glXUseXFont.3gl




Name

  glXUseXFont -	create bitmap display lists from an X font


C Specification

  void glXUseXFont( Font font,
		    int	first,
		    int	count,
		    int	listBase )


Parameters


  font	    Specifies the font from which character glyphs are to be taken.


  first	    Specifies the index	of the first glyph to be taken.


  count	    Specifies the number of glyphs to be taken.


  listBase  Specifies the index	of the first display list to be	generated.


Description

  glXUseXFont generates	count display lists, named listBase through
  listBase+count-1, each containing a single glBitmap command.	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 zero.  Finally, the glyph's image	is converted
  to the appropriate format for	glBitmap.

  Using	glXUseXFont may	be more	efficient than accessing the X font and
  generating the display lists explicitly, both	because	the display lists are
  created on the server	without	requiring a round trip of the glyph data, and
  because 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 and	are
  not defined in font.	glXUseXFont is ignored if there	is no current GLX
  context.


Errors

  BadFont is generated if font is not a	valid font.

  GLXBadContextState is	generated if the current GLX context is	in display-
  list construction mode.


  GLXBadCurrentWindow is generated if the drawable associated with the
  current context of the calling thread	is a window, and that window is	no
  longer valid.



See Also

  glBitmap, glXMakeCurrent




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Last Edited: Mon, May 22, 1995

AFV