HP b2600 Administration Manual page 63

{
/* Since the Atom exists, request the property's contents. */
bytesAfter = 0;
numLongs = ( nVisuals * sizeof(OverlayVisualPropertyRec) + 3 ) / 4;
XGetWindowProperty(display, RootWindow(display, screen),
overlayVisualsAtom, 0, numLongs, False,
AnyPropertyType, &actualType, &actualFormat,
&numLongs, &bytesAfter, &pOverlayVisuals);
if ( bytesAfter != 0 ) {/* Serious Failure Here */} ;
/* Loop through the pOverlayVisuals array. */
...
nOVisuals = numLongs/sizeof(OverlayVisualPropertyRec);
pOVis = pOverlayVisuals;
while (--nOVisuals >= 0)
{
if ( pOVis->transparentType == TransparentPixel )
{/* Found a transparent overlay visual, set ident. aside. */};
pOVis++;
}
XFree(pOverlayVisuals);
/* There might be some additional checking of the found
transparent overlay visuals wanted; e.g., for depth. */
}
XFree(pVisuals);
}
This program fragment is not complete; its main purpose is to give the idea of how to find an overlay
visual having transparency.
HCRX Colormaps
The following information discusses the number of supported colormaps for the HCRX configurations.
HP VISUALIZE-EG(8): 8 Image planes
The image planes contain the default colormap permanently installed in the hardware plus one other
hardware colormap available to applications. No issues involving transparency exist because of the lack
of Overlay planes.
HCRX-8[Z], HP [Dual] VISUALIZE-EG and HP VISUALIZE-8: Eight Overlay
Planes and Two Depth-8 Banks of Image Planes
When the default visual is in the overlay planes (default location) and the screen option
EnableOverlayTransparency is not set, the overlay planes contain the default colormap permanently
Page 63
Graphics Administration Guide for HP-UX 10.20