[whatwg] Request: Canvas Tag CSS

[Krzysztof Żelechowski]

Dnia 08-04-2008, Wt o godzinie 12:39 +0200, Thomas Broyer pisze:
> On Tue, Apr 8, 2008 at 11:37 AM, Greg Houston wrote:
> >
> >  Between Anne, Thomas and I, we have clearly shown that the individual
> >  shapes within a <canvas> element can indeed be effected by CSS at the
> >  time of their rendering and re-rendering(such as in an animation).
> 
> "at the time of their rendering" is the key. You cannot they are
> "affected by CSS", it's just that your script reads the current
> property value from a stylesheet and uses it to draw the shapes.
> "Affected by CSS" would mean (at least that's my interpretation)
> reacting to CSS changes
> (document.styleSheets[0].cssRules[0].style.color = "black"; or simply
> selecting an alternate stylesheet from your browsers "view" menu).
> Maybe you could say "initialized from CSS"...

It is, however, far more convenient to initialize from JSON.

> 
> >  I have proposed a solution that greatly simplifies effecting canvas
> >  shapes with CSS. Anne and Thomas have offered two work-arounds, one of
> >  which is rather complex, and the other is a strange hack and only
> >  slightly less complex.
> 
> Anne also proposed you the Simplest Thing That Could Possibly Work:
> use search/replace in both CSS and JS.
> Want to change #123456 into #567890? search #123456 and replace with #567890.

Search for #123456 and replace with preferred_colour_for_feature_X()

> 
> I understand what you're asking for, I just don't see the need, as it
> seems to me it'll do more harm than good: as soon as designers will
> start to style your canvas using CSS, they'll start using properties
> that you don't "support" in your drawing script.
> I mean, as Matthieu said, canvas is imperative while CSS is
> declarative, so most of CSS cannot be used with canvas. The only thing
> you can do is read values from the CSS and use them in your canvas
> script.
> In my opinion, you'd rather have a script consisting only of variable
> definitions (à la *.ini or *.properties files) and have your designers
> only update this file (and never touch nor even see the script
> responsible for the actual drawing).

I would recommend using functions instead of variables, 
or using JSON for the whole feature set.

Chris