Extract brushed data programmatically

Hi everyone smarter than me, (Upfront--> Can I get some Matlab Engineer/Guru eyes on this ?)

I'm looking to extract exactly WHICH data points have been brushed by the user in a scatter plot.

Clearly this is tracked somewhere, because if you right click the plot you can

1. Export the brushed data to a variable
2. Delete brushed/unbrushed points
3. Copy to the command line

How can I get that list of brushed data programmatically?

My ultimate goal is to brush a linked set of scatter plots, but but a first step is to just select a collection of points, and get a logical selection out again.

I'd like to hook into the pre-built work Matlab engineers have done, rather than home brew a janky and slow version.

Does anyone know where Matlab keeps this secret sauce?

------------------------------

Here's what I've tried so far

My best guess starting point is using the struct() function to display hidden internal properties of the brush object.

However, despite the new field "ModeHandle", I can't find what I'm after once I've done that.

-------------------------

Example of my flow:

% make a scatter plot
x = 0.1:0.1:100;
y = sin(x)./x;
scatter(x,y);

b = brush;      % make the brush object
b.Enable = 'on' % enable brushing

Off I go to brush (see photo above)

Now expose the hidden brush object

b2 = struct(b); % Make brush object show all hidden properties

ModeHandle field appears, but I can't seem to find where the brushed points/ properies are.

I've delved deep into ModeHandle, with no luck.

Any help navigating the ModeHandle field would be appreciated.

[Allen]

It looks like this topic has already been covered. See @Yair Altman's answer to the linked post.

https://www.mathworks.com/matlabcentral/answers/1563016-how-to-find-brushed-data

I am also including the link he proivded to his Undocumented Matlab webpage.

https://undocumentedmatlab.com/articles/hidden-hg2-plot-functionality

[Scott Smith]

Awesome! Thanks so much! This and the accepted answer have been a big help!

Answer 1

[Adam Danz]

To get the coordinates of selected data points, you can follow the example in this answer.

That answer shows that BrushData is a property of the object that has been brushed and contains a logical index of the data points that were selected. You can use this logical index to extract the coordinates from the XData, YData, ZData properties (for most graphics objects).

[Scott Smith]

So helpful. I wish that this was easier to find out/ that "BrushedData" wasn't a hidden property.

Thanks!

Answer 2

[Scott Smith]

Also as the original poster,

This does in fact work for scatter plots and (I imagine) linked scatter plots where simultaneous brushing is being exceuted properly.

quick example code

x = 0:0.1:100;
y = sin(x)./x;

s = scatter(x,y);
brush on

Then just brush desired data

Finally to get a logical/index of the brushed data

BData = get(s,'BrushData');