glPixelZoom
NAME
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 called
between a call to glBegin and the
corresponding call to glEnd.
ASSOCIATED GETS
glGet with argument
GL_ZOOM_X
glGet with argument
GL_ZOOM_Y
SEE ALSO
glCopyPixels,
glDrawPixels
back to the OpenGL index page
© 1995 Uwe Behrens. All rights reserved.