xsetstandardcolormap(3x11) [ultrix man page]

XSetStandardColormap(3X11)												XSetStandardColormap(3X11)

Name
       XSetStandardColormap, XGetStandardColormap - set or get standard colormaps

Syntax
       XSetStandardColormap(display, w, colormap, property)
	     Display *display;
	     Window w;
	     XStandardColormap *colormap;
	     Atom property;	/* RGB_BEST_MAP, etc. */

       Status XGetStandardColormap(display, w, colormap_return, property)
	     Display *display;
	     Window w;
	     XStandardColormap *colormap_return;
	     Atom property;	/* RGB_BEST_MAP, etc. */

Arguments
       colormap  Specifies the colormap.

       colormap_return
		 Returns the colormap associated with the specified atom.

       display	 Specifies the connection to the X server.

       property  Specifies the property name.

       w	 Specifies the window.

Description
       The function usually is only used by window 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 (not required for RGB_DEFAULT_MAP)

	    o	 Determine the color capabilities of the display.

	    o	 Call or to allocate cells in the colormap.

	    o	 Call to store appropriate color values in the colormap.

	    o	 Fill in the descriptive members in the structure.

	    o	 Attach the property to the root window.

	    o	 Use to make the resource permanent.

       5.   Ungrab the server.

       can generate and errors.

       The  function  returns the colormap definition associated with the atom supplied as the property argument.  For example, to fetch the stan-
       dard colormap for a display, you use with the following syntax:

       XGetStandardColormap(dpy, DefaultRootWindow(dpy), &cmap, XA_RGB_GRAY_MAP);

       Once you have fetched a standard colormap, you can use it to convert RGB values into pixel values.  For example,  given	an  structure  and
       floating-point RGB coefficients in the range 0.0 to 1.0, you can compose pixel values with the following C expression:

       pixel = base_pixel
	    + ((unsigned long) (0.5 + r * red_max)) * red_mult
	    + ((unsigned long) (0.5 + g * green_max)) * green_mult
	    + ((unsigned long) (0.5 + b * blue_max)) * blue_mult;

       The  use of addition rather than logical OR for composing pixel values permits allocations where the RGB value is not aligned to bit bound-
       aries.

       can generate and errors.

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

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

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

See Also
       Guide to the Xlib Library

															XSetStandardColormap(3X11)

XGetRGBColormaps()														XGetRGBColormaps()

Name
  XGetRGBColormaps - obtain the XStandardColormap structure associated with the specified property.

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

Arguments
  display   Specifies a connection to an X server; returned from XOpenDisplay().

  w	    Specifies the window.

  std_colormap_return
	    Returns the XStandardColormap structure.

  count_return
	    Returns the number of colormaps.

  property  Specifies the property name.

Returns
  Zero on failure, non-zero on success.

Availability
  Release 4 and later.

Description
  XGetRGBColormaps()  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 non-zero status.  Otherwise, none of the fields are set, and XGetRGBColormaps() returns a
  zero status.	If the visualid field is not present, XGetRGBColormaps() assumes the default visual for the screen on  which  the  window  is
  located;  if the killid field is not present, it is assumed to have a value of None, which indicates that the resources cannot be released.
  Note that it is the caller's responsibility to honor the ICCCM restriction that only RGB_DEFAULT_MAP contain more than one definition.

  XGetRGBColormaps() does not install the colormaps into the hardware colormap, it does not allocate entries, and it  does  not  even  create
  virtual  colormaps.	It  just provides information about designs of colormap and the IDs of the colormaps if some other client has already
  created them.  The application can otherwise attempt to create a virtual colormap of the appropriate type, and allocate its entries accord-
  ing  to the information in the XStandardColormap structure.  Installing the colormap must then be done with XInstallColormap(), in coopera-
  tion with the window manager.  Any of these steps could fail, and the application should be prepared.

  If the server or another client has already created a standard colormap of this type, then its ID will be returned in the  colormap  member
  of the XStandardColormap structure.  Some servers and window managers, particular on high-performance workstations, will create some or all
  of the standard colormaps so they can be quickly installed when needed by applications.

  An application should go through the standard colormap creation process only if it needs the special qualities of  the  standard  colormaps
  and  if  another  client has not already created them.  For one, they allow the application to convert RGB values into pixel values quickly
  because the mapping is predictable.  Given an XStandardColormap structure for an XA_RGB_BEST_MAP colormap, and floating point  RGB  coeffi-
  cients in the range 0.0 to 1.0, you can compose pixel values with the following C expression:

     pixel = base_pixel
	+ ((unsigned long) (0.5 + r * red_max)) * red_mult
	+ ((unsigned long) (0.5 + g * green_max)) * green_mult
	+ ((unsigned long) (0.5 + b * blue_max)) * blue_mult;

  The  use of addition rather than logical-OR for composing pixel values permits allocations where the RGB value is not aligned to bit bound-
  aries.

  XGetRGBColormaps() supersedes XGetStandardColormap().

  For more information, see Volume One, Chapter 7, Color.

Structures
     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;		 /* added by ICCCM version 1 */
	 XID killid;			 /* added by ICCCM version 1 */
     } XStandardColormap;

Errors
  BadAtom
  BadWindow

See Also
  XAllocStandardColormap(), XSetRGBColormaps().

Xlib - Window Manager Hints													XGetRGBColormaps()