MBitmapClip BitmapNumber.w[,X.w,Y.w,Width.w,Height.w][,Active] ; Active=On/Off. Define Bitmap's clip window

Specifies the position (X,Y) and size (WidthxHeight) of the clip window to be
used for the specified chunky Bitmap object. Clipping may also be turned On or
Off using the additional `active' parameter. The window should be fully within
the limits of the Bitmap's graphic and the Width should be a multiple of 4.