CODEWITHSUNDEEP
matlabmatlab-figure
Black Dagger
Black Dagger

Reputation: 399

Display plot information only when cursor is on it - Matlab

I have a plot like this enter image description here

There are 30 lines on this plot and each line corresponds to a particular object. Now I want to display all the object's name. But I don't want a messy legend with 30 entries.

What I want is to be able to hover the cursor over any line (or use the data cursor) and then it object's name should appear.

Is that possible to do in Matlab. Thanks!

Upvotes: 1

Views: 227

Answers (1)

gnovice
gnovice

Reputation: 125864

Implementing text that appears when hovering over an object is doable, but can be quite involved. It would require setting a WindowButtonMotionFcn callback for your figure which would continuously check the CurrentPoint property of the figure to determine if it was within your axes of interest, and if so then check the CurrentPoint property of that axes and compute which child plot object is the closest.

If you're willing to allow the user to click and not just hover for text to appear, that's much simpler. You could set the ButtonDownFcn callback of each plotted line to display text in a given location. Here's an example that creates two line objects and assigns them a callback function that will display the Tag of the line that is clicked on at the cursor point:

function line_click_example

  hAxes = axes('NextPlot', 'add', 'ButtonDownFcn', @clear_text);
  hLines = line(hAxes, [1:10; 1:10].', [rand(10, 1) rand(10, 1)+1]);
  set(hLines, 'ButtonDownFcn', @line_click_fcn, ...
              'Tag', {'Line 1'; 'Line 2'});
  hText = text(hAxes, 0, 0, '');

  function line_click_fcn(hSource, ~)
    cursorPosition = get(get(hSource, 'Parent'), 'CurrentPoint');
    set(hText, 'Position', cursorPosition(1, [1 2]), ...
               'String', get(hSource, 'Tag'));
  end

  function clear_text(~, ~)
    set(hText, 'Position', [0 0], 'String', '');
  end

end

Here, I've also set the ButtonDownFcn of the axes so that it will clear the text object, meaning that clicking on any region of the axes that isn't over one of the two lines will remove the displayed text. Notice also that, since line_click_fcn and clear_text are nested functions, they will both have access to hText and be able to modify it.

Upvotes: 1

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