This refers to just a patch that hasn't been accepted, hasn't been worked on for quite a while, and AFAIR doesn't apply cleanly anymore.

That said the added functionality is very nice and welcome.

Good stuff! I have some comments and questions:

1. datacursor cannot be moved/adjusted/deleted after initial placement? Would like to be able to unstick and move and delete. Need this fairly badly.

2. there is no way to add a user-defined function to display data values in a different format, e.g. as YYYY-MM-DD using datestr()? Note that <nrjank> comment1 below hints at some such matlab functionality that would be desirable, namely the UpdateFcn — Callback function that formats data tip text. Really need this.

For a concrete example off how matlab can do this, see https://www.mathworks.com/matlabcentral/answers/117068-how-can-i-view-the-formatted-date-string-datestr-while-using-date-cursor-for-a-plot-containing-date

3. datacursor does not react to a changing zoom level, but rather stays in a fixed position on the canvas? This is maybe a bit tricky to fix, but "would be nice".

4. Could we get just a few lines of a manual to explain what each mouse button is supposed to do, etc)?


Thanks, datacursor is a very useful addition to Octave.

"patch", "surface" and "image" objects also have x/y/zdata that could be displayed in the data tooltip. Basically anything that is displayed in axes must have some kind of x/y/zdata information. That is why I asked whether it might make sense to use the "axes" function instead of changing a whole lot of plotting functions.
I don't think any interpolation should be done.

Like I also wrote, it wouldn't be necessary to support all of these graphics objects in a first version. But support for them can be added in the future.

For 3d scenes, I think that it would be possible to find the point closest to the line of sight given by the two coordinates in the axes property "currentpoint". But that also would only be a "nice-to-have" for a first version.

Another point: It might be good to have a solid background for the annotation to make it easier to read the numbers in busy graphs.

I think linking it to axes is probably not a good idea - think of patches, what does the cursor need to point to? interpolate in 2D? (or 3D?)
Would linking through __plt__.m not catch most "line" and "point" occurrences?

A datacursor for 3D is challenging - any position along a line perpendicular to the projection on the canvas is a valid coordinate point, what should datacursor return in case of stacked surfaces or solid 3D objects? But maybe there is a clever way to do it. If it operates on 3D polylines or "wrinkled' 3D polygons it could work.

It's quite a "rough" patch, glancing through it :-) But the good thing is, now the line numbers match.

As I wrote in comment #6, the only relevant stanzas in the v3 patch were the two new functions, and adding a call to  __datacursor_menu__ in the end of scripts/plot/draw/private/__plt__.m and apparently _stem_.m. and scripts/plot/draw/stairs.m.

I've manually weeded out the unneeded hunks and attached the cleaned up patch. Perhaps hunk #3 is troublesome but it's easy to see what needs to be done after trying to apply it.

Still I'm unsure if the call to __datacursor_menu__ needs to be entered into more plot functions. Maybe also 3D plot functions.


(file #48977)

It might be a personal preference. But I find it much easier to see what changed when working with patches. They don't have to be perfect...

Before turning it into a cset it seems some more work needs to be done.

Essentially the patch boils down to:

• adding __datacursor_menu__.m and __datacursor__.m into scripts/plot/draw/private/
• adding a call to __datacursor_menu__ in the end of scripts/plot/draw/private/__plt__.m and apparently __stem__.m

but maybe it needs to be called in other basic plotting functions as well; that has to be sorted out.

If the plot window is closed, do the listeners installed by the new functions have to be deleted explicitly?

It has to be sorted out why, after requesting the cursor XY data, hitting the Enter key is needed to get the variable into scope.

The prefix for Windows paths is made in mxe-octave no need to explicitly add it.

A personal not: compared to Panxto's original .m files
(https://octave.1599824.n4.nabble.com/Data-cursor-in-Octave-tp4681801p4681843.html)
this v3 patch has just black annotations in quite a big font (Panxto's had another color for each new annotation and in smaller font, both of which I liked better)

Could you provide a Mercurial patch against the current default branch with these changes?
The currently provided format makes it difficult to review the change.

I've updated the data cursor menu and function:
- the issue with the right click mouse button is fixed
- the Data menu now also appears in stem and stairs plots

To install the new version, download the datacursor-v2.zip archive and copy it to your <prefix>/share/octave/<version> directory (<prefix> is /usr for Linux, c:\octave for Windows and <version> is Octave version number) and unzip it.





(file #40594)

Thanks to the work of Pantxo Diribarne (look here), I was able to hack Octave to get a data cursor in 2D plots.

Here is how to do in Octave 4.0.x or 4.2.x:

In the attached zip file, you'll find three .m files. Copy these three files to <prefix>/share/octave/<version>/m/plot/draw/private , where <prefix> is /usr for Linux, c:\octave for Windows, etc. and <version> is Octave version number.

2. Launch Octave gui and plot some curve, like this:

x=[0:0.01:2*pi]; y=sin(x); plot(x,y);

Then you'll see the sinus curve in a figure window. In the figure menu, at the rightmost position, you'll see a new 'Data' menu item, where you can add a new data cursor, show/hide data cursors or get cursor data. See the attached screenshot as an example.

You can have several data cursors at the same time, with different colors, fonts, etc. Just right click on a data cursor to change its properties.

This works with nearly all 2D plots (semilogx, semilogy, loglog, subplot) but doesn't work with 3D plots (the Data menu is not displayed in this case).

There are some minor issues, but it works quite well...

Note that, when you do a right mouse click, position the mouse on the arrow head and not on the text, otherwise the data cursor will move to the mouse position.