svgedit/src/editor/Rulers.js

import { getTypeMap } from '../common/units.js';
import rulersTemplate from './templates/rulersTemplate.js';
/**
 *
 */
class Rulers {
  /**
   * @type {Module}
  */
  constructor (editor) {
    // Make [1,2,5] array
    this.rulerIntervals = [];
    for (let i = 0.1; i < 1e5; i *= 10) {
      this.rulerIntervals.push(i);
      this.rulerIntervals.push(2 * i);
      this.rulerIntervals.push(5 * i);
    }
    this.svgCanvas = editor.svgCanvas;
    this.editor = editor;
    // add rulers component to the DOM
    this.editor.$svgEditor.append(rulersTemplate.content.cloneNode(true));
    const { $id } = this.svgCanvas;
    this.rulerX = $id('ruler_x');
    this.rulerY = $id('ruler_y');
    this.rulerCorner = $id('ruler_corner');
  }
  display (on) {
    if (on) {
      this.rulerX.style.removeProperty('display');
      this.rulerY.style.removeProperty('display');
      this.rulerCorner.style.removeProperty('display');
    } else {
      this.rulerX.style.display = 'none';
      this.rulerY.style.display = 'none';
      this.rulerCorner.style.display = 'none';
    }
  }
  /**
   * @type {Module}
  */
  manageScroll () {
    if (this.rulerX) this.rulerX.scrollLeft = this.editor.workarea.scrollLeft;
    if (this.rulerY) this.rulerY.scrollTop = this.editor.workarea.scrollTop;
  }

  /**
   *
   * @param {HTMLDivElement} [scanvas]
   * @param {Float} [zoom]
   * @returns {void}
   */
  updateRulers (scanvas, zoom) {
    if (!zoom) { zoom = this.svgCanvas.getZoom(); }
    if (!scanvas) { scanvas = document.getElementById('svgcanvas'); }

    let d; let i;
    const limit = 30000;
    const contentElem = this.svgCanvas.getContentElem();
    const units = getTypeMap();
    const unit = units[this.editor.configObj.curConfig.baseUnit]; // 1 = 1px

    // draw x ruler then y ruler
    for (d = 0; d < 2; d++) {
      const isX = (d === 0);
      const dim = isX ? 'x' : 'y';
      const lentype = isX ? 'width' : 'height';
      const contentDim = Number(contentElem.getAttribute(dim));
      const { $id } = this.svgCanvas;
      const $hcanvOrig = $id('ruler_' + dim).querySelector('canvas');

      // Bit of a hack to fully clear the canvas in Safari & IE9
      const $hcanv = $hcanvOrig.cloneNode(true);
      // eslint-disable-next-line no-unsanitized/property
      $hcanvOrig.replaceWith($hcanv);

      const hcanv = $hcanv;

      // Set the canvas size to the width of the container
      let rulerLen;
      if(lentype === 'width'){
        rulerLen = parseFloat(getComputedStyle(scanvas, null).width.replace("px", ""));
      } else if(lentype === 'height'){
        rulerLen = parseFloat(getComputedStyle(scanvas, null).height.replace("px", ""));
      }
      const totalLen = rulerLen;
      hcanv.parentNode.style[lentype] = totalLen + 'px';
      let ctx = hcanv.getContext('2d');
      let ctxArr; let num; let ctxArrNum;

      ctx.fillStyle = 'rgb(200,0,0)';
      ctx.fillRect(0, 0, hcanv.width, hcanv.height);

      // Remove any existing canvasses
      const elements = Array.prototype.filter.call($hcanv.parentNode.children, function(child){
        return child !== $hcanv;
      });
      Array.from(elements).forEach(function(element) {
        element.remove();
      });

      // Create multiple canvases when necessary (due to browser limits)
      if (rulerLen >= limit) {
        ctxArrNum = Number.parseInt(rulerLen / limit) + 1;
        ctxArr = [];
        ctxArr[0] = ctx;
        let copy;
        for (i = 1; i < ctxArrNum; i++) {
          hcanv[lentype] = limit;
          copy = hcanv.cloneNode(true);
          hcanv.parentNode.append(copy);
          ctxArr[i] = copy.getContext('2d');
        }

        copy[lentype] = rulerLen % limit;

        // set copy width to last
        rulerLen = limit;
      }

      hcanv[lentype] = rulerLen;

      const uMulti = unit * zoom;

      // Calculate the main number interval
      const rawM = 50 / uMulti;
      let multi = 1;
      for (i = 0; i < this.rulerIntervals.length; i++) {
        num = this.rulerIntervals[i];
        multi = num;
        if (rawM <= num) {
          break;
        }
      }

      const bigInt = multi * uMulti;

      ctx.font = '9px sans-serif';

      let rulerD = ((contentDim / uMulti) % multi) * uMulti;
      let labelPos = rulerD - bigInt;
      // draw big intervals
      let ctxNum = 0;
      while (rulerD < totalLen) {
        labelPos += bigInt;
        // const realD = rulerD - contentDim; // Currently unused

        const curD = Math.round(rulerD) + 0.5;
        if (isX) {
          ctx.moveTo(curD, 15);
          ctx.lineTo(curD, 0);
        } else {
          ctx.moveTo(15, curD);
          ctx.lineTo(0, curD);
        }

        num = (labelPos - contentDim) / uMulti;
        let label;
        if (multi >= 1) {
          label = Math.round(num);
        } else {
          const decs = String(multi).split('.')[1].length;
          label = num.toFixed(decs);
        }

        // Change 1000s to Ks
        if (label !== 0 && label !== 1000 && label % 1000 === 0) {
          label = (label / 1000) + 'K';
        }

        if (isX) {
          ctx.fillText(label, rulerD + 2, 8);
        } else {
          // draw label vertically
          const str = String(label).split('');
          for (i = 0; i < str.length; i++) {
            ctx.fillText(str[i], 1, (rulerD + 9) + i * 9);
          }
        }

        const part = bigInt / 10;
        // draw the small intervals
        for (i = 1; i < 10; i++) {
          let subD = Math.round(rulerD + part * i) + 0.5;
          if (ctxArr && subD > rulerLen) {
            ctxNum++;
            ctx.stroke();
            if (ctxNum >= ctxArrNum) {
              i = 10;
              rulerD = totalLen;
              continue;
            }
            ctx = ctxArr[ctxNum];
            rulerD -= limit;
            subD = Math.round(rulerD + part * i) + 0.5;
          }

          // odd lines are slighly longer
          const lineNum = (i % 2) ? 12 : 10;
          if (isX) {
            ctx.moveTo(subD, 15);
            ctx.lineTo(subD, lineNum);
          } else {
            ctx.moveTo(15, subD);
            ctx.lineTo(lineNum, subD);
          }
        }
        rulerD += bigInt;
      }
      ctx.strokeStyle = '#000';
      ctx.stroke();
    }
  }
}

export default Rulers;