Re: Contributing COLRv1

[Roderick Sheeter]

Wrt a standalone Skia program, we did make a test tool to render with Skia so we could compare rendering from the original svg to rendering the COLR v1 font version of it. https://chromium-review.googlesource.com/c/chromium/src/+/2282815 shows it.

Cheers, Rod S.

On Thu, Jan 14, 2021 at 7:57 AM Werner LEMBERG <wl@gnu.org> wrote:

Dominik,


I've just merged the 'colr' branch to master (with some minor tweaks
as discussed) and pushed it to the FreeType git repository at

  https://gitlab.freedesktop.org/freetype/freetype

Let's see whether mirroring to Savannah works as expected...

>> (1) How can your code be tested?  It should be eventually fuzzed,
>>     too.
>
> Currently we have a test pipeline as part of
> https://github.com/googlefonts/nanoemoji that builds a COLRv1 font
> from SVG images, [...]

OK.

>> (2) Is a test font already available?  In this case, could you
>>     contribute code to Armin's repository to enable fuzzing?
>>
>>       https://github.com/freetype/freetype2-testing
>
> Yes, as Rod explained COLRv1 fonts are available here:
> https://github.com/googlefonts/color-fonts/tree/master/fonts.

Thanks.

> While developing, I made a simple test that traverses the graph of a
> COLRv1 font using FreeType API and outputs the retrieved data.  I
> will contribute a fuzzer to freetype2-testing for COLRv1 based on
> that code in order to exercise the COLRv1 API in fuzzing.

Great!

> We are aiming for having prototype-level support for COLRv1 in
> Chrome soon (behind a flag).

Please inform us as soon as such a Chromium build is publicly
available!

> Unfortunately, I don't think we can provide a Qt application, as
> this would require new rasterization (on top of the FreeType API),
> and we focus on the rasterization implementation in Skia.

Qt was just an example – a stand-alone Skia program would be as
nice :-)

> In addition, I have one more change that I found while working on
> the Chromium COLRv1 prototype:
> https://github.com/drott/freetype2-colr/commit/d71b1d8240075ce5421103efc0387f2dbe0e3aaf
> / branch colrTablePresenceChecks

Ah, I forgot to merge this; will add it soon.


    Werner