[Octave-bug-tracker] [bug #50356] axis "square" does not force square

[Vic Norton]

URL:
  <http://savannah.gnu.org/bugs/?50356>

                 Summary: axis "square" does not force square
                 Project: GNU Octave
            Submitted by: vicnorton
            Submitted on: Sun 19 Feb 2017 09:36:58 PM UTC
                Category: Plotting with gnuplot
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: Incorrect Result
                  Status: None
             Assigned to: None
         Originator Name: vicnorton
        Originator Email: 
             Open/Closed: Open
         Discussion Lock: Any
                 Release: 4.2.0
        Operating System: Mac OS

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Details:


% square_bug.m  - when square does not mean square
do_plot = 3;
xrect = [0 1.5 1.5 0 0];
yrect = [0 0 2.0 2.0 0];
if do_plot
  figure(do_plot)
  clf;
  plot(xrect, yrect, "-k");
  axis([0, 1.5, 0, 2.0], "square");  % or replace "square" with "equal"
  set(gca, ...
    "xlim", [0 1.5], "ylim", [0 2.0], ...
    "xtick", [0 : 0.25 : 1.55], "ytick", [0 : 0.25 : 2.0] ...
  );
%  set(gca, "dataaspectratiomode", "manual");  % uncomment for square 
  get(gca, "dataaspectratio")
  get(gca, "dataaspectratiomode")
endif
%{
1. First run of square_bug. Figure 3 opens as a square with different x
   and y scales and textual output:
     ans = dataaspectratio     = 1.5000   2.0000   1.0000
     ans = dataapsectratiomode = auto
   The image has been saved in "square_bug_1.pdf".
2. Now contract the width of Figure 3. The square turns into a rectangle.
   On running square_bug again, the same rectangular Figure 3 window
   reappears with the same rectangle in it. The textual output is also
   unchanged:
     ans = dataaspectratio     = 1.5000   2.0000   1.0000
     ans = dataapsectratiomode = auto
   The "dataaspectratio" is incorrect. The rectangular image has been
   saved in "square_bug_2.pdf".
3. Now uncomment the
     set(gca, "dataaspectratiomode", "manual");
   line and run square-bug once again. The Figure 3 window remains the
   same, but now we have a square, the listed "dataapectratio" now means
   something, and the "dataapsectratiomode" has changed to "manual":
     ans = dataaspectratio     = 1.5000   2.0000   1.0000
     ans = dataapsectratiomode = manual
   The result is shown in "square_bug_3.pdf".
4. Proposal: when axis is set to "square", "dataapsectratiomode" should
   always be "manual". This does happen when axis is set to "equal". To
   see this, change "square" to "equal", close all figure windows,
   comment out the "dataaspectratiomode", and run the same three
   experiments again. Actually, when you run the first experiment, you
   will see
     ans = dataaspectratio     = 1   1   1
     ans = dataapsectratiomode = manual
   and the relative x and y scales on the recangle will remain the same
   no matter how you manipulate the Figure 3 window.
5. The three images, square_bug_#.pdf, were produced with
      graphics_toolkit gnuplot;
      setenv GNUTERM qt;
   and
      Export to PDF
   from the gnuplot_qt Figure 3 window.
%}





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File Attachments:


-------------------------------------------------------
Date: Sun 19 Feb 2017 09:36:58 PM UTC  Name: square_bug_1.pdf  Size: 5kB   By:
vicnorton

<http://savannah.gnu.org/bugs/download.php?file_id=39794>
-------------------------------------------------------
Date: Sun 19 Feb 2017 09:36:58 PM UTC  Name: square_bug_2.pdf  Size: 5kB   By:
vicnorton

<http://savannah.gnu.org/bugs/download.php?file_id=39795>
-------------------------------------------------------
Date: Sun 19 Feb 2017 09:36:58 PM UTC  Name: square_bug_3.pdf  Size: 5kB   By:
vicnorton

<http://savannah.gnu.org/bugs/download.php?file_id=39796>

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