clc
clear all
close all

x = 0:0.1:10;
y = sin(x);

h = figure(1);
hObj = plot(x,y);
index = [25 75 100];
hold on
for i = 1:3
    cursorMode = datacursormode(h);
    hDatatip = cursorMode.createDatatip(hObj);
    pos = [x(index(i)) y(index(i))];
    set(get(hDatatip,'DataCursor'), 'DataIndex',index(i), 'TargetPoint',pos);
    set(hDatatip, 'Position', pos);
    updateDataCursors(cursorMode);
end
hold off

I was able to get the contour data accessible within myupdatefnc, however I noticed that eventData.Position returns the absolute x,y position, whereas my contour z data might have a certain step size between data points such that the absolute x,y position doesn’t access the array correctly. Is there a way to do this without also pulling in my original x,y vectors, step size, etc and doing all the math myself? Doing the math and pulling the data in is fine…just wanted to avoid the extra bulk if possible.

@Aselia/CW – In your updateFcn(~,eventData) function, you can fetch the clicked position via eventData.Position and based on this position you can compose your custom datatip text (which is returned as the output of updateFcn). Simply find a way to get the contours data accessible in your updateFcn (there are multiple ways to do this, all of them pretty standard/documented) and you’re basically done.

Also to clarify, this is within a GUI, which allows users the ability to choose which of a set of, say, 10 types of data they want, as many as they want, to be plotted. So an automatic way of doing this, rather than passing in 3 specific data sets and pulling them out manually based on the current x,y would be helpful.

[cs1,h1] = contour(x1,y1,z1);
hold on;
[cs2,h2] = contour(x2,y2,z2);
[cs3,h3] = contour(x3,y3,z3);

Generally with data cursor, I’d have to click around in the plot to get the data cursor to show each of the z1, z2, z3 data separately, along with its legend entry, hoping I click on the exact contour I want.

I would like to see if there’s a way to use myupdatefnc to show all 3 z data values at a particular x,y position in a single data cursor. Do you know if this is possible? Thank you!

@Jacopo – in R2019a the property is called PointDataCursors. Since it’s a private property of the datacursoremode, you cannot access it directly. Instead, use struct(dcm).PointDataCursors. I am not aware of a way to change the data-cursor defaults – perhaps there is a way, I just never bothered to look for one.

>> dcm=datacursormode(figHandle)
dcm = 
  DataCursorManager with properties:
        SnapToDataVertex: 'on'
            DisplayStyle: 'datatip'
    DefaultExportVarName: 'cursor_info'
             Interpreter: 'tex'
               UpdateFcn: @(varargin)obj.manageDatatips(varargin{:})
                  Enable: 'on'
                  Figure: [1×1 Figure]

>> dcm.DataCursors
Unrecognized method, property, or field 'DataCursors' for class 'matlab.graphics.shape.internal.DataCursorManager'.

In particular, I would like to know if there is a way to change the default aspect of the markers for a given figure, since the workaround I’ve found is to change each property (marker shape, size, edge color, face color,…), then force an update (with pause), then change another property and so on.
This method has however few drawbacks:
-first, the middle step settings flash on the screen (and without the pause command between them, they are not accepted);
-second the changes are only temporary and I should update them every time the markers are drawn again, including during the resize of the figure/axes

I tried to have a look with the getundoc function, but I couldn’t really find anything useful.
Thanks,
Jacopo

@Mike – you can modify the tip background via the TipHandle and/or BackgroundAlpha:

hDataTip.TipHandle.FaceColor = 'm';  % or: [1,0,1]
hDataTip.BackgroundAlpha = 0.65;