XCreateColormap(3)

NAME

   XCreateColormap, XCopyColormapAndFree, XFreeColormap, XColor - create,
   copy, or destroy colormaps and color structure

SYNTAX

   Colormap XCreateColormap(Display *display, Window w, Visual *visual,
          int alloc);

   Colormap XCopyColormapAndFree(Display *display, Colormap colormap);

   int XFreeColormap(Display *display, Colormap colormap);

ARGUMENTS

   alloc     Specifies the colormap entries to be allocated.  You can pass
             AllocNone or AllocAll.

   colormap  Specifies the colormap that you want to create, copy, set, or
             destroy.

   display   Specifies the connection to the X server.

   visual    Specifies a visual type supported on the screen.  If the
             visual type is not one supported by the screen, a BadMatch
             error results.

   w         Specifies the window on whose screen you want to create a
             colormap.

DESCRIPTION

   The XCreateColormap function creates a colormap of the specified visual
   type for the screen on which the specified window resides and returns
   the colormap ID associated with it.  Note that the specified window is
   only used to determine the screen.

   The initial values of the colormap entries are undefined for the visual
   classes GrayScale, PseudoColor, and DirectColor.  For StaticGray,
   StaticColor, and TrueColor, the entries have defined values, but those
   values are specific to the visual and are not defined by X.  For
   StaticGray, StaticColor, and TrueColor, alloc must be AllocNone, or a
   BadMatch error results.  For the other visual classes, if alloc is
   AllocNone, the colormap initially has no allocated entries, and clients
   can allocate them.  For information about the visual types, see section
   3.1.

   If alloc is AllocAll, the entire colormap is allocated writable.  The
   initial values of all allocated entries are undefined.  For GrayScale
   and PseudoColor, the effect is as if an XAllocColorCells call returned
   all pixel values from zero to N - 1, where N is the colormap entries
   value in the specified visual.  For DirectColor, the effect is as if an
   XAllocColorPlanes call returned a pixel value of zero and red_mask,
   green_mask, and blue_mask values containing the same bits as the
   corresponding masks in the specified visual.  However, in all cases,
   none of these entries can be freed by using XFreeColors.

   XCreateColormap can generate BadAlloc, BadMatch, BadValue, and
   BadWindow errors.

   The XCopyColormapAndFree function creates a colormap of the same visual
   type and for the same screen as the specified colormap and returns the
   new colormap ID.  It also moves all of the client's existing allocation
   from the specified colormap to the new colormap with their color values
   intact and their read-only or writable characteristics intact and frees
   those entries in the specified colormap.  Color values in other entries
   in the new colormap are undefined.  If the specified colormap was
   created by the client with alloc set to AllocAll, the new colormap is
   also created with AllocAll, all color values for all entries are copied
   from the specified colormap, and then all entries in the specified
   colormap are freed.  If the specified colormap was not created by the
   client with AllocAll, the allocations to be moved are all those pixels
   and planes that have been allocated by the client using XAllocColor,
   XAllocNamedColor, XAllocColorCells, or XAllocColorPlanes and that have
   not been freed since they were allocated.

   XCopyColormapAndFree can generate BadAlloc and BadColor errors.

   The XFreeColormap function deletes the association between the colormap
   resource ID and the colormap and frees the colormap storage.  However,
   this function has no effect on the default colormap for a screen.  If
   the specified colormap is an installed map for a screen, it is
   uninstalled (see XUninstallColormap).  If the specified colormap is
   defined as the colormap for a window (by XCreateWindow,
   XSetWindowColormap, or XChangeWindowAttributes), XFreeColormap changes
   the colormap associated with the window to None and generates a
   ColormapNotify event.  X does not define the colors displayed for a
   window with a colormap of None.

   XFreeColormap can generate a BadColor error.

STRUCTURES

   The XColor structure contains:

   typedef struct {
           unsigned long pixel;    /* pixel value */
           unsigned short red, green, blue;        /* rgb values */
           char flags;     /* DoRed, DoGreen, DoBlue */
           char pad;
   } XColor;

   The red, green, and blue values are always in the range 0 to 65535
   inclusive, independent of the number of bits actually used in the
   display hardware.  The server scales these values down to the range
   used by the hardware.  Black is represented by (0,0,0), and white is
   represented by (65535,65535,65535).  In some functions, the flags
   member controls which of the red, green, and blue members is used and
   can be the inclusive OR of zero or more of DoRed, DoGreen, and DoBlue.

DIAGNOSTICS

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

   BadColor  A value for a Colormap argument does not name a defined
             Colormap.

   BadMatch  An InputOnly window is used as a Drawable.

   BadMatch  Some argument or pair of arguments has the correct type and
             range but fails to match in some other way required by the
             request.

   BadValue  Some numeric value falls outside the range of values accepted
             by the request.  Unless a specific range is specified for an
             argument, the full range defined by the argument's type is
             accepted.  Any argument defined as a set of alternatives can
             generate this error.

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

SEE ALSO

   XAllocColor(3), XChangeWindowAttributes(3), XCreateWindow(3),
   XQueryColor(3), XStoreColors(3)
   Xlib - C Language X Interface

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