void ClearRectangle(Bitmap *, int, int, int, int);
void ClearRectangleOnBackground(Bitmap *, int, int, int, int);
void BlitBitmapMasked(Bitmap *, Bitmap *, int, int, int, int, int, int);
+boolean DrawingDeactivated(int, int, int, int);
boolean DrawingOnBackground(int, int);
boolean DrawingAreaChanged();
void BlitBitmapOnBackground(Bitmap *, Bitmap *, int, int, int, int, int, int);