[Octave-bug-tracker] [bug #58015] axis equal 'clears' the plot

[anonymous]

URL:
  <https://savannah.gnu.org/bugs/?58015>

                 Summary: axis equal 'clears' the plot
                 Project: GNU Octave
            Submitted by: None
            Submitted on: Sat 21 Mar 2020 07:11:37 PM UTC
                Category: Plotting
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: Incorrect Result
                  Status: None
             Assigned to: None
         Originator Name: Aron Bergman
        Originator Email: address@hidden
             Open/Closed: Open
                 Release: 5.2.0
         Discussion Lock: Any
        Operating System: GNU/Linux

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Details:

I'm doing a lab in numerical analysis where we are given a function that will
generate a plot with the fill command. The plot is supposed to look like a
circle, but when generating the polygons it looks like an ellipse due to the
axis scaling, so the last command is `axis equal`, but this seems to clear the
plot for me.

I looked into the problem myself and when debugging axis.m[1] I found that
works fine up until line 234[2], after that line the plot seems to be cleared.
I ran the program again and kept track of the value of "plotboxaspectratio"
and after it had been set on line 234 I reset it and the plot showed up
again.

The original value of "plotboxaspectratio" was [1 1 1.25] and after playing
around with it for a while I came to the conclusion that the plot will be
cleared for values < 1.25. 

I don't understand the reason why the aspect ratio of the z-value would impact
this 2D plot, so I don't feel comfortable making a suggestion to a fix. 

[1]
https://hg.savannah.gnu.org/hgweb/octave/file/a7ba8d4a1da2/scripts/plot/appearance/axis.m
[2]
https://hg.savannah.gnu.org/hgweb/octave/file/a7ba8d4a1da2/scripts/plot/appearance/axis.m#l234




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