[Octave-bug-tracker] [bug #65384] image 'cdata' property fails to update class-dependent color behavior

[Nicholas Jankowski]

URL:
  <https://savannah.gnu.org/bugs/?65384>

                 Summary: image 'cdata' property fails to update
class-dependent color behavior
                   Group: GNU Octave
               Submitter: nrjank
               Submitted: Wed 28 Feb 2024 05:54:58 PM EST
                Category: Plotting
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: Incorrect Result
                  Status: Confirmed
             Assigned to: None
         Originator Name: 
        Originator Email: 
             Open/Closed: Open
                 Release: dev
         Discussion Lock: Any
        Operating System: Any
           Fixed Release: None
         Planned Release: None


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Follow-up Comments:


-------------------------------------------------------
Date: Wed 28 Feb 2024 05:54:58 PM EST By: Nicholas Jankowski <nrjank>
following on the conversation in bug #56175, matlab 2023b and octave behave
differently when an image object's CData property has it's class type changed.
E.g:



figure
H = imagesc (zeros (16, 16, 3));
set (H, 'CData', rand (16));


both programs first produces a black image, then the set command creates an
image with randomly colored squares. After both the imagesc and set commands
class(get(H, "CData")) returns 'double'. 


figure
H = imagesc (zeros (16, 16, 3, 'uint8'));
set (H, 'CData', rand (16));


In this example, both again produce a black image.  Then with the set command
Matlab produces the randomly colored squares. class(get(H, "CData")) returns
uint8 after the imagesc and double after the set.  

Octave produces the same black image, but then after the set command it
changes to a solid dark purple. class(get(H, "CData") returns 'uint8' and
'double' before and after the set as expected, and the CData is the same 0's
and random [0,1] values as matlab.  Both programs have cdatamapping set to
'scaled'.  







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