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 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