XSetFunction()															    XSetFunction()

Name
  XSetFunction - set the bitwise logical operation in a graphics context.

Synopsis
  XSetFunction(display, gc, function)
	Display *display;
	GC gc;
	int function;

Arguments
  display  Specifies a connection to an X server; returned from XOpenDisplay().

  gc	   Specifies the graphics context.

  function
	   Specifies the logical operation you want for the specified graphics context.  See Description for the choices and their meanings.

Description
  XSetFunction()  sets the logical operation applied between the source pixel values (generated by the drawing request) and existing destina-
  tion pixel values (already in the window or pixmap) to generate the final destination pixel values in a drawing request (what  is  actually
  drawn  to  the  window  or  pixmap).	Of course, the plane_mask and clip_mask in the GC also affect this operation by preventing drawing to
  planes and pixels respectively. GXcopy, GXinvert, and GXxor are the only logical operations that are commonly used.

  See Volume One, Chapter 5, The Graphics Context, for more information about the logical function.

  The function symbols and their logical definitions are:

  Symbol	  Value   Meaning
  GXclear	  0x0	  0
  GXand 	  0x1	  src AND dst
  GXandReverse	  0x2	  src AND (NOT dst)
  GXcopy	  0x3	  src
  GXandInverted   0x4	  (NOT src) AND dst
  GXnoop	  0x5	  dst
  GXxor 	  0x6	  src XOR dst
  GXor		  0x7	  src OR dst
  GXnor 	  0x8	  (NOT src) AND (NOT dst)
  GXequiv	  0x9	  (NOT src) XOR dst
  GXinvert	  0xa	  (NOT dst)
  GXorReverse	  0xb	  src OR (NOT dst)

  Symbol	   Bit	 Meaning
  GXcopyInverted   0xc	 (NOT src)
  GXorInverted	   0xd	 (NOT src)OR dst
  GXnand	   0xe	 (NOT src) OR (NOT dst)
  GXset 	   0xf	 1

Errors
  BadAlloc
  BadGC
  BadValue

See Also
  XDefaultGC(), XChangeGC(), XCopyGC(), XCreateGC(), XFreeGC(), XGContextFromGC(), XSetArcMode(), XSetBackground(), XSetClipMask(),  XSetCli-
  pOrigin(),  XSetClipRectangles(),  XSetDashes(),  XSetFillRule(),  XSetFillStyle(),  XSetForeground(), XSetGraphicsExposures(), XSetLineAt-
  tributes(), XSetPlaneMask(), XSetState(), XSetStipple(), XSetSubwindowMode(), XSetTSOrigin().

Xlib - Graphics Context 													    XSetFunction()