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