- From: Alan Gresley <alan@css-class.com>
- Date: Sat, 28 Sep 2013 16:17:03 +1000
- To: Dirk Schulze <dschulze@adobe.com>
- CC: Rik Cabanier <cabanier@gmail.com>, "Tab Atkins Jr." <jackalmage@gmail.com>, Simon Sapin <simon.sapin@exyr.org>, www-style list <www-style@w3.org>
On 25/09/2013 4:27 PM, Dirk Schulze wrote: > > On Sep 25, 2013, at 7:50 AM, Rik Cabanier <cabanier@gmail.com> wrote: > >> >> >> >> On Tue, Sep 24, 2013 at 10:29 PM, Dirk Schulze <dschulze@adobe.com> wrote: >> >> On Sep 25, 2013, at 7:20 AM, Rik Cabanier <cabanier@gmail.com> wrote: >> >>> >>> >>> >>> On Tue, Sep 24, 2013 at 10:15 PM, Dirk Schulze <dschulze@adobe.com> wrote: >>> >>> On Sep 25, 2013, at 12:43 AM, Rik Cabanier <cabanier@gmail.com> wrote: >>> >>>> On Tue, Sep 24, 2013 at 3:25 PM, Tab Atkins Jr. <jackalmage@gmail.com> wrote: >>>> On Tue, Sep 24, 2013 at 3:14 PM, Rik Cabanier <cabanier@gmail.com> wrote: >>>>> On Tue, Sep 24, 2013 at 2:58 PM, Tab Atkins Jr. <jackalmage@gmail.com> >>>>> wrote: >>>>>> On Tue, Sep 24, 2013 at 2:31 PM, Rik Cabanier <cabanier@gmail.com> wrote: >>>>>>> The compositing/blending spec doesn't talk about converting colors [1] >>>>>>> All >>>>>>> the formulas (except for 4 special ones) work on individual color >>>>>>> channels, >>>>>>> regardless of what they represent. >>>>>> >>>>>> Those channels appear to be assumed to be RGB. >>>>> >>>>> Can you point out where that is so I can update the spec? >>>> >>>> Hmm, I guess it actually doesn't. The few examples that give explicit >>>> color numbers are all written with RGB, but there's nothing outside >>>> the examples that actually talks about the color value. >>>> >>>> Great. I made a not to add CMYK (and spot?) examples for the next version. >>> >>> We already have CMYK so the note would make sense in this level already, wouldn't it? >>> >>> Is there any support for CMYK as an output color space? >>> >>> Even though WebKit does not preserve CMYK (and transforms it into RGB) for CSS, it has proper CMYK handling in Canvas (in Safari). And CSS Compositing addresses Canvas as well. >>> >>> Really? Canvas is always RGBA; how would you create a CMYK canvas? >> >> You can specify CMYK colors for drawing and WebKit/Safari does exactly that. It draws with the specified CMYK colors. >> >> Sure, but you won't draw CMYK pixels. The color is somehow converted to RGB and then the operation draws with the converted color. > > The stroke operation for example is done with: > > CGContextSetCMYKStrokeColor(); > > Greetings, > Dirk Ok, stroke operation for example is done with CGContextSetCMYKStrokeColor() but a typical display device has RGB pixels. There must be a conversion somehow from CMYK pixels to RGB pixels or does CGContextSetCMYKStrokeColor() only work with printing? Alan -- Alan Gresley http://css-3d.org/ http://css-class.com/
Received on Saturday, 28 September 2013 06:17:33 UTC