[Octave-bug-tracker] [bug #49137] some grayscale images are displayed badly

[Francesco Potortì]

URL:
  <http://savannah.gnu.org/bugs/?49137>

                 Summary: some grayscale images are displayed badly
                 Project: GNU Octave
            Submitted by: pot
            Submitted on: Tue 20 Sep 2016 02:38:01 PM CEST
                Category: Plotting
                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: 4.0.3
        Operating System: GNU/Linux

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Details:

This behaviour is the same with gnuplot and fltk, and happens with the
attached file (which is the reduction of 1980x1980 original which exhibits the
same problem).


> imshow bug.jpg   # bad
> im = imread("bug.jpg");
> imshow(im)       #good
> close all
> subplot(3,2,1)
> image(im)        #bad


The instructions marked as #bad both generate a flat picture with a single
bordeaux colour.

The instruction marked as #good generates the correct picture, in different
levels of grey.

As a workaround, for both #bad cases if I first convert the grey image to RGB
then the display is correct:

im = repmat(im,1,1,3);



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File Attachments:


-------------------------------------------------------
Date: Tue 20 Sep 2016 02:38:01 PM CEST  Name: bug.jpg  Size: 1kB   By: pot

<http://savannah.gnu.org/bugs/download.php?file_id=38562>

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