{
/* 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
{
if (
{/* 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 ColormapsThe following information discusses the number of supported colormaps for the HCRX configurations.
HPThe 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.
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
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