On 2009-08-18 16:27+0100 Alban Rochel wrote:
> Hello everyone,
>
> I have started updating the Qt drivers to handle PLESC_FLUSH, and trying
> this on example x17c, I've noticed serious speed issues, which led me to
> this observation: when the chart is regenerated, the plot is cleared
> with a call to plfill:
> plfill(4, &x[0], &y[0]);
> where x={0.,1.,1.,0.} and y={0.,0.,1.,1.} (line 182, plstrip.c)
>
> This is an issue for the Qt driver as this one buffers all the commands
> in the page, and thus all the layers are drawn every time the chart is
> regenerated (which is a lot!). I could trap such fills and map them to a
> clearBuffer(), but I wonder if it wouldn't be more sensible to change
> the fill to a call to plP_esc(PLESC_CLEAR, NULL) if the driver supports it?
>
> Sorry if my question is naive, just wondering...
I think this is a good idea (using plclear which calls plP_esc, but which
has a fallback if the driver doesn't implement) which I have committed to
plstripc.c as of revision 10286. Hope this change makes it possible for you
to get roughly the same speed with -dev qt and -dev xwin. Of course, there
are built-in delays (using usleep or poll) for example 17 to make it mimic
the speed of an old-fashioned chart recorder so you will never get blazing
speed with this example.
Oops, it just struck me that some of you here may have never seen a chart
recorder in action unless you visited a tech museum. :-) Anyhow, the
current speed of example 17 with -dev xwin is about right.
Alan
__________________________
Alan W. Irwin
Astronomical research affiliation with Department of Physics and Astronomy,
University of Victoria (astrowww.phys.uvic.ca).
Programming affiliations with the FreeEOS equation-of-state implementation
for stellar interiors (freeeos.sf.net); PLplot scientific plotting software
package (plplot.org); the libLASi project (unifont.org/lasi); the Loads of
Linux Links project (loll.sf.net); and the Linux Brochure Project
(lbproject.sf.net).
__________________________
Linux-powered Science
__________________________
------------------------------------------------------------------------------
Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day
trial. Simplify your report design, integration and deployment - and focus on
what you do best, core application coding. Discover what's new with
Crystal Reports now. http://p.sf.net/sfu/bobj-july
_______________________________________________
Plplot-devel mailing list
Plplot-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/plplot-devel
