Canvas over SVG Bug Part 2 (2015)

Canvas over SVG Bug: Part 2

source: gist.github.com/gists/1311230 6

<!DOCTYPE html>
<html>
<head>
  <title>Canvas over SVG Bug: Part 2</title>
  <style type="text/css">
    #chart { width:240px; height:240px; background-color: #f7f2c5; position: relative }
    #canvas1 { background-color: #f7f2c5; display: table-row-group }
    #description { margin: 0px 20px; width:580px }
    h1 { font-size: 1.2em; line-height: 1.2em; margin: 5px 5px 5px 60px;}
    circle { stroke: #ff0000; stroke-width: 4px; fill: #ffffff; fill-opacity: 0.2 }
    ul.vlist { margin: 5px; display: inline-table }
    ul.vlist li { margin: 5px; list-style-type: none }
    ul.hlist { margin: 5px }
    ul.hlist li { margin: 5px; display: inline-table; vertical-align: top; list-style-type: none }
    fieldset { margin: 0px 40px 10px 20px }
    canvas {
      image-rendering: optimizeSpeed !important;
      image-rendering: -moz-crisp-edges !important;
      image-rendering: -webkit-optimize-contrast !important;
      image-rendering: optimize-contrast !important;
      -ms-interpolation-mode: nearest-neighbor !important;
    }
  </style>
</head>
<div id="container">
  <h1 id="title">Canvas over SVG Bug</h1>
  <ul class="hlist">
    <li>
      <canvas id='canvas1' width="240", height="240"></canvas>
      <div id='chart'>
        <svg width="240" height="240">
          <g transform="translate(20,20)">
            <rect width="200" height="200" style="fill: #eeeeee; " pointer-events="all"></rect>
            <circle cx="100" cy="100" r="60"></circle>
          </g>
        </svg>
      </div>
    </li>
    <li>
      <div id="description">
        <fieldset>
          <legend>Canvas Controller</legend>
          <label><button type="button" id="create-canvas">Create Canvas</button></label>
          <label><button type="button" id="draw-canvas">Draw Into Canvas</button></label>
        </fieldset>
        <p>
          This page exposed a <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=695959">
          Canvas-related bug in FireFox</a> and in 
          <a href="https://social.msdn.microsoft.com/Forums/en-US/iewebdevelopment/thread/9c1e01fb-2592-4f6f-a623-edcfb655e8e5">IE9</a>. 
          Initially there is a gray SVG document with a
          red circle. After clicking the <b>Create Canvas</b> button a Canvas object is created
          with a red border and a translucent green background. This Canvas object is layered
          above the SVG object and inset by 10px. When you then click the <b>Draw Into Canvas</b>
          button a blue line is drawn into the Canvas.        </p>
        <p>
          On FireFox 7.0.1, FireFox Nightly and IE9 when the ctx.stroke() function is called
          to complete the line the background of the canvas is erased and becomes transparent.
        </p>
        <p>
          This only replicates part of the problem described here:
          <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=695959">Canvas-related bug in FireFox</a>.
          When starting the model in this page <a href="https://stepheneb.github.com/avalanche2d-js/avalanche2d.html">
          Avalanche-JS Demo</a> no lines are drawn in the graph on the right while the model is running.
          This is the time that the Canvas object is being draw into.
        </p>
        <p>
          This is a WIP attempt to more fully replicate the bug by adding in more elements similar
          to the actual application. So far I have been unsuccessful and only the first part of 
          the bug is exposed. The simpler version of the Canvas over SVG Bug is here: 
          <a href="https://bl.ocks.org/1302790">https://bl.ocks.org/1302790</a>
        </p>
      </div>
    </li>
  </ul>
</div>
<script type="text/javascript">

window.onload=function() {

var plot, canvas, ctx1, ctx2;
    var chart = document.getElementById("chart");
    var canvas1 = document.getElementById("canvas1");

function createHeatMap() {
      var ctx2 = canvas1.getContext('2d');
      ctx2.fillStyle = "rgb(0,0,0)";
      ctx2.globalCompositeOperation = "destination-atop";

canvas1.style.width = canvas1.clientWidth + 'px';
      canvas1.style.height = canvas1.clientHeight + 'px';
      canvas1.width = 60;
      canvas1.height = 60;

var imageData = ctx2.getImageData(0, 0, 60, 60);
      var data = imageData.data;
      var pix_index = 0;
      for (var y = 0; y < 60; y++) {
          ycols = y * 60;
          pix_index = ycols * 4;
          for (var x = 0; x < 60; x++) {
              data[pix_index]     = Math.floor(Math.random()*255);
              data[pix_index + 1] = Math.floor(Math.random()*255);
              data[pix_index + 2] = Math.floor(Math.random()*255);
              data[pix_index + 3] = 255;
              pix_index += 4;
          }
      };
      ctx2.putImageData(imageData, 0, 0);
    };
    
    createHeatMap();

var create_canvas = document.getElementById("create-canvas");
    var draw_canvas  =  document.getElementById("draw-canvas");
    
    function createCanvasButton () {
      createCanvas();
    };

create_canvas.onclick = createCanvasButton;

function drawCanvasButton () {
      drawInCanvas();
    };

draw_canvas.onclick = drawCanvasButton;
    
  };
</script>
</body>
</html>