Variable gradient colors in COLRv1 with Glyphs and fontmake

Glyphs
1

Hi

I’m trying to create a demo for a variable COLRv1 font with a CLOR axis using Glyphs (or fontmake).

I created a test source with G4. (I changed the file format version to 3 because, for some reason, fontmake raises an error: expected string or bytes-like object, got 'list'. That’s another story and probably something to discuss in a separate issue.)

N.glyphs (2.5 KB)

I have two masters with the same glyph outline, but different gradient colors and positions. The gradient itself exports correctly as COLRv1, but there is no variation in the G4 export.

Interestingly, in fontmake’s output, the gradient’s position/geometry interpolates correctly along the CLOR axis, but the gradient colors remain those of the first master and don’t change when moving along the axis.

G4 version:

G4

fontmake version:

fontmake

i’m wondering if i’m not doing this right or it’s the lake of implementation and considered for the future updates?

2

Variable COLRv1 is not yet available but work in progress. The color font changes are quite expansive compared to Glyphs 3, so we first want to validate the new color layer capabilities.

4

Thank you! I’m really looking forward to it and surely it will unlock a lot of exciting possibilities!