Tk_GetColormap(3) Tk Library Procedures 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.
CONST 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 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
Tk 4.0 Tk_GetColormap(3)
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