画布像素数据的跨浏览器规范？

Question

Does anyone happen to know how far back the current canvas pixel-data spec goes in various browsers? And if "not that far", what the previous spec(s) were?

When you call or push pixels, you get / send:

ImageData
  data:   Uint8ClampedArray
  width:  Number
  height: Number

But I know that it used to just be:

{
  data:   Array
  width:  Number
  height: Number
}

So if I'm generating ImageData, how do I detect what I need to generate? Is ImageData && Uint8ClampedArray sufficient? And do I immediately fall back to Object / Array , or something else? Wasn't there a pixel array at some point?

[edit] caniuse says IE10 and Opera Mini don't support Uint8ClampedArray, so... ?

Answer 1

When calling ctx.getImageData() , the specs require the UserAgent to return a TypedArray without specifying which type. The support for TypedArray start with IE10. But, like in IE9, the data property of the ImageData object is a CanvasPixelArray , which has no Constructor method available.

But anyway, the best and IMK only cross-browser way to get the correct ArrayBuffer needed for ImageData Object, is to call ctx.createImageData(width,height) .

Then you can get its data array and you are sure its type will be correct.