NAME

scrmask - define a clipping mask for the screen

SYNOPSIS

C
scrmask(left, right, bottom, top)
Screencoord left, right, bottom, top;

FORTRAN
subroutine scrmas(left, right, bottom, top)
integer*2 left, right, bottom, top

Pascal
procedure scrmask(left, right, bottom, top: Screencoord);

DESCRIPTION

Scrmask makes it possible to do fine character clipping.  A call to viewport sets both the viewport and the screen mask to the same area, which is defined by the left, right, bottom, and top boundaries.  A call to scrmask sets only the screen mask, which should be placed entirely within the viewport.  Strings that begin outside the viewport will be clipped out; this is gross clipping.  Strings which begin inside the viewport but outside the screen mask will be clipped to the pixel boundaries of the screen mask.  This is called fine clipping.  All drawing commands are also clipped to this viewport, but it is only useful for characters; gross clipping is sufficient for all other primitives.  For an illustration of clipping, see Figure 3.5 of the IRIS Graphics Library. 

SEE ALSO

getscrmask, viewport
 

Version 2.3  —  July 04, 1985