[MPEG-OTSPEC] WD for AMD 2 and COLR v1 enhancements

[Georg Seifert]

I don’t think we need to have control for M x N layers. Assigning a layer group ID would be sufficient. And I don’t think in most cases we need more than three groups (e.g. background/shadow, body, highlights; and in most cases body and highlights can be drawn together). This will not add much complexity. Draw all layers from each group for all glyph in the text box. I don’t think special control for blending between glyphs is needed, just draw then as it is now.

so instead of drawing:

    A.layer0, A.layer1, A.layer2, B.layer0, B.layer1, B.layer2 

we do (assuming that layer0 and layer1 are in one group):

    A.layer0, A.layer1, B.layer0, B.layer1, A.layer2, B.layer2

Georg