*nix Documentation Project
·  Home
 +   man pages
·  Linux HOWTOs
·  FreeBSD Tips
·  *niX Forums

  man pages->IRIX man pages -> Tk/getgc (3)              


Tk_GetGC(3Tk)							 Tk_GetGC(3Tk)

NAME    [Toc]    [Back]

     Tk_GetGC, Tk_FreeGC - maintain database of	read-only graphics contexts

SYNOPSIS    [Toc]    [Back]

     #include <tk.h>

     Tk_GetGC(tkwin, valueMask,	valuePtr)

     Tk_FreeGC(display,	gc)

ARGUMENTS    [Toc]    [Back]

     Tk_Window	     tkwin	 (in)	   Token for window in which the
					   graphics context will be used.

     unsigned long   valueMask	 (in)	   Mask	of bits	(such as GCForeground
					   or GCStipple) indicating which
					   fields of *valuePtr are valid.

     XGCValues	     *valuePtr	 (in)	   Pointer to structure	describing the
					   desired values for the graphics

     Display	     *display	 (in)	   Display for which gc	was allocated.

     GC		     gc		 (in)	   X identifier	for graphics context
					   that	is no longer needed.  Must
					   have	been allocated by Tk_GetGC.

DESCRIPTION    [Toc]    [Back]

     Tk_GetGC and Tk_FreeGC manage a collection	of graphics contexts being
     used by an	application.  The procedures allow graphics contexts to	be
     shared, thereby avoiding the server overhead that would be	incurred if a
     separate GC were created for each use.  Tk_GetGC takes arguments
     describing	the desired graphics context and returns an X identifier for a
     GC	that fits the description.  The	graphics context that is returned will
     have default values in all	of the fields not specified explicitly by
     valueMask and valuePtr.

     Tk_GetGC maintains	a database of all the graphics contexts	it has
     created.  Whenever	possible, a call to Tk_GetGC will return an existing
     graphics context rather than creating a new one.  This approach can
     substantially reduce server overhead, so Tk_GetGC should generally	be
     used in preference	to the Xlib procedure XCreateGC, which creates a new
     graphics context on each call.

     Since the return values of	Tk_GetGC are shared, callers should never
     modify the	graphics contexts returned by Tk_GetGC.	 If a graphics context
     must be modified dynamically, then	it should be created by	calling
     XCreateGC instead of Tk_GetGC.

									Page 1

Tk_GetGC(3Tk)							 Tk_GetGC(3Tk)

     When a graphics context is	no longer needed, Tk_FreeGC should be called
     to	release	it.  There should be exactly one call to Tk_FreeGC for each
     call to Tk_GetGC.	When a graphics	context	is no longer in	use anywhere
     (i.e. it has been freed as	many times as it has been gotten) Tk_FreeGC
     will release it to	the X server and delete	it from	the database.

KEYWORDS    [Toc]    [Back]

     graphics context

									PPPPaaaaggggeeee 2222
[ Back ]
 Similar pages
Name OS Title
getcursor IRIX maintain database of cursors
getcursor IRIX maintain database of cursors
getcolor IRIX maintain database of colors
getfontstr IRIX maintain database of fonts
getcolor IRIX maintain database of colors
getbitmap IRIX maintain database of single-plane pixmaps
dglopen IRIX opens a Graphics Library connection to a graphics server
makecontext HP-UX manipulate user contexts
swapcontext HP-UX manipulate user contexts
glcgetallcontexts IRIX return an array of GLC contexts
Copyright © 2004-2005 DeniX Solutions SRL
newsletter delivery service