HP Color Recovery

Color Recovery is a technique that generates a better picture by eliminating the graininess caused by traditional dithering techniques. It is available on these graphics devices:

•Integrated Color Graphics and plug-in Color Graphics cards

•HP VISUALIZE-EG

•HCRX-8[Z], HCRX-24[Z]

•HP VISUALIZE-8, HP VISUALIZE-24, and HP VISUALIZE-48[XP]

•HP VISUALIZE-FX2, HP VISUALIZE-FX4, and HP VISUALIZE-FX6

Color Recovery is available when using either depth-8 PseudoColor or depth-8 TrueColor visuals on supported devices.

There are two components to the Color Recovery process. First, a different dither-cell size (16X2) is used when rendering shaded polygons. Second, a digital filter is used when displaying the contents of the frame buffer to the screen.

Under some conditions, Color Recovery can produce undesirable artifacts in the image (this also happens with dithering, but the artifacts are different). However, images rendered with Color Recovery are seldom worse than what dithering produces. In most cases, Color Recovery produces significantly better pictures than dithering.

Color Recovery is available by default for all depth-8 color visuals on devices that support the feature. If, for some reason, you wish to disable Color Recovery, set the DisableColorRecovery Screen Option in the X*screens file before starting the server

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Note: This disables Color Recovery for 3D APIs as well).

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Color Recovery is enabled in conjunction with a particular X colormap that is associated with your window. If the X colormap is not installed in hardware, you may not see the effect of the Color Recovery filter (you may not even see the correct colors for that window). Given that more than one hardware colormap (or "color lookup table") is available, this should happen infrequently.

The Color Recovery colormap is a read-only colormap. Any attempts to change it will be ignored and no error will be reported.

Access to the Color Recovery capability is transparent when using a 3D graphics API such as Starbase, HP-PHIGS or PEX. If you are producing graphics using Xlib calls, your application must perform some of the necessary processing. The method to access Color Recovery via Xlib is described in a section called "Accessing HP Color Recovery Technology via Xlib" in the device-dependent sections.

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Graphics Administration Guide for HP-UX 10.20