third_party/WebKit/LayoutTests/fast/canvas/canvas-longlived-context.js

   1 description("This test ensures that Canvas and CanvasRenderingContext2D work correctly if the rendering context outlives the canvas element");
   2
   3 function dataToArray(data) {
   4     var result = new Array(data.length)
   5     for (var i = 0; i < data.length; i++)
   6         result[i] = data[i];
   7     return result;
   8 }
   9
  10 function getPixel(x, y) {
  11     var data = context.getImageData(x,y,1,1);
  12     if (!data) // getImageData failed, which should never happen
  13         return [-1,-1,-1,-1];
  14     return dataToArray(data.data);
  15 }
  16
  17 function pixelShouldBe(x, y, colour) {
  18     shouldBe("getPixel(" + [x, y] +")", "["+colour+"]");
  19 }
  20
  21 function prepareCanvas() {
  22     var context = document.createElement("canvas").getContext("2d");
  23     context.fillStyle = "green";
  24     context.fillRect(0,0,100,100);
  25     return context;
  26 }
  27
  28 function clobberGC(count) {
  29     for (var i = 0; i < 5000; ++i)
  30         ({a: i*i*i*0.5+"str", b: i/Math.sqrt(i)});
  31     if (count > 0)
  32         clobberGC(count-1);
  33 }
  34
  35 function test() {
  36     context = prepareCanvas();
  37     clobberGC(40);
  38     pixelShouldBe(50, 50, [0, 128, 0, 255]);
  39 }
  40 test();