This gs 5.50 patch extends the
X-windows device with the property IncrementalUpdate to
allow finer control of the display update policy.
When set to false changes to the picture become
visible only on showpage, copypage and
redraw, avoiding most flicker. Initially the property is
true for reasons of compatibility.
[ /IncrementalUpdate false currentdevice putdeviceprops pop
tar xvzf gnu-gs-5.50.tar.gz; tar xvzf
gs5.50-change-2.tgz and proceed with the usual
installation.
XCopyArea is used for updates, leaving
some flicker on frequently updated pictures. As an example,
consider this animation. The biggest
problem are shapes that appear only partially on the screen (in
particular horizontal lines, but also more noisy phenomena). Note,
that most so called double buffer implementations don't do anything
better than that.
Ideally, DOUBLE-BUFFER would solve the problem.
However, most implementations are broken, as demonstrated with these programs
by Stefan Kral.
Watch his project
page for further progress.
Further, the SYNC extension should allow to wait
with XSyncAwait for a system counter for the refreshes of
the screen. However, XFree and many other implementations only
provide the system counter SERVERTIME.
A possible solution using XFree specifica is proposed by Stefan Kral.