Definition of identical glyph

[plehegar]

The definition of identical glyph use in section 9.5 is not adequate in the general case in which glyph mapping process is context sensitive. For example 'f' and 'i' may map to a ligature glyph for font F0 but to distinct glyphs for font F1. Similarly, for Arabic text and other complex scripts, the glyph mapping process is based on the font's GSUB tables and the set of active features and language bindings.

(raised by Glenn Adams on 2015-09-21)
From tracker issue http://www.w3.org/AudioVideo/TT/tracker/issues/428

[palemieux]

Addressed at c7eefbe

Glyphs are defined, for the purposes of the HRM, as a tuple consisting of a single character and associated styles. The HRM accounts for complex scripts, where there is rarely a one-to-one mapping between codepoints and glyphs, by reducing the performance of the glyph buffer.

[nigelmegitt]

I've added comments directly to commit c7eefbe since that's the easiest way to point to specific lines.