Set the current planemask
#include <gf/gf.h> void gf_context_set_planemask( gf_context_t context, unsigned planemask );
This function sets the current planemask. A planemask is a 32-bit value which represents bits in pixels that are not drawn when they are written to the display surface, allowing you to “protect” specific bits. For example, if you draw a black background (0x000000), use gf_context_set_planemask() to mask the green bits (0x00ff00), and then draw a white foreground (0xffffff), you will see magenta displayed (0xff00ff) because the green bits are protected.
The format of the planemask corresponds directly to the format of the destination surface data, so you must pay attention to the format in order to use this parameter correctly.
QNX Graphics Framework