[whatwg] Canvas element

Dimitri Glazkov dimitri.glazkov at gmail.com
Wed Apr 20 15:40:11 PDT 2005

Oh yeah, I agree on programmable image being quite useful. The
question is why only limit the capability to a special CANVAS element
(whose semantics are questionable), when any block-level element could
have this ability.

The thing is, programmable image is with almost 100% certainty will be
a presentational graphic. And presentational graphic has no place in
markup. Therefore, if you utilize rendering context to create a
dynamic image, you won't necessarily be doing it inside of an IMG (or
CANVAS) element -- the dynamic image will be a presentational graphic
for the content, expressed in markup.

Take your example with eyes and hair, for instance. This is the markup
that I would expect seeing instead of a canvas element (I am
improvising here):

<span class="photorobot">
<span class="hairColor">green</span>
<span class="eyeColor">yellow</span>
<span class="mouthType">puckered</span>

Then the behavior would be attached to span.photorobot to create a
canvas and draw a mug shot.

Oddly enough, I just wrote about this whole graphics and markup thing
this weekend:



On 4/20/05, Dean Edwards <dean at edwards.name> wrote:
> dolphinling wrote:
> > +1
> >
> >
> > I would ask what semantics canvas has. ol means the content is an
> > ordered list, em means the content is emphasized, span and div mean the
> > content is different, but in a way not associated with any element. Even
> > img and object mean the content is external, (usually) with non-html
> > semantics.
> >
> > At best I can see canvas being equivelant to img and object, but without
> > the use case of the content being external. But even so, they come with
> > default semantics (the image or whatever else is being represented in
> > them) whereas canvas doesn't, it has to be scripted in.
> >
> > So am I missing something here? What semantics does canvas have?
> >
> I see the CANVAS element as analogous to the IMG element. It has similar
> content (it's ultimately an image) but that content is defined
> differently (using script).
> I can certainly see the advantage of having a programmable image. One
> use may be for generating avatars. It would be easier to combine skin
> tone, hair colour, eyes etc programmatically than have thousands of
> images sitting on the server.
> I agree that it may be open to abuse but I've never been convinced that
> this is a good reason to disallow anything.
> -dean

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