# related specs

- CanvasRenderingContext2D
  - https://html.spec.whatwg.org/multipage/scripting.html#canvasrenderingcontext2d
  - https://html.spec.whatwg.org/multipage/scripting.html#pixel-manipulation
 - WebIDL
  - http://heycam.github.io/webidl/#es-double

# description

1. `CanvasRenderingContext2D.putImageData` says that to throw a NotSupportedError exception if any of the arguments are not finite, and the methods takes `double` as its arguments.

2. On the other hand, by WebIDL spec, `double` value type raises `TypeError` if the value is not finite when conversioning from ECMAScript to IDL Value.

3. By the above, `CanvasRenderingContext2D.putImageData` cannot throw a `NotSupportedError` because WebIDL conversion steps will raise a `TypeError` before arguments are passed to `CanvasRenderingContext2D.putImageData`, if values of arguments are not finite.

4. I found the same spec issue with "HTML Canvas 2D Context Editor's Draft 13 November 2014": http://www.w3.org/html/wg/drafts/2dcontext/html5_canvas_CR/#dom-context-2d-putimagedata