Display drivers that handle raster fonts can also handle TrueType fonts without modification. GDI supports TrueType in display drivers by building FONTINFO structures that contain rasterized glyph bitmaps. GDI passes a pointer to this structure to the driver's ExtTextOut or StrBlt function along with the string to be displayed.
Display drivers can handle text in TrueType fonts almost identically to text in regular raster fonts. One important difference, however, is that TrueType glyphs are designed to be more readable by minimizing the gaps between glyphs—in fact, some glyphs overlap. To take full advantage of the design and maintain performance, display drivers may need some modification to allow for overlapping glyphs.