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GL3.2 for AIX: Graphics Library (GL) Technical Reference

screenspace Subroutine

Purpose

Makes a program interpret graphics positions as absolute screen coordinates.

Libraries

Graphics Library

C (libgl.a)

FORTRAN (libfgl.a)

C Syntax

void screenspace( )

FORTRAN Syntax

SUBROUTINE SCREEN

Description

The screenspace subroutine makes a program interpret graphics positions as absolute screen coordinates. This allows pixels and locations outside a program's window to be read. The origin, in screen coordinates, is at the lower left corner of the screen. In window coordinates the origin is at the lower left corner of the user-defined window.

The screenspace subroutine is equivalent to:

int xmin, ymin;
getorigin(&xmin, &ymin);
viewport(-xmin, XMAXSCREEN-xmin,-ymin,YMAXSCREEN-ymin);
ortho2(-0.5,1279.5,-0.5,1023.5); 
Note: This subroutine cannot be used to add to a display list.

Implementation Specifics

This subroutine is part of GL in the AIXwindows Environment/6000 Version 1, Release 2 with AIXwindows/3D Feature.

Files

/usr/include/gl/gl.h Contains C language constant and variable type definitions for GL.
/usr/include/gl/fgl.h Contains FORTRAN constant and variable type definitions for GL.

Related Information

Returning the position of a window with the getorigin subroutine.

Defining a 2-D orthographic transformation with the ortho2 subroutine.

Setting the area of the window used for all drawing with the viewport subroutine.

AIX Graphics Library Overview, Using Viewports and Screenmasks, and Working with Coordinate Systems.


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