How to reach data stored in handles in a ButtownFcn?

Question

I am trying to compare the click-obtained coordinates with a loaded matrix MT.

I wrote a "loadMT" function to load the matrix MT, stored it into handles, and when it's finished it gives this(which I believe is a sign that MT has been stored in handles)

        figure1: 173.0090
          y_lbl: 11.0092
lbl_last_action: 10.0092
 AverageModulus: 9.0092
          axes1: 4.0092
         slider: 3.0092
         LoadMT: 0.0092
      LoadImage: 174.0090
         output: 173.0090
      frameName: [599x1 struct]
       pathname: [1x43 char]
       no_frame: 599
             MT: [4318x7 double]
   currentframe: 101

Mouse click coordinate was obtained in a way recommended by this post MATLAB how to get mouse click coordinates. The core code is

imageHandle = imshow(imObj);
set(imageHandle,'ButtonDownFcn',@ImageClickCallback);

function ImageClickCallback ( objectHandle , eventData )
MT=handles.MT;
axesHandle  = get(objectHandle,'Parent');
coordinates = get(axesHandle,'CurrentPoint'); 
coordinates = coordinates(1,1:2);

And it has worked and I have got the coordinate.(without the MT=handles.MT line)

However，when I click the image, it gives this error, means I failed to extract MT from the handles

Undefined variable "handles" or class "handles.MT".

Error in GUI>ImageClickCallback (line 159)
MT=handles.MT;

How may I pass the MT from handles to a local variables here? My searching results really confuse me. Thanks in advance

Answer 1

Try this

set(imageHandle,'ButtonDownFcn',{@ImageClickCallback,handles};

Also in your function ImageClickCallback you need to add a category for handles as so:

function ImageClickCallback(objectHandle, eventData, handles)