glXUseXFont Subroutine

Purpose

Creates bitmap display lists from an X font.

Library

OpenGL C bindings library: libGL.a

C Syntax

void glXUseXFont(Font font
                 int First
                 int Count
                 int ListBase)

Description

The glXUseXFont subroutine generates Count display lists, with each containing a single glBitmap command. These lists are named ListBase through ListBase+Count-1. The parameters of the glBitmap command of display list ListBase+i are derived from glyph first+i. Bitmap parameters Xorig, Yorig, Width, and Height are computed from font metrics as descent-1, -lbearing, rbearing-lbearing, and ascent+descent, respectively. Xmove is taken from the glyph's Width metric, and Ymove is set to 0 (zero). Finally, the glyph's image is converted to the appropriate format for the glBitmap command.

Using the glXUseXFont subroutine may be more efficient than accessing the X font and generating the display lists explicitly, since display lists are created on the server without requiring the glyph data to make a round-trip. Also, the server may choose to delay the creation of each bitmap until it is accessed.

Empty display lists are created for all glyphs that are requested but not defined in the Font parameter.

The glXUseXFont subroutine is ignored if there is no current GLX context.

Parameters

Error Codes

Files

Related Information

The glXMakeCurrent subroutine.

OpenGL in the AIXwindows (GLX) Environment.

OpenGL Overview.