fglPixelZoom(3G) OpenGL Reference fglPixelZoom(3G)NAMEfglPixelZoom - specify the pixel zoom factors
FORTRAN SPECIFICATION
SUBROUTINE fglPixelZoom( REAL*4 xfactor,
REAL*4 yfactor )
PARAMETERS
xfactor, yfactor Specify the x and y zoom factors for pixel write
operations.
DESCRIPTIONfglPixelZoom specifies values for the x and y zoom factors. During the
execution of fglDrawPixels or fglCopyPixels, 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 fglPixelZoom is executed between the
execution of fglBegin and the corresponding execution of fglEnd.
ASSOCIATED GETS
fglGet with argument GL_ZOOM_X
fglGet with argument GL_ZOOM_Y
fglGet with argument GL_INTERLACE_SGIX
MACHINE DEPENDENCIES
The SGIX_interlace extension is supported only on InfiniteReality
systems, on RealityEngine, RealityEngine2, and VTX systems, on Octane2
VPro systems, and on O2 systems.
On InfiniteReality systems, the absolute values of the zoom factors must
be strictly less than 128. If not, they are clamped and GL_INVALID_VALUE
is generated.
Pixel zoom factors are snapped to fixed point precision on O2 systems,
Indy and XL systems, XS, XZ, Elan, and Extreme systems. fglGet will
return these values.
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fglPixelZoom(3G) OpenGL Reference fglPixelZoom(3G)SEE ALSO
fglCopyPixels, fglEnable, fglDrawPixels.
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