Tk_GetColormap(3) Tk (4.0) Tk_GetColormap(3)
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NAME
Tk_GetColormap, Tk_FreeColormap - allocate and free
colormaps
SYNOPSIS
#include <tk.h>
Colormap
Tk_GetColormap(interp, tkwin, string)
Tk_FreeColormap(display, colormap)
ARGUMENTS
Tcl_Interp *interp (in) Interpreter to use for error
reporting.
Tk_Window tkwin (in) Token for window in which
colormap will be used.
char *string (in) Selects a colormap: either
new or the name of a window
with the same screen and
visual as tkwin.
Display *display (in) Display for which colormap
was allocated.
Colormap colormap (in) Colormap to free; must have
been returned by a previous
call to Tk_GetColormap or
Tk_GetVisual.
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DESCRIPTION
These procedures are used to manage colormaps.
Tk_GetColormap returns a colormap suitable for use in tkwin.
If its string argument is new then a new colormap is
created; otherwise string must be the name of another
window with the same screen and visual as tkwin, and the
colormap from that window is returned. If string doesn't
make sense, or if it refers to a window on a different
screen from tkwin or with a different visual than tkwin,
then Tk_GetColormap returns None and leaves an error message
in interp->result.
Tk_FreeColormap should be called when a colormap returned by
Tk_GetColormap is no longer needed. Tk maintains a
reference count for each colormap returned by
Tk_GetColormap, so there should eventually be one call to
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Tk_GetColormap(3) Tk (4.0) Tk_GetColormap(3)
Tk_FreeColormap for each call to Tk_GetColormap. When a
colormap's reference count becomes zero, Tk releases the X
colormap.
Tk_GetVisual and Tk_GetColormap work together, in that a new
colormap created by Tk_GetVisual may later be returned by
Tk_GetColormap. The reference counting mechanism for
colormaps includes both procedures, so callers of
Tk_GetVisual must also call Tk_FreeColormap to release the
colormap. If Tk_GetColormap is called with a string value
of new then the resulting colormap will never be returned by
Tk_GetVisual; however, it can be used in other windows by
calling Tk_GetColormap with the original window's name as
string.
KEYWORDS
colormap
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