On 2016-10-12 15:06-0700 Alan W. Irwin wrote:

> @Hazen and other Qt5 users here.  Once I move to the latest Qt5 cmake
> support methods, we will be on much less shaky ground with Qt5, but I
> will still consider our Qt5 support to be experimental because there
> are still text alignment issues which I have worked around with a
> semiempirical displacement of text compared to the Qt4 case.  See
> discussion in commentary of bindings/qt_gui/plqt.cpp concerning
> "Empirical Y offset".
> It's possible the issue is the default text alignment we are using for
> Qt5 is not correct, and we have to do some specific library startup
> for the Qt5 case to make its text alignment consistent with the Qt4
> text alignment.
> @Hazen: Would you be willing to look at this possibility?

Never mind concerning this text alignment question.  I discovered overnight 
that I
have always had access to the development version of Qt5 using Debian
Jessie, but the name of the packages has changed from the Qt4 versions
which is why I didn't find the Qt5 versions before this.

So once I installed the relevant packages I was able to configure
PLplot using -DPLPLOT_USE_QT5=ON, and build everything Qt related
without issues.

@Pedro: note I did not run into the issue you did concerning the Qt5
version.  But maybe that is because my system version of Qt5 (5.3.2)
is closer to the minimum version we currently express in the
find_package commands, 5.2.0.


I immediately noticed vertical alignment issues in the qt device
results for that configuration.  So I removed the vertical offset we
had used previously to compensate for known vertical alignment issues
with early versions of Qt5 (commit c58020c), and the result was
perfect vertical alignment for -dev qtwidget and -dev pdfqt, but still
not svgqt.  (For more details about the tests I ran concerning this,
see the commit message for c58020c.) So it appears all our alignment
troubles with Qt5 are in the process of disappearing as Qt5 alignment
bugs are fixed, and we have now finally been able to move to a version
of our code which does no vertical (or horizontal) alignment
adjustments for Qt5 to attempt to compensate for alignment bugs in
those libraries.  So I am extremely happy with this result as we
finally "get one foot on dry land".

Next Qt5 steps are for me to bump the minimum Qt5 version we support
to 5.3.2 (which _might_ solve Pedros problem with the Qt5 version he
is using), try out pyqt5, and completely change the method used to
configure Qt5 to the most modern variant possible.  I suspect all
target_link_libraries plain/keyword mixed signature issues will
disappear with that change, and if so and also assuming pyqt5 works,
then I _finally_ plan to remove the "experimental" description from
the PLPLOT_USE_QT5 option, and turn on that option by default, which
has been my goal for a very long time.

So those interested in Qt5 should stay tuned....

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); the Time
Ephemerides project (timeephem.sf.net); PLplot scientific plotting
software package (plplot.sf.net); the libLASi project
(unifont.org/lasi); the Loads of Linux Links project (loll.sf.net);
and the Linux Brochure Project (lbproject.sf.net).

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