mapcolor(3G)							  mapcolor(3G)

NAME    [Toc]    [Back]

     mapcolor -	changes	a color	map entry

C SPECIFICATION    [Toc]    [Back]

     void mapcolor(i, red, green, blue)
     Colorindex	i;
     short red,	green, blue;

PARAMETERS    [Toc]    [Back]

     i	     expects the index into the	color map.

     red     expects an	intensity value	in the range 0 to 255 for red to be
	     associated	with the index.

     green   expects an	intensity value	in the range 0 to 255 for green	to be
	     associated	with the index.

     blue    expects an	intensity value	in the range 0 to 255 for blue to be
	     associated	with the index.

DESCRIPTION    [Toc]    [Back]

     mapcolor loads entry i of the color map for the current drawing mode with
     (red, green, blue).  Pixels written with color index i are	displayed with
     the specified RGB intensities.  The valid range for i depends on the
     number of bitplanes available in the current drawing and buffer modes,
     i.e. the value returned by	getplanes.  Using Ni to	represent 2 raised to
     the return	value of getplanes in drawing mode i, the valid	ranges are:

	  NORMALDRAW   0 to Nn-1.
	  OVERDRAW     1 to No-1.
	  UNDERDRAW    0 to Nu-1.
	  PUPDRAW      1 to Np-1.
	  CURSORDRAW   1 to getgdesc(GD_BITS_CURSOR).

     If	Ni is 1, then no indices are valid.  Invalid indices are ignored by
     mapcolor.

     In	multimap mode, mapcolor	updates	only the small color map currently
     selected by setmap.

     The color map entry that controls the color of the	cross-hair cursor
     (cursor type CCROSS) is returned by the getgdesc inquiry
     GD_CROSSHAIR_CINDEX.

SEE ALSO    [Toc]    [Back]

     color, curstype, drawmode,	gammaramp, getgdesc, getmcolor,	getplanes,
     glcompat, setmap

NOTES    [Toc]    [Back]

     This subroutine is	available only in immediate mode.





									Page 1






mapcolor(3G)							  mapcolor(3G)



     On	the IRIS-4D G, you should not alter the	top 256	colors (color indices
     3840 to 4095).  The system	uses these colors for the cursor, overlay bitplanes,
 and RGB mode. If you alter	the colors to which these features are
     mapped, some screen features will appear in strange colors.

     In	IRIX 4.0, mapcolor is implemented as an	emulation layer	on top of the
     request XStoreColors.  In order to	avoid a	serious	degradation in performance,
 mapcolor requests are buffered and only sent to the	window server
     when an input routine (e.g. qtest)	or gflush is called.

     In	situations where the immediate results of mapcolor are more important
     than speed, there is a glcompat call to disable this behavior.


									PPPPaaaaggggeeee 2222