Tk_GetColormap(3) Tk Library Procedures Tk_GetColormap(3) 







Tk_GetColormap, Tk_PreserveColormap, Tk_FreeColormap - allocate
    and free colormaps








#include <tk.h>

Colormap
Tk_GetColormap(interp, tkwin, string)

Tk_PreserveColormap(display, colormap)

Tk_FreeColormap(display, colormap)









  
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.
    
    

    

  










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.


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 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.








colormap, visual







  

    4.0
    Tk