Extensions; Double Buffer Extension (Dbe); Determining Swap Performance; Display Power Management Signaling (Dpms) - HP zx2000 Supplementary Manual

configuring an X Server on HP-UX

extensions

double buffer extension (DBE)

DBE is an extension to the X Server that provides a double-buffering API. For more information
about DBE and the API, consult the DBE manual pages:
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DBE
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XdbeQueryExtension
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XdbeGetVisualInfo
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XdbeFreeVisualInfo
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XdbeScreenVisualInfo
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XdbeAllocateBackBufferName
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XdbeDeallocateBackBufferName
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XdbeSwapBuffers
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XdbeBeginIdiom
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XdbeEndIdiom
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XdbeGetBackBufferAttributes

determining swap performance

The DBE API does not allow users to determine if double buffering in a visual is through
software or hardware. However, the API does provide a way to determine relative swapping
performance on a per visual basis. The XdbeScreenVisualInfo() function returns information
about the swapping performance levels for the double-buffering visuals on a display. A visual
with a higher performance level is likely to have better double-buffer graphics performance than
a visual with a lower performance level. Nothing can be deduced from any of the following: the
magnitude of the difference of two performance levels, a performance level in isolation, or
comparing performance levels from different servers.

display power management signaling (DPMS)

Monitors constitute a large percentage of the power used by a workstation even when not actively
in use (i.e. during screen blanking). In order to reduce the power consumption, the Video
Electronic Standards Association (VESA) has defined a Display Power Management Signaling
(DPMS) standard which can be used to greatly reduce the amount of power being used by a
monitor during screen blanking.
The following table is a description of the states that are defined by VESA. The Power Savings
column indicates (roughly) the level of power savings achieved in the given state. The Recovery
Time is the amount of time that the screen takes to return to a usable state when the screen saver
is turned off (for example, by pressing a key or by moving the mouse).
4–16 Graphics Administration Guide