chrome/test/data/third_party/spaceport/js/sprites/renderers/canvasDrawImagePartialClear.js

   1 define([ 'util/ensureCallback', 'sprites/canvas' ], function (ensureCallback, canvas) {
   2     function RenderContext(sourceData, frameData) {
   3         this.sourceData = sourceData;
   4         this.frameData = frameData;
   5
   6         this.previousTransforms = null;
   7         this.previousFrameIndex = null;
   8
   9         this.canvas = canvas();
  10
  11         this.context = this.canvas.getContext('2d');
  12         this.context.globalCompositeOperation = 'source-over';
  13     }
  14
  15     RenderContext.prototype.load = function load(callback) {
  16         callback = ensureCallback(callback);
  17
  18         document.body.appendChild(this.canvas);
  19
  20         callback(null);
  21     };
  22
  23     RenderContext.prototype.unload = function unload() {
  24         if (this.canvas.parentNode) {
  25             this.canvas.parentNode.removeChild(this.canvas);
  26         }
  27     };
  28
  29     RenderContext.prototype.clear = function clear() {
  30         this.canvas.width = this.canvas.width;
  31         this.previousTransforms = null;
  32     };
  33
  34     RenderContext.prototype.renderFrame = function renderFrame(frameIndex) {
  35         var context = this.context;
  36         var sourceData = this.sourceData;
  37
  38         var transforms = this.frameData[frameIndex];
  39         var count = transforms.length;
  40         var i;
  41
  42         var previousTransforms = this.previousTransforms;
  43         if (previousTransforms) {
  44             // We clear with an extra 1px border to clear smoothed edges
  45             var frameInfo = sourceData.getFrameInfo(this.previousFrameIndex);
  46             var width = frameInfo.width + 2;
  47             var height = frameInfo.height + 2;
  48             for (i = 0; i < count; ++i) {
  49                 var m = previousTransforms[i].matrix;
  50                 context.setTransform(m[0], m[1], m[3], m[4], m[2], m[5]);
  51                 context.clearRect(-1, -1, width, height);
  52             }
  53         }
  54
  55         for (i = 0; i < count; ++i) {
  56             var m = transforms[i].matrix;
  57             context.setTransform(m[0], m[1], m[3], m[4], m[2], m[5]);
  58             sourceData.drawToCanvas(context, 0, 0, frameIndex);
  59         }
  60
  61         this.previousTransforms = transforms;
  62         this.previousFrameIndex = frameIndex;
  63     };
  64
  65     return function (element, frameData) {
  66         return new RenderContext(element, frameData);
  67     };
  68 });