METHOD FOR RENDERING GLYPHS USING A LAYOUT SERVICES LIBRARY

Rendering glyphs using a layout services library. A layout services library provides a set of text-processing functions for use by a client program. The text-processing functions access font information stored in the font tables insulating the client program from the details of the font table formats. The layout services library may be used to identify glyph variants and to position glyphs along a base line for a run of text. To identify glyph variants, the layout services library scans the run of text to identify the locations of characters having alternative glyph forms. The layout services library creates a list of feature parameter structures, each of which contains a count of the number of glyph alternates that apply for each identified character. The client program assembles a list of identical characters which have different parameters and presents a list of all glyph variants to the user who chooses one of the alternatives. To position glyphs, the layout services library assembles data that describes the advance of a virtual pen point from glyph to glyph along the base line, an X-placement value, and a Y-placement value. The X-placement value and the Y-placement value are used to position the glyph with respect to the virtual pen point on the base line.