XCreateColormap
Syntax
Colormap XCreateColormap(display, w, visual, alloc)
Display *display;
Window w;
Visual *visual;
int alloc;
Arguments
| display
| Specifies the connection to the X server.
|
| w
| Specifies the window on whose screen you want to create a colormap.
|
| visual
| Specifies a visual type supported on the screen.
If the visual type is not one supported by the screen,
a
BadMatch
error results.
|
| alloc
| Specifies the colormap entries to be allocated.
You can pass
AllocNone
or
AllocAll.
|
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 "Visual Types".
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.
Diagnostics
| BadAlloc
| The server failed to allocate the requested
source or server memory.
|
| 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.
|
| BadPixmap
| A value for a Pixmap argument does not name a
defined Pixmap.
|
| 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(),
XChangeWindowAttributes(),
XCopyColormapAndFree(),
XCreateWindow(),
XFreeColormap(),
XQueryColor(),
XStoreColors(),
"
Creating, Copying, and Destroying Colormaps".
Christophe Tronche, [email protected]
