FlushWindowBuffer [ wNum | _FBAutoFlushOff | _FBAutoFlushOn ]
Under MacOS X, all drawing to a window is intercepted and stored ("buffered") by the Window Server. The Window Server normally transfers the drawing to the screen only when your program executes a
HandleEvents statement. You can force an early update with
wNum is omitted, or is 0, the current output window is flushed by the MacOS X Window Server. If
wNum is non-zero, window
wNum is flushed.
The default behavior of the FutureBasic runtime is to flush the current output window each time a
print statement is performed. You can control that behavior:
FlushWindowBuffer _FBAutoFlushOff will turn off the automatic flushing. You still can force the flushing for a specific window with
FlushWindowBuffer _FBAutoFlushOn will restore the automatic flushing.
FlushWindowBuffer command has no effect unless the program is running under MacOS X. Because of coalesced updates in MacOS X 10.4 Macho-O binaries, this does nothing if called too soon (0 or 1 tick) after the previous call.
// In this example, there is no HandleEvents,
// and so FlushWindowBuffer is needed to
// make the drawing visible under MacOS X.
plot 0,0 to 500,500
until fn button // wait for mouse-down