How do I display custom text for the data cursor?

I want to customize the text that is displayed in the text box when I use the data cursor tool.

I want to use my own labels instead of the standard X and Y coordinates that are being displayed. How do I do this? 

Answer 1

[MathWorks Support Team]

For doing this, you need to make use of the "Edit Text Update Function" from the Data Cursor Tool context menu. 

Here is a detailed example that walks you through the different steps involved. 

1. Create a simple scatter plot as follows : 

>> scatter(rand(1,10), rand(1,10));

2. After the plot opens, click on the "Data Cursor" tool. 

3. Right click anywhere inside the plot, and select "Edit Text Update Function".

4. Edit the code in such a way that the "output_txt" variable is the label you want to display next to the selected point. This example function displays "High Risk" if both "x" and "y" values are greater than 0.5, and "Low Risk" otherwise :

====

function output_txt = display_risk(obj,event_obj)
% Display the position of the data cursor
% obj          Currently not used (empty)
% event_obj    Handle to event object
% output_txt   Data cursor text string (string or cell array of strings).

% Get the position of the point being clicked on 
pos = get(event_obj,'Position');

% If both X and Y values are greater than 0.5, label it as high risk
% Else label it as low risk

if pos(1) > 0.5 && pos(2) > 0.5
    output_txt = {'High Risk'};
else
    output_txt = {'Low Risk'};
end

====

5. Save the file with the appropriate name. In this case "display_risk.m"

6. The "Data Cursor" should now display the custom labels according to the point being selected.

7. To use the same functionality for another plot, select the "Data Cursor" tool, right-click and select "Select Text Update Function", and choose the appropriate function you want to use. 

Answer 2

[Giuseppe Naselli]

Hi, thanks for this but the explanation is a bit vague.

• Could you please explain a bit better where the display_risk.m needs to be saved?
• And if we want to include it in a stand-alone function that is shared with others?
• is there a way of making the display_risk function to read data from the workspace?
• In other words, suppose I want to create a function that has x,y,z as inputs where x = coordinate x,y = coordinate y,z = text to be displayed when the cursor clicks on the corresponding point

Thanks in advance G

[Steven Lord]

The third example on the documentation page for the datacursormode function shows how to set a custom data cursor update function programmatically. Since you say you want to "include it in a stand-alone function that is shared with others" that may be easier for your application.