[Octave-bug-tracker] [bug #44415] OpenGL plotted image has vertical line every 4096 pixels

[Dan Sebald]

URL:
  <http://savannah.gnu.org/bugs/?44415>

                 Summary: OpenGL plotted image has vertical line every 4096
pixels
                 Project: GNU Octave
            Submitted by: sebald
            Submitted on: Tue 03 Mar 2015 08:22:07 PM GMT
                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:

I'm seeing for both FLTK and Qt graphics toolkits vertical lines in an image
plot every 4096 pixels.  See the attached image for the result after running
the commands


N = 30000;
grd = repmat((1:N)/N, 20, 1);
image(32*grd);


My guess is that this might be an OpenGL bug, but I just want to confirm.  So
could someone please try the above lines and let me know if the same thing is
happening for others.

Why OpenGL?  Well, the data isn't an issue as the pixels seem all in their
proper locations.  If one changes the size of the window, the underlying image
is affected but the white lines aren't.  If those lines were in the data, the
lines would alias (i.e., sometimes be nonvisible), but they are always
present.  It seems to me the only way it could be an Octave bug is if the
Octave isn't setting up OpenGL correctly somehow.



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File Attachments:


-------------------------------------------------------
Date: Tue 03 Mar 2015 08:22:07 PM GMT  Name: Screenshot-Figure 1-1.png  Size:
13kB   By: sebald

<http://savannah.gnu.org/bugs/download.php?file_id=33236>

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