- From: Erik Dahlstrom <ed@opera.com>
- Date: Mon, 20 Sep 2010 10:50:17 +0200
- To: public-fx@w3.org
The issue of CSS3 color syntax and support in SVG has been raised as an issue in the SVG WG tracker: http://www.w3.org/Graphics/SVG/WG/track/issues/2224 There are at least two implementations (Firefox and Opera) supporting the rgba/hsla syntax for svg content (for the properties where it makes sense, e.g fill, stroke, stop-color etc). I think it's up to the SVG WG to decide if CSS3 Colors should be a requirement or not for SVG2 (and how it's applied to svg content), so I'm not sure what, if anything, needs to be discussed in the public-fx taskforce relating to this. Cheers /Erik On Wed, 02 Jun 2010 14:50:05 +0200, Dean Jackson <dino@apple.com> wrote: > My personal take is that rgba should be supported in SVG content. I'd be > interested to hear arguments against it (*). > > The alpha in the color should be added to the start of the list of alpha > blends used in the final compositing (which is a list of > multiplications). eg. > > fill: rgba(0, 0, 0, 0.5); > fill-opacity: 0.6; > opacity: 0.7; > > ... would end up (in the absence of other styles) painting a 0.5 * 0.6 * > 0.7 = 0.21 opaque black. > > (*) I argued against it myself when CSS was adding it back in the day, > because I preferred the way SVG had separated opacity - it allows you to > animate a fill/stroke opacity independently of color. But rgba is > well-loved now, and it would have been impractical to add -opacity > properties for every place that CSS could use a color. > > Dean > > On 01/06/2010, at 8:43 AM, Jonathan Kliegman wrote: > >> I was looking at Webkit, specifiaclly bug 16183 >> (https://bugs.webkit.org/show_bug.cgi?id=16183) - SVG doesn't support >> rgba() colors. I was planning on fixing this but after reading the SVG >> spec at http://www.w3.org/TR/SVG11/ which states that SVG supports CSS2 >> color specifications I'm unsure if this should be fixed or not. rgba() >> was introduced with CSS3 so is technically not supported by SVG. >> >> Looking at other implementations Chrome and webkit-head both render a >> rgba() color as pure black. Safari 4.0.5 I've seen render it as either >> black or missing. Firefox does render it properly. Batiq fails to >> render and gives an error: "The attribute "stroke" represents an >> invalid CSS value ("rgba(0, 255, 0, 0.5)")." >> >> Looking at this bug from an end user perspective it would be good to >> add this feature in as its likely that people will build sites that >> aren't strictly compliant and would want things to just work. However >> I'm always wary of making changes that go against a published standard >> as that path can lead to ugliness, divergent standards and future >> headaches. >> >> What I'm looking for from the community is feedback on what the right >> thing to do here with respect to webkit is. Is it worth the >> convenience to the user to add support for rgba() to the SVG code? >> >> -Jon >> > > -- Erik Dahlstrom, Core Technology Developer, Opera Software Co-Chair, W3C SVG Working Group Personal blog: http://my.opera.com/macdev_ed
Received on Monday, 20 September 2010 08:50:56 UTC