CSC517 OffScreenCanvas Servo

About Off Screen Canvas: The HTML specification defines a <canvas> element that can use a 2d or 3d rendering context. A new specification was recently developed that defines a canvas that can be used without being associated with an in-page canvas element, allowing for more efficient rendering.

Problem Statement:

typedef (OffscreenCanvasRenderingContext2D or WebGLRenderingContext or WebGL2RenderingContext) OffscreenRenderingContext;

dictionary ImageEncodeOptions {
  DOMString type = "image/png";
  unrestricted double quality = 1.0;
};

enum OffscreenRenderingContextId { "2d", "webgl", "webgl2" };

[Constructor([EnforceRange] unsigned long long width, [EnforceRange] unsigned long long height), Exposed=(Window,Worker), Transferable]
[Pref="dom.offscreen_canvas.enabled"]
interface OffscreenCanvas : EventTarget {
  attribute [EnforceRange] unsigned long long width;
  attribute [EnforceRange] unsigned long long height;

  OffscreenRenderingContext? getContext(OffscreenRenderingContextId contextId, optional any options = null);
  ImageBitmap transferToImageBitmap();
  //Promise<Blob> convertToBlob(optional ImageEncodeOptions options);
};