third_party/WebKit/LayoutTests/fast/canvas/getPutImageDataPairTest.html

   1 <!DOCTYPE html>
   2 <title>putImageData(getImageData) pair test</title>
   3 <body class="show_output">
   4 <h3>Test that putImageData(getImageData) pair leaves canvas ImageData the same.</h3>
   5 <canvas id="c" class="output" width="64" height="64"><p class="fallback">FAIL (fallback content)</p></canvas>
   6 <br>
   7 Result: <a id="result"></a>
   8 <script>
   9 if (window.testRunner)
  10     testRunner.dumpAsText();
  11
  12 var canvas = document.getElementById("c");
  13 var ctx = canvas.getContext("2d");
  14 var passed = getPutImageData(50, ctx, 0, 0, 0, 0.0);
  15 passed |= getPutImageData(50, ctx, 0, 0, 0, 0.5);
  16 passed |= getPutImageData(50, ctx, 0, 0, 0, 1.0);
  17 passed |= getPutImageData(50, ctx, 127, 128, 129, 0.49);
  18 passed |= getPutImageData(50, ctx, 127, 128, 129, 0.51);
  19 passed |= getPutImageData(50, ctx, 127, 128, 129, 0.5);
  20 passed |= getPutImageData(50, ctx, 128, 128, 128, 0.0);
  21 passed |= getPutImageData(50, ctx, 128, 128, 128, 0.5);
  22 passed |= getPutImageData(50, ctx, 128, 128, 128, 1.0);
  23
  24 var result_a = document.getElementById("result");
  25 if (!passed)
  26     result_a.innerHTML = "FAIL";
  27 else
  28     result_a.innerHTML = "PASS";
  29
  30 function getPutImageData(numIters, ctx, r, g, b, a) {
  31     var x = 0, y = 0, w = ctx.canvas.width, h = ctx.canvas.height;
  32
  33     // Paint the canvas green to start
  34     ctx.fillStyle = color;
  35     ctx.fillRect(x,y,w,h);
  36
  37     // Now paint the canvas a random hue of gray
  38     var color = 'rgba(' + r + ',' + g + ',' + b + ',' + a + ')';
  39     ctx.fillStyle = color;
  40     ctx.fillRect(x,y,w,h);
  41
  42     // Get the current "original" image data
  43     var origImageData = ctx.getImageData(x, y, w, h);
  44     ctx.putImageData(origImageData, x, y);
  45
  46     // Get and put the image data 'numIters' times
  47     for(var i = 0; i < numIters; i++)
  48         ctx.putImageData(ctx.getImageData(x,y,w,h), x,y);
  49
  50     // Grab new current image data
  51     var currImageData = ctx.getImageData(x, y, w, h);
  52
  53     // Verify that original and new current image datas are equal
  54     for(var i = 0; i < currImageData.data.length; i++) {
  55         var origSubpixel = origImageData.data[i];
  56         var currSubpixel = currImageData.data[i];
  57
  58         // If even 1 subpixel is off, return failure
  59         if (origSubpixel != currSubpixel)
  60             return false;
  61     }
  62     return true;
  63 }
  64 </script>