1991-2006 Silicon Graphics, Inc.

glPixelZoom

3G

glPixelZoom

specify the pixel zoom factors

# C Specification

                    void glPixelZoom
                    GLfloat xfactor
                    GLfloat yfactor

## Parameters

`xfactor`

`yfactor`

- Specify the x and y zoom factors for pixel write operations.

## Description

`glPixelZoom` specifies values for the x and y zoom factors. During the execution of

glDrawPixels

or

glCopyPixels

, if ( xr , yr ) is the current raster position, and a given element is in the mth row and nth column of the pixel rectangle, then pixels whose centers are in the rectangle with corners at

( xr + n · xfactor , yr + m · yfactor )

( xr + n + 1 · xfactor , yr + m + 1 · yfactor )

are candidates for replacement. Any pixel whose center lies on the bottom or left edge of this rectangular region is also modified.

Pixel zoom factors are not limited to positive values. Negative zoom factors reflect the resulting image about the current raster position.

## Errors

`GL_INVALID_OPERATION` is generated if `glPixelZoom` is executed between the execution of

glBegin

and the corresponding execution of

glEnd

.

## Associated Gets

glGet

with argument `GL_ZOOM_X`

glGet

with argument `GL_ZOOM_Y`

## See Also

glCopyPixels

,

glDrawPixels

## Copyright

Copyright 1991-2006 Silicon Graphics, Inc. This document is licensed under the SGI Free Software B License. For details, see http://oss.sgi.com/projects/FreeB/.