Re: [Plplot-general] clearWidget crashes after pljoin

[Alan W. I. <ir...@be...>]

On 2009-06-16 16:21+0100 MaaTt wrote:

> Dear all,
>
> I am totally new to plplot, so any advice is greatly appreciated.
> Thank you all in advance (even reading the below)
>
> In brief, I am wondering if anyone can help me out by telling me
> - why clearWidget crashes after pljoin is called;
> - what plclear actually does;

Hi Matt:

I just discovered today that the qt device had the sense of dev_clear
reversed.  From the plclear code in plpage.c, if the driver sets
pls->dev_clear=1; then the device is called with PLESC_CLEAR to allow the
device to handle plclear itself.  Otherwise, ff the driver sets
pls->dev_clear=0, then a PLplot core fallback is used (overwrite the page
with the background colour) which seems perfectly fine to me as a way to
simulate clearing the (sub-)page.  Indeed, most drivers are content with
this PLplot core fallback for clearing the page.  Only the wxwidgets device
handles PLESC_CLEAR at this time, and pls->dev_clear=0 for all other devices
(usually by default) except for qt.cpp.  That device inconsistently set
pls->dev_clear=1 while not handling PLESC_CLEAR.  I have now (revision 10056
in our svn trunk version) fixed that inconsistency bug by setting
pls->dev_clear=0 throughout the qt device driver following what is done
for most other device drivers.

Will you please try the svn trunk version of Plplot to see if that solves
your clear issues?

You haven't yet replied to my suggestion of downloading a modern Qt4 version
for your Linux platform. Does that suggestion solve the inconsistency you
were getting between your Linux results with old Qt4 and your windows
results with modern Qt4?

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
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