[Octave-bug-tracker] [bug #54554] When plotting large arrays, some graphic elements are not visible

[anonymous]

URL:
  <http://savannah.gnu.org/bugs/?54554>

                 Summary: When plotting large arrays, some graphic elements
are not visible
                 Project: GNU Octave
            Submitted by: None
            Submitted on: Wed 22 Aug 2018 08:56:05 PM UTC
                Category: Plotting
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: None
                  Status: None
             Assigned to: None
         Originator Name: Asa Packer
        Originator Email: address@hidden
             Open/Closed: Open
         Discussion Lock: Any
                 Release: 4.4.1
        Operating System: Microsoft Windows

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Details:

Hi,

I installed octave-4.4.1-w64-installer.exe on my Windows 10 1803 x64 box, and
some plots that worked fine in 4.4.0 are now not working.  I am using the qt
graphics toolkit.

When I do a plot of a very large array, some of the graphic elements are not
visible.  For example, if I do


plot(zeros(1,150000))


there is nothing shown in my plot at all when the plot window first opens. 
However, if I maximize the plot window (and click Autoscale), then the
expected horizontal line appears, although it is paler than the normal plot
color.  With a larger array, like length 1000000, even maximizing the window
doesn't show anything.

If I rename the opengl32.dll file in octave's bin folder, then this problem
goes away.  So this is not a showstopper for me.

As another data point, if I do


plot(sin((1:250000)*2*pi/250000))


then with the plot window at the default size, the top and bottom of the sine
wave don't show up, although the rest of the wave does (see attached
screenshot).  If I maximize the plot window, then the entire wave is visible.

Not sure what other info might be relevant, but I am happy to provide more or
do other tests if it would help.

Thanks!

Asa



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File Attachments:


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Date: Wed 22 Aug 2018 08:56:05 PM UTC  Name: plot.PNG  Size: 12KiB   By: None

<http://savannah.gnu.org/bugs/download.php?file_id=44827>

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