HP Workstation zx2000 OpenGL 1.1 Reference for HP-UX 11.x - Page 337

P glPixelZoom glPixelZoom 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 Chapter 14 337