Re: [css-images] Negative implications of linear gradient color space choice in CSS

On Mon, Jan 25, 2016 at 3:48 PM, Tab Atkins Jr. <jackalmage@gmail.com>
wrote:

> On Mon, Jan 25, 2016 at 3:29 PM, Xidorn Quan <quanxunzhen@gmail.com>
> wrote:
> > On Tue, Jan 26, 2016 at 6:22 AM, Tab Atkins Jr. <jackalmage@gmail.com>
> wrote:
> >> On Mon, Jan 25, 2016 at 11:17 AM, Rik Cabanier <cabanier@gmail.com>
> wrote:
> >>> On Mon, Jan 25, 2016 at 10:58 AM, Tab Atkins Jr. <jackalmage@gmail.com
> >
> >>> wrote:
> >>>> On Mon, Jan 25, 2016 at 10:53 AM, Rik Cabanier <cabanier@gmail.com>
> wrote:
> >>>> > Are you worried about the computed value of the 'transparent'
> keyword in
> >>>> > the
> >>>> > gradient? If so, that one doesn't resolve to an rgba color.
> >>>>
> >>>> Sure it does.  (Or it should be doing so, for consistency - colors
> >>>> should be computed in computed values.)
> >>>
> >>> It does not. I tried Edge, Safari 9, latest Chrome and Firefox.
> >>
> >> Then that's a bug, either in the specs or the implementations.  There
> >> is absolutely no reason a color should serialize differently based on
> >> whether it's bare or wrapped in a gradient function.
> >
> > Given all impls current agree with the same behavior here, I guess we
> > can probably make 'transparent' a keyword value in gradient function
> > to simulate premultiplied effect, and revert the general cases to
> > non-premultiplied...
>
> If and only if there's not a significant number of gradients out there
> that currently write out transparent with rgba() syntax, or that use
> near-transparent colors that'll significant change behavior here.
>

Given that a major browser has a different implementation and no bug
reports, that number is likely small.
Also, when we made the change in the other browsers, there were no user
reported bugs that we closed.


> And we (Blink) must store the input string somewhere so we can output
> it back literally, because I *know* that we parse that into an
> #AARRGGBB 4-byte int and operate on it like that.  So it doesn't
> matter whether you type "transparent" or "rgba(0,0,0,0)", you get
> 0x00000000 either way.


It looks like Safari, Edge and Chrome return the original CSS input string.
Firefox resolves color names to their rgba equivalents, but not
'transparent'