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XAllocStandardColormap(3)	XLIB FUNCTIONS	     XAllocStandardColormap(3)

       XAllocStandardColormap,	XSetRGBColormaps, XGetRGBColormaps, XStandard-
       Colormap	- allocate, set, or read a standard colormap structure

       XStandardColormap *XAllocStandardColormap(void);

       void XSetRGBColormaps(Display  *display,	 Window	 w,  XStandardColormap
	      *std_colormap, int count,	Atom property);

       Status  XGetRGBColormaps(Display	 *display, Window w, XStandardColormap
	      **std_colormap_return, int *count_return,	Atom property);

       display	 Specifies the connection to the X server.

       count	 Specifies the number of colormaps.

		 Returns the number of colormaps.

       property	 Specifies the property	name.

		 Specifies the XStandardColormap structure to be used.

		 Returns the XStandardColormap structure.

       The XAllocStandardColormap function allocates and returns a pointer  to
       a  XStandardColormap structure.	Note that all fields in	the XStandard-
       Colormap	structure are initially	set to zero.  If  insufficient	memory
       is  available, XAllocStandardColormap returns NULL.  To free the	memory
       allocated to this structure, use	XFree.

       The XSetRGBColormaps function replaces the RGB colormap	definition  in
       the  specified  property	on the named window.  If the property does not
       already exist, XSetRGBColormaps sets the	RGB colormap definition	in the
       specified  property on the named	window.	 The property is stored	with a
       type of RGB_COLOR_MAP and a format of 32.  Note that it is the caller's
       responsibility to honor the ICCCM restriction that only RGB_DEFAULT_MAP
       contain more than one definition.

       The XSetRGBColormaps function usually is	only used by window or session
       managers.  To create a standard colormap, follow	this procedure:

       1.   Open a new connection to the same server.

       2.   Grab the server.

       3.   See	if the property	is on the property list	of the root window for
	    the	screen.

       4.   If the desired property is not present:

	    o	 Create	a colormap (unless you are using the default  colormap
		 of the	screen).

	    o	 Determine the color characteristics of	the visual.

	    o	 Allocate cells	in the colormap	(or create it with AllocAll).

	    o	 Call  XStoreColors  to	 store appropriate color values	in the

	    o	 Fill in the  descriptive  members  in	the  XStandardColormap

	    o	 Attach	the property to	the root window.

	    o	 Use XSetCloseDownMode to make the resource permanent.

       5.   Ungrab the server.

       XSetRGBColormaps	can generate BadAlloc, BadAtom,	and BadWindow errors.

       The  XGetRGBColormaps  function	returns	 the  RGB colormap definitions
       stored in the specified property	on the named window.  If the  property
       exists,	is  of type RGB_COLOR_MAP, is of format	32, and	is long	enough
       to contain a colormap definition, XGetRGBColormaps allocates and	 fills
       in  space  for the returned colormaps and returns a nonzero status.  If
       the visualid is not present, XGetRGBColormaps assumes the default  vis-
       ual for the screen on which the window is located; if the killid	is not
       present,	None is	assumed, which indicates that the resources cannot  be
       released.   Otherwise, none of the fields are set, and XGetRGBColormaps
       returns a zero status.  Note that it is the caller's responsibility  to
       honor the ICCCM restriction that	only RGB_DEFAULT_MAP contain more than
       one definition.

       XGetRGBColormaps	can generate BadAtom and BadWindow errors.

       The XStandardColormap structure contains:

       /* Hints	*/

       #de-    ReleaseByFreeingCol-   (	   (XID)
       fine    ormap		      1L)
       /* Values */
       typedef struct {
	       Colormap	colormap;
	       unsigned	long red_max;
	       unsigned	long red_mult;
	       unsigned	long green_max;
	       unsigned	long green_mult;
	       unsigned	long blue_max;
	       unsigned	long blue_mult;
	       unsigned	long base_pixel;
	       VisualID	visualid;
	       XID killid;
       } XStandardColormap;

       The  colormap  member  is  the  colormap	created	by the XCreateColormap
       function.  The red_max, green_max, and blue_max members give the	 maxi-
       mum  red, green,	and blue values, respectively.	Each color coefficient
       ranges from zero	to its max, inclusive.	For example, a common colormap
       allocation is 3/3/2 (3 planes for red, 3	planes for green, and 2	planes
       for blue).  This	colormap would have red_max = 7, green_max  =  7,  and
       blue_max	 =  3.	 An  alternate allocation that uses only 216 colors is
       red_max = 5, green_max =	5, and blue_max	= 5.

       The red_mult, green_mult, and blue_mult members give the	scale  factors
       used  to	 compose  a  full  pixel  value.   (See	 the discussion	of the
       base_pixel members for further information.)  For a  3/3/2  allocation,
       red_mult	 might be 32, green_mult might be 4, and blue_mult might be 1.
       For a 6-colors-each allocation, red_mult	might be 36, green_mult	 might
       be 6, and blue_mult might be 1.

       The base_pixel member gives the base pixel value	used to	compose	a full
       pixel value.  Usually, the base_pixel is	obtained from a	 call  to  the
       XAllocColorPlanes function.  Given integer red, green, and blue coeffi-
       cients in their appropriate ranges, one then can	compute	a  correspond-
       ing pixel value by using	the following expression:

       (r * red_mult + g * green_mult +	b * blue_mult +	base_pixel) & 0xFFFFFFFF

       For  GrayScale  colormaps,  only	 the  colormap,	red_max, red_mult, and
       base_pixel members are defined.	The other  members  are	 ignored.   To
       compute a GrayScale pixel value,	use the	following expression:

       (gray * red_mult	+ base_pixel) &	0xFFFFFFFF

       Negative	 multipliers  can be represented by converting the 2's comple-
       ment representation of the multiplier into an unsigned long and storing
       the  result  in	the  appropriate  _mult	field.	The step of masking by
       0xFFFFFFFF effectively converts the resulting positive multiplier  into
       a negative one.	The masking step will take place automatically on many
       machine architectures, depending	on the size of the integer  type  used
       to do the computation,

       The  visualid  member  gives the	ID number of the visual	from which the
       colormap	was created.  The killid member	gives a	resource ID that indi-
       cates  whether  the  cells held by this standard	colormap are to	be re-
       leased by freeing the colormap ID or by calling the  XKillClient	 func-
       tion  on	 the  indicated	resource.  (Note that this method is necessary
       for allocating out of an	existing colormap.)

       The properties containing the XStandardColormap	information  have  the
       type RGB_COLOR_MAP.

       BadAlloc	 The  server  failed  to  allocate  the	 requested resource or
		 server	memory.

       BadAtom	 A value for an	Atom argument does not name a defined Atom.

       BadWindow A value for a Window argument does not	name a defined Window.

       XAllocColor(3), XCreateColormap(3), XFree(3), XSetCloseDownMode(3)
       Xlib - C	Language X Interface

X Version 11			 libX11	1.6.12	     XAllocStandardColormap(3)


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