bugGNU Octave - Bugs: bug #50825, colorbar shows reversed color...


bug #50825: colorbar shows reversed color scheme using gnuplot 4.x

Submitter:  Alois Schlögl <schloegl>
Submitted:  Tue 18 Apr 2017 11:46:03 AM UTC
Category:  Plotting with gnuplot Severity:  3 - Normal
Priority:  3 - Low Item Group:  Regression
Status:  Confirmed Assigned to:  None
Originator Name:  Open/Closed:  * Open
Release:  * 4.2.1 Operating System:  * GNU/Linux
Fixed Release:  None Planned Release:  None
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Tue 18 Apr 2017 04:59:04 PM UTC, comment #3: 

I can confirm the same with gnuplot 4.6.

There were many improvements made to support gnuplot 5 in Octave 4.2, and also some effort made to ensure that those changes didn't break anything essential with gnuplot 4.6. I'm sure a patch would be welcome to solve this as long as it doesn't also break the correct behavior with gnuplot 5.

Mike Miller <mtmiller>
Group Member
Tue 18 Apr 2017 04:49:00 PM UTC, comment #2: 

I can confirm when using gnuplot 5.0.6, the problem is gone.
In my earlier test I've been using gnuplot 4.6.6 from debian/jessie.

The release notes of Octave 4.2 [1] say :
** gnuplot 4.4 is now the minimum version supported by Octave.
but there is no indication that gnuplot 4.6 must not be used.

With earlier version of octave (e.g. 4.0.0, 3.8), gnuplot 4.6 was working fine. Checking the config.log from octave 4.2.0 and 4.2.1 do not provide any hint that gnuplot 4.6 would not be supported.

[1] https://www.gnu.org/software/octave/NEWS-4.2.html

Alois Schlögl <schloegl>
Tue 18 Apr 2017 12:57:50 PM UTC, comment #1: 

I cannot reproduce with gnuplot 5.0.5 (attached) (octave 4.2.1).


Dmitri A. Sergatskov <dasergatskov>
Tue 18 Apr 2017 11:46:03 AM UTC, original submission:  

When plotting the colorbar with gnuplot, the colorscheme is reversed. When using fltk, and qt, the colorscheme is fine (see attachedments. The following script was used to generate the figures. 

for g = {'fltk','gnuplot','qt'}
close all
imagesc(x); colorbar

Alois Schlögl <schloegl>


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Attach Files:

Attached Files
file #40437:  5x5.gnuplot.png added by dasergatskov (12KiB - image/png)
file #40433:  test_colorbar.m added by schloegl (173B - text/x-objcsrc)
file #40434:  5x5.fltk.png added by schloegl (14KiB - image/png)
file #40435:  5x5.gnuplot.png added by schloegl (14KiB - image/png)
file #40436:  5x5.qt.png added by schloegl (14KiB - image/png)


Depends on the following items: None found

Items that depend on this one: None found


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    Follow 10 latest changes.

    Date Changed by Updated Field Previous Value => Replaced by
    2017-04-18 mtmiller Priority5 - Normal 3 - Low
        Item GroupUnexpected Error or Warning Regression
        StatusNone Confirmed
        Summarycolorbar shows reversed color scheme colorbar shows reversed color scheme using gnuplot 4.x
    2017-04-18 dasergatskov Attached File- Added 5x5.gnuplot.png, #40437
    2017-04-18 schloegl Attached File- Added test_colorbar.m, #40433
        Attached File- Added 5x5.fltk.png, #40434
        Attached File- Added 5x5.gnuplot.png, #40435
        Attached File- Added 5x5.qt.png, #40436
        Carbon-Copy- Added -email is unavailable-

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