Extensions; Double Buffer Extension (Dbe); Determining Swap Performance - HP c3700 - Workstation Administration Manual

configuring X Windows on HP-UX (other graphics cards)

extensions

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
man pages:
DBE
XdbeQueryExtension
XdbeGetVisualInfo
XdbeFreeVisualInfo
XdbeScreenVisualInfo
XdbeAllocateBackBufferName
XdbeDeallocateBackBufferName
XdbeSwapBuffers
XdbeBeginIdiom
XdbeEndIdiom
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.
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