[whatwg] canvas elements <rect> <polygon> etc

[ddailey]

Maciej wrote:
>
> <canvas> is a programmatic immediate mode drawing surface. For 
> retained-mode structured graphics, SVG would be your solution. Both 
> things are useful.

I would like to believe that Canvas is useful, but being both naive and 
stubborn, I don't yet see why.

In reading through the WHATWG draft, there are about N things that it seems 
to be talking about. I see N-2 of those as redundant with the SVG specs. The 
two components that jump out at me as missing from SVG are getImageData and 
putImageData -- the former being used, as I understand it, by Opera and 
perhaps others, to interrogate pixel values and to gather rectangular 
sub-bitmaps. Both of these are things that it would be nice (for me) if SVG 
had. The other N-2 things are already present in SVG,  in addition to N*5 
other things that are not in Canvas.

Those who have worked with Canvas for the past several years have probably 
written documents somewhere to explain just why the two specs (SVG and 
Canvas) should not be merged. If someone could point me toward that 
rationale, I will emerge enlightened and grateful (having shed both my 
naivite and my stubbornness).

In the meantime asking browser developers to implement both SVG and Canvas 
(given what looks like a high percentage of overlap in function) just seems 
like a way to artificially pump up staffing levels on browser development 
projects.

ddailey