MATLAB how to get mouse click coordinates

Question

I have made my GUI using GUIDE. I have an axes (tag=axes1). An image is displayed in the axes. When i click on the image(inside axes) I need to get the coordinates. I get the coordinate values when image is not added to axes.But image is displayed in axes do no obtain the axes. How to get the coordinates?

Answer 1

Let's assume that you've plotted the image with handle imageHandle that:

imageHandle = imshow(imageObj);

You should assign the ButtonDownFcn to the image handle not the axes handle that:

set(imageHandle,'ButtonDownFcn',@ImageClickCallback);

and get the mouse coordinates from this function as follows:

function ImageClickCallback ( objectHandle , eventData )
   axesHandle  = get(objectHandle,'Parent');
   coordinates = get(axesHandle,'CurrentPoint'); 
   coordinates = coordinates(1,1:2);
   %// then here you can use coordinates as you want ...
end

You can try this small demo to check my answer:

function demoOnImageClick
clc;clear;
imObj = rand(500,500);
figure;
hAxes = axes();
imageHandle = imshow(imObj);
set(imageHandle,'ButtonDownFcn',@ImageClickCallback);

function ImageClickCallback ( objectHandle , eventData )
axesHandle  = get(objectHandle,'Parent');
coordinates = get(axesHandle,'CurrentPoint'); 
coordinates = coordinates(1,1:2);
message     = sprintf('x: %.1f , y: %.1f',coordinates (1) ,coordinates (2));
helpdlg(message);
end

end

Answer 2

You can get the axes handle from the image handle by

ah = get( imageHandle, 'Parent' );

Then you can get the mouse click position by

p = get( ah, 'CurrentPoint' );