Tk_GetColormap, Tk_PreserveColormap, Tk_FreeColormap — allocate and free colormaps
- Tk_GetColormap, Tk_PreserveColormap, Tk_FreeColormap — allocate and free colormaps
- #include <tk.h>
- Tk_GetColormap(interp, tkwin, string)
- Tk_PreserveColormap(display, colormap)
- Tk_FreeColormap(display, colormap)
Tk_GetColormap(interp, tkwin, string)
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 does not 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's result.
- 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 or preserve; must have been returned by a previous
call to Tk_GetColormap or Tk_GetVisual.
Tk_PreserveColormap increases the internal reference count for a
colormap previously returned by Tk_GetColormap, which allows the
colormap to be stored in several locations without knowing which order
they will be released.
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 and each
call to Tk_PreserveColormap.
When a colormap's reference count becomes zero, Tk releases the
Tk_GetVisual and Tk_GetColormap work together, in that
a new colormap created by Tk_GetVisual may later be returned
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.
Copyright © 1994 The Regents of the University of California.
Copyright © 1994-1996 Sun Microsystems, Inc.