MATLAB: Convert CurrentPoint to X and Y Value.

currentpointhandles

This is where we are getting stuck. We would appreciate any insight.

We have a basic figure (linear plot using: and we are using ‘CurrentPoint’ in the code to extract a value from the graph.

Here is the input:

     function FcnName(src,evnt,a)
     cp = get(gcf, 'CurrentPoint')
     disp('click down!!!!')
     disp(a)
     end

Here is the output:

     cp = 341 257

but what we need is the "real" x and y value. Is there a way to accomplish this?

Amanda

Best Answer

x=get(gco,'Xdata');
y=get(gco,'Ydata')

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MATLAB: Get position when using uicontextmenu

Instead of a context menu, use a ButtonDownFcn that responds to a mouse click on the object. It's lighter weight than a context menu and requires only 1 click rather than a right-click + selection.

Here's a demo using your idea: It outputs the (x,y) coordinates to the command window and marks the most recently selected coordinate with a red 'x'. hObj is the handle to the line object you're clicking. eventM is a structure that contains the coordinates of the point you selected and the button used to select it.

figure
x = randn(1,20);
y = randn(1,20);
% menu = uicontextmenu();
hs = scatter(x,y); 
hs.ButtonDownFcn = @clickPointFcn; 
hold on
function clickPointFcn(hObj,event)
% Do whatever you want with that....
fprintf('x = %f, y = %f\n',event.IntersectionPoint(1:2))
% Search and remove previous 'recent selection'
delete(findall(hObj.Parent, 'Tag','recentSelection'))
% Add 'x' to mark selection 
plot(event.IntersectionPoint(1),event.IntersectionPoint(2), 'rx', 'tag','recentSelection')
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MATLAB: How to get values of X,Y,Z when i point courser on the graph

Method 1: use data tips

% Create demo scatter plot
x = linspace(0,3*pi,200);
y = cos(x) + rand(1,200);
sz = 25;
c = linspace(1,10,length(x));
s = scatter(x,y,sz,c,'filled');
% Add an additional row to the data tips showing the color value
datatipRow = dataTipTextRow('C',c);
s.DataTipTemplate.DataTipRows(end+1) = datatipRow;
% Now click on any point to produce the data tip (image below)

Method 2: return value to command window (or anywhere else you'd like)

This uses ginput() which allows the user to click on any space within the axes. It then computes the nearest point and returns its (x,y) coordinate and color value.

% User must select 1 point
[x,y] = ginput(1); 
% Get (x,y) coordinates for all points
% *** This assumes the entire point was made with the one 
% call to scatter() instead of several calls to scatter(). 
h = gco(); 
hx = h.XData; 
hy = h.YData; 
hc = h.CData; 
% Find the nearest point to selection
d = sqrt((x-hx).^2 + (y-hy).^2); 
[~,minIdx] = min(d); 
% Return the (x,y) and color data
fprintf('(x,y,c) = (%.3f,%.3f,%.3f)\n',hx(minIdx),hy(minIdx),hc(minIdx));

Best Answer

Related Solutions

MATLAB: Get position when using uicontextmenu

MATLAB: How to get values of X,Y,Z when i point courser on the graph

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