scrmask(3g) — 4D1 2.0



     scrmask(3G)                                           scrmask(3G)



     NAME

          scrmask - defines a clipping mask for fine character

          clipping


     SPECIFICATION

          C         scrmask(left, right, bottom, top)

                    Screencoord left, right, bottom, top;




          FORTRAN   subroutine scrmas(left, right, bottom, top)

                    integer*4 left, right, bottom, top


     DESCRIPTION

          scrmask provides fine character clipping. viewport sets the

          same area for both the viewport and the screenmask, which

          left, right, bottom, top define.  scrmask sets only the

          screenmask, which must be placed entirely within the

          viewport.


          Strings that begin outside the viewport are clipped out;

          this is called gross clipping.  Strings that begin inside

          the viewport but outside the screenmask are clipped to the

          pixel boundaries of the screenmask; this is called fine

          clipping.  All drawing routines are also clipped to the

          viewport, but scrmask is only useful for characters; gross

          clipping is sufficient for all other primitives.


     SEE ALSO

          getscrmask, viewport


          Programming Guide, Section 4.4, Viewports
























     Page 1                                          (printed 8/20/87)
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