Urgent!! I need to create a callback function in my GUI and I need HELP!!!

Hey guys,

I am new to creating GUIs in Matlab so I have a question on how exactly to use a callback function. I created a GUI that has a plot and a slider and in the axis callback function I added a code I have to rotate a 2D plot. I then want to be able to use the slider to change the value of the variable that rotates the 2D plot. I think I need to use a callback function to do this but I am very confused how they work. Please help!

Also here is my code:

    function varargout = untitled2(varargin) % UNTITLED2 MATLAB code for untitled2.fig % UNTITLED2, by itself, creates a new UNTITLED2 or raises the existing % singleton*. % % H = UNTITLED2 returns the handle to a new UNTITLED2 or the handle to % the existing singleton*. % % UNTITLED2('CALLBACK',hObject,eventData,handles,...) calls the local % function named CALLBACK in UNTITLED2.M with the given input arguments. % % UNTITLED2('Property','Value',...) creates a new UNTITLED2 or raises the % existing singleton*. Starting from the left, property value pairs are % applied to the GUI before untitled2_OpeningFcn gets called. An % unrecognized property name or invalid value makes property application % stop. All inputs are passed to untitled2_OpeningFcn via varargin. % % *See GUI Options on GUIDE's Tools menu. Choose "GUI allows only one % instance to run (singleton)". % % See also: GUIDE, GUIDATA, GUIHANDLES

    % Edit the above text to modify the response to help untitled2
    % Last Modified by GUIDE v2.5 13-Sep-2013 17:16:22
    % Begin initialization code - DO NOT EDIT
    gui_Singleton = 1;
    gui_State = struct('gui_Name',       mfilename, ...
                       'gui_Singleton',  gui_Singleton, ...
                       'gui_OpeningFcn', @untitled2_OpeningFcn, ...
                       'gui_OutputFcn',  @untitled2_OutputFcn, ...
                       'gui_LayoutFcn',  [] , ...
                       'gui_Callback',   []);
    if nargin && ischar(varargin{1})
        gui_State.gui_Callback = str2func(varargin{1});
    end
    if nargout
        [varargout{1:nargout}] = gui_mainfcn(gui_State, varargin{:});
    else
        gui_mainfcn(gui_State, varargin{:});
    end
    % End initialization code - DO NOT EDIT
    % --- Executes just before untitled2 is made visible.
    function untitled2_OpeningFcn(hObject, eventdata, handles, varargin)
    % This function has no output args, see OutputFcn.
    % hObject    handle to figure
    % eventdata  reserved - to be defined in a future version of MATLAB
    % handles    structure with handles and user data (see GUIDATA)
    % varargin   command line arguments to untitled2 (see VARARGIN)
    % Choose default command line output for untitled2
    handles.output = hObject;
    % Update handles structure
    guidata(hObject, handles);
    % UIWAIT makes untitled2 wait for user response (see UIRESUME)
    % uiwait(handles.figure1);
    % --- Outputs from this function are returned to the command line.
    function varargout = untitled2_OutputFcn(hObject, eventdata, handles) 
    % varargout  cell array for returning output args (see VARARGOUT);
    % hObject    handle to figure
    % eventdata  reserved - to be defined in a future version of MATLAB
    % handles    structure with handles and user data (see GUIDATA)
    % Get default command line output from handles structure
    varargout{1} = handles.output;
    % --- Executes on slider movement.
    function slider1_Callback(hObject, eventdata, handles)
    % hObject    handle to slider1 (see GCBO)
    % eventdata  reserved - to be defined in a future version of MATLAB
    % handles    structure with handles and user data (see GUIDATA)
    % Hints: get(hObject,'Value') returns position of slider
    %        get(hObject,'Min') and
    %get(hObject,'Max') to determine range of slider
    % --- Executes during object creation, after setting all properties.
    function slider1_CreateFcn(hObject, eventdata, handles)
    % hObject    handle to slider1 (see GCBO)
    % eventdata  reserved - to be defined in a future version of MATLAB
    % handles    empty - handles not created until after all CreateFcns called
    % Hint: slider controls usually have a light gray background.
    if isequal(get(hObject,'BackgroundColor'), get(0,'defaultUicontrolBackgroundColor'))
        set(hObject,'BackgroundColor',[.9 .9 .9]);
    end
    % --- Executes during object creation, after setting all properties.
    function axes1_CreateFcn(hObject, eventdata, handles)
    % hObject    handle to axes1 (see GCBO)
    % eventdata  reserved - to be defined in a future version of MATLAB
    % handles    empty - handles not created until after all CreateFcns called
    % Hint: place code in OpeningFcn to populate axes1
    % define the x- and y-data for the original line we would like to rotate
      %handles = guihandles(gcbo)
       %wave=get(handles.slider1,'Value') 
    x=[1; 2; 3; 4];
    c=[4 ;5; 67; 6];
    y = c;
    %close all
    % create a matrix of these points, which will be useful in future calculations
    v = [x y];
    % choose a point which will be the center of rotation
    x_center = x(1);
    y_center = y(1);
    % create a matrix which will be used later in calculations
    center = repmat([x_center; y_center], 1, length(x));
    % define a 60 degree counter-clockwise rotation matrix
    theta=78
    R = [cosd(theta) -sind(theta); sind(theta) cosd(theta)];
    % do the rotation...
    %s = v - center; % shift points in the plane so that the center of rotation is at the origin
    %so = R*s; % apply the rotation about the origin
    %vo = so + center; % shift again so the origin goes back to the desired center of rotation
    % this can be done in one line as:
     vo = R*((v - center')') + center;
    % pick out the vectors of rotated x- and y-data
    x_rotated = vo(1,:);
    y_rotated = vo(2,:);
    % make a plot
    subplot(2,1,1)
    plot(x, y, 'k-', x_rotated, y_rotated, 'r-', x_center, y_center, 'bo');
    axis equal
So basically in this code I want to be able to move the slider and the value that I move it to I want it to be set as the variable theta and I want the graph to update with the different thetas as I move the slider.

Also please don't ask me to try another way to rotate a graph, this is the way that I need to do that.

Thanks!

[Jan]

It is surprising that the occurring of the term "urgent" is highly correlated to a a (here partially) missing code formatting. Please read: http://www.mathworks.com/matlabcentral/answers/29922-why-your-question-is-not-urgent-or-an-emergency

Answer 1

[John Petersen]

you have a callback function already, but you put all your code in the createfcn which doesn't execute after creation. Try putting your code in the slider callback.