void BlitBitmapMasked(Bitmap *, Bitmap *, int, int, int, int, int, int);
boolean DrawingOnBackground(int, int);
void BlitBitmapOnBackground(Bitmap *, Bitmap *, int, int, int, int, int, int);
void BlitBitmapMasked(Bitmap *, Bitmap *, int, int, int, int, int, int);
boolean DrawingOnBackground(int, int);
void BlitBitmapOnBackground(Bitmap *, Bitmap *, int, int, int, int, int, int);