MATLAB: How to get the data selected by the user with the datacursor in a Gui

callbackdatacursorguistandalone

I have been tryng to create a gui where a user selects a point in a graph. I want to get the user selection to run another function later. I tried to create a function callback in the points in the graph but did not work. How do I create a callback to the graph points?

Thanks.

Best Answer

An example with a line object, save as file and run exampleGUI:

function exampleGUI
lnH(1) = line(1:12,-1:10, 'lines'  ,'none',  'marker' ,'.',  'markers',15,...
                          'markere','k'   ,  'buttond',@ln_buttond);
% Additional enlarged marker to highlight selected point
lnH(2) = line(1,-1,  'lines'  ,'none',  'marker' ,'o',...
                      'markere','r'  ,  'markers',8);
      function ln_buttond(varargin)
          % Retrieve Xdata and Ydata 
          XY = get(lnH(1),{'Xdata','Ydata'});
          % Get mouse position inside axes
          cpaxes = get(gca,'currentpoint');
          % Index the click
          idx    = abs(cpaxes(1) - XY{1}) < 0.25;
          % Highligth with bigger marker
          set(lnH(2),'Ydata',XY{2}(idx),'Xdata',XY{1}(idx));
      end
  end

Oleg

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MATLAB: Is the “ButtonDownFcn” callback for the axes not activated when I click on an object in the axes

An axes' "ButtonDownFcn" callback is only executed when you click on the axis itself, not the objects in the axis. The "ButtonDownFcn" callback for the child objects will be executed instead.

If you want the axes' "ButtonDownFcn" callback function to be executed regardless of where you click in the axes, try the following:

1. Set the "HitTest" property for the axis' child objects to 'off'. The "HitTest" property determines whether the object can become the current object when it is clicked on. If the "HitTest" property is set to 'off', then the object below it will become the current object, which could be another of the axes' child objects or the axes itself. If all of the axes' child objects have their "HitTest" property set to 'off', then the axes will become the current object and its "ButtonDownFcn" callback will be executed.

set(h,'HitTest','off')

2. Specify the desired callback function as the figure's "WindowButtonDownFcn" property. The "WindowButtonDownFcn" callback is executed whenever you click in the figure, and is executed before the "ButtonDownFcn" callback of any objects, including the figure itself.

set(gcf,'WindowButtonDownFcn','disp(''axis callback'')')

3. Define the "ButtonDownFcn" callbacks for the axes' child objects, so they have the same effect as calling the axes' "ButtonDownFcn" callback. This may include determining the object's Parent (the axes), and passing its handle as an input instead of the object's handle.

set(h,'ButtonDownFcn','disp(''axis callback'')')

MATLAB: Continuous Linking of 2 Plots

Here's a small GUI, the main part is ln_button and in particular you have to customize what happens at its end, I just plot some random numbers.

keyPressFcn and moveArrow are just there to make it fancy, you don't need to click the graph but you can browse the graph with arrow keys.

Also, you could speed it up by creating a line object s.ln(3) in the first axis, assign it a dummy value and then just substitute the plot with a set(s.ln(3),'Ydata',...,'Xdata',...).

function myGUI

% Figure

s.fh = figure('Units','pixels','Pos',[200 100 800 600],...
              'Numbert','off','Menubar','none','KeyPress',@keyPressFcn);
% Two axes
s.a(1) = axes('Units','pixels','Pos',[60  50 680 210]);
s.a(2) = axes('Units','pixels','Pos',[60 350 680 210],'Xlim',[1,100]);

% Line object in first axis

s.ln(1) = line(1:100,(.1:.1:10) + rand(1,100),...
               'lines','none','marker','.','markers',5,...
               'markere','k','buttond',{@ln_buttond});
% Additional enlarged marker to highlight selected point
s.ln(2) = line(-1,-1,'lines','none','marker','o',...
                     'markere','r','markers',5);

% ln_buttond --------------------------------------------------------------

      function ln_buttond(varargin)
          XY = get(s.ln(1),{'Xdata','Ydata'});
          % If mouse click
          if isempty(varargin{end})
              cpaxes = get(s.a(2),'currentpoint');
              idx    = abs(cpaxes(1) - XY{1}) < .5;
          else
              idx = varargin{end};
          end
          % Set marker
          set(s.ln(2),'Ydata',XY{2}(idx),'Xdata',XY{1}(idx));
          % Plot on first axis (from the bottom)
          plot(s.a(1),rand(100,1),rand(100,1))
      end

% keyPressFcn -------------------------------------------------------------

      function keyPressFcn(varargin)
          % Parse Keyboard Inputs
          switch upper(varargin{2}.Key)
              case 'LEFTARROW'
                  moveArrow(-1)
              case 'RIGHTARROW'
                  moveArrow(+1)
          end
      end

% moveArrow ---------------------------------------------------------------

      function moveArrow(step)
          % Retrieve pos of red marker and maxX
          X = get(s.ln(2),'Xdata');
          X = X + step;
          % Retrieve Xlim
          Xlimits = get(s.a(2),'Xlim');
          % Crossed Xlimits
          if X >= Xlimits(1) && X <= Xlimits(2)
              ln_buttond(X)
          end
      end
  end

Best Answer

Related Solutions

MATLAB: Is the “ButtonDownFcn” callback for the axes not activated when I click on an object in the axes

MATLAB: Continuous Linking of 2 Plots

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