[MPEG-OTSPEC] COLR v1 updates for AMD 2

[Peter Constable]

At the last SC29/WG3 meeting, a few open issues regarding COLR v1 were discussed with consensus to have these addressed in the working draft. These included some details regarding radial gradients in certain edge cases, interpolation of colours in gradients, and handling of sRGB colours (linear vs. non-linear scales) in blending. Since then, a few other issues were also identified through review of the WD or in work on implementations.

With input from Google partners, Chris Lilley, Vlad, Just van Rossum, and engineers at Microsoft, I've made revisions in the proposed WD in the Google Fonts repo<https://github.com/googlefonts/colr-gradients-spec/blob/master/OFF_AMD2_WD.md> for these various issues:


  *   Issue #39: Add support for sweep gradients in COLR v1<https://github.com/MPEGGroup/OpenFontFormat/issues/39>
  *   Issue #40: In COLRv1 current design for linear gradients doesn't work well with transforms<https://github.com/MPEGGroup/OpenFontFormat/issues/40>
  *   Issue #41: [AMD2 WD: COLR v1] Address "TBDs" in working draft regarding open issues on radial gradients<https://github.com/MPEGGroup/OpenFontFormat/issues/41>
  *   Issue #42: [AMD2 WD: COLR v1] Address "TBD" in working draft regarding interpolation of colours<https://github.com/MPEGGroup/OpenFontFormat/issues/42>
  *   Issue #43: [AMD2 WD: COLR v1] Add paint formats for more compact representations in non-variable fonts<https://github.com/MPEGGroup/OpenFontFormat/issues/43>
  *   Issue #44: [AMD2 WD: COLR v1] Add discussion of bounding box and transformation in variable fonts<https://github.com/MPEGGroup/OpenFontFormat/issues/44>

Links to relevant pull requests in the Google Fonts repo are provided in the comments for each issue.

Along the way, there were other smaller revisions made in the proposed WD.



Peter
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.aau.at/pipermail/mpeg-otspec/attachments/20210222/c97e58fe/attachment.html>