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

The first step in defining the mapping from world coordinates to screen coordinates is to choose an area of the screen to display an image.  This area is called the viewport and is specified in screen coordinates.  The portion of world space described by one of the commands window, ortho, or perspective is mapped into the viewport.  The arguments to the viewport command define a rectangular area on the screen by the left, right, bottom, and top coordinates.  This command also loads the screenmask. 

SEE ALSO

scrmask, getviewport, popviewport, pushviewport

Version 2.4  —  May 08, 1986