ButtonDownFcn function question on guitar tuner

Hi there! I am trying to figure out what this part of the code does.( Program link http://www.mathworks.com/matlabcentral/fileexchange/26367-guitar-tuner/content/GuitarTuner.m )

function figure1_ButtonDownFcn(hObject, eventdata, handles) % hObject handle to figure1 (see GCBO) % eventdata reserved - to be defined in a future version of MATLAB % handles structure with handles and user data (see GUIDATA)

The comment says "Executes on mouse press over figure background." I need more information on this one though because all you have to do when the program runs is to click on the "rec" button and play the note you want , so that the tuner shows you whether the note you hit is correct or not. Does this part of code appear when you do something specific when setting up stuff on GUI??

Answer 1

[Joakim Magnusson]

There is no code in the buttonDownFcn, it don't seem to do anything and seems unnecessary? Anyway if you open the .fig file in guide and dubbelclick in the background so the property inspector appears for the figure. There you can see buttondownFcn and right to the text there is a button, if you click on that button the part of code you asked about is auto-generated.

[John Bitzios]

Thanks a lot joakim! So this function is useful so we can click on items?? help me out I am a newbee here :D

[Joakim Magnusson]

Sort of yes, if you want to know more about the function the documentation explains quite well. In the property inspector you can right click on "buttonDownFcn and click on "what's this".

[John Bitzios]

Thanks again my friend! I ll check it!

[John Bitzios]

I deleted the part of the code that included ButtonDownFcn but the program still works fine...I dont see the importance of this code...

[Joakim Magnusson]

I would guess it was just leftovers that someone forgot to remove.

Answer 2

[Joakim Magnusson]

at function playbutton1_Callback(hObject, eventdata, handles) it says set(hObject,'CData',PlayEnabled);

What is CData and how can it become PlayEnabled?? What other parameters can CData take??

I belive CData has something to do with the buttons appaerance and i think PlayEnabled is just what the author named the appearance to.

[John Bitzios]

Damn right my friend! Now I noticed that it is attached to the buttonicons section!!

Answer 3

[John Bitzios]

at function playbutton1_Callback(hObject, eventdata, handles) it says set(hObject,'CData',PlayEnabled);

What is CData and how can it become PlayEnabled?? What other parameters can CData take??