Re: [css-color] more detailed proposal for "compositing-space"

> On Mar 23, 2016, at 10:45 pm, Rik Cabanier <cabanier@gmail.com> wrote:
> 
> On Tue, Mar 22, 2016 at 10:15 PM, Florian Rivoal <florian@rivoal.net <mailto:florian@rivoal.net>> wrote:
> 
>> On Mar 23, 2016, at 12:58, Rik Cabanier <cabanier@gmail.com <mailto:cabanier@gmail.com>> wrote:
>> 
>> All,
>> 
>> here is a more detailed proposal for the compositing-space CSS property.
>> 
>> * compositing-space is a non-inherited property that creates a stacking context if a color space is specified.
>> 
>> * It takes the current values:
>> - "default": the default value which doesn't create a new space
>> - "uncalibrated": composite in the color space of the output device
>> - "sRGB"/"P3"/"BT.2020": composite in the specified standard color space then map to the output device
>> - "url(path.to.a.icc.profile)": composite with the supplied profile , then map to the output space
>> 
>> * The root element has a value of "uncalibrated" by default.
>> 
>> * The value is not animatable
>> 
>> * Applies to all elements. In SVG, it applies to container elements, graphics elements and graphics referencing elements
> 
> I agree about the overall idea, syntax, and choice of the default value in general and on the root element.
> 
> Thanks for the feedback. I agree with all of your points.
>  
> For the url notation, I think you should be able to point to an icc profile or to an image with an embedded profile. Or preferably, we add a layer of indirection, and icc profiles or images with embedded profiles can be turned into named color spaces that can be used by this property using @color-profile.
> 
> Also, I hope we can make it so that "composite in the .... color space" means not only compositing and blending, but any kind of color math, including for example gradients.
> 
> Yes. it should apply to everything.
>  
> I would add "CIELab" to the list of predefined names. As discussed elsewhere, composition/color math in that space gives pretty results, and even if that's subjective, using CIELab as a working space is a thing that exists and is sometime desired, and that would be the natural way to ask for it.
> 
>  After getting feedback, I agree it's a reasonable option.
> I worry that the implementation cost is too high and the feature too advanced for most users.

This is true. For WebKit we don’t have control over the colorspace in which compositing takes place. This proposal just isn’t readily implementable.

Simon