Selecting points on a streaming webcam image in a GUI

Good morning!

I'm trying to figure out how to select a point in streaming webcam data that is being displayed in a GUI (the intent is to then track those points and do some simple math with them like calculate angles as they change in real time).

Where I'm stuck is that I can't figure out how to appropriately assign the ButtonDownFcn in order to get the x,y coordinates on click.

How it's set up:

I made a GUI with GUIDE, put in an axis object, and have it labeled as handles.axesCamera1. To stream, I made a togglebutton handles.onOff, and use this to start/stop streaming. When it's on: while handles.onOff == 1 handles.time = now; handles.imgCurr = snapshot(handles.cam); imshow(handles.imgCurr,'Parent',handles.axesCamera1); drawnow(); handles.onOff = get(handles.togglebuttonStream,'Value'); guidata(hObject, handles); end

I then have a button that has a callback that starts with this line: h = get('Parent',handles.axes1Camera); set(h,'ButtonDownFcn',@captureImageClick);

where

function captureImageClick(handles,eventdata,hObject)

    h = findobj(handles.axesCamera1,'Parent');
    coords = get(h,'CurrentPoint');
    x = coords(1);
    y = coords(2);

% if isempty(handles.ptType) % handles.ptType(1:length(coords(1))) = {'p'}; % elseif ~isempty(handles.ptType) % handles.ptType(end+1:end+1+length(x)-1) = {'p'}; % end

    %append coordinates for points
    if ~isempty(handles.trackPoints)
        handles.trackPoints = [handles.trackPoints; [x y]];
    else
        handles.trackPoints = [x y];
    end

% handles.numClicked = handles.numClicked + 1;

    guidata(hObject, handles);

But in debugging captureImageClick never fires. Am I thinking about this correctly? Or am I just getting the handle reference wrong?

Thanks for any help!