3.1.1.6 Drawing Text

Text is drawn as a sequence of bitmaps that, when put together, form a line of text. Each bitmap represents a glyph and has additional offset parameters that participate in the positioning of the bitmap in the sequence. The bitmaps themselves must be produced by the server.

When drawing a glyph run, the rasterization engine picks the set of glyph bitmaps that most closely match the final resolution at which the glyphs in the glyph run have to be drawn, based on the current device transform. Each glyph bitmap of a set representing the same glyph is known as a realization of that glyph. The server MAY provide any number of realizations for each glyph. It MUST provide at least one realization for each glyph used in the scene graph. Determining the scaling factor at which the glyphs are rendered is an implementation-specific detail and depends on the rasterizer logic.