AMD2 WD, new subclause 5.7.11.3 "Color table formats" - color glyph composition

[vlevantovsky]

LayerV1List table allows up to 256 paint layers be defined; among them - layers defined using PaintComposite allow nested COLR v1 glyphs be used as paint layers that comprise a directed acyclic graph. Potential issues for implementations may include:

• Lack of specification of the minimal supported depth of the graph (I believe font developers need an assurance, and implementers need guidance, that certain number of nested levels shall be supported), and
• Lack of clarity in described expected behavior if a cyclic graph entry is detected.

The review is needed - both for the proposed new wording of implementation behavior and to suggest additional language for minimal graph depth support.

[vlevantovsky]

Resolved as part of the ISO/IEC 14496-22:2019 Working Draft AMD2, closing the issue.