ct2 - Object with x and y values (second control point)
+* @param {Point} pt - Object with x and y values (third point)
+* @returns {Point[]} Array of two "smoothed" point objects
+*/
+export const smoothControlPoints = (ct1, ct2, pt) => {
+  // each point must not be the origin
+  const x1 = ct1.x - pt.x
+  const y1 = ct1.y - pt.y
+  const x2 = ct2.x - pt.x
+  const y2 = ct2.y - pt.y
+
+  if ((x1 !== 0 || y1 !== 0) && (x2 !== 0 || y2 !== 0)) {
+    const
+      r1 = Math.sqrt(x1 * x1 + y1 * y1)
+    const r2 = Math.sqrt(x2 * x2 + y2 * y2)
+    const nct1 = svgCanvas.getSvgRoot().createSVGPoint()
+    const nct2 = svgCanvas.getSvgRoot().createSVGPoint()
+    let anglea = Math.atan2(y1, x1)
+    let angleb = Math.atan2(y2, x2)
+    if (anglea < 0) { anglea += 2 * Math.PI }
+    if (angleb < 0) { angleb += 2 * Math.PI }
+
+    const angleBetween = Math.abs(anglea - angleb)
+    const angleDiff = Math.abs(Math.PI - angleBetween) / 2
+
+    let newAnglea; let newAngleb
+    if (anglea - angleb > 0) {
+      newAnglea = angleBetween < Math.PI ? (anglea + angleDiff) : (anglea - angleDiff)
+      newAngleb = angleBetween < Math.PI ? (angleb - angleDiff) : (angleb + angleDiff)
+    } else {
+      newAnglea = angleBetween < Math.PI ? (anglea - angleDiff) : (anglea + angleDiff)
+      newAngleb = angleBetween < Math.PI ? (angleb + angleDiff) : (angleb - angleDiff)
+    }
+
+    // rotate the points
+    nct1.x = r1 * Math.cos(newAnglea) + pt.x
+    nct1.y = r1 * Math.sin(newAnglea) + pt.y
+    nct2.x = r2 * Math.cos(newAngleb) + pt.x
+    nct2.y = r2 * Math.sin(newAngleb) + pt.y
+
+    return [nct1, nct2]
+  }
+  return undefined
+}
+
+/**
+* @function module:path.getPath_
+* @param {SVGPathElement} elem
+* @returns {module:path.Path}
+*/
+export const getPath_ = (elem) => {
+  let p = pathData[elem.id]
+  if (!p) {
+    p = pathData[elem.id] = new Path(elem)
+  }
+  return p
+}
+
+/**
+* @function module:path.removePath_
+* @param {string} id
+* @returns {void}
+*/
+export const removePath_ = (id) => {
+  if (id in pathData) { delete pathData[id] }
+}
+
+let newcx; let newcy; let oldcx; let oldcy; let angle
+
+const getRotVals = (x, y) => {
+  let dx = x - oldcx
+  let dy = y - oldcy
+
+  // rotate the point around the old center
+  let r = Math.sqrt(dx * dx + dy * dy)
+  let theta = Math.atan2(dy, dx) + angle
+  dx = r * Math.cos(theta) + oldcx
+  dy = r * Math.sin(theta) + oldcy
+
+  // dx,dy should now hold the actual coordinates of each
+  // point after being rotated
+
+  // now we want to rotate them around the new center in the reverse direction
+  dx -= newcx
+  dy -= newcy
+
+  r = Math.sqrt(dx * dx + dy * dy)
+  theta = Math.atan2(dy, dx) - angle
+
+  return {
+    x: r * Math.cos(theta) + newcx,
+    y: r * Math.sin(theta) + newcy
+  }
+}
+
+// If the path was rotated, we must now pay the piper:
+// Every path point must be rotated into the rotated coordinate system of
+// its old center, then determine the new center, then rotate it back
+// This is because we want the path to remember its rotation
+
+/**
+* @function module:path.recalcRotatedPath
+* @todo This is still using ye olde transform methods, can probably
+* be optimized or even taken care of by `recalculateDimensions`
+* @returns {void}
+*/
+export const recalcRotatedPath = () => {
+  const currentPath = path.elem
+  angle = getRotationAngle(currentPath, true)
+  if (!angle) { return }
+  // selectedBBoxes[0] = path.oldbbox;
+  const oldbox = path.oldbbox // selectedBBoxes[0],
+  oldcx = oldbox.x + oldbox.width / 2
+  oldcy = oldbox.y + oldbox.height / 2
+  const box = getBBox(currentPath)
+  newcx = box.x + box.width / 2
+  newcy = box.y + box.height / 2
+
+  // un-rotate the new center to the proper position
+  const dx = newcx - oldcx
+  const dy = newcy - oldcy
+  const r = Math.sqrt(dx * dx + dy * dy)
+  const theta = Math.atan2(dy, dx) + angle
+
+  newcx = r * Math.cos(theta) + oldcx
+  newcy = r * Math.sin(theta) + oldcy
+
+  const list = currentPath.pathSegList
+
+  let i = list.numberOfItems
+  while (i) {
+    i -= 1
+    const seg = list.getItem(i)
+    const type = seg.pathSegType
+    if (type === 1) { continue }
+
+    const rvals = getRotVals(seg.x, seg.y)
+    const points = [rvals.x, rvals.y]
+    if (seg.x1 && seg.x2) {
+      const cVals1 = getRotVals(seg.x1, seg.y1)
+      const cVals2 = getRotVals(seg.x2, seg.y2)
+      points.splice(points.length, 0, cVals1.x, cVals1.y, cVals2.x, cVals2.y)
+    }
+    replacePathSeg(type, i, points)
+  } // loop for each point
+
+  /* box = */ getBBox(currentPath)
+  // selectedBBoxes[0].x = box.x; selectedBBoxes[0].y = box.y;
+  // selectedBBoxes[0].width = box.width; selectedBBoxes[0].height = box.height;
+
+  // now we must set the new transform to be rotated around the new center
+  const Rnc = svgCanvas.getSvgRoot().createSVGTransform()
+  const tlist = currentPath.transform.baseVal
+  Rnc.setRotate((angle * 180.0 / Math.PI), newcx, newcy)
+  tlist.replaceItem(Rnc, 0)
+}
+
+// ====================================
+// Public API starts here
+
+/**
+* @function module:path.clearData
+* @returns {void}
+*/
+export const clearData = () => {
+  pathData = {}
+}
+
+// Making public for mocking
+/**
+* @function module:path.reorientGrads
+* @param {Element} elem
+* @param {SVGMatrix} m
+* @returns {void}
+*/
+export const reorientGrads = (elem, m) => {
+  const bb = utilsGetBBox(elem)
+  for (let i = 0; i < 2; i++) {
+    const type = i === 0 ? 'fill' : 'stroke'
+    const attrVal = elem.getAttribute(type)
+    if (attrVal && attrVal.startsWith('url(')) {
+      const grad = getRefElem(attrVal)
+      if (grad.tagName === 'linearGradient') {
+        let x1 = grad.getAttribute('x1') || 0
+        let y1 = grad.getAttribute('y1') || 0
+        let x2 = grad.getAttribute('x2') || 1
+        let y2 = grad.getAttribute('y2') || 0
+
+        // Convert to USOU points
+        x1 = (bb.width * x1) + bb.x
+        y1 = (bb.height * y1) + bb.y
+        x2 = (bb.width * x2) + bb.x
+        y2 = (bb.height * y2) + bb.y
+
+        // Transform those points
+        const pt1 = transformPoint(x1, y1, m)
+        const pt2 = transformPoint(x2, y2, m)
+
+        // Convert back to BB points
+        const gCoords = {
+          x1: (pt1.x - bb.x) / bb.width,
+          y1: (pt1.y - bb.y) / bb.height,
+          x2: (pt2.x - bb.x) / bb.width,
+          y2: (pt2.y - bb.y) / bb.height
+        }
+
+        const newgrad = grad.cloneNode(true)
+        for (const [key, value] of Object.entries(gCoords)) {
+          newgrad.setAttribute(key, value)
+        }
+        newgrad.id = svgCanvas.getNextId()
+        findDefs().append(newgrad)
+        elem.setAttribute(type, 'url(#' + newgrad.id + ')')
+      }
+    }
+  }
+}
+
+/**
+* This is how we map paths to our preferred relative segment types.
+* @name module:path.pathMap
+* @type {GenericArray}
+*/
+const pathMap = [
+  0, 'z', 'M', 'm', 'L', 'l', 'C', 'c', 'Q', 'q', 'A', 'a',
+  'H', 'h', 'V', 'v', 'S', 's', 'T', 't'
+]
+
+/**
+ * Convert a path to one with only absolute or relative values.
+ * @todo move to pathActions.js
+ * @function module:path.convertPath
+ * @param {SVGPathElement} pth - the path to convert
+ * @param {boolean} toRel - true of convert to relative
+ * @returns {string}
+ */
+export const convertPath = (pth, toRel) => {
+  const { pathSegList } = pth
+  const len = pathSegList.numberOfItems
+  let curx = 0; let cury = 0
+  let d = ''
+  let lastM = null
+
+  for (let i = 0; i < len; ++i) {
+    const seg = pathSegList.getItem(i)
+    // if these properties are not in the segment, set them to zero
+    let x = seg.x || 0
+    let y = seg.y || 0
+    let x1 = seg.x1 || 0
+    let y1 = seg.y1 || 0
+    let x2 = seg.x2 || 0
+    let y2 = seg.y2 || 0
+
+    const type = seg.pathSegType
+    let letter = pathMap[type][toRel ? 'toLowerCase' : 'toUpperCase']()
+
+    switch (type) {
+      case 1: // z,Z closepath (Z/z)
+        d += 'z'
+        if (lastM && !toRel) {
+          curx = lastM[0]
+          cury = lastM[1]
+        }
+        break
+      case 12: // absolute horizontal line (H)
+        x -= curx
+      // Fallthrough
+      case 13: // relative horizontal line (h)
+        if (toRel) {
+          y = 0
+          curx += x
+          letter = 'l'
+        } else {
+          y = cury
+          x += curx
+          curx = x
+          letter = 'L'
+        }
+        // Convert to "line" for easier editing
+        d += pathDSegment(letter, [[x, y]])
+        break
+      case 14: // absolute vertical line (V)
+        y -= cury
+      // Fallthrough
+      case 15: // relative vertical line (v)
+        if (toRel) {
+          x = 0
+          cury += y
+          letter = 'l'
+        } else {
+          x = curx
+          y += cury
+          cury = y
+          letter = 'L'
+        }
+        // Convert to "line" for easier editing
+        d += pathDSegment(letter, [[x, y]])
+        break
+      case 2: // absolute move (M)
+      case 4: // absolute line (L)
+      case 18: // absolute smooth quad (T)
+      case 10: // absolute elliptical arc (A)
+        x -= curx
+        y -= cury
+      // Fallthrough
+      case 5: // relative line (l)
+      case 3: // relative move (m)
+      case 19: // relative smooth quad (t)
+        if (toRel) {
+          curx += x
+          cury += y
+        } else {
+          x += curx
+          y += cury
+          curx = x
+          cury = y
+        }
+        if (type === 2 || type === 3) { lastM = [curx, cury] }
+
+        d += pathDSegment(letter, [[x, y]])
+        break
+      case 6: // absolute cubic (C)
+        x -= curx; x1 -= curx; x2 -= curx
+        y -= cury; y1 -= cury; y2 -= cury
+      // Fallthrough
+      case 7: // relative cubic (c)
+        if (toRel) {
+          curx += x
+          cury += y
+        } else {
+          x += curx; x1 += curx; x2 += curx
+          y += cury; y1 += cury; y2 += cury
+          curx = x
+          cury = y
+        }
+        d += pathDSegment(letter, [[x1, y1], [x2, y2], [x, y]])
+        break
+      case 8: // absolute quad (Q)
+        x -= curx; x1 -= curx
+        y -= cury; y1 -= cury
+      // Fallthrough
+      case 9: // relative quad (q)
+        if (toRel) {
+          curx += x
+          cury += y
+        } else {
+          x += curx; x1 += curx
+          y += cury; y1 += cury
+          curx = x
+          cury = y
+        }
+        d += pathDSegment(letter, [[x1, y1], [x, y]])
+        break
+      // Fallthrough
+      case 11: // relative elliptical arc (a)
+        if (toRel) {
+          curx += x
+          cury += y
+        } else {
+          x += curx
+          y += cury
+          curx = x
+          cury = y
+        }
+        d += pathDSegment(letter, [[seg.r1, seg.r2]], [
+          seg.angle,
+          (seg.largeArcFlag ? 1 : 0),
+          (seg.sweepFlag ? 1 : 0)
+        ], [x, y])
+        break
+      case 16: // absolute smooth cubic (S)
+        x -= curx; x2 -= curx
+        y -= cury; y2 -= cury
+      // Fallthrough
+      case 17: // relative smooth cubic (s)
+        if (toRel) {
+          curx += x
+          cury += y
+        } else {
+          x += curx; x2 += curx
+          y += cury; y2 += cury
+          curx = x
+          cury = y
+        }
+        d += pathDSegment(letter, [[x2, y2], [x, y]])
+        break
+    } // switch on path segment type
+  } // for each segment
+  return d
+}
+
+/**
+ * TODO: refactor callers in `convertPath` to use `getPathDFromSegments` instead of this function.
+ * Legacy code refactored from `svgcanvas.pathActions.convertPath`.
+ * @param {string} letter - path segment command (letter in potentially either case from {@link module:path.pathMap}; see [SVGPathSeg#pathSegTypeAsLetter]{@link https://www.w3.org/TR/SVG/single-page.html#paths-__svg__SVGPathSeg__pathSegTypeAsLetter})
+ * @param {GenericArray<GenericArray<Integer>>} points - x,y points
+ * @param {GenericArray<GenericArray<Integer>>} [morePoints] - x,y points
+ * @param {Integer[]} [lastPoint] - x,y point
+ * @returns {string}
+ */
+const pathDSegment = (letter, points, morePoints, lastPoint) => {
+  points.forEach((pnt, i) => {
+    points[i] = shortFloat(pnt)
+  })
+  let segment = letter + points.join(' ')
+  if (morePoints) {
+    segment += ' ' + morePoints.join(' ')
+  }
+  if (lastPoint) {
+    segment += ' ' + shortFloat(lastPoint)
+  }
+  return segment
+}
+
+/**
+* Group: Path edit functions.
+* Functions relating to editing path elements.
+*/
+export const pathActions = pathActionsMethod
+// end pathActions

packages/svgcanvas/recalculate.js

@@ -0,0 +1,794 @@
+/**
+ * Recalculate.
+ * @module recalculate
+ * @license MIT
+ */
+
+import { NS } from './namespaces.js'
+import { convertToNum } from './units.js'
+import { getRotationAngle, getHref, getBBox, getRefElem } from './utilities.js'
+import { BatchCommand, ChangeElementCommand } from './history.js'
+import { remapElement } from './coords.js'
+import {
+  isIdentity, matrixMultiply, transformPoint, transformListToTransform,
+  hasMatrixTransform
+} from './math.js'
+import {
+  mergeDeep
+} from '../../src/common/util.js'
+
+let svgCanvas
+
+/**
+* @interface module:recalculate.EditorContext
+*/
+/**
+ * @function module:recalculate.EditorContext#getSvgRoot
+ * @returns {SVGSVGElement} The root DOM element
+ */
+/**
+ * @function module:recalculate.EditorContext#getStartTransform
+ * @returns {string}
+*/
+/**
+ * @function module:recalculate.EditorContext#setStartTransform
+ * @param {string} transform
+ * @returns {void}
+ */
+
+/**
+* @function module:recalculate.init
+* @param {module:recalculate.EditorContext} editorContext
+* @returns {void}
+*/
+export const init = (canvas) => {
+  svgCanvas = canvas
+}
+
+/**
+* Updates a `<clipPath>`s values based on the given translation of an element.
+* @function module:recalculate.updateClipPath
+* @param {string} attr - The clip-path attribute value with the clipPath's ID
+* @param {Float} tx - The translation's x value
+* @param {Float} ty - The translation's y value
+* @returns {void}
+*/
+export const updateClipPath = (attr, tx, ty) => {
+  const path = getRefElem(attr).firstChild
+  const cpXform = path.transform.baseVal
+  const newxlate = svgCanvas.getSvgRoot().createSVGTransform()
+  newxlate.setTranslate(tx, ty)
+
+  cpXform.appendItem(newxlate)
+
+  // Update clipPath's dimensions
+  recalculateDimensions(path)
+}
+
+/**
+* Decides the course of action based on the element's transform list.
+* @function module:recalculate.recalculateDimensions
+* @param {Element} selected - The DOM element to recalculate
+* @returns {Command} Undo command object with the resulting change
+*/
+export const recalculateDimensions = (selected) => {
+  if (!selected) return null
+  const svgroot = svgCanvas.getSvgRoot()
+  const dataStorage = svgCanvas.getDataStorage()
+  const tlist = selected.transform?.baseVal
+  // remove any unnecessary transforms
+  if (tlist?.numberOfItems > 0) {
+    let k = tlist.numberOfItems
+    const noi = k
+    while (k--) {
+      const xform = tlist.getItem(k)
+      if (xform.type === 0) {
+        tlist.removeItem(k)
+        // remove identity matrices
+      } else if (xform.type === 1) {
+        if (isIdentity(xform.matrix)) {
+          if (noi === 1) {
+            // Overcome Chrome bug (though only when noi is 1) with
+            //    `removeItem` preventing `removeAttribute` from
+            //    subsequently working
+            // See https://bugs.chromium.org/p/chromium/issues/detail?id=843901
+            selected.removeAttribute('transform')
+            return null
+          }
+          tlist.removeItem(k)
+        }
+        // remove zero-degree rotations
+      } else if (xform.type === 4 && xform.angle === 0) {
+        tlist.removeItem(k)
+      }
+    }
+    // End here if all it has is a rotation
+    if (tlist.numberOfItems === 1 &&
+      getRotationAngle(selected)) { return null }
+  }
+
+  // if this element had no transforms, we are done
+  if (!tlist || tlist.numberOfItems === 0) {
+    // Chrome apparently had a bug that requires clearing the attribute first.
+    selected.setAttribute('transform', '')
+    // However, this still next line currently doesn't work at all in Chrome
+    selected.removeAttribute('transform')
+    // selected.transform.baseVal.clear(); // Didn't help for Chrome bug
+    return null
+  }
+
+  // TODO: Make this work for more than 2
+  if (tlist) {
+    let mxs = []
+    let k = tlist.numberOfItems
+    while (k--) {
+      const xform = tlist.getItem(k)
+      if (xform.type === 1) {
+        mxs.push([xform.matrix, k])
+      } else if (mxs.length) {
+        mxs = []
+      }
+    }
+    if (mxs.length === 2) {
+      const mNew = svgroot.createSVGTransformFromMatrix(matrixMultiply(mxs[1][0], mxs[0][0]))
+      tlist.removeItem(mxs[0][1])
+      tlist.removeItem(mxs[1][1])
+      tlist.insertItemBefore(mNew, mxs[1][1])
+    }
+
+    // combine matrix + translate
+    k = tlist.numberOfItems
+    if (k >= 2 && tlist.getItem(k - 2).type === 1 && tlist.getItem(k - 1).type === 2) {
+      const mt = svgroot.createSVGTransform()
+
+      const m = matrixMultiply(
+        tlist.getItem(k - 2).matrix,
+        tlist.getItem(k - 1).matrix
+      )
+      mt.setMatrix(m)
+      tlist.removeItem(k - 2)
+      tlist.removeItem(k - 2)
+      tlist.appendItem(mt)
+    }
+  }
+
+  // If it still has a single [M] or [R][M], return null too (prevents BatchCommand from being returned).
+  switch (selected.tagName) {
+    // Ignore these elements, as they can absorb the [M]
+    case 'line':
+    case 'polyline':
+    case 'polygon':
+    case 'path':
+      break
+    default:
+      if ((tlist.numberOfItems === 1 && tlist.getItem(0).type === 1) ||
+        (tlist.numberOfItems === 2 && tlist.getItem(0).type === 1 && tlist.getItem(0).type === 4)) {
+        return null
+      }
+  }
+  // Grouped SVG element
+  const gsvg = (dataStorage.has(selected, 'gsvg')) ? dataStorage.get(selected, 'gsvg') : undefined
+  // we know we have some transforms, so set up return variable
+  const batchCmd = new BatchCommand('Transform')
+
+  // store initial values that will be affected by reducing the transform list
+  let changes = {}
+  let initial = null
+  let attrs = []
+  switch (selected.tagName) {
+    case 'line':
+      attrs = ['x1', 'y1', 'x2', 'y2']
+      break
+    case 'circle':
+      attrs = ['cx', 'cy', 'r']
+      break
+    case 'ellipse':
+      attrs = ['cx', 'cy', 'rx', 'ry']
+      break
+    case 'foreignObject':
+    case 'rect':
+    case 'image':
+      attrs = ['width', 'height', 'x', 'y']
+      break
+    case 'use':
+    case 'text':
+    case 'tspan':
+      attrs = ['x', 'y']
+      break
+    case 'polygon':
+    case 'polyline': {
+      initial = {}
+      initial.points = selected.getAttribute('points')
+      const list = selected.points
+      const len = list.numberOfItems
+      changes.points = new Array(len)
+      for (let i = 0; i < len; ++i) {
+        const pt = list.getItem(i)
+        changes.points[i] = { x: pt.x, y: pt.y }
+      }
+      break
+    } case 'path':
+      initial = {}
+      initial.d = selected.getAttribute('d')
+      changes.d = selected.getAttribute('d')
+      break
+  } // switch on element type to get initial values
+
+  if (attrs.length) {
+    attrs.forEach((attr) => {
+      changes[attr] = convertToNum(attr, selected.getAttribute(attr))
+    })
+  } else if (gsvg) {
+    // GSVG exception
+    changes = {
+      x: Number(gsvg.getAttribute('x')) || 0,
+      y: Number(gsvg.getAttribute('y')) || 0
+    }
+  }
+
+  // if we haven't created an initial array in polygon/polyline/path, then
+  // make a copy of initial values and include the transform
+  if (!initial) {
+    initial = mergeDeep({}, changes)
+    for (const [attr, val] of Object.entries(initial)) {
+      initial[attr] = convertToNum(attr, val)
+    }
+  }
+  // save the start transform value too
+  initial.transform = svgCanvas.getStartTransform() || ''
+
+  let oldcenter; let newcenter
+
+  // if it's a regular group, we have special processing to flatten transforms
+  if ((selected.tagName === 'g' && !gsvg) || selected.tagName === 'a') {
+    const box = getBBox(selected)
+
+    oldcenter = { x: box.x + box.width / 2, y: box.y + box.height / 2 }
+    newcenter = transformPoint(
+      box.x + box.width / 2,
+      box.y + box.height / 2,
+      transformListToTransform(tlist).matrix
+    )
+    // let m = svgroot.createSVGMatrix();
+
+    // temporarily strip off the rotate and save the old center
+    const gangle = getRotationAngle(selected)
+    if (gangle) {
+      const a = gangle * Math.PI / 180
+      const s = Math.abs(a) > (1.0e-10) ? Math.sin(a) / (1 - Math.cos(a)) : 2 / a
+      for (let i = 0; i < tlist.numberOfItems; ++i) {
+        const xform = tlist.getItem(i)
+        if (xform.type === 4) {
+          // extract old center through mystical arts
+          const rm = xform.matrix
+          oldcenter.y = (s * rm.e + rm.f) / 2
+          oldcenter.x = (rm.e - s * rm.f) / 2
+          tlist.removeItem(i)
+          break
+        }
+      }
+    }
+
+    const N = tlist.numberOfItems
+    let tx = 0; let ty = 0; let operation = 0
+
+    let firstM
+    if (N) {
+      firstM = tlist.getItem(0).matrix
+    }
+
+    let oldStartTransform
+    // first, if it was a scale then the second-last transform will be it
+    if (N >= 3 && tlist.getItem(N - 2).type === 3 &&
+      tlist.getItem(N - 3).type === 2 && tlist.getItem(N - 1).type === 2) {
+      operation = 3 // scale
+
+      // if the children are unrotated, pass the scale down directly
+      // otherwise pass the equivalent matrix() down directly
+      const tm = tlist.getItem(N - 3).matrix
+      const sm = tlist.getItem(N - 2).matrix
+      const tmn = tlist.getItem(N - 1).matrix
+
+      const children = selected.childNodes
+      let c = children.length
+      while (c--) {
+        const child = children.item(c)
+        tx = 0
+        ty = 0
+        if (child.nodeType === 1) {
+          const childTlist = child.transform.baseVal
+
+          // some children might not have a transform (<metadata>, <defs>, etc)
+          if (!childTlist) { continue }
+
+          const m = transformListToTransform(childTlist).matrix
+
+          // Convert a matrix to a scale if applicable
+          // if (hasMatrixTransform(childTlist) && childTlist.numberOfItems == 1) {
+          //   if (m.b==0 && m.c==0 && m.e==0 && m.f==0) {
+          //     childTlist.removeItem(0);
+          //     const translateOrigin = svgroot.createSVGTransform(),
+          //       scale = svgroot.createSVGTransform(),
+          //       translateBack = svgroot.createSVGTransform();
+          //     translateOrigin.setTranslate(0, 0);
+          //     scale.setScale(m.a, m.d);
+          //     translateBack.setTranslate(0, 0);
+          //     childTlist.appendItem(translateBack);
+          //     childTlist.appendItem(scale);
+          //     childTlist.appendItem(translateOrigin);
+          //   }
+          // }
+
+          const angle = getRotationAngle(child)
+          oldStartTransform = svgCanvas.getStartTransform()
+          // const childxforms = [];
+          svgCanvas.setStartTransform(child.getAttribute('transform'))
+          if (angle || hasMatrixTransform(childTlist)) {
+            const e2t = svgroot.createSVGTransform()
+            e2t.setMatrix(matrixMultiply(tm, sm, tmn, m))
+            childTlist.clear()
+            childTlist.appendItem(e2t)
+            // childxforms.push(e2t);
+            // if not rotated or skewed, push the [T][S][-T] down to the child
+          } else {
+            // update the transform list with translate,scale,translate
+
+            // slide the [T][S][-T] from the front to the back
+            // [T][S][-T][M] = [M][T2][S2][-T2]
+
+            // (only bringing [-T] to the right of [M])
+            // [T][S][-T][M] = [T][S][M][-T2]
+            // [-T2] = [M_inv][-T][M]
+            const t2n = matrixMultiply(m.inverse(), tmn, m)
+            // [T2] is always negative translation of [-T2]
+            const t2 = svgroot.createSVGMatrix()
+            t2.e = -t2n.e
+            t2.f = -t2n.f
+
+            // [T][S][-T][M] = [M][T2][S2][-T2]
+            // [S2] = [T2_inv][M_inv][T][S][-T][M][-T2_inv]
+            const s2 = matrixMultiply(t2.inverse(), m.inverse(), tm, sm, tmn, m, t2n.inverse())
+
+            const translateOrigin = svgroot.createSVGTransform()
+            const scale = svgroot.createSVGTransform()
+            const translateBack = svgroot.createSVGTransform()
+            translateOrigin.setTranslate(t2n.e, t2n.f)
+            scale.setScale(s2.a, s2.d)
+            translateBack.setTranslate(t2.e, t2.f)
+            childTlist.appendItem(translateBack)
+            childTlist.appendItem(scale)
+            childTlist.appendItem(translateOrigin)
+          } // not rotated
+          batchCmd.addSubCommand(recalculateDimensions(child))
+          svgCanvas.setStartTransform(oldStartTransform)
+        } // element
+      } // for each child
+      // Remove these transforms from group
+      tlist.removeItem(N - 1)
+      tlist.removeItem(N - 2)
+      tlist.removeItem(N - 3)
+    } else if (N >= 3 && tlist.getItem(N - 1).type === 1) {
+      operation = 3 // scale
+      const m = transformListToTransform(tlist).matrix
+      const e2t = svgroot.createSVGTransform()
+      e2t.setMatrix(m)
+      tlist.clear()
+      tlist.appendItem(e2t)
+      // next, check if the first transform was a translate
+      // if we had [ T1 ] [ M ] we want to transform this into [ M ] [ T2 ]
+      // therefore [ T2 ] = [ M_inv ] [ T1 ] [ M ]
+    } else if ((N === 1 || (N > 1 && tlist.getItem(1).type !== 3)) &&
+      tlist.getItem(0).type === 2) {
+      operation = 2 // translate
+      const T_M = transformListToTransform(tlist).matrix
+      tlist.removeItem(0)
+      const mInv = transformListToTransform(tlist).matrix.inverse()
+      const M2 = matrixMultiply(mInv, T_M)
+
+      tx = M2.e
+      ty = M2.f
+
+      if (tx !== 0 || ty !== 0) {
+        // we pass the translates down to the individual children
+        const children = selected.childNodes
+        let c = children.length
+
+        const clipPathsDone = []
+        while (c--) {
+          const child = children.item(c)
+          if (child.nodeType === 1) {
+            // Check if child has clip-path
+            if (child.getAttribute('clip-path')) {
+              // tx, ty
+              const attr = child.getAttribute('clip-path')
+              if (!clipPathsDone.includes(attr)) {
+                updateClipPath(attr, tx, ty)
+                clipPathsDone.push(attr)
+              }
+            }
+
+            oldStartTransform = svgCanvas.getStartTransform()
+            svgCanvas.setStartTransform(child.getAttribute('transform'))
+
+            const childTlist = child.transform?.baseVal
+            // some children might not have a transform (<metadata>, <defs>, etc)
+            if (childTlist) {
+              const newxlate = svgroot.createSVGTransform()
+              newxlate.setTranslate(tx, ty)
+              if (childTlist.numberOfItems) {
+                childTlist.insertItemBefore(newxlate, 0)
+              } else {
+                childTlist.appendItem(newxlate)
+              }
+              batchCmd.addSubCommand(recalculateDimensions(child))
+              // If any <use> have this group as a parent and are
+              // referencing this child, then impose a reverse translate on it
+              // so that when it won't get double-translated
+              const uses = selected.getElementsByTagNameNS(NS.SVG, 'use')
+              const href = '#' + child.id
+              let u = uses.length
+              while (u--) {
+                const useElem = uses.item(u)
+                if (href === getHref(useElem)) {
+                  const usexlate = svgroot.createSVGTransform()
+                  usexlate.setTranslate(-tx, -ty)
+                  useElem.transform.baseVal.insertItemBefore(usexlate, 0)
+                  batchCmd.addSubCommand(recalculateDimensions(useElem))
+                }
+              }
+              svgCanvas.setStartTransform(oldStartTransform)
+            }
+          }
+        }
+        svgCanvas.setStartTransform(oldStartTransform)
+      }
+      // else, a matrix imposition from a parent group
+      // keep pushing it down to the children
+    } else if (N === 1 && tlist.getItem(0).type === 1 && !gangle) {
+      operation = 1
+      const m = tlist.getItem(0).matrix
+      const children = selected.childNodes
+      let c = children.length
+      while (c--) {
+        const child = children.item(c)
+        if (child.nodeType === 1) {
+          oldStartTransform = svgCanvas.getStartTransform()
+          svgCanvas.setStartTransform(child.getAttribute('transform'))
+          const childTlist = child.transform?.baseVal
+
+          if (!childTlist) { continue }
+
+          const em = matrixMultiply(m, transformListToTransform(childTlist).matrix)
+          const e2m = svgroot.createSVGTransform()
+          e2m.setMatrix(em)
+          childTlist.clear()
+          childTlist.appendItem(e2m, 0)
+
+          batchCmd.addSubCommand(recalculateDimensions(child))
+          svgCanvas.setStartTransform(oldStartTransform)
+
+          // Convert stroke
+          // TODO: Find out if this should actually happen somewhere else
+          const sw = child.getAttribute('stroke-width')
+          if (child.getAttribute('stroke') !== 'none' && !isNaN(sw)) {
+            const avg = (Math.abs(em.a) + Math.abs(em.d)) / 2
+            child.setAttribute('stroke-width', sw * avg)
+          }
+        }
+      }
+      tlist.clear()
+      // else it was just a rotate
+    } else {
+      if (gangle) {
+        const newRot = svgroot.createSVGTransform()
+        newRot.setRotate(gangle, newcenter.x, newcenter.y)
+        if (tlist.numberOfItems) {
+          tlist.insertItemBefore(newRot, 0)
+        } else {
+          tlist.appendItem(newRot)
+        }
+      }
+      if (tlist.numberOfItems === 0) {
+        selected.removeAttribute('transform')
+      }
+      return null
+    }
+
+    // if it was a translate, put back the rotate at the new center
+    if (operation === 2) {
+      if (gangle) {
+        newcenter = {
+          x: oldcenter.x + firstM.e,
+          y: oldcenter.y + firstM.f
+        }
+
+        const newRot = svgroot.createSVGTransform()
+        newRot.setRotate(gangle, newcenter.x, newcenter.y)
+        if (tlist.numberOfItems) {
+          tlist.insertItemBefore(newRot, 0)
+        } else {
+          tlist.appendItem(newRot)
+        }
+      }
+      // if it was a resize
+    } else if (operation === 3) {
+      const m = transformListToTransform(tlist).matrix
+      const roldt = svgroot.createSVGTransform()
+      roldt.setRotate(gangle, oldcenter.x, oldcenter.y)
+      const rold = roldt.matrix
+      const rnew = svgroot.createSVGTransform()
+      rnew.setRotate(gangle, newcenter.x, newcenter.y)
+      const rnewInv = rnew.matrix.inverse()
+      const mInv = m.inverse()
+      const extrat = matrixMultiply(mInv, rnewInv, rold, m)
+
+      tx = extrat.e
+      ty = extrat.f
+
+      if (tx !== 0 || ty !== 0) {
+        // now push this transform down to the children
+        // we pass the translates down to the individual children
+        const children = selected.childNodes
+        let c = children.length
+        while (c--) {
+          const child = children.item(c)
+          if (child.nodeType === 1) {
+            oldStartTransform = svgCanvas.getStartTransform()
+            svgCanvas.setStartTransform(child.getAttribute('transform'))
+            const childTlist = child.transform?.baseVal
+            const newxlate = svgroot.createSVGTransform()
+            newxlate.setTranslate(tx, ty)
+            if (childTlist.numberOfItems) {
+              childTlist.insertItemBefore(newxlate, 0)
+            } else {
+              childTlist.appendItem(newxlate)
+            }
+
+            batchCmd.addSubCommand(recalculateDimensions(child))
+            svgCanvas.setStartTransform(oldStartTransform)
+          }
+        }
+      }
+
+      if (gangle) {
+        if (tlist.numberOfItems) {
+          tlist.insertItemBefore(rnew, 0)
+        } else {
+          tlist.appendItem(rnew)
+        }
+      }
+    }
+    // else, it's a non-group
+  } else {
+    // TODO: box might be null for some elements (<metadata> etc), need to handle this
+    const box = getBBox(selected)
+
+    // Paths (and possbly other shapes) will have no BBox while still in <defs>,
+    // but we still may need to recalculate them (see issue 595).
+    // TODO: Figure out how to get BBox from these elements in case they
+    // have a rotation transform
+
+    if (!box && selected.tagName !== 'path') return null
+
+    let m // = svgroot.createSVGMatrix();
+    // temporarily strip off the rotate and save the old center
+    const angle = getRotationAngle(selected)
+    if (angle) {
+      oldcenter = { x: box.x + box.width / 2, y: box.y + box.height / 2 }
+      newcenter = transformPoint(
+        box.x + box.width / 2,
+        box.y + box.height / 2,
+        transformListToTransform(tlist).matrix
+      )
+
+      const a = angle * Math.PI / 180
+      const s = (Math.abs(a) > (1.0e-10))
+        ? Math.sin(a) / (1 - Math.cos(a))
+        // TODO: This blows up if the angle is exactly 0!
+        : 2 / a
+
+      for (let i = 0; i < tlist.numberOfItems; ++i) {
+        const xform = tlist.getItem(i)
+        if (xform.type === 4) {
+          // extract old center through mystical arts
+          const rm = xform.matrix
+          oldcenter.y = (s * rm.e + rm.f) / 2
+          oldcenter.x = (rm.e - s * rm.f) / 2
+          tlist.removeItem(i)
+          break
+        }
+      }
+    }
+
+    // 2 = translate, 3 = scale, 4 = rotate, 1 = matrix imposition
+    let operation = 0
+    const N = tlist.numberOfItems
+
+    // Check if it has a gradient with userSpaceOnUse, in which case
+    // adjust it by recalculating the matrix transform.
+
+    const fill = selected.getAttribute('fill')
+    if (fill?.startsWith('url(')) {
+      const paint = getRefElem(fill)
+      if (paint) {
+        let type = 'pattern'
+        if (paint?.tagName !== type) type = 'gradient'
+        const attrVal = paint.getAttribute(type + 'Units')
+        if (attrVal === 'userSpaceOnUse') {
+          // Update the userSpaceOnUse element
+          m = transformListToTransform(tlist).matrix
+          const gtlist = paint.transform.baseVal
+          const gmatrix = transformListToTransform(gtlist).matrix
+          m = matrixMultiply(m, gmatrix)
+          const mStr = 'matrix(' + [m.a, m.b, m.c, m.d, m.e, m.f].join(',') + ')'
+          paint.setAttribute(type + 'Transform', mStr)
+        }
+      }
+    }
+
+    // first, if it was a scale of a non-skewed element, then the second-last
+    // transform will be the [S]
+    // if we had [M][T][S][T] we want to extract the matrix equivalent of
+    // [T][S][T] and push it down to the element
+    if (N >= 3 && tlist.getItem(N - 2).type === 3 &&
+      tlist.getItem(N - 3).type === 2 && tlist.getItem(N - 1).type === 2) {
+      // Removed this so a <use> with a given [T][S][T] would convert to a matrix.
+      // Is that bad?
+      //  && selected.nodeName != 'use'
+      operation = 3 // scale
+      m = transformListToTransform(tlist, N - 3, N - 1).matrix
+      tlist.removeItem(N - 1)
+      tlist.removeItem(N - 2)
+      tlist.removeItem(N - 3)
+      // if we had [T][S][-T][M], then this was a skewed element being resized
+      // Thus, we simply combine it all into one matrix
+    } else if (N === 4 && tlist.getItem(N - 1).type === 1) {
+      operation = 3 // scale
+      m = transformListToTransform(tlist).matrix
+      const e2t = svgroot.createSVGTransform()
+      e2t.setMatrix(m)
+      tlist.clear()
+      tlist.appendItem(e2t)
+      // reset the matrix so that the element is not re-mapped
+      m = svgroot.createSVGMatrix()
+      // if we had [R][T][S][-T][M], then this was a rotated matrix-element
+      // if we had [T1][M] we want to transform this into [M][T2]
+      // therefore [ T2 ] = [ M_inv ] [ T1 ] [ M ] and we can push [T2]
+      // down to the element
+    } else if ((N === 1 || (N > 1 && tlist.getItem(1).type !== 3)) &&
+      tlist.getItem(0).type === 2) {
+      operation = 2 // translate
+      const oldxlate = tlist.getItem(0).matrix
+      const meq = transformListToTransform(tlist, 1).matrix
+      const meqInv = meq.inverse()
+      m = matrixMultiply(meqInv, oldxlate, meq)
+      tlist.removeItem(0)
+      // else if this child now has a matrix imposition (from a parent group)
+      // we might be able to simplify
+    } else if (N === 1 && tlist.getItem(0).type === 1 && !angle) {
+      // Remap all point-based elements
+      m = transformListToTransform(tlist).matrix
+      switch (selected.tagName) {
+        case 'line':
+          changes = {
+            x1: selected.getAttribute('x1'),
+            y1: selected.getAttribute('y1'),
+            x2: selected.getAttribute('x2'),
+            y2: selected.getAttribute('y2')
+          }
+        // Fallthrough
+        case 'polyline':
+        case 'polygon':
+          changes.points = selected.getAttribute('points')
+          if (changes.points) {
+            const list = selected.points
+            const len = list.numberOfItems
+            changes.points = new Array(len)
+            for (let i = 0; i < len; ++i) {
+              const pt = list.getItem(i)
+              changes.points[i] = { x: pt.x, y: pt.y }
+            }
+          }
+        // Fallthrough
+        case 'path':
+          changes.d = selected.getAttribute('d')
+          operation = 1
+          tlist.clear()
+          break
+        default:
+          break
+      }
+      // if it was a rotation, put the rotate back and return without a command
+      // (this function has zero work to do for a rotate())
+    } else {
+      // operation = 4; // rotation
+      if (angle) {
+        const newRot = svgroot.createSVGTransform()
+        newRot.setRotate(angle, newcenter.x, newcenter.y)
+
+        if (tlist.numberOfItems) {
+          tlist.insertItemBefore(newRot, 0)
+        } else {
+          tlist.appendItem(newRot)
+        }
+      }
+      if (tlist.numberOfItems === 0) {
+        selected.removeAttribute('transform')
+      }
+      return null
+    }
+
+    // if it was a translate or resize, we need to remap the element and absorb the xform
+    if (operation === 1 || operation === 2 || operation === 3) {
+      remapElement(selected, changes, m)
+    } // if we are remapping
+
+    // if it was a translate, put back the rotate at the new center
+    if (operation === 2) {
+      if (angle) {
+        if (!hasMatrixTransform(tlist)) {
+          newcenter = {
+            x: oldcenter.x + m.e,
+            y: oldcenter.y + m.f
+          }
+        }
+        const newRot = svgroot.createSVGTransform()
+        newRot.setRotate(angle, newcenter.x, newcenter.y)
+        if (tlist.numberOfItems) {
+          tlist.insertItemBefore(newRot, 0)
+        } else {
+          tlist.appendItem(newRot)
+        }
+      }
+      // We have special processing for tspans:  Tspans are not transformable
+      // but they can have x,y coordinates (sigh).  Thus, if this was a translate,
+      // on a text element, also translate any tspan children.
+      if (selected.tagName === 'text') {
+        const children = selected.childNodes
+        let c = children.length
+        while (c--) {
+          const child = children.item(c)
+          if (child.tagName === 'tspan') {
+            const tspanChanges = {
+              x: Number(child.getAttribute('x')) || 0,
+              y: Number(child.getAttribute('y')) || 0
+            }
+            remapElement(child, tspanChanges, m)
+          }
+        }
+      }
+      // [Rold][M][T][S][-T] became [Rold][M]
+      // we want it to be [Rnew][M][Tr] where Tr is the
+      // translation required to re-center it
+      // Therefore, [Tr] = [M_inv][Rnew_inv][Rold][M]
+    } else if (operation === 3 && angle) {
+      const { matrix } = transformListToTransform(tlist)
+      const roldt = svgroot.createSVGTransform()
+      roldt.setRotate(angle, oldcenter.x, oldcenter.y)
+      const rold = roldt.matrix
+      const rnew = svgroot.createSVGTransform()
+      rnew.setRotate(angle, newcenter.x, newcenter.y)
+      const rnewInv = rnew.matrix.inverse()
+      const mInv = matrix.inverse()
+      const extrat = matrixMultiply(mInv, rnewInv, rold, matrix)
+
+      remapElement(selected, changes, extrat)
+      if (angle) {
+        if (tlist.numberOfItems) {
+          tlist.insertItemBefore(rnew, 0)
+        } else {
+          tlist.appendItem(rnew)
+        }
+      }
+    }
+  } // a non-group
+
+  // if the transform list has been emptied, remove it
+  if (tlist.numberOfItems === 0) {
+    selected.removeAttribute('transform')
+  }
+
+  batchCmd.addSubCommand(new ChangeElementCommand(selected, initial))
+
+  return batchCmd
+}

packages/svgcanvas/rollup.config.js

@@ -0,0 +1,38 @@
+/* eslint-env node */
+// This rollup script is run by the command:
+// 'npm run build'
+
+import rimraf from 'rimraf'
+import babel from '@rollup/plugin-babel'
+import { nodeResolve } from '@rollup/plugin-node-resolve'
+import commonjs from '@rollup/plugin-commonjs'
+import { terser } from 'rollup-plugin-terser'
+// import progress from 'rollup-plugin-progress';
+import filesize from 'rollup-plugin-filesize'
+
+// remove existing distribution
+rimraf('./dist', () => console.info('recreating dist'))
+
+// config for svgedit core module
+const config = [{
+  input: ['./svgcanvas.js'],
+  output: [
+    {
+      format: 'es',
+      inlineDynamicImports: true,
+      sourcemap: true,
+      file: 'dist/svgcanvas.js'
+    }
+  ],
+  plugins: [
+    nodeResolve({
+      browser: true,
+      preferBuiltins: false
+    }),
+    commonjs(),
+    babel({ babelHelpers: 'bundled', exclude: [/\/core-js\//] }), // exclude core-js to avoid circular dependencies.
+    terser({ keep_fnames: true }), // keep_fnames is needed to avoid an error when calling extensions.
+    filesize()
+  ]
+}]
+export default config

packages/svgcanvas/sanitize.js

@@ -0,0 +1,252 @@
+/**
+ * Tools for SVG sanitization.
+ * @module sanitize
+ * @license MIT
+ *
+ * @copyright 2010 Alexis Deveria, 2010 Jeff Schiller
+ */
+
+import { getReverseNS, NS } from './namespaces.js'
+import { getHref, setHref, getUrlFromAttr } from './utilities.js'
+
+const REVERSE_NS = getReverseNS()
+
+// Todo: Split out into core attributes, presentation attributes, etc. so consistent
+/**
+ * This defines which elements and attributes that we support (or at least
+ * don't remove).
+ * @type {PlainObject}
+ */
+/* eslint-disable max-len */
+const svgGenericWhiteList = ['class', 'id', 'display', 'transform', 'style']
+const svgWhiteList_ = {
+  // SVG Elements
+  a: ['clip-path', 'clip-rule', 'fill', 'fill-opacity', 'fill-rule', 'filter', 'mask', 'opacity', 'stroke', 'stroke-dasharray', 'stroke-dashoffset', 'stroke-linecap', 'stroke-linejoin', 'stroke-miterlimit', 'stroke-opacity', 'stroke-width', 'systemLanguage', 'xlink:href', 'xlink:title'],
+  circle: ['clip-path', 'clip-rule', 'cx', 'cy', 'enable-background', 'fill', 'fill-opacity', 'fill-rule', 'filter', 'mask', 'opacity', 'r', 'requiredFeatures', 'stroke', 'stroke-dasharray', 'stroke-dashoffset', 'stroke-linecap', 'stroke-linejoin', 'stroke-miterlimit', 'stroke-opacity', 'stroke-width', 'systemLanguage'],
+  clipPath: ['clipPathUnits'],
+  defs: [],
+  desc: [],
+  ellipse: ['clip-path', 'clip-rule', 'cx', 'cy', 'fill', 'fill-opacity', 'fill-rule', 'filter', 'mask', 'opacity', 'requiredFeatures', 'rx', 'ry', 'stroke', 'stroke-dasharray', 'stroke-dashoffset', 'stroke-linecap', 'stroke-linejoin', 'stroke-miterlimit', 'stroke-opacity', 'stroke-width', 'systemLanguage'],
+  feBlend: ['in', 'in2'],
+  feColorMatrix: ['in', 'type', 'value', 'result', 'values'],
+  feComposite: ['in', 'operator', 'result', 'in2'],
+  feFlood: ['flood-color', 'in', 'result', 'flood-opacity'],
+  feGaussianBlur: ['color-interpolation-filters', 'in', 'requiredFeatures', 'stdDeviation', 'result'],
+  feMerge: [],
+  feMergeNode: ['in'],
+  feMorphology: ['in', 'operator', 'radius'],
+  feOffset: ['dx', 'in', 'dy', 'result'],
+  filter: ['color-interpolation-filters', 'filterRes', 'filterUnits', 'height', 'primitiveUnits', 'requiredFeatures', 'width', 'x', 'xlink:href', 'y'],
+  foreignObject: ['font-size', 'height', 'opacity', 'requiredFeatures', 'width', 'x', 'y'],
+  g: ['clip-path', 'clip-rule', 'fill', 'fill-opacity', 'fill-rule', 'filter', 'mask', 'opacity', 'requiredFeatures', 'stroke', 'stroke-dasharray', 'stroke-dashoffset', 'stroke-linecap', 'stroke-linejoin', 'stroke-miterlimit', 'stroke-opacity', 'stroke-width', 'systemLanguage', 'font-family', 'font-size', 'font-style', 'font-weight', 'text-anchor'],
+  image: ['clip-path', 'clip-rule', 'filter', 'height', 'mask', 'opacity', 'requiredFeatures', 'systemLanguage', 'width', 'x', 'xlink:href', 'xlink:title', 'y'],
+  line: ['clip-path', 'clip-rule', 'fill', 'fill-opacity', 'fill-rule', 'filter', 'marker-end', 'marker-mid', 'marker-start', 'mask', 'opacity', 'requiredFeatures', 'stroke', 'stroke-dasharray', 'stroke-dashoffset', 'stroke-linecap', 'stroke-linejoin', 'stroke-miterlimit', 'stroke-opacity', 'stroke-width', 'systemLanguage', 'x1', 'x2', 'y1', 'y2'],
+  linearGradient: ['gradientTransform', 'gradientUnits', 'requiredFeatures', 'spreadMethod', 'systemLanguage', 'x1', 'x2', 'xlink:href', 'y1', 'y2'],
+  marker: ['markerHeight', 'markerUnits', 'markerWidth', 'orient', 'preserveAspectRatio', 'refX', 'refY', 'se_type', 'systemLanguage', 'viewBox'],
+  mask: ['height', 'maskContentUnits', 'maskUnits', 'width', 'x', 'y'],
+  metadata: [],
+  path: ['clip-path', 'clip-rule', 'd', 'enable-background', 'fill', 'fill-opacity', 'fill-rule', 'filter', 'marker-end', 'marker-mid', 'marker-start', 'mask', 'opacity', 'requiredFeatures', 'stroke', 'stroke-dasharray', 'stroke-dashoffset', 'stroke-linecap', 'stroke-linejoin', 'stroke-miterlimit', 'stroke-opacity', 'stroke-width', 'systemLanguage'],
+  pattern: ['height', 'patternContentUnits', 'patternTransform', 'patternUnits', 'requiredFeatures', 'systemLanguage', 'viewBox', 'width', 'x', 'xlink:href', 'y'],
+  polygon: ['clip-path', 'clip-rule', 'fill', 'fill-opacity', 'fill-rule', 'filter', 'marker-end', 'marker-mid', 'marker-start', 'mask', 'opacity', 'points', 'requiredFeatures', 'stroke', 'stroke-dasharray', 'stroke-dashoffset', 'stroke-linecap', 'stroke-linejoin', 'stroke-miterlimit', 'stroke-opacity', 'stroke-width', 'systemLanguage', 'sides', 'shape', 'edge', 'point', 'starRadiusMultiplier', 'r', 'radialshift', 'r2', 'orient', 'cx', 'cy'],
+  polyline: ['clip-path', 'clip-rule', 'fill', 'fill-opacity', 'fill-rule', 'filter', 'marker-end', 'marker-mid', 'marker-start', 'mask', 'opacity', 'points', 'requiredFeatures', 'stroke', 'stroke-dasharray', 'stroke-dashoffset', 'stroke-linecap', 'stroke-linejoin', 'stroke-miterlimit', 'stroke-opacity', 'stroke-width', 'systemLanguage', 'se:connector'],
+  radialGradient: ['cx', 'cy', 'fx', 'fy', 'gradientTransform', 'gradientUnits', 'r', 'requiredFeatures', 'spreadMethod', 'systemLanguage', 'xlink:href'],
+  rect: ['clip-path', 'clip-rule', 'fill', 'fill-opacity', 'fill-rule', 'filter', 'height', 'mask', 'opacity', 'requiredFeatures', 'rx', 'ry', 'stroke', 'stroke-dasharray', 'stroke-dashoffset', 'stroke-linecap', 'stroke-linejoin', 'stroke-miterlimit', 'stroke-opacity', 'stroke-width', 'systemLanguage', 'width', 'x', 'y'],
+  stop: ['offset', 'requiredFeatures', 'stop-opacity', 'systemLanguage', 'stop-color', 'gradientUnits', 'gradientTransform'],
+  style: ['type'],
+  svg: ['clip-path', 'clip-rule', 'enable-background', 'filter', 'height', 'mask', 'preserveAspectRatio', 'requiredFeatures', 'systemLanguage', 'version', 'viewBox', 'width', 'x', 'xmlns', 'xmlns:se', 'xmlns:xlink', 'xmlns:oi', 'oi:animations', 'y', 'stroke-linejoin', 'fill-rule', 'aria-label', 'stroke-width', 'fill-rule', 'xml:space'],
+  switch: ['requiredFeatures', 'systemLanguage'],
+  symbol: ['fill', 'fill-opacity', 'fill-rule', 'filter', 'font-family', 'font-size', 'font-style', 'font-weight', 'opacity', 'overflow', 'preserveAspectRatio', 'requiredFeatures', 'stroke', 'stroke-dasharray', 'stroke-dashoffset', 'stroke-linecap', 'stroke-linejoin', 'stroke-miterlimit', 'stroke-opacity', 'stroke-width', 'systemLanguage', 'viewBox', 'width', 'height'],
+  text: ['clip-path', 'clip-rule', 'fill', 'fill-opacity', 'fill-rule', 'filter', 'font-family', 'font-size', 'font-style', 'font-weight', 'mask', 'opacity', 'requiredFeatures', 'stroke', 'stroke-dasharray', 'stroke-dashoffset', 'stroke-linecap', 'stroke-linejoin', 'stroke-miterlimit', 'stroke-opacity', 'stroke-width', 'systemLanguage', 'text-anchor', 'letter-spacing', 'word-spacing', 'text-decoration', 'textLength', 'lengthAdjust', 'x', 'xml:space', 'y'],
+  textPath: ['method', 'requiredFeatures', 'spacing', 'startOffset', 'systemLanguage', 'xlink:href'],
+  title: [],
+  tspan: ['clip-path', 'clip-rule', 'dx', 'dy', 'fill', 'fill-opacity', 'fill-rule', 'filter', 'font-family', 'font-size', 'font-style', 'font-weight', 'mask', 'opacity', 'requiredFeatures', 'rotate', 'stroke', 'stroke-dasharray', 'stroke-dashoffset', 'stroke-linecap', 'stroke-linejoin', 'stroke-miterlimit', 'stroke-opacity', 'stroke-width', 'systemLanguage', 'text-anchor', 'textLength', 'x', 'xml:space', 'y'],
+  use: ['clip-path', 'clip-rule', 'fill', 'fill-opacity', 'fill-rule', 'filter', 'height', 'mask', 'stroke', 'stroke-dasharray', 'stroke-dashoffset', 'stroke-linecap', 'stroke-linejoin', 'stroke-miterlimit', 'stroke-opacity', 'stroke-width', 'width', 'x', 'xlink:href', 'y', 'overflow'],
+
+  // MathML Elements
+  annotation: ['encoding'],
+  'annotation-xml': ['encoding'],
+  maction: ['actiontype', 'other', 'selection'],
+  math: ['xmlns'],
+  menclose: ['notation'],
+  merror: [],
+  mfrac: ['linethickness'],
+  mi: ['mathvariant'],
+  mmultiscripts: [],
+  mn: [],
+  mo: ['fence', 'lspace', 'maxsize', 'minsize', 'rspace', 'stretchy'],
+  mover: [],
+  mpadded: ['lspace', 'width', 'height', 'depth', 'voffset'],
+  mphantom: [],
+  mprescripts: [],
+  mroot: [],
+  mrow: ['xlink:href', 'xlink:type', 'xmlns:xlink'],
+  mspace: ['depth', 'height', 'width'],
+  msqrt: [],
+  mstyle: ['displaystyle', 'mathbackground', 'mathcolor', 'mathvariant', 'scriptlevel'],
+  msub: [],
+  msubsup: [],
+  msup: [],
+  mtable: ['align', 'columnalign', 'columnlines', 'columnspacing', 'displaystyle', 'equalcolumns', 'equalrows', 'frame', 'rowalign', 'rowlines', 'rowspacing', 'width'],
+  mtd: ['columnalign', 'columnspan', 'rowalign', 'rowspan'],
+  mtext: [],
+  mtr: ['columnalign', 'rowalign'],
+  munder: [],
+  munderover: [],
+  none: [],
+  semantics: []
+}
+/* eslint-enable max-len */
+
+// add generic attributes to all elements of the whitelist
+Object.keys(svgWhiteList_).forEach((element) => { svgWhiteList_[element] = [...svgWhiteList_[element], ...svgGenericWhiteList] })
+
+// Produce a Namespace-aware version of svgWhitelist
+const svgWhiteListNS_ = {}
+Object.entries(svgWhiteList_).forEach(([elt, atts]) => {
+  const attNS = {}
+  Object.entries(atts).forEach(([_i, att]) => {
+    if (att.includes(':')) {
+      const v = att.split(':')
+      attNS[v[1]] = NS[(v[0]).toUpperCase()]
+    } else {
+      attNS[att] = att === 'xmlns' ? NS.XMLNS : null
+    }
+  })
+  svgWhiteListNS_[elt] = attNS
+})
+
+/**
+* Sanitizes the input node and its children.
+* It only keeps what is allowed from our whitelist defined above.
+* @function module:sanitize.sanitizeSvg
+* @param {Text|Element} node - The DOM element to be checked (we'll also check its children) or text node to be cleaned up
+* @returns {void}
+*/
+export const sanitizeSvg = (node) => {
+  // Cleanup text nodes
+  if (node.nodeType === 3) { // 3 === TEXT_NODE
+    // Trim whitespace
+    node.nodeValue = node.nodeValue.trim()
+    // Remove if empty
+    if (!node.nodeValue.length) {
+      node.remove()
+    }
+  }
+
+  // We only care about element nodes.
+  // Automatically return for all non-element nodes, such as comments, etc.
+  if (node.nodeType !== 1) { // 1 == ELEMENT_NODE
+    return
+  }
+
+  const doc = node.ownerDocument
+  const parent = node.parentNode
+  // can parent ever be null here?  I think the root node's parent is the document...
+  if (!doc || !parent) {
+    return
+  }
+
+  const allowedAttrs = svgWhiteList_[node.nodeName]
+  const allowedAttrsNS = svgWhiteListNS_[node.nodeName]
+  // if this element is supported, sanitize it
+  if (typeof allowedAttrs !== 'undefined') {
+    const seAttrs = []
+    let i = node.attributes.length
+    while (i--) {
+      // if the attribute is not in our whitelist, then remove it
+      const attr = node.attributes.item(i)
+      const attrName = attr.nodeName
+      const attrLocalName = attr.localName
+      const attrNsURI = attr.namespaceURI
+      // Check that an attribute with the correct localName in the correct namespace is on
+      // our whitelist or is a namespace declaration for one of our allowed namespaces
+      if (attrNsURI !== allowedAttrsNS[attrLocalName] && attrNsURI !== NS.XMLNS &&
+       !(attrNsURI === NS.XMLNS && REVERSE_NS[attr.value])) {
+        // Bypassing the whitelist to allow se: and oi: prefixes
+        // We can add specific namepaces on demand for now.
+        // Is there a more appropriate way to do this?
+        if (attrName.startsWith('se:') || attrName.startsWith('oi:') || attrName.startsWith('data-')) {
+          // We should bypass the namespace aswell
+          const seAttrNS = (attrName.startsWith('se:')) ? NS.SE : ((attrName.startsWith('oi:')) ? NS.OI : null)
+          seAttrs.push([attrName, attr.value, seAttrNS])
+        } else {
+          console.warn(`sanitizeSvg: attribute ${attrName} in element ${node.nodeName} not in whitelist is removed`)
+          node.removeAttributeNS(attrNsURI, attrLocalName)
+        }
+      }
+
+      // For the style attribute, rewrite it in terms of XML presentational attributes
+      if (attrName === 'style') {
+        const props = attr.value.split(';')
+        let p = props.length
+        while (p--) {
+          const [name, val] = props[p].split(':')
+          const styleAttrName = (name || '').trim()
+          const styleAttrVal = (val || '').trim()
+          // Now check that this attribute is supported
+          if (allowedAttrs.includes(styleAttrName)) {
+            node.setAttribute(styleAttrName, styleAttrVal)
+          }
+        }
+        node.removeAttribute('style')
+      }
+    }
+
+    Object.values(seAttrs).forEach(([att, val, ns]) => {
+      node.setAttributeNS(ns, att, val)
+    })
+
+    // for some elements that have a xlink:href, ensure the URI refers to a local element
+    // (but not for links)
+    const href = getHref(node)
+    if (href &&
+      ['filter', 'linearGradient', 'pattern',
+        'radialGradient', 'textPath', 'use'].includes(node.nodeName) && href[0] !== '#') {
+      // remove the attribute (but keep the element)
+      setHref(node, '')
+      console.warn(`sanitizeSvg: attribute href in element ${node.nodeName} pointing to a non-local reference (${href}) is removed`)
+      node.removeAttributeNS(NS.XLINK, 'href')
+    }
+
+    // Safari crashes on a <use> without a xlink:href, so we just remove the node here
+    if (node.nodeName === 'use' && !getHref(node)) {
+      console.warn(`sanitizeSvg: element ${node.nodeName} without a xlink:href is removed`)
+      node.remove()
+      return
+    }
+    // if the element has attributes pointing to a non-local reference,
+    // need to remove the attribute
+    Object.values(['clip-path', 'fill', 'filter', 'marker-end', 'marker-mid', 'marker-start', 'mask', 'stroke'], (attr) => {
+      let val = node.getAttribute(attr)
+      if (val) {
+        val = getUrlFromAttr(val)
+        // simply check for first character being a '#'
+        if (val && val[0] !== '#') {
+          node.setAttribute(attr, '')
+          console.warn(`sanitizeSvg: attribute ${attr} in element ${node.nodeName} pointing to a non-local reference (${val}) is removed`)
+          node.removeAttribute(attr)
+        }
+      }
+    })
+
+    // recurse to children
+    i = node.childNodes.length
+    while (i--) { sanitizeSvg(node.childNodes.item(i)) }
+  // else (element not supported), remove it
+  } else {
+    // remove all children from this node and insert them before this node
+    // TODO: in the case of animation elements this will hardly ever be correct
+    console.warn(`sanitizeSvg: element ${node.nodeName} not supported is removed`)
+    const children = []
+    while (node.hasChildNodes()) {
+      children.push(parent.insertBefore(node.firstChild, node))
+    }
+
+    // remove this node from the document altogether
+    node.remove()
+
+    // call sanitizeSvg on each of those children
+    let i = children.length
+    while (i--) { sanitizeSvg(children[i]) }
+  }
+}

packages/svgcanvas/select.js

@@ -0,0 +1,543 @@
+/**
+ * DOM element selection box tools.
+ * @module select
+ * @license MIT
+ *
+ * @copyright 2010 Alexis Deveria, 2010 Jeff Schiller
+ */
+
+import { isWebkit } from '../../src/common/browser.js'
+import { getRotationAngle, getBBox, getStrokedBBox } from './utilities.js'
+import { transformListToTransform, transformBox, transformPoint } from './math.js'
+
+let svgCanvas
+let selectorManager_ // A Singleton
+// change radius if touch screen
+const gripRadius = window.ontouchstart ? 10 : 4
+
+/**
+* Private class for DOM element selection boxes.
+*/
+export class Selector {
+  /**
+  * @param {Integer} id - Internally identify the selector
+  * @param {Element} elem - DOM element associated with this selector
+  * @param {module:utilities.BBoxObject} [bbox] - Optional bbox to use for initialization (prevents duplicate `getBBox` call).
+  */
+  constructor (id, elem, bbox) {
+    // this is the selector's unique number
+    this.id = id
+
+    // this holds a reference to the element for which this selector is being used
+    this.selectedElement = elem
+
+    // this is a flag used internally to track whether the selector is being used or not
+    this.locked = true
+
+    // this holds a reference to the <g> element that holds all visual elements of the selector
+    this.selectorGroup = svgCanvas.createSVGElement({
+      element: 'g',
+      attr: { id: ('selectorGroup' + this.id) }
+    })
+
+    // this holds a reference to the path rect
+    this.selectorRect = svgCanvas.createSVGElement({
+      element: 'path',
+      attr: {
+        id: ('selectedBox' + this.id),
+        fill: 'none',
+        stroke: '#22C',
+        'stroke-width': '1',
+        'stroke-dasharray': '5,5',
+        // need to specify this so that the rect is not selectable
+        style: 'pointer-events:none'
+      }
+    })
+    this.selectorGroup.append(this.selectorRect)
+
+    // this holds a reference to the grip coordinates for this selector
+    this.gripCoords = {
+      nw: null,
+      n: null,
+      ne: null,
+      e: null,
+      se: null,
+      s: null,
+      sw: null,
+      w: null
+    }
+
+    this.reset(this.selectedElement, bbox)
+  }
+
+  /**
+  * Used to reset the id and element that the selector is attached to.
+  * @param {Element} e - DOM element associated with this selector
+  * @param {module:utilities.BBoxObject} bbox - Optional bbox to use for reset (prevents duplicate getBBox call).
+  * @returns {void}
+  */
+  reset (e, bbox) {
+    this.locked = true
+    this.selectedElement = e
+    this.resize(bbox)
+    this.selectorGroup.setAttribute('display', 'inline')
+  }
+
+  /**
+  * Show the resize grips of this selector.
+  * @param {boolean} show - Indicates whether grips should be shown or not
+  * @returns {void}
+  */
+  showGrips (show) {
+    const bShow = show ? 'inline' : 'none'
+    selectorManager_.selectorGripsGroup.setAttribute('display', bShow)
+    const elem = this.selectedElement
+    this.hasGrips = show
+    if (elem && show) {
+      this.selectorGroup.append(selectorManager_.selectorGripsGroup)
+      Selector.updateGripCursors(getRotationAngle(elem))
+    }
+  }
+
+  /**
+  * Updates the selector to match the element's size.
+  * @param {module:utilities.BBoxObject} [bbox] - BBox to use for resize (prevents duplicate getBBox call).
+  * @returns {void}
+  */
+  resize (bbox) {
+    const dataStorage = svgCanvas.getDataStorage()
+    const selectedBox = this.selectorRect
+    const mgr = selectorManager_
+    const selectedGrips = mgr.selectorGrips
+    const selected = this.selectedElement
+    const zoom = svgCanvas.getZoom()
+    let offset = 1 / zoom
+    const sw = selected.getAttribute('stroke-width')
+    if (selected.getAttribute('stroke') !== 'none' && !isNaN(sw)) {
+      offset += (sw / 2)
+    }
+
+    const { tagName } = selected
+    if (tagName === 'text') {
+      offset += 2 / zoom
+    }
+
+    // loop and transform our bounding box until we reach our first rotation
+    const tlist = selected.transform.baseVal
+    const m = transformListToTransform(tlist).matrix
+
+    // This should probably be handled somewhere else, but for now
+    // it keeps the selection box correctly positioned when zoomed
+    m.e *= zoom
+    m.f *= zoom
+
+    if (!bbox) {
+      bbox = getBBox(selected)
+    }
+    // TODO: getBBox (previous line) already knows to call getStrokedBBox when tagName === 'g'. Remove this?
+    // TODO: getBBox doesn't exclude 'gsvg' and calls getStrokedBBox for any 'g'. Should getBBox be updated?
+    if (tagName === 'g' && !dataStorage.has(selected, 'gsvg')) {
+      // The bbox for a group does not include stroke vals, so we
+      // get the bbox based on its children.
+      const strokedBbox = getStrokedBBox([selected.childNodes])
+      if (strokedBbox) {
+        bbox = strokedBbox
+      }
+    }
+
+    // apply the transforms
+    const l = bbox.x; const t = bbox.y; const w = bbox.width; const h = bbox.height
+    // bbox = {x: l, y: t, width: w, height: h}; // Not in use
+
+    // we need to handle temporary transforms too
+    // if skewed, get its transformed box, then find its axis-aligned bbox
+
+    // *
+    offset *= zoom
+
+    const nbox = transformBox(l * zoom, t * zoom, w * zoom, h * zoom, m)
+    const { aabox } = nbox
+    let nbax = aabox.x - offset
+    let nbay = aabox.y - offset
+    let nbaw = aabox.width + (offset * 2)
+    let nbah = aabox.height + (offset * 2)
+
+    // now if the shape is rotated, un-rotate it
+    const cx = nbax + nbaw / 2
+    const cy = nbay + nbah / 2
+
+    const angle = getRotationAngle(selected)
+    if (angle) {
+      const rot = svgCanvas.getSvgRoot().createSVGTransform()
+      rot.setRotate(-angle, cx, cy)
+      const rotm = rot.matrix
+      nbox.tl = transformPoint(nbox.tl.x, nbox.tl.y, rotm)
+      nbox.tr = transformPoint(nbox.tr.x, nbox.tr.y, rotm)
+      nbox.bl = transformPoint(nbox.bl.x, nbox.bl.y, rotm)
+      nbox.br = transformPoint(nbox.br.x, nbox.br.y, rotm)
+
+      // calculate the axis-aligned bbox
+      const { tl } = nbox
+      let minx = tl.x
+      let miny = tl.y
+      let maxx = tl.x
+      let maxy = tl.y
+
+      const { min, max } = Math
+
+      minx = min(minx, min(nbox.tr.x, min(nbox.bl.x, nbox.br.x))) - offset
+      miny = min(miny, min(nbox.tr.y, min(nbox.bl.y, nbox.br.y))) - offset
+      maxx = max(maxx, max(nbox.tr.x, max(nbox.bl.x, nbox.br.x))) + offset
+      maxy = max(maxy, max(nbox.tr.y, max(nbox.bl.y, nbox.br.y))) + offset
+
+      nbax = minx
+      nbay = miny
+      nbaw = (maxx - minx)
+      nbah = (maxy - miny)
+    }
+
+    const dstr = 'M' + nbax + ',' + nbay +
+      ' L' + (nbax + nbaw) + ',' + nbay +
+      ' ' + (nbax + nbaw) + ',' + (nbay + nbah) +
+      ' ' + nbax + ',' + (nbay + nbah) + 'z'
+
+    const xform = angle ? 'rotate(' + [angle, cx, cy].join(',') + ')' : ''
+
+    // TODO(codedread): Is this needed?
+    //  if (selected === selectedElements[0]) {
+    this.gripCoords = {
+      nw: [nbax, nbay],
+      ne: [nbax + nbaw, nbay],
+      sw: [nbax, nbay + nbah],
+      se: [nbax + nbaw, nbay + nbah],
+      n: [nbax + (nbaw) / 2, nbay],
+      w: [nbax, nbay + (nbah) / 2],
+      e: [nbax + nbaw, nbay + (nbah) / 2],
+      s: [nbax + (nbaw) / 2, nbay + nbah]
+    }
+    selectedBox.setAttribute('d', dstr)
+    this.selectorGroup.setAttribute('transform', xform)
+    Object.entries(this.gripCoords).forEach(([dir, coords]) => {
+      selectedGrips[dir].setAttribute('cx', coords[0])
+      selectedGrips[dir].setAttribute('cy', coords[1])
+    })
+
+    // we want to go 20 pixels in the negative transformed y direction, ignoring scale
+    mgr.rotateGripConnector.setAttribute('x1', nbax + (nbaw) / 2)
+    mgr.rotateGripConnector.setAttribute('y1', nbay)
+    mgr.rotateGripConnector.setAttribute('x2', nbax + (nbaw) / 2)
+    mgr.rotateGripConnector.setAttribute('y2', nbay - (gripRadius * 5))
+
+    mgr.rotateGrip.setAttribute('cx', nbax + (nbaw) / 2)
+    mgr.rotateGrip.setAttribute('cy', nbay - (gripRadius * 5))
+    // }
+  }
+
+  // STATIC methods
+  /**
+  * Updates cursors for corner grips on rotation so arrows point the right way.
+  * @param {Float} angle - Current rotation angle in degrees
+  * @returns {void}
+  */
+  static updateGripCursors (angle) {
+    const dirArr = Object.keys(selectorManager_.selectorGrips)
+    let steps = Math.round(angle / 45)
+    if (steps < 0) { steps += 8 }
+    while (steps > 0) {
+      dirArr.push(dirArr.shift())
+      steps--
+    }
+    Object.values(selectorManager_.selectorGrips).forEach((gripElement, i) => {
+      gripElement.setAttribute('style', ('cursor:' + dirArr[i] + '-resize'))
+    })
+  }
+}
+
+/**
+* Manage all selector objects (selection boxes).
+*/
+export class SelectorManager {
+  /**
+   * Sets up properties and calls `initGroup`.
+   */
+  constructor () {
+    // this will hold the <g> element that contains all selector rects/grips
+    this.selectorParentGroup = null
+
+    // this is a special rect that is used for multi-select
+    this.rubberBandBox = null
+
+    // this will hold objects of type Selector (see above)
+    this.selectors = []
+
+    // this holds a map of SVG elements to their Selector object
+    this.selectorMap = {}
+
+    // this holds a reference to the grip elements
+    this.selectorGrips = {
+      nw: null,
+      n: null,
+      ne: null,
+      e: null,
+      se: null,
+      s: null,
+      sw: null,
+      w: null
+    }
+
+    this.selectorGripsGroup = null
+    this.rotateGripConnector = null
+    this.rotateGrip = null
+
+    this.initGroup()
+  }
+
+  /**
+  * Resets the parent selector group element.
+  * @returns {void}
+  */
+  initGroup () {
+    const dataStorage = svgCanvas.getDataStorage()
+    // remove old selector parent group if it existed
+    if (this.selectorParentGroup?.parentNode) {
+      this.selectorParentGroup.remove()
+    }
+
+    // create parent selector group and add it to svgroot
+    this.selectorParentGroup = svgCanvas.createSVGElement({
+      element: 'g',
+      attr: { id: 'selectorParentGroup' }
+    })
+    this.selectorGripsGroup = svgCanvas.createSVGElement({
+      element: 'g',
+      attr: { display: 'none' }
+    })
+    this.selectorParentGroup.append(this.selectorGripsGroup)
+    svgCanvas.getSvgRoot().append(this.selectorParentGroup)
+
+    this.selectorMap = {}
+    this.selectors = []
+    this.rubberBandBox = null
+
+    // add the corner grips
+    Object.keys(this.selectorGrips).forEach((dir) => {
+      const grip = svgCanvas.createSVGElement({
+        element: 'circle',
+        attr: {
+          id: ('selectorGrip_resize_' + dir),
+          fill: '#22C',
+          r: gripRadius,
+          style: ('cursor:' + dir + '-resize'),
+          // This expands the mouse-able area of the grips making them
+          // easier to grab with the mouse.
+          // This works in Opera and WebKit, but does not work in Firefox
+          // see https://bugzilla.mozilla.org/show_bug.cgi?id=500174
+          'stroke-width': 2,
+          'pointer-events': 'all'
+        }
+      })
+
+      dataStorage.put(grip, 'dir', dir)
+      dataStorage.put(grip, 'type', 'resize')
+      this.selectorGrips[dir] = grip
+      this.selectorGripsGroup.append(grip)
+    })
+
+    // add rotator elems
+    this.rotateGripConnector =
+      svgCanvas.createSVGElement({
+        element: 'line',
+        attr: {
+          id: ('selectorGrip_rotateconnector'),
+          stroke: '#22C',
+          'stroke-width': '1'
+        }
+      })
+    this.selectorGripsGroup.append(this.rotateGripConnector)
+
+    this.rotateGrip =
+      svgCanvas.createSVGElement({
+        element: 'circle',
+        attr: {
+          id: 'selectorGrip_rotate',
+          fill: 'lime',
+          r: gripRadius,
+          stroke: '#22C',
+          'stroke-width': 2,
+          style: `cursor:url(${svgCanvas.curConfig.imgPath}/rotate.svg) 12 12, auto;`
+        }
+      })
+    this.selectorGripsGroup.append(this.rotateGrip)
+    dataStorage.put(this.rotateGrip, 'type', 'rotate')
+
+    if (document.getElementById('canvasBackground')) { return }
+
+    const [width, height] = svgCanvas.curConfig.dimensions
+    const canvasbg = svgCanvas.createSVGElement({
+      element: 'svg',
+      attr: {
+        id: 'canvasBackground',
+        width,
+        height,
+        x: 0,
+        y: 0,
+        overflow: (isWebkit() ? 'none' : 'visible'), // Chrome 7 has a problem with this when zooming out
+        style: 'pointer-events:none'
+      }
+    })
+
+    const rect = svgCanvas.createSVGElement({
+      element: 'rect',
+      attr: {
+        width: '100%',
+        height: '100%',
+        x: 0,
+        y: 0,
+        'stroke-width': 1,
+        stroke: '#000',
+        fill: '#FFF',
+        style: 'pointer-events:none'
+      }
+    })
+    canvasbg.append(rect)
+    svgCanvas.getSvgRoot().insertBefore(canvasbg, svgCanvas.getSvgContent())
+  }
+
+  /**
+  *
+  * @param {Element} elem - DOM element to get the selector for
+  * @param {module:utilities.BBoxObject} [bbox] - Optional bbox to use for reset (prevents duplicate getBBox call).
+  * @returns {Selector} The selector based on the given element
+  */
+  requestSelector (elem, bbox) {
+    if (!elem) { return null }
+
+    const N = this.selectors.length
+    // If we've already acquired one for this element, return it.
+    if (typeof this.selectorMap[elem.id] === 'object') {
+      this.selectorMap[elem.id].locked = true
+      return this.selectorMap[elem.id]
+    }
+    for (let i = 0; i < N; ++i) {
+      if (!this.selectors[i]?.locked) {
+        this.selectors[i].locked = true
+        this.selectors[i].reset(elem, bbox)
+        this.selectorMap[elem.id] = this.selectors[i]
+        return this.selectors[i]
+      }
+    }
+    // if we reached here, no available selectors were found, we create one
+    this.selectors[N] = new Selector(N, elem, bbox)
+    this.selectorParentGroup.append(this.selectors[N].selectorGroup)
+    this.selectorMap[elem.id] = this.selectors[N]
+    return this.selectors[N]
+  }
+
+  /**
+  * Removes the selector of the given element (hides selection box).
+  *
+  * @param {Element} elem - DOM element to remove the selector for
+  * @returns {void}
+  */
+  releaseSelector (elem) {
+    if (!elem) { return }
+    const N = this.selectors.length
+    const sel = this.selectorMap[elem.id]
+    if (!sel?.locked) {
+      // TODO(codedread): Ensure this exists in this module.
+      console.warn('WARNING! selector was released but was already unlocked')
+    }
+    for (let i = 0; i < N; ++i) {
+      if (this.selectors[i] && this.selectors[i] === sel) {
+        delete this.selectorMap[elem.id]
+        sel.locked = false
+        sel.selectedElement = null
+        sel.showGrips(false)
+
+        // remove from DOM and store reference in JS but only if it exists in the DOM
+        try {
+          sel.selectorGroup.setAttribute('display', 'none')
+        } catch (e) { /* empty fn */ }
+
+        break
+      }
+    }
+  }
+
+  /**
+  * @returns {SVGRectElement} The rubberBandBox DOM element. This is the rectangle drawn by
+  * the user for selecting/zooming
+  */
+  getRubberBandBox () {
+    if (!this.rubberBandBox) {
+      this.rubberBandBox =
+        svgCanvas.createSVGElement({
+          element: 'rect',
+          attr: {
+            id: 'selectorRubberBand',
+            fill: '#22C',
+            'fill-opacity': 0.15,
+            stroke: '#22C',
+            'stroke-width': 0.5,
+            display: 'none',
+            style: 'pointer-events:none'
+          }
+        })
+      this.selectorParentGroup.append(this.rubberBandBox)
+    }
+    return this.rubberBandBox
+  }
+}
+
+/**
+ * An object that creates SVG elements for the canvas.
+ *
+ * @interface module:select.SVGFactory
+ */
+/**
+ * @function module:select.SVGFactory#createSVGElement
+ * @param {module:utilities.EditorContext#addSVGElementsFromJson} jsonMap
+ * @returns {SVGElement}
+ */
+/**
+ * @function module:select.SVGFactory#svgRoot
+ * @returns {SVGSVGElement}
+ */
+/**
+ * @function module:select.SVGFactory#svgContent
+ * @returns {SVGSVGElement}
+ */
+/**
+ * @function module:select.SVGFactory#getZoom
+ * @returns {Float} The current zoom level
+ */
+
+/**
+ * @typedef {GenericArray} module:select.Dimensions
+ * @property {Integer} length 2
+ * @property {Float} 0 Width
+ * @property {Float} 1 Height
+ */
+/**
+ * @typedef {PlainObject} module:select.Config
+ * @property {string} imgPath
+ * @property {module:select.Dimensions} dimensions
+ */
+
+/**
+ * Initializes this module.
+ * @function module:select.init
+ * @param {module:select.Config} config - An object containing configurable parameters (imgPath)
+ * @param {module:select.SVGFactory} svgFactory - An object implementing the SVGFactory interface.
+ * @returns {void}
+ */
+export const init = (canvas) => {
+  svgCanvas = canvas
+  selectorManager_ = new SelectorManager()
+}
+
+/**
+ * @function module:select.getSelectorManager
+ * @returns {module:select.SelectorManager} The SelectorManager instance.
+ */
+export const getSelectorManager = () => selectorManager_

packages/svgcanvas/selection.js

@@ -0,0 +1,482 @@
+/**
+ * Tools for selection.
+ * @module selection
+ * @license MIT
+ * @copyright 2011 Jeff Schiller
+ */
+
+import { NS } from './namespaces.js'
+import {
+  getBBox,
+  getStrokedBBoxDefaultVisible
+} from './utilities.js'
+import {
+  transformPoint,
+  transformListToTransform,
+  rectsIntersect
+} from './math.js'
+import * as hstry from './history.js'
+import { getClosest } from '../../src/common/util.js'
+
+const { BatchCommand } = hstry
+let svgCanvas = null
+
+/**
+ * @function module:selection.init
+ * @param {module:selection.selectionContext} selectionContext
+ * @returns {void}
+ */
+export const init = (canvas) => {
+  svgCanvas = canvas
+  svgCanvas.getMouseTarget = getMouseTargetMethod
+  svgCanvas.clearSelection = clearSelectionMethod
+  svgCanvas.addToSelection = addToSelectionMethod
+  svgCanvas.getIntersectionList = getIntersectionListMethod
+  svgCanvas.runExtensions = runExtensionsMethod
+  svgCanvas.groupSvgElem = groupSvgElem
+  svgCanvas.prepareSvg = prepareSvg
+  svgCanvas.recalculateAllSelectedDimensions = recalculateAllSelectedDimensions
+  svgCanvas.setRotationAngle = setRotationAngle
+}
+
+/**
+ * Clears the selection. The 'selected' handler is then optionally called.
+ * This should really be an intersection applying to all types rather than a union.
+ * @name module:selection.SvgCanvas#clearSelection
+ * @type {module:draw.DrawCanvasInit#clearSelection|module:path.EditorContext#clearSelection}
+ * @fires module:selection.SvgCanvas#event:selected
+ */
+const clearSelectionMethod = (noCall) => {
+  const selectedElements = svgCanvas.getSelectedElements()
+  selectedElements.forEach((elem) => {
+    if (!elem) {
+      return
+    }
+
+    svgCanvas.selectorManager.releaseSelector(elem)
+  })
+  svgCanvas?.setEmptySelectedElements()
+
+  if (!noCall) {
+    svgCanvas.call('selected', svgCanvas.getSelectedElements())
+  }
+}
+
+/**
+ * Adds a list of elements to the selection. The 'selected' handler is then called.
+ * @name module:selection.SvgCanvas#addToSelection
+ * @type {module:path.EditorContext#addToSelection}
+ * @fires module:selection.SvgCanvas#event:selected
+ */
+const addToSelectionMethod = (elemsToAdd, showGrips) => {
+  const selectedElements = svgCanvas.getSelectedElements()
+  if (!elemsToAdd.length) {
+    return
+  }
+  // find the first null in our selectedElements array
+
+  let firstNull = 0
+  while (firstNull < selectedElements.length) {
+    if (selectedElements[firstNull] === null) {
+      break
+    }
+    ++firstNull
+  }
+
+  // now add each element consecutively
+  let i = elemsToAdd.length
+  while (i--) {
+    let elem = elemsToAdd[i]
+    if (!elem || !elem.getBBox) {
+      continue
+    }
+
+    if (elem.tagName === 'a' && elem.childNodes.length === 1) {
+      // Make "a" element's child be the selected element
+      elem = elem.firstChild
+    }
+
+    // if it's not already there, add it
+    if (!selectedElements.includes(elem)) {
+      selectedElements[firstNull] = elem
+
+      // only the first selectedBBoxes element is ever used in the codebase these days
+      // if (j === 0) selectedBBoxes[0] = utilsGetBBox(elem);
+      firstNull++
+      const sel = svgCanvas.selectorManager.requestSelector(elem)
+
+      if (selectedElements.length > 1) {
+        sel.showGrips(false)
+      }
+    }
+  }
+  if (!selectedElements.length) {
+    return
+  }
+  svgCanvas.call('selected', selectedElements)
+
+  if (selectedElements.length === 1) {
+    svgCanvas.selectorManager
+      .requestSelector(selectedElements[0])
+      .showGrips(showGrips)
+  }
+
+  // make sure the elements are in the correct order
+  // See: https://www.w3.org/TR/DOM-Level-3-Core/core.html#Node3-compareDocumentPosition
+
+  selectedElements.sort((a, b) => {
+    if (a && b && a.compareDocumentPosition) {
+      return 3 - (b.compareDocumentPosition(a) & 6)
+    }
+    if (!a) {
+      return 1
+    }
+    return 0
+  })
+
+  // Make sure first elements are not null
+  while (!selectedElements[0]) {
+    selectedElements.shift(0)
+  }
+}
+/**
+ * @name module:svgcanvas.SvgCanvas#getMouseTarget
+ * @type {module:path.EditorContext#getMouseTarget}
+ */
+const getMouseTargetMethod = (evt) => {
+  if (!evt) {
+    return null
+  }
+  let mouseTarget = evt.target
+
+  // if it was a <use>, Opera and WebKit return the SVGElementInstance
+  if (mouseTarget.correspondingUseElement) {
+    mouseTarget = mouseTarget.correspondingUseElement
+  }
+
+  // for foreign content, go up until we find the foreignObject
+  // WebKit browsers set the mouse target to the svgcanvas div
+  if (
+    [NS.MATH, NS.HTML].includes(mouseTarget.namespaceURI) &&
+    mouseTarget.id !== 'svgcanvas'
+  ) {
+    while (mouseTarget.nodeName !== 'foreignObject') {
+      mouseTarget = mouseTarget.parentNode
+      if (!mouseTarget) {
+        return svgCanvas.getSvgRoot()
+      }
+    }
+  }
+
+  // Get the desired mouseTarget with jQuery selector-fu
+  // If it's root-like, select the root
+  const currentLayer = svgCanvas.getCurrentDrawing().getCurrentLayer()
+  const svgRoot = svgCanvas.getSvgRoot()
+  const container = svgCanvas.getDOMContainer()
+  const content = svgCanvas.getSvgContent()
+  if ([svgRoot, container, content, currentLayer].includes(mouseTarget)) {
+    return svgCanvas.getSvgRoot()
+  }
+
+  // If it's a selection grip, return the grip parent
+  if (getClosest(mouseTarget.parentNode, '#selectorParentGroup')) {
+    // While we could instead have just returned mouseTarget,
+    // this makes it easier to indentify as being a selector grip
+    return svgCanvas.selectorManager.selectorParentGroup
+  }
+
+  while (
+    !mouseTarget?.parentNode?.isSameNode(
+      svgCanvas.getCurrentGroup() || currentLayer
+    )
+  ) {
+    mouseTarget = mouseTarget.parentNode
+  }
+
+  return mouseTarget
+}
+/**
+ * @typedef {module:svgcanvas.ExtensionMouseDownStatus|module:svgcanvas.ExtensionMouseUpStatus|module:svgcanvas.ExtensionIDsUpdatedStatus|module:locale.ExtensionLocaleData[]|void} module:svgcanvas.ExtensionStatus
+ * @tutorial ExtensionDocs
+ */
+/**
+ * @callback module:svgcanvas.ExtensionVarBuilder
+ * @param {string} name The name of the extension
+ * @returns {module:svgcanvas.SvgCanvas#event:ext_addLangData}
+ */
+/**
+ * @callback module:svgcanvas.ExtensionNameFilter
+ * @param {string} name
+ * @returns {boolean}
+ */
+/* eslint-disable max-len */
+/**
+ * @todo Consider: Should this return an array by default, so extension results aren't overwritten?
+ * @todo Would be easier to document if passing in object with key of action and vars as value; could then define an interface which tied both together
+ * @function module:svgcanvas.SvgCanvas#runExtensions
+ * @param {"mouseDown"|"mouseMove"|"mouseUp"|"zoomChanged"|"IDsUpdated"|"canvasUpdated"|"toolButtonStateUpdate"|"selectedChanged"|"elementTransition"|"elementChanged"|"langReady"|"langChanged"|"addLangData"|"workareaResized"} action
+ * @param {module:svgcanvas.SvgCanvas#event:ext_mouseDown|module:svgcanvas.SvgCanvas#event:ext_mouseMove|module:svgcanvas.SvgCanvas#event:ext_mouseUp|module:svgcanvas.SvgCanvas#event:ext_zoomChanged|module:svgcanvas.SvgCanvas#event:ext_IDsUpdated|module:svgcanvas.SvgCanvas#event:ext_canvasUpdated|module:svgcanvas.SvgCanvas#event:ext_toolButtonStateUpdate|module:svgcanvas.SvgCanvas#event:ext_selectedChanged|module:svgcanvas.SvgCanvas#event:ext_elementTransition|module:svgcanvas.SvgCanvas#event:ext_elementChanged|module:svgcanvas.SvgCanvas#event:ext_langReady|module:svgcanvas.SvgCanvas#event:ext_langChanged|module:svgcanvas.SvgCanvas#event:ext_addLangData|module:svgcanvas.SvgCanvas#event:ext_workareaResized|module:svgcanvas.ExtensionVarBuilder} [vars]
+ * @param {boolean} [returnArray]
+ * @returns {GenericArray<module:svgcanvas.ExtensionStatus>|module:svgcanvas.ExtensionStatus|false} See {@tutorial ExtensionDocs} on the ExtensionStatus.
+ */
+/* eslint-enable max-len */
+const runExtensionsMethod = (
+  action,
+  vars,
+  returnArray
+) => {
+  let result = returnArray ? [] : false
+  for (const [name, ext] of Object.entries(svgCanvas.getExtensions())) {
+    if (typeof vars === 'function') {
+      vars = vars(name) // ext, action
+    }
+    if (ext.eventBased) {
+      const event = new CustomEvent('svgedit', {
+        detail: {
+          action,
+          vars
+        }
+      })
+      document.dispatchEvent(event)
+    } else if (ext[action]) {
+      if (returnArray) {
+        result.push(ext[action](vars))
+      } else {
+        result = ext[action](vars)
+      }
+    }
+  }
+  return result
+}
+
+/**
+ * Get all elements that have a BBox (excludes `<defs>`, `<title>`, etc).
+ * Note that 0-opacity, off-screen etc elements are still considered "visible"
+ * for this function.
+ * @function module:svgcanvas.SvgCanvas#getVisibleElementsAndBBoxes
+ * @param {Element} parent - The parent DOM element to search within
+ * @returns {ElementAndBBox[]} An array with objects that include:
+ */
+const getVisibleElementsAndBBoxes = (parent) => {
+  if (!parent) {
+    const svgContent = svgCanvas.getSvgContent()
+    parent = svgContent.children // Prevent layers from being included
+  }
+  const contentElems = []
+  const elements = parent.children
+  Array.from(elements).forEach((elem) => {
+    if (elem.getBBox) {
+      contentElems.push({ elem, bbox: getStrokedBBoxDefaultVisible([elem]) })
+    }
+  })
+  return contentElems.reverse()
+}
+
+/**
+ * This method sends back an array or a NodeList full of elements that
+ * intersect the multi-select rubber-band-box on the currentLayer only.
+ *
+ * We brute-force `getIntersectionList` for browsers that do not support it (Firefox).
+ *
+ * Reference:
+ * Firefox does not implement `getIntersectionList()`, see {@link https://bugzilla.mozilla.org/show_bug.cgi?id=501421}.
+ * @function module:svgcanvas.SvgCanvas#getIntersectionList
+ * @param {SVGRect} rect
+ * @returns {Element[]|NodeList} Bbox elements
+ */
+const getIntersectionListMethod = (rect) => {
+  const zoom = svgCanvas.getZoom()
+  if (!svgCanvas.getRubberBox()) {
+    return null
+  }
+
+  const parent =
+    svgCanvas.getCurrentGroup() ||
+    svgCanvas.getCurrentDrawing().getCurrentLayer()
+
+  let rubberBBox
+  if (!rect) {
+    rubberBBox = getBBox(svgCanvas.getRubberBox())
+    const bb = svgCanvas.getSvgContent().createSVGRect();
+
+    ['x', 'y', 'width', 'height', 'top', 'right', 'bottom', 'left'].forEach(
+      (o) => {
+        bb[o] = rubberBBox[o] / zoom
+      }
+    )
+    rubberBBox = bb
+  } else {
+    rubberBBox = svgCanvas.getSvgContent().createSVGRect()
+    rubberBBox.x = rect.x
+    rubberBBox.y = rect.y
+    rubberBBox.width = rect.width
+    rubberBBox.height = rect.height
+  }
+
+  const resultList = []
+  if (svgCanvas.getCurBBoxes().length === 0) {
+    // Cache all bboxes
+    svgCanvas.setCurBBoxes(getVisibleElementsAndBBoxes(parent))
+  }
+  let i = svgCanvas.getCurBBoxes().length
+  while (i--) {
+    const curBBoxes = svgCanvas.getCurBBoxes()
+    if (!rubberBBox.width) {
+      continue
+    }
+    if (rectsIntersect(rubberBBox, curBBoxes[i].bbox)) {
+      resultList.push(curBBoxes[i].elem)
+    }
+  }
+
+  // addToSelection expects an array, but it's ok to pass a NodeList
+  // because using square-bracket notation is allowed:
+  // https://www.w3.org/TR/DOM-Level-2-Core/ecma-script-binding.html
+  return resultList
+}
+
+/**
+ * @typedef {PlainObject} ElementAndBBox
+ * @property {Element} elem - The element
+ * @property {module:utilities.BBoxObject} bbox - The element's BBox as retrieved from `getStrokedBBoxDefaultVisible`
+ */
+
+/**
+ * Wrap an SVG element into a group element, mark the group as 'gsvg'.
+ * @function module:svgcanvas.SvgCanvas#groupSvgElem
+ * @param {Element} elem - SVG element to wrap
+ * @returns {void}
+ */
+const groupSvgElem = (elem) => {
+  const dataStorage = svgCanvas.getDataStorage()
+  const g = document.createElementNS(NS.SVG, 'g')
+  elem.replaceWith(g)
+  g.appendChild(elem)
+  dataStorage.put(g, 'gsvg', elem)
+  g.id = svgCanvas.getNextId()
+}
+
+/**
+ * Runs the SVG Document through the sanitizer and then updates its paths.
+ * @function module:svgcanvas.SvgCanvas#prepareSvg
+ * @param {XMLDocument} newDoc - The SVG DOM document
+ * @returns {void}
+ */
+const prepareSvg = (newDoc) => {
+  svgCanvas.sanitizeSvg(newDoc.documentElement)
+
+  // convert paths into absolute commands
+  const paths = [...newDoc.getElementsByTagNameNS(NS.SVG, 'path')]
+  paths.forEach((path) => {
+    const convertedPath = svgCanvas.pathActions.convertPath(path)
+    path.setAttribute('d', convertedPath)
+    svgCanvas.pathActions.fixEnd(path)
+  })
+}
+
+/**
+ * Removes any old rotations if present, prepends a new rotation at the
+ * transformed center.
+ * @function module:svgcanvas.SvgCanvas#setRotationAngle
+ * @param {string|Float} val - The new rotation angle in degrees
+ * @param {boolean} preventUndo - Indicates whether the action should be undoable or not
+ * @fires module:svgcanvas.SvgCanvas#event:changed
+ * @returns {void}
+ */
+const setRotationAngle = (val, preventUndo) => {
+  const selectedElements = svgCanvas.getSelectedElements()
+  // ensure val is the proper type
+  val = Number.parseFloat(val)
+  const elem = selectedElements[0]
+  const oldTransform = elem.getAttribute('transform')
+  const bbox = getBBox(elem)
+  const cx = bbox.x + bbox.width / 2
+  const cy = bbox.y + bbox.height / 2
+  const tlist = elem.transform.baseVal
+
+  // only remove the real rotational transform if present (i.e. at index=0)
+  if (tlist.numberOfItems > 0) {
+    const xform = tlist.getItem(0)
+    if (xform.type === 4) {
+      tlist.removeItem(0)
+    }
+  }
+  // find Rnc and insert it
+  if (val !== 0) {
+    const center = transformPoint(
+      cx,
+      cy,
+      transformListToTransform(tlist).matrix
+    )
+    const Rnc = svgCanvas.getSvgRoot().createSVGTransform()
+    Rnc.setRotate(val, center.x, center.y)
+    if (tlist.numberOfItems) {
+      tlist.insertItemBefore(Rnc, 0)
+    } else {
+      tlist.appendItem(Rnc)
+    }
+  } else if (tlist.numberOfItems === 0) {
+    elem.removeAttribute('transform')
+  }
+
+  if (!preventUndo) {
+    // we need to undo it, then redo it so it can be undo-able! :)
+    // TODO: figure out how to make changes to transform list undo-able cross-browser?
+    let newTransform = elem.getAttribute('transform')
+    // new transform is something like: 'rotate(5 1.39625e-8 -11)'
+    // we round the x so it becomes 'rotate(5 0 -11)'
+    if (newTransform) {
+      const newTransformArray = newTransform.split(' ')
+      const round = (num) => Math.round(Number(num) + Number.EPSILON)
+      const x = round(newTransformArray[1])
+      newTransform = `${newTransformArray[0]} ${x} ${newTransformArray[2]}`
+    }
+
+    if (oldTransform) {
+      elem.setAttribute('transform', oldTransform)
+    } else {
+      elem.removeAttribute('transform')
+    }
+    svgCanvas.changeSelectedAttribute(
+      'transform',
+      newTransform,
+      selectedElements
+    )
+    svgCanvas.call('changed', selectedElements)
+  }
+  // const pointGripContainer = getElement('pathpointgrip_container');
+  // if (elem.nodeName === 'path' && pointGripContainer) {
+  //   pathActions.setPointContainerTransform(elem.getAttribute('transform'));
+  // }
+  const selector = svgCanvas.selectorManager.requestSelector(
+    selectedElements[0]
+  )
+  selector.resize()
+  svgCanvas.getSelector().updateGripCursors(val)
+}
+
+/**
+ * Runs `recalculateDimensions` on the selected elements,
+ * adding the changes to a single batch command.
+ * @function module:svgcanvas.SvgCanvas#recalculateAllSelectedDimensions
+ * @fires module:svgcanvas.SvgCanvas#event:changed
+ * @returns {void}
+ */
+const recalculateAllSelectedDimensions = () => {
+  const text =
+    svgCanvas.getCurrentResizeMode() === 'none' ? 'position' : 'size'
+  const batchCmd = new BatchCommand(text)
+  const selectedElements = svgCanvas.getSelectedElements()
+
+  selectedElements.forEach((elem) => {
+    const cmd = svgCanvas.recalculateDimensions(elem)
+    if (cmd) {
+      batchCmd.addSubCommand(cmd)
+    }
+  })
+
+  if (!batchCmd.isEmpty()) {
+    svgCanvas.addCommandToHistory(batchCmd)
+    svgCanvas.call('changed', selectedElements)
+  }
+}

packages/svgcanvas/svgroot.js

@@ -0,0 +1,36 @@
+/**
+ * Tools for SVG Root Element.
+ * @module svgcanvas
+ * @license MIT
+ *
+ * @copyright 2010 Alexis Deveria, 2010 Jeff Schiller
+ */
+import { NS } from './namespaces.js'
+import { text2xml } from './utilities.js'
+
+/**
+* @function module:svgcanvas.svgRootElement svgRootElement the svg node and its children.
+* @param {Element} svgdoc - window.document
+* @param {ArgumentsArray} dimensions - dimensions of width and height
+* @returns {svgRootElement}
+*/
+export const svgRootElement = function (svgdoc, dimensions) {
+  return svgdoc.importNode(
+    text2xml(
+      `<svg id="svgroot" xmlns="${NS.SVG}" xlinkns="${NS.XLINK}" width="${dimensions[0]}" 
+        height="${dimensions[1]}" x="${dimensions[0]}" y="${dimensions[1]}" overflow="visible">
+        <defs>
+          <filter id="canvashadow" filterUnits="objectBoundingBox">
+            <feGaussianBlur in="SourceAlpha" stdDeviation="4" result="blur"/>
+            <feOffset in="blur" dx="5" dy="5" result="offsetBlur"/>
+            <feMerge>
+              <feMergeNode in="offsetBlur"/>
+              <feMergeNode in="SourceGraphic"/>
+            </feMerge>
+          </filter>
+        </defs>
+      </svg>`
+    ).documentElement,
+    true
+  )
+}

packages/svgcanvas/text-actions.js

@@ -0,0 +1,530 @@
+/**
+ * @module text-actions Tools for Text edit functions
+ * @license MIT
+ *
+ * @copyright 2010 Alexis Deveria, 2010 Jeff Schiller
+ */
+
+import { NS } from './namespaces.js'
+import {
+  transformPoint, getMatrix
+} from './math.js'
+import {
+  assignAttributes, getElement, getBBox as utilsGetBBox
+} from './utilities.js'
+import {
+  supportsGoodTextCharPos
+} from '../../src/common/browser.js'
+
+let svgCanvas = null
+
+/**
+* @function module:text-actions.init
+* @param {module:text-actions.svgCanvas} textActionsContext
+* @returns {void}
+*/
+export const init = (canvas) => {
+  svgCanvas = canvas
+}
+
+/**
+* Group: Text edit functions
+* Functions relating to editing text elements.
+* @namespace {PlainObject} textActions
+* @memberof module:svgcanvas.SvgCanvas#
+*/
+export const textActionsMethod = (function () {
+  let curtext
+  let textinput
+  let cursor
+  let selblock
+  let blinker
+  let chardata = []
+  let textbb // , transbb;
+  let matrix
+  let lastX; let lastY
+  let allowDbl
+
+  /**
+*
+* @param {Integer} index
+* @returns {void}
+*/
+  function setCursor (index) {
+    const empty = (textinput.value === '')
+    textinput.focus()
+
+    if (!arguments.length) {
+      if (empty) {
+        index = 0
+      } else {
+        if (textinput.selectionEnd !== textinput.selectionStart) { return }
+        index = textinput.selectionEnd
+      }
+    }
+
+    const charbb = chardata[index]
+    if (!empty) {
+      textinput.setSelectionRange(index, index)
+    }
+    cursor = getElement('text_cursor')
+    if (!cursor) {
+      cursor = document.createElementNS(NS.SVG, 'line')
+      assignAttributes(cursor, {
+        id: 'text_cursor',
+        stroke: '#333',
+        'stroke-width': 1
+      })
+      getElement('selectorParentGroup').append(cursor)
+    }
+
+    if (!blinker) {
+      blinker = setInterval(function () {
+        const show = (cursor.getAttribute('display') === 'none')
+        cursor.setAttribute('display', show ? 'inline' : 'none')
+      }, 600)
+    }
+
+    const startPt = ptToScreen(charbb.x, textbb.y)
+    const endPt = ptToScreen(charbb.x, (textbb.y + textbb.height))
+
+    assignAttributes(cursor, {
+      x1: startPt.x,
+      y1: startPt.y,
+      x2: endPt.x,
+      y2: endPt.y,
+      visibility: 'visible',
+      display: 'inline'
+    })
+
+    if (selblock) { selblock.setAttribute('d', '') }
+  }
+
+  /**
+*
+* @param {Integer} start
+* @param {Integer} end
+* @param {boolean} skipInput
+* @returns {void}
+*/
+  function setSelection (start, end, skipInput) {
+    if (start === end) {
+      setCursor(end)
+      return
+    }
+
+    if (!skipInput) {
+      textinput.setSelectionRange(start, end)
+    }
+
+    selblock = getElement('text_selectblock')
+    if (!selblock) {
+      selblock = document.createElementNS(NS.SVG, 'path')
+      assignAttributes(selblock, {
+        id: 'text_selectblock',
+        fill: 'green',
+        opacity: 0.5,
+        style: 'pointer-events:none'
+      })
+      getElement('selectorParentGroup').append(selblock)
+    }
+
+    const startbb = chardata[start]
+    const endbb = chardata[end]
+
+    cursor.setAttribute('visibility', 'hidden')
+
+    const tl = ptToScreen(startbb.x, textbb.y)
+    const tr = ptToScreen(startbb.x + (endbb.x - startbb.x), textbb.y)
+    const bl = ptToScreen(startbb.x, textbb.y + textbb.height)
+    const br = ptToScreen(startbb.x + (endbb.x - startbb.x), textbb.y + textbb.height)
+
+    const dstr = 'M' + tl.x + ',' + tl.y +
+' L' + tr.x + ',' + tr.y +
+' ' + br.x + ',' + br.y +
+' ' + bl.x + ',' + bl.y + 'z'
+
+    assignAttributes(selblock, {
+      d: dstr,
+      display: 'inline'
+    })
+  }
+
+  /**
+*
+* @param {Float} mouseX
+* @param {Float} mouseY
+* @returns {Integer}
+*/
+  function getIndexFromPoint (mouseX, mouseY) {
+    // Position cursor here
+    const pt = svgCanvas.getSvgRoot().createSVGPoint()
+    pt.x = mouseX
+    pt.y = mouseY
+
+    // No content, so return 0
+    if (chardata.length === 1) { return 0 }
+    // Determine if cursor should be on left or right of character
+    let charpos = curtext.getCharNumAtPosition(pt)
+    if (charpos < 0) {
+      // Out of text range, look at mouse coords
+      charpos = chardata.length - 2
+      if (mouseX <= chardata[0].x) {
+        charpos = 0
+      }
+    } else if (charpos >= chardata.length - 2) {
+      charpos = chardata.length - 2
+    }
+    const charbb = chardata[charpos]
+    const mid = charbb.x + (charbb.width / 2)
+    if (mouseX > mid) {
+      charpos++
+    }
+    return charpos
+  }
+
+  /**
+*
+* @param {Float} mouseX
+* @param {Float} mouseY
+* @returns {void}
+*/
+  function setCursorFromPoint (mouseX, mouseY) {
+    setCursor(getIndexFromPoint(mouseX, mouseY))
+  }
+
+  /**
+*
+* @param {Float} x
+* @param {Float} y
+* @param {boolean} apply
+* @returns {void}
+*/
+  function setEndSelectionFromPoint (x, y, apply) {
+    const i1 = textinput.selectionStart
+    const i2 = getIndexFromPoint(x, y)
+
+    const start = Math.min(i1, i2)
+    const end = Math.max(i1, i2)
+    setSelection(start, end, !apply)
+  }
+
+  /**
+*
+* @param {Float} xIn
+* @param {Float} yIn
+* @returns {module:math.XYObject}
+*/
+  function screenToPt (xIn, yIn) {
+    const out = {
+      x: xIn,
+      y: yIn
+    }
+    const zoom = svgCanvas.getZoom()
+    out.x /= zoom
+    out.y /= zoom
+
+    if (matrix) {
+      const pt = transformPoint(out.x, out.y, matrix.inverse())
+      out.x = pt.x
+      out.y = pt.y
+    }
+
+    return out
+  }
+
+  /**
+*
+* @param {Float} xIn
+* @param {Float} yIn
+* @returns {module:math.XYObject}
+*/
+  function ptToScreen (xIn, yIn) {
+    const out = {
+      x: xIn,
+      y: yIn
+    }
+
+    if (matrix) {
+      const pt = transformPoint(out.x, out.y, matrix)
+      out.x = pt.x
+      out.y = pt.y
+    }
+    const zoom = svgCanvas.getZoom()
+    out.x *= zoom
+    out.y *= zoom
+
+    return out
+  }
+
+  /**
+*
+* @param {Event} evt
+* @returns {void}
+*/
+  function selectAll (evt) {
+    setSelection(0, curtext.textContent.length)
+    evt.target.removeEventListener('click', selectAll)
+  }
+
+  /**
+*
+* @param {Event} evt
+* @returns {void}
+*/
+  function selectWord (evt) {
+    if (!allowDbl || !curtext) { return }
+    const zoom = svgCanvas.getZoom()
+    const ept = transformPoint(evt.pageX, evt.pageY, svgCanvas.getrootSctm())
+    const mouseX = ept.x * zoom
+    const mouseY = ept.y * zoom
+    const pt = screenToPt(mouseX, mouseY)
+
+    const index = getIndexFromPoint(pt.x, pt.y)
+    const str = curtext.textContent
+    const first = str.substr(0, index).replace(/[a-z\d]+$/i, '').length
+    const m = str.substr(index).match(/^[a-z\d]+/i)
+    const last = (m ? m[0].length : 0) + index
+    setSelection(first, last)
+
+    // Set tripleclick
+    svgCanvas.$click(evt.target, selectAll)
+
+    setTimeout(function () {
+      evt.target.removeEventListener('click', selectAll)
+    }, 300)
+  }
+
+  return /** @lends module:svgcanvas.SvgCanvas#textActions */ {
+    /**
+* @param {Element} target
+* @param {Float} x
+* @param {Float} y
+* @returns {void}
+*/
+    select (target, x, y) {
+      curtext = target
+      svgCanvas.textActions.toEditMode(x, y)
+    },
+    /**
+* @param {Element} elem
+* @returns {void}
+*/
+    start (elem) {
+      curtext = elem
+      svgCanvas.textActions.toEditMode()
+    },
+    /**
+* @param {external:MouseEvent} evt
+* @param {Element} mouseTarget
+* @param {Float} startX
+* @param {Float} startY
+* @returns {void}
+*/
+    mouseDown (evt, mouseTarget, startX, startY) {
+      const pt = screenToPt(startX, startY)
+
+      textinput.focus()
+      setCursorFromPoint(pt.x, pt.y)
+      lastX = startX
+      lastY = startY
+
+      // TODO: Find way to block native selection
+    },
+    /**
+* @param {Float} mouseX
+* @param {Float} mouseY
+* @returns {void}
+*/
+    mouseMove (mouseX, mouseY) {
+      const pt = screenToPt(mouseX, mouseY)
+      setEndSelectionFromPoint(pt.x, pt.y)
+    },
+    /**
+* @param {external:MouseEvent} evt
+* @param {Float} mouseX
+* @param {Float} mouseY
+* @returns {void}
+*/
+    mouseUp (evt, mouseX, mouseY) {
+      const pt = screenToPt(mouseX, mouseY)
+
+      setEndSelectionFromPoint(pt.x, pt.y, true)
+
+      // TODO: Find a way to make this work: Use transformed BBox instead of evt.target
+      // if (lastX === mouseX && lastY === mouseY
+      //   && !rectsIntersect(transbb, {x: pt.x, y: pt.y, width: 0, height: 0})) {
+      //   svgCanvas.textActions.toSelectMode(true);
+      // }
+
+      if (
+        evt.target !== curtext &&
+  mouseX < lastX + 2 &&
+  mouseX > lastX - 2 &&
+  mouseY < lastY + 2 &&
+  mouseY > lastY - 2
+      ) {
+        svgCanvas.textActions.toSelectMode(true)
+      }
+    },
+    /**
+* @function
+* @param {Integer} index
+* @returns {void}
+*/
+    setCursor,
+    /**
+* @param {Float} x
+* @param {Float} y
+* @returns {void}
+*/
+    toEditMode (x, y) {
+      allowDbl = false
+      svgCanvas.setCurrentMode('textedit')
+      svgCanvas.selectorManager.requestSelector(curtext).showGrips(false)
+      // Make selector group accept clicks
+      /* const selector = */ svgCanvas.selectorManager.requestSelector(curtext) // Do we need this? Has side effect of setting lock, so keeping for now, but next line wasn't being used
+      // const sel = selector.selectorRect;
+
+      svgCanvas.textActions.init()
+
+      curtext.style.cursor = 'text'
+
+      // if (supportsEditableText()) {
+      //   curtext.setAttribute('editable', 'simple');
+      //   return;
+      // }
+
+      if (!arguments.length) {
+        setCursor()
+      } else {
+        const pt = screenToPt(x, y)
+        setCursorFromPoint(pt.x, pt.y)
+      }
+
+      setTimeout(function () {
+        allowDbl = true
+      }, 300)
+    },
+    /**
+* @param {boolean|Element} selectElem
+* @fires module:svgcanvas.SvgCanvas#event:selected
+* @returns {void}
+*/
+    toSelectMode (selectElem) {
+      svgCanvas.setCurrentMode('select')
+      clearInterval(blinker)
+      blinker = null
+      if (selblock) { selblock.setAttribute('display', 'none') }
+      if (cursor) { cursor.setAttribute('visibility', 'hidden') }
+      curtext.style.cursor = 'move'
+
+      if (selectElem) {
+        svgCanvas.clearSelection()
+        curtext.style.cursor = 'move'
+
+        svgCanvas.call('selected', [curtext])
+        svgCanvas.addToSelection([curtext], true)
+      }
+      if (!curtext?.textContent.length) {
+        // No content, so delete
+        svgCanvas.deleteSelectedElements()
+      }
+
+      textinput.blur()
+
+      curtext = false
+
+      // if (supportsEditableText()) {
+      //   curtext.removeAttribute('editable');
+      // }
+    },
+    /**
+* @param {Element} elem
+* @returns {void}
+*/
+    setInputElem (elem) {
+      textinput = elem
+    },
+    /**
+* @returns {void}
+*/
+    clear () {
+      if (svgCanvas.getCurrentMode() === 'textedit') {
+        svgCanvas.textActions.toSelectMode()
+      }
+    },
+    /**
+* @param {Element} _inputElem Not in use
+* @returns {void}
+*/
+    init (_inputElem) {
+      if (!curtext) { return }
+      let i; let end
+      // if (supportsEditableText()) {
+      //   curtext.select();
+      //   return;
+      // }
+
+      if (!curtext.parentNode) {
+        // Result of the ffClone, need to get correct element
+        const selectedElements = svgCanvas.getSelectedElements()
+        curtext = selectedElements[0]
+        svgCanvas.selectorManager.requestSelector(curtext).showGrips(false)
+      }
+
+      const str = curtext.textContent
+      const len = str.length
+
+      const xform = curtext.getAttribute('transform')
+
+      textbb = utilsGetBBox(curtext)
+
+      matrix = xform ? getMatrix(curtext) : null
+
+      chardata = []
+      chardata.length = len
+      textinput.focus()
+
+      curtext.removeEventListener('dblclick', selectWord)
+      curtext.addEventListener('dblclick', selectWord)
+
+      if (!len) {
+        end = { x: textbb.x + (textbb.width / 2), width: 0 }
+      }
+
+      for (i = 0; i < len; i++) {
+        const start = curtext.getStartPositionOfChar(i)
+        end = curtext.getEndPositionOfChar(i)
+
+        if (!supportsGoodTextCharPos()) {
+          const zoom = svgCanvas.getZoom()
+          const offset = svgCanvas.contentW * zoom
+          start.x -= offset
+          end.x -= offset
+
+          start.x /= zoom
+          end.x /= zoom
+        }
+
+        // Get a "bbox" equivalent for each character. Uses the
+        // bbox data of the actual text for y, height purposes
+
+        // TODO: Decide if y, width and height are actually necessary
+        chardata[i] = {
+          x: start.x,
+          y: textbb.y, // start.y?
+          width: end.x - start.x,
+          height: textbb.height
+        }
+      }
+
+      // Add a last bbox for cursor at end of text
+      chardata.push({
+        x: end.x,
+        width: 0
+      })
+      setSelection(textinput.selectionStart, textinput.selectionEnd, true)
+    }
+  }
+}())

packages/svgcanvas/touch.js

@@ -0,0 +1,51 @@
+// http://ross.posterous.com/2008/08/19/iphone-touch-events-in-javascript/
+/**
+ *
+ * @param {Event} ev
+ * @returns {void}
+ */
+const touchHandler = (ev) => {
+  ev.preventDefault()
+  const { changedTouches } = ev
+  const first = changedTouches[0]
+
+  let type = ''
+  switch (ev.type) {
+    case 'touchstart': type = 'mousedown'; break
+    case 'touchmove': type = 'mousemove'; break
+    case 'touchend': type = 'mouseup'; break
+    default: return
+  }
+
+  const { screenX, screenY, clientX, clientY } = first
+  const simulatedEvent = new MouseEvent(type, {
+    // Event interface
+    bubbles: true,
+    cancelable: true,
+    // UIEvent interface
+    view: window,
+    detail: 1, // click count
+    // MouseEvent interface (customized)
+    screenX,
+    screenY,
+    clientX,
+    clientY,
+    // MouseEvent interface (defaults) - these could be removed
+    ctrlKey: false,
+    altKey: false,
+    shiftKey: false,
+    metaKey: false,
+    button: 0, // main button (usually left)
+    relatedTarget: null
+  })
+  if (changedTouches.length < 2) {
+    first.target.dispatchEvent(simulatedEvent)
+  }
+}
+
+export const init = (svgCanvas) => {
+  svgCanvas.svgroot.addEventListener('touchstart', touchHandler)
+  svgCanvas.svgroot.addEventListener('touchmove', touchHandler)
+  svgCanvas.svgroot.addEventListener('touchend', touchHandler)
+  svgCanvas.svgroot.addEventListener('touchcancel', touchHandler)
+}

packages/svgcanvas/undo.js

@@ -0,0 +1,279 @@
+/**
+ * Tools for undo.
+ * @module undo
+ * @license MIT
+ * @copyright 2011 Jeff Schiller
+ */
+import * as draw from './draw.js'
+import * as hstry from './history.js'
+import {
+  getRotationAngle, getBBox as utilsGetBBox, setHref, getStrokedBBoxDefaultVisible
+} from './utilities.js'
+import {
+  isGecko
+} from '../../src/common/browser.js'
+import {
+  transformPoint, transformListToTransform
+} from './math.js'
+
+const {
+  UndoManager, HistoryEventTypes
+} = hstry
+
+let svgCanvas = null
+
+/**
+* @function module:undo.init
+* @param {module:undo.undoContext} undoContext
+* @returns {void}
+*/
+export const init = (canvas) => {
+  svgCanvas = canvas
+  canvas.undoMgr = getUndoManager()
+}
+
+export const getUndoManager = () => {
+  return new UndoManager({
+    /**
+     * @param {string} eventType One of the HistoryEvent types
+     * @param {module:history.HistoryCommand} cmd Fulfills the HistoryCommand interface
+     * @fires module:undo.SvgCanvas#event:changed
+     * @returns {void}
+     */
+    handleHistoryEvent (eventType, cmd) {
+      const EventTypes = HistoryEventTypes
+      // TODO: handle setBlurOffsets.
+      if (eventType === EventTypes.BEFORE_UNAPPLY || eventType === EventTypes.BEFORE_APPLY) {
+        svgCanvas.clearSelection()
+      } else if (eventType === EventTypes.AFTER_APPLY || eventType === EventTypes.AFTER_UNAPPLY) {
+        const elems = cmd.elements()
+        svgCanvas.pathActions.clear()
+        svgCanvas.call('changed', elems)
+        const cmdType = cmd.type()
+        const isApply = (eventType === EventTypes.AFTER_APPLY)
+        if (cmdType === 'MoveElementCommand') {
+          const parent = isApply ? cmd.newParent : cmd.oldParent
+          if (parent === svgCanvas.getSvgContent()) {
+            draw.identifyLayers()
+          }
+        } else if (cmdType === 'InsertElementCommand' || cmdType === 'RemoveElementCommand') {
+          if (cmd.parent === svgCanvas.getSvgContent()) {
+            draw.identifyLayers()
+          }
+          if (cmdType === 'InsertElementCommand') {
+            if (isApply) {
+              svgCanvas.restoreRefElements(cmd.elem)
+            }
+          } else if (!isApply) {
+            svgCanvas.restoreRefElements(cmd.elem)
+          }
+          if (cmd.elem?.tagName === 'use') {
+            svgCanvas.setUseData(cmd.elem)
+          }
+        } else if (cmdType === 'ChangeElementCommand') {
+          // if we are changing layer names, re-identify all layers
+          if (cmd.elem.tagName === 'title' &&
+            cmd.elem.parentNode.parentNode === svgCanvas.getSvgContent()
+          ) {
+            draw.identifyLayers()
+          }
+          const values = isApply ? cmd.newValues : cmd.oldValues
+          // If stdDeviation was changed, update the blur.
+          if (values.stdDeviation) {
+            svgCanvas.setBlurOffsets(cmd.elem.parentNode, values.stdDeviation)
+          }
+          if (cmd.elem.tagName === 'text') {
+            const [dx, dy] = [cmd.newValues.x - cmd.oldValues.x,
+              cmd.newValues.y - cmd.oldValues.y]
+
+            const tspans = cmd.elem.children
+
+            for (let i = 0; i < tspans.length; i++) {
+              let x = Number(tspans[i].getAttribute('x'))
+              let y = Number(tspans[i].getAttribute('y'))
+
+              const unapply = (eventType === EventTypes.AFTER_UNAPPLY)
+              x = unapply ? x - dx : x + dx
+              y = unapply ? y - dy : y + dy
+
+              tspans[i].setAttribute('x', x)
+              tspans[i].setAttribute('y', y)
+            }
+          }
+        }
+      }
+    }
+  })
+}
+
+/**
+* Hack for Firefox bugs where text element features aren't updated or get
+* messed up. See issue 136 and issue 137.
+* This function clones the element and re-selects it.
+* @function module:svgcanvas~ffClone
+* @todo Test for this bug on load and add it to "support" object instead of
+* browser sniffing
+* @param {Element} elem - The (text) DOM element to clone
+* @returns {Element} Cloned element
+*/
+export const ffClone = function (elem) {
+  if (!isGecko()) { return elem }
+  const clone = elem.cloneNode(true)
+  elem.before(clone)
+  elem.remove()
+  svgCanvas.selectorManager.releaseSelector(elem)
+  svgCanvas.setSelectedElements(0, clone)
+  svgCanvas.selectorManager.requestSelector(clone).showGrips(true)
+  return clone
+}
+
+/**
+* This function makes the changes to the elements. It does not add the change
+* to the history stack.
+* @param {string} attr - Attribute name
+* @param {string|Float} newValue - String or number with the new attribute value
+* @param {Element[]} elems - The DOM elements to apply the change to
+* @returns {void}
+*/
+export const changeSelectedAttributeNoUndoMethod = (attr, newValue, elems) => {
+  if (attr === 'id') {
+    // if the user is changing the id, then de-select the element first
+    // change the ID, then re-select it with the new ID
+    // as this change can impact other extensions, a 'renamedElement' event is thrown
+    const elem = elems[0]
+    const oldId = elem.id
+    if (oldId !== newValue) {
+      svgCanvas.clearSelection()
+      elem.id = newValue
+      svgCanvas.addToSelection([elem], true)
+      svgCanvas.call('elementRenamed', { elem, oldId, newId: newValue })
+    }
+    return
+  }
+  const selectedElements = svgCanvas.getSelectedElements()
+  const zoom = svgCanvas.getZoom()
+  if (svgCanvas.getCurrentMode() === 'pathedit') {
+    // Editing node
+    svgCanvas.pathActions.moveNode(attr, newValue)
+  }
+  elems = elems ?? selectedElements
+  let i = elems.length
+  const noXYElems = ['g', 'polyline', 'path']
+
+  while (i--) {
+    let elem = elems[i]
+    if (!elem) { continue }
+
+    // Set x,y vals on elements that don't have them
+    if ((attr === 'x' || attr === 'y') && noXYElems.includes(elem.tagName)) {
+      const bbox = getStrokedBBoxDefaultVisible([elem])
+      const diffX = attr === 'x' ? newValue - bbox.x : 0
+      const diffY = attr === 'y' ? newValue - bbox.y : 0
+      svgCanvas.moveSelectedElements(diffX * zoom, diffY * zoom, true)
+      continue
+    }
+
+    let oldval = attr === '#text' ? elem.textContent : elem.getAttribute(attr)
+    if (!oldval) { oldval = '' }
+    if (oldval !== String(newValue)) {
+      if (attr === '#text') {
+        // const oldW = utilsGetBBox(elem).width;
+        elem.textContent = newValue
+
+        // FF bug occurs on on rotated elements
+        if ((/rotate/).test(elem.getAttribute('transform'))) {
+          elem = ffClone(elem)
+        }
+        // Hoped to solve the issue of moving text with text-anchor="start",
+        // but this doesn't actually fix it. Hopefully on the right track, though. -Fyrd
+      } else if (attr === '#href') {
+        setHref(elem, newValue)
+      } else if (newValue) {
+        elem.setAttribute(attr, newValue)
+      } else if (typeof newValue === 'number') {
+        elem.setAttribute(attr, newValue)
+      } else {
+        elem.removeAttribute(attr)
+      }
+
+      // Go into "select" mode for text changes
+      // NOTE: Important that this happens AFTER elem.setAttribute() or else attributes like
+      // font-size can get reset to their old value, ultimately by svgEditor.updateContextPanel(),
+      // after calling textActions.toSelectMode() below
+      if (svgCanvas.getCurrentMode() === 'textedit' && attr !== '#text' && elem.textContent.length) {
+        svgCanvas.textActions.toSelectMode(elem)
+      }
+
+      // Use the Firefox ffClone hack for text elements with gradients or
+      // where other text attributes are changed.
+      if (isGecko() &&
+        elem.nodeName === 'text' &&
+        (/rotate/).test(elem.getAttribute('transform')) &&
+        (String(newValue).startsWith('url') || (['font-size', 'font-family', 'x', 'y'].includes(attr) && elem.textContent))) {
+        elem = ffClone(elem)
+      }
+      // Timeout needed for Opera & Firefox
+      // codedread: it is now possible for this function to be called with elements
+      // that are not in the selectedElements array, we need to only request a
+      // selector if the element is in that array
+      if (selectedElements.includes(elem)) {
+        setTimeout(function () {
+          // Due to element replacement, this element may no longer
+          // be part of the DOM
+          if (!elem.parentNode) { return }
+          svgCanvas.selectorManager.requestSelector(elem).resize()
+        }, 0)
+      }
+      // if this element was rotated, and we changed the position of this element
+      // we need to update the rotational transform attribute
+      const angle = getRotationAngle(elem)
+      if (angle !== 0 && attr !== 'transform') {
+        const tlist = elem.transform?.baseVal
+        let n = tlist.numberOfItems
+        while (n--) {
+          const xform = tlist.getItem(n)
+          if (xform.type === 4) {
+            // remove old rotate
+            tlist.removeItem(n)
+
+            const box = utilsGetBBox(elem)
+            const center = transformPoint(
+              box.x + box.width / 2, box.y + box.height / 2, transformListToTransform(tlist).matrix
+            )
+            const cx = center.x
+            const cy = center.y
+            const newrot = svgCanvas.getSvgRoot().createSVGTransform()
+            newrot.setRotate(angle, cx, cy)
+            tlist.insertItemBefore(newrot, n)
+            break
+          }
+        }
+      }
+    } // if oldValue != newValue
+  } // for each elem
+}
+
+/**
+* Change the given/selected element and add the original value to the history stack.
+* If you want to change all `selectedElements`, ignore the `elems` argument.
+* If you want to change only a subset of `selectedElements`, then send the
+* subset to this function in the `elems` argument.
+* @function module:svgcanvas.SvgCanvas#changeSelectedAttribute
+* @param {string} attr - String with the attribute name
+* @param {string|Float} val - String or number with the new attribute value
+* @param {Element[]} elems - The DOM elements to apply the change to
+* @returns {void}
+*/
+export const changeSelectedAttributeMethod = function (attr, val, elems) {
+  const selectedElements = svgCanvas.getSelectedElements()
+  elems = elems || selectedElements
+  svgCanvas.undoMgr.beginUndoableChange(attr, elems)
+
+  changeSelectedAttributeNoUndoMethod(attr, val, elems)
+
+  const batchCmd = svgCanvas.undoMgr.finishUndoableChange()
+  if (!batchCmd.isEmpty()) {
+    // svgCanvas.addCommandToHistory(batchCmd);
+    svgCanvas.undoMgr.addCommandToHistory(batchCmd)
+  }
+}

packages/svgcanvas/units.js

@@ -0,0 +1,260 @@
+/**
+ * Tools for working with units.
+ * @module units
+ * @license MIT
+ *
+ * @copyright 2010 Alexis Deveria, 2010 Jeff Schiller
+ */
+
+const NSSVG = 'http://www.w3.org/2000/svg'
+
+const wAttrs = ['x', 'x1', 'cx', 'rx', 'width']
+const hAttrs = ['y', 'y1', 'cy', 'ry', 'height']
+const unitAttrs = ['r', 'radius', ...wAttrs, ...hAttrs]
+
+// Container of elements.
+let elementContainer_
+
+// Stores mapping of unit type to user coordinates.
+let typeMap_ = {}
+
+/**
+ * @interface module:units.ElementContainer
+ */
+/**
+ * @function module:units.ElementContainer#getBaseUnit
+ * @returns {string} The base unit type of the container ('em')
+ */
+/**
+ * @function module:units.ElementContainer#getElement
+ * @returns {?Element} An element in the container given an id
+ */
+/**
+ * @function module:units.ElementContainer#getHeight
+ * @returns {Float} The container's height
+ */
+/**
+ * @function module:units.ElementContainer#getWidth
+ * @returns {Float} The container's width
+ */
+/**
+ * @function module:units.ElementContainer#getRoundDigits
+ * @returns {Integer} The number of digits number should be rounded to
+ */
+
+/**
+ * @typedef {PlainObject} module:units.TypeMap
+ * @property {Float} em
+ * @property {Float} ex
+ * @property {Float} in
+ * @property {Float} cm
+ * @property {Float} mm
+ * @property {Float} pt
+ * @property {Float} pc
+ * @property {Integer} px
+ * @property {0} %
+ */
+
+/**
+ * Initializes this module.
+ *
+ * @function module:units.init
+ * @param {module:units.ElementContainer} elementContainer - An object implementing the ElementContainer interface.
+ * @returns {void}
+ */
+export const init = function (elementContainer) {
+  elementContainer_ = elementContainer
+
+  // Get correct em/ex values by creating a temporary SVG.
+  const svg = document.createElementNS(NSSVG, 'svg')
+  document.body.append(svg)
+  const rect = document.createElementNS(NSSVG, 'rect')
+  rect.setAttribute('width', '1em')
+  rect.setAttribute('height', '1ex')
+  rect.setAttribute('x', '1in')
+  svg.append(rect)
+  const bb = rect.getBBox()
+  svg.remove()
+
+  const inch = bb.x
+  typeMap_ = {
+    em: bb.width,
+    ex: bb.height,
+    in: inch,
+    cm: inch / 2.54,
+    mm: inch / 25.4,
+    pt: inch / 72,
+    pc: inch / 6,
+    px: 1,
+    '%': 0
+  }
+}
+
+/**
+* Group: Unit conversion functions.
+*/
+
+/**
+ * @function module:units.getTypeMap
+ * @returns {module:units.TypeMap} The unit object with values for each unit
+*/
+export const getTypeMap = () => {
+  return typeMap_
+}
+
+/**
+* @typedef {GenericArray} module:units.CompareNumbers
+* @property {Integer} length 2
+* @property {Float} 0
+* @property {Float} 1
+*/
+
+/**
+* Rounds a given value to a float with number of digits defined in
+* `round_digits` of `saveOptions`
+*
+* @function module:units.shortFloat
+* @param {string|Float|module:units.CompareNumbers} val - The value (or Array of two numbers) to be rounded
+* @returns {Float|string} If a string/number was given, returns a Float. If an array, return a string
+* with comma-separated floats
+*/
+export const shortFloat = (val) => {
+  const digits = elementContainer_.getRoundDigits()
+  if (!isNaN(val)) {
+    return Number(Number(val).toFixed(digits))
+  }
+  if (Array.isArray(val)) {
+    return shortFloat(val[0]) + ',' + shortFloat(val[1])
+  }
+  return Number.parseFloat(val).toFixed(digits) - 0
+}
+
+/**
+* Converts the number to given unit or baseUnit.
+* @function module:units.convertUnit
+* @param {string|Float} val
+* @param {"em"|"ex"|"in"|"cm"|"mm"|"pt"|"pc"|"px"|"%"} [unit]
+* @returns {Float}
+*/
+export const convertUnit = (val, unit) => {
+  unit = unit || elementContainer_.getBaseUnit()
+  // baseVal.convertToSpecifiedUnits(unitNumMap[unit]);
+  // const val = baseVal.valueInSpecifiedUnits;
+  // baseVal.convertToSpecifiedUnits(1);
+  return shortFloat(val / typeMap_[unit])
+}
+
+/**
+* Sets an element's attribute based on the unit in its current value.
+*
+* @function module:units.setUnitAttr
+* @param {Element} elem - DOM element to be changed
+* @param {string} attr - Name of the attribute associated with the value
+* @param {string} val - Attribute value to convert
+* @returns {void}
+*/
+export const setUnitAttr = (elem, attr, val) => {
+  elem.setAttribute(attr, val)
+}
+
+const attrsToConvert = {
+  line: ['x1', 'x2', 'y1', 'y2'],
+  circle: ['cx', 'cy', 'r'],
+  ellipse: ['cx', 'cy', 'rx', 'ry'],
+  foreignObject: ['x', 'y', 'width', 'height'],
+  rect: ['x', 'y', 'width', 'height'],
+  image: ['x', 'y', 'width', 'height'],
+  use: ['x', 'y', 'width', 'height'],
+  text: ['x', 'y']
+}
+
+/**
+* Converts all applicable attributes to the configured baseUnit.
+* @function module:units.convertAttrs
+* @param {Element} element - A DOM element whose attributes should be converted
+* @returns {void}
+*/
+export const convertAttrs = (element) => {
+  const elName = element.tagName
+  const unit = elementContainer_.getBaseUnit()
+  const attrs = attrsToConvert[elName]
+  if (!attrs) { return }
+
+  attrs.forEach((attr) => {
+    const cur = element.getAttribute(attr)
+    if (cur && !isNaN(cur)) {
+      element.setAttribute(attr, (cur / typeMap_[unit]) + unit)
+    }
+  })
+}
+
+/**
+* Converts given values to numbers. Attributes must be supplied in
+* case a percentage is given.
+*
+* @function module:units.convertToNum
+* @param {string} attr - Name of the attribute associated with the value
+* @param {string} val - Attribute value to convert
+* @returns {Float} The converted number
+*/
+export const convertToNum = (attr, val) => {
+  // Return a number if that's what it already is
+  if (!isNaN(val)) { return val - 0 }
+  if (val.substr(-1) === '%') {
+    // Deal with percentage, depends on attribute
+    const num = val.substr(0, val.length - 1) / 100
+    const width = elementContainer_.getWidth()
+    const height = elementContainer_.getHeight()
+
+    if (wAttrs.includes(attr)) {
+      return num * width
+    }
+    if (hAttrs.includes(attr)) {
+      return num * height
+    }
+    return num * Math.sqrt((width * width) + (height * height)) / Math.sqrt(2)
+  }
+  const unit = val.substr(-2)
+  const num = val.substr(0, val.length - 2)
+  // Note that this multiplication turns the string into a number
+  return num * typeMap_[unit]
+}
+
+/**
+* Check if an attribute's value is in a valid format.
+* @function module:units.isValidUnit
+* @param {string} attr - The name of the attribute associated with the value
+* @param {string} val - The attribute value to check
+* @param {Element} selectedElement
+* @returns {boolean} Whether the unit is valid
+*/
+export const isValidUnit = (attr, val, selectedElement) => {
+  if (unitAttrs.includes(attr)) {
+    // True if it's just a number
+    if (!isNaN(val)) {
+      return true
+    }
+    // Not a number, check if it has a valid unit
+    val = val.toLowerCase()
+    return Object.keys(typeMap_).some((unit) => {
+      const re = new RegExp('^-?[\\d\\.]+' + unit + '$')
+      return re.test(val)
+    })
+  }
+  if (attr === 'id') {
+    // if we're trying to change the id, make sure it's not already present in the doc
+    // and the id value is valid.
+
+    let result = false
+    // because getElement() can throw an exception in the case of an invalid id
+    // (according to https://www.w3.org/TR/xml-id/ IDs must be a NCName)
+    // we wrap it in an exception and only return true if the ID was valid and
+    // not already present
+    try {
+      const elem = elementContainer_.getElement(val)
+      result = (!elem || elem === selectedElement)
+    } catch (e) { console.error(e) }
+    return result
+  }
+  return true
+}