3.1.1.6.1 Glyph Cache

The client of this protocol MUST provide support for the sharing of glyph bitmaps across multiple channels belonging to the same connection set as defined in section 3.1.1.1. The repository of shared glyph bitmaps is known as the Glyph Cache.

The function of the Glyph Cache is to store unique bitmaps representing characters available in a font set. The entries are grouped in font face sets identified by a font face handle. Within a font face set, individual glyph bitmaps are identified by a glyph index. The server MUST create font face sets for all the fonts used in the scene graph, and for all the scales at which it will render the fonts without scaling. If, at rasterization time, a font face of the exact needed scale is not available, the rasterization engine MUST pick the font face that is closest in scale.