How to extract information from a 'WindowButtonUpFcn'?

Hi all,

I am using 'WindowButtonDownFcn' in a figure to do some work when I use the mouse. So my code includes a declaration of that function:

My_Figure.WindowButtonDownFcn = {@Do_When_Mouse_Button_pressed,Var_1,Var_2};

Of course, inside 'Do_When_Mouse_Button_pressed' I have a code saying what do do when the mouse button is up again. So is looks something like this:

function Do_When_Mouse_Button_pressed(src,Var_1,Var_2)
src.WindowButtonUpFcn = @Do_When_Mouse_Button_Released;

My problem is that I want to get some variables out from 'Do_When_Mouse_Button_Released'. I cannot figure out how to do that. The usual way of using:

[src.WindowButtonUpFcn,My_Ans] = @Do_When_Mouse_Button_Released;

Together with:

function My_Ans = Do_When_Mouse_Button_Released(src,Vars)

doesn't work.

Can anyone help?

Thanks,

Alon

Answer 1

[Walter Roberson]

Callbacks are always provided with two arguments, source object, and event description. You only allowed for one automatic argument, source object.

It is not possible to return anything from a callback function, except if that callback is acting as a filter such as a position constraint callback.

http://matlab.wikia.com/wiki/FAQ#How_can_I_share_data_between_callback_functions_in_my_GUI.28s.29.3F

[Alon Rozen]

Thanks Walter,

I read carefully the attached link and understood. I solved it by sending down the main GUI handle, together with its hObject, and then wrote to it some results and saved it by using guidata function. I see that there is no simple workaround.

Thanks again!