fix(text-actions): Calculate accumulated transform matrix for text inside groups (#1082)

When editing text inside a group element, the text cursor was appearing
in the wrong position because only the text element's own transform was
being considered, ignoring transforms from parent groups.

This change:
- Adds a new #getAccumulatedMatrix() method that traverses up the DOM tree
  from the text element to the SVG content element, collecting and multiplying
  all transform matrices along the way
- Updates the init() method to use this accumulated matrix instead of just
  the text element's transform
- Updates test mock to include getSvgContent() method

Fixes the issue where editing text inside a transformed group would show
the cursor at the wrong position.

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

packages/svgcanvas/core/text-actions.js

@@ -6,7 +6,7 @@
  */
 
 import { NS } from './namespaces.js'
-import { transformPoint, getMatrix } from './math.js'
+import { transformPoint, matrixMultiply, getTransformList, transformListToTransform } from './math.js'
 import {
   assignAttributes,
   getElement,
@@ -44,6 +44,40 @@ class TextActions {
   #lastY = null
   #allowDbl = false
 
+  /**
+   * Get the accumulated transformation matrix from the element up to the SVG content element.
+   * This includes transforms from all parent groups, fixing the issue where text cursor
+   * appears in the wrong position when editing text inside a transformed group.
+   * @param {Element} elem - The element to get the accumulated matrix for
+   * @returns {SVGMatrix|null} The accumulated transformation matrix, or null if none
+   * @private
+   */
+  #getAccumulatedMatrix = (elem) => {
+    const svgContent = svgCanvas.getSvgContent()
+    const matrices = []
+
+    let current = elem
+    while (current && current !== svgContent && current.nodeType === 1) {
+      const tlist = getTransformList(current)
+      if (tlist && tlist.numberOfItems > 0) {
+        const matrix = transformListToTransform(tlist).matrix
+        matrices.unshift(matrix) // Add to beginning to maintain correct order
+      }
+      current = current.parentNode
+    }
+
+    if (matrices.length === 0) {
+      return null
+    }
+
+    if (matrices.length === 1) {
+      return matrices[0]
+    }
+
+    // Multiply all matrices together
+    return matrixMultiply(...matrices)
+  }
+
   /**
    *
    * @param {Integer} index
@@ -526,11 +560,12 @@ class TextActions {
     const str = this.#curtext.textContent
     const len = str.length
 
-    const xform = this.#curtext.getAttribute('transform')
-
     this.#textbb = utilsGetBBox(this.#curtext)
 
-    this.#matrix = xform ? getMatrix(this.#curtext) : null
+    // Calculate accumulated transform matrix including all parent groups
+    // This fixes the issue where text cursor appears in wrong position
+    // when editing text inside a group with transforms
+    this.#matrix = this.#getAccumulatedMatrix(this.#curtext)
 
     this.#chardata = []
     this.#chardata.length = len

tests/unit/text-actions.test.js

@@ -18,12 +18,17 @@ describe('TextActions', () => {
     svgRoot.setAttribute('height', '480')
     document.body.append(svgRoot)
 
+    // Create svgContent element (container for SVG content)
+    const svgContent = document.createElementNS(NS.SVG, 'svg')
+    svgContent.id = 'svgcontent'
+    svgRoot.append(svgContent)
+
     textElement = document.createElementNS(NS.SVG, 'text')
     textElement.setAttribute('x', '100')
     textElement.setAttribute('y', '100')
     textElement.setAttribute('id', 'text1')
     textElement.textContent = 'Test'
-    svgRoot.append(textElement)
+    svgContent.append(textElement)
 
     // Mock text measurement methods
     textElement.getStartPositionOfChar = vi.fn((i) => ({ x: 100 + i * 10, y: 100 }))
@@ -55,6 +60,7 @@ describe('TextActions', () => {
     // Mock svgCanvas
     svgCanvas = {
       getSvgRoot: () => svgRoot,
+      getSvgContent: () => svgContent,
       getZoom: () => 1,
       setCurrentMode: vi.fn(),
       clearSelection: vi.fn(),