[Octave-bug-tracker] [bug #52398] Qt toolkit plot loses track of axes proportion when containing window is shrunk small

[Dan Sebald]

URL:
  <http://savannah.gnu.org/bugs/?52398>

                 Summary: Qt toolkit plot loses track of axes proportion when
containing window is shrunk small
                 Project: GNU Octave
            Submitted by: sebald
            Submitted on: Mon 13 Nov 2017 06:09:49 AM UTC
                Category: Plotting with OpenGL
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: Incorrect Result
                  Status: None
             Assigned to: None
         Originator Name: 
        Originator Email: 
             Open/Closed: Open
         Discussion Lock: Any
                 Release: dev
        Operating System: GNU/Linux

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Details:

Testing the following example from https://savannah.gnu.org/bugs/?52389 :


graphics_toolkit qt
plot(randn(1,20))
legend('Normal')
title 'QT'


I've found that Qt has a bug in which shrinking the figure window height to
very small then expanding messes up the plot boundaries so that the axes are
magnified drastically. See the attached example screen capture.

It looks as though FLTK has its window size forced to a minimum that won't
allow such a situation to arise. I recall gnuplot terminals having similar
problems too (nothing to do with Octave). Rather than digging into the issue,
programmers for gnuplot also have gone the route of ensuring a minimum window
size, i.e., avoid the situation.  Programmers have probably put the minimum
size constraint on FLTK because its not the easiest issue to deal with.  There
is border space for axes titles and tick annotation to take into account when
computing available space, etc.

It would be nice to have a most graceful solution, but this is a problem that
doesn't arise often so the minimum window size seems fine.  Note that FLTK
toolkit window will jump to the minimum size even if I syntactically supply
plot size property values that are very small.  The Qt toolkit window should
adjust in a similar way to user-input .  That is, something like this

set(gcf, 'outerposition', [135 521 511 40])

behaves as follows:


octave:5> graphics_toolkit fltk
octave:6> figure
octave:7> plot(randn(1,20))
octave:8> legend('Normal')
octave:9> title 'FLTK'
octave:10> set(gcf, 'outerposition', [135 521 511 40])
octave:11> get(gcf, 'outerposition')
ans =

   466   474   511   147



where I put in height 40 (too small) and Octave adjusted that to 147.



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File Attachments:


-------------------------------------------------------
Date: Mon 13 Nov 2017 06:09:49 AM UTC  Name:
shrink_then_expand_qt_plot_Screenshot from 2017-11-10 23-56-56.png  Size:
12KiB   By: sebald

<http://savannah.gnu.org/bugs/download.php?file_id=42382>

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