If the window is buffered, disabling flushWindow prevents drawing from being automatically flushed by the NSViewdisplay... methods from the window’s backing store to the screen. This method permits several views to be drawn before the results are shown to the user.
Flushing should be disabled only temporarily, while the window’s display is being updated. Each disableFlushWindow message must be paired with a subsequent enableFlushWindow message. Invocations of these methods can be nested; flushing isn’t reenabled until the last enableFlushWindow message is sent.
Splices the window’s cached image rectangles, if any, back into its raster image (and buffer if it has one), undoing the effect of any drawing performed within those areas since they were established using cacheImageInRect:.