MSScroll X1.w,Y1.w,Width.w,Height.w,X2.w,Y2.w[,SourceBitmapNum.w[,CustomOffsets.l]] ; Copy bm 2 bm and st 2 st

Stencil-Scrolls an area within the currently used chunky Bitmap, or using a
different source Bitmap if specified. If SScrollCut is Off, a normal `SBlit'
will be performed in which the source Bitmap's graphic will be copied to the
destination Bitmap's graphic, and the source Bitmap's stencil is copied to the
destination Bitmap's stencil. If SScrollCut is On, the destination Bitmap's
stencil will be used to protect areas of the destination Bitmap's graphic,
instead of copying the source stencil into the destination stencil,
effectively scrolling the source image `behind' the protected parts of the
destination. The destination Bitmap should have a stencil. If CustomOffsets.l is
specified then a list of custom values will be used for each row of the scroll.
Please refer to MScroll for detailed information on the list format and what it
does.