bugGNU Octave - Bugs: bug #53980, Interactive zoom on plotyy has...


bug #53980: Interactive zoom on plotyy has multiple errors (at least with qt)

Submitter:  Georg Wiora <gwiora>
Submitted:  Fri 25 May 2018 11:49:10 AM UTC
Category:  Plotting Severity:  3 - Normal
Priority:  5 - Normal Item Group:  None
Status:  Confirmed Assigned to:  None
Originator Name:  gwiora Open/Closed:  * Open
Release:  * 4.4.0 Operating System:  * Microsoft Windows
Fixed Release:  None Planned Release:  None
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Wed 10 Nov 2021 09:04:34 AM UTC, comment #4: 

comment #3:

> Zoom on the two y-axes is random. It may be depending on the mouse position over the graph which of the two axes is zoomed, but this not really reproducible.

Placing the mouse cursor exactly on one of the two y-axes allows to control which one zooms.

Georg Wiora <gwiora>
Wed 10 Nov 2021 09:02:02 AM UTC, comment #3: 

On QT windows 7 octave 6.4.0 the x-zoom is now correctly working with mouse wheel, there are no duplicated x-axes any more.
Zoom on the two y-axes is random. It may be depending on the mouse position over the graph which of the two axes is zoomed, but this not really reproducible.

Pressing autoscale does only restore the latest scaled y-axis and the x-axis.

Georg Wiora <gwiora>
Mon 26 Nov 2018 07:57:01 AM UTC, comment #2: 

I suggest proceeding this bug to status "confirmed".

Georg Wiora <gwiora>
Wed 22 Aug 2018 12:51:52 PM UTC, comment #1: 

For my Octave 4.4.0 on Windows 7 32-bit all graphics toolkits (gnuplot, qt, fltk) for plotyy behaves as:

- Pressing autoscale after zooming produces two different x axis;
- pressing Z+, rotating mouse wheel with cursor exactly (place where looking glass connected to hande - exactly over plotted line) over right axis data plot do change zoom for it;
- autoscale seems scaling the last zoomed axis;
- autoscale produces proper y-axis, but wrong line plot for provided example code - it differs from plot exactly after executing plotyy;

-  The zoom does only work on datasets for the right y axis, left not zoomed.
- Doubleclick on plot produces two different x axis, selecting autoscale all axes from menu - also works wrong (see qt section).

- after zooming plot for left y-axis data is gone and does not possible to bring it back

Sergey Parfenyuk <sergniko>
Fri 25 May 2018 11:49:10 AM UTC, original submission:  

When creating a plot from two data sets on two y axis with plotyy the interactive zoom tool misbehaves in multiple ways:
 - The zoom does only work on datasets for the left y axis.
 - Data sets for the right axis are not zoomed
 - This leads to two different but overlapping x-axis. Obviously the x-axis is created twice.

1. I recommend removing the second instance of x-axis. I guess this should be done in plotyy implementation.

2. The qt interactive zoom tool has to be made aware of the second y axis and the data sets belonging to it.

Example code to create a plotyy:

x = 1:10
y1 = linspace(1,0,10)
y2 = linspace(0,1,10)
plotyy(x,y1, x,y2)

Test with other graphics toolkits may be needed.

Georg Wiora <gwiora>


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  • -email is unavailable- added by pantxo (Updated the item)
  • -email is unavailable- added by sergniko (Posted a comment)
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    Follows 1 latest change.

    Date Changed by Updated Field Previous Value => Replaced by
    2018-11-27 pantxo StatusNone Confirmed

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