[whatwg] ImageData constructor questions

[Dirk Schulze]

Hi, 

I was reading the spec part about ImageData [1].

1) 
I noticed that createImageData() is explicit that it represent a transparent black rectangle. The constructor for ImageData is not that explicit.

2)
The last step of the 2nd constructor that takes an Uint8ClampedArray says:
"	• Return a new ImageData object whose width is sw, whose height is height, and whose data is source.”

Is data a reference to the original source or a copy of source? For the former, there might be two ImageData objects referencing the same ByteArray. How would that be useful?

Greetings,
Dirk

[1] http://www.whatwg.org/specs/web-apps/current-work/multipage/the-canvas-element.html#dfnReturnLink-7 (4.12.4.2.16 Pixel manipulation)