[cairo] Color fonts

Uli Schlachter psychon at znc.in
Sat Jul 15 08:05:50 UTC 2017

On 07.07.2017 15:23, Matthias Clasen wrote:
> On Sat, Jul 1, 2017 at 2:25 AM, Uli Schlachter <psychon at znc.in> wrote:
>> On 30.06.2017 17:29, Behdad Esfahbod wrote:
>>> On Jun 30, 2017 7:51 PM, "Matthias Clasen" <mclasen at redhat.com> wrote:
>>> On Fri, 2017-06-30 at 17:02 +0200, Uli Schlachter wrote:
>>>> On 28.06.2017 14:23, Behdad Esfahbod wrote:
>>>>> All of you have asked me about the status of color fonts in
>>>>> cairo.  There's
>>>>> some discussion here:
>>>> what was the solution to make this fit into cairo's drawing model?
>>>> Text
>>>> / glyphs are used as a mask and a mask does not have colors.
>>> There is no solution to that. The assumption in cairo's drawing model
>>> about glyphs/fonts has simply been invalidated by reality.
>>> Correct.
>> Okay... so what is the new model? What happens when I draw a color glyph
>> with operator XOR and a red source?
> The red source is ignored for color glyphs because they are used as the
> source.

Hi again,

I just came up with another question: How are overlapping glyphs handled?

Let's say I have a red glyph and a blue glyph and I draw them in such a
way that they overlap. Let's say this additionally overlaps with a
non-colored glyph in the same position and I use a green source with 50%
alpha (cairo_set_source_rgba(cr, 0, 1, 0, 0.5)).

What's the visible result?

<alanc> I think someone had a Xprint version of glxgears at one point,
    but benchmarking how many GL pages you can print per second
    was deemed too silly to merge

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