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[Octave-bug-tracker] [bug #49130] uint8 images are not shown correctly b


From: Rik
Subject: [Octave-bug-tracker] [bug #49130] uint8 images are not shown correctly by imshow with gnuplot
Date: Tue, 20 Sep 2016 15:16:29 +0000 (UTC)
User-agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:43.0) Gecko/20100101 Firefox/43.0

Update of bug #49130 (project octave):

                  Status:                    None => Confirmed              

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Follow-up Comment #8:

>From the documentation for caxis


caxis controls the mapping of data values to the colormap. It affects any
surface, patch, or image with indexed CData and CDataMapping set to scaled. It
does not affect surfaces, patches, or images with true color CData or with
CDataMapping set to direct.


So, according to Mathworks, we shouldn't be putting any "direct" data through
mapcdata.

But, as I understand it, clamping has to happen for both "direct" and "scaled"
cdatamapping.  For example, if the size of the direct colormap is small there
will definitely be out of bounds index values.  As an example


graphics_toolkit qt
I = 1 + uint8 (63 * rand (64,64));   # Data in range [1, 64] 
imshow (I);
colormap (jet (8))                   # Most indices will now be > 8, map to
red




    _______________________________________________________

Reply to this item at:

  <http://savannah.gnu.org/bugs/?49130>

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