NAME

viewport − allocates an area of the screen for an image

SPECIFICATION

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

FORTRAN
subroutine viewpo(left, right, bottom, top)
integer*4 left, right, bottom, top

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

DESCRIPTION

viewport specifies, in screen coordinates, the area of the screen that displays an image.  Specifying the viewport is the first step in mapping world coordinates to screen coordinates.  The portion of world space that window, ortho, or perspective describes is mapped into the viewport.  left, right, bottom, and top coordinates define a rectangular area on the screen. 

viewport also loads the screenmask. 

SEE ALSO

scrmask, getviewport, popviewport, pushviewport IRIS Graphics Programming, Section 4.4, Viewports

Version 2.5  —  April 22, 1987