GLPIXELZOOM() MachTen Programmer’s Manual GLPIXELZOOM()

NAME
glPixelZoom - specify the pixel zoom factors

C SPECIFICATION
void glPixelZoom( GLfloat xfactor,
GLfloat yfactor )

delim $$

PARAMETERS
xfactor, yfactor Specify the $x$ and $y$ zoom factors for
pixel write operations.

DESCRIPTION
glPixelZoom specifies values for the $x$ and $y$ zoom fac-
tors. During the execution of glDrawPixels or glCopyPix-
els, if ($xr $, $yr $) is the current raster position, and
a given element is in the $m$th row and $n$th column of
the pixel rectangle, then pixels whose centers are in the
rectangle with corners at

($xr ~+~ n cdot "xfactor"$, $yr ~+~ m cdot "yfactor"$)

($xr ~+~ (n+1) cdot "xfactor"$, $yr ~+~ (m+1) cdot "yfactor"$)

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 exe-
cuted between the execution of glBegin and the correspond-
ing execution of glEnd.

ASSOCIATED GETS
glGet with argument GL_ZOOM_X
glGet with argument GL_ZOOM_Y