MMaskScrollCookieToStencil X1.w,Y1.w,Width.w,Height.w,X2.w,Y2.w[,SourceShapeNum.w] ; Copy cookie2stencil & cut

Does the same as MMaskScroll except that the source of the operation will be a
chunky Shape's cookie which will be mask-blitted to the stencil of a chunky
Bitmap.