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/.