MATLAB Basics: Setting a background image for a GUI

October 16th, 2007

MATLAB Basics: Setting a background image for a GUI

here

http://blogs.mathworks.com/pick/category/video/

http://blogs.mathworks.com/pick/category/matlab-basics/

By Doug Hull

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43 Responses to “MATLAB Basics: Setting a background image for a GUI”

Craig Miller replied on October 17th, 2007 at 13:40 UTC :

Nifty idea. Is there a way to do this without using imshow from the Image Processing Toolbox, with just ‘plain’ Matlab?

Thanks,
Craig

Doug replied on October 30th, 2007 at 08:36 UTC :

With a little work, IMAGE should do fine here also. It is just that IMSHOW, from the image processing toolbox, takes care of many book keeping type tasks for you so your image always looks great.

Doug

Vaibhav Bedia replied on January 12th, 2008 at 10:52 UTC :

I am having some problems with the background image.Things work fine once but if i close MATLAB and start the GUI again the axes loses its TAG and hence the axes becomes invisible.I need to rename it manually everytime.Is there a way to solve this?

xiaolan replied on January 18th, 2008 at 01:11 UTC :

May i know how to put an image on a button? i don’t want any wordings on the button, i just want to have image on it.

Thanks.

Doug replied on January 21st, 2008 at 10:21 UTC :

xiaolan,

You can put an image in a button like this:

a = uicontrol(’style’,'pushbutton’)
set(a,’cdata’,rand(10,10,3))

I set he cdata to a random RGB matrix, but you can use whatever you like.

Doug

tasha replied on October 28th, 2008 at 04:43 UTC :

i really need help on my MATLAB GUI program. can anyone help me? please email me at intan_tassya@yahoo.com if you’re wiling to help me.

i’ve create a simple GUI interface. im using MATLAB V.7.2.. but i don’t even know how to input the function . for example, total_area= area1+area2 when we press the ‘calculate’ button. can anyone show me 1 clear example on this matter, i need to complete my project within 1 week starting from today…i’ve read all your comments etc, but i couldnt understand it.. besides, im importing the jpeg image into the axes which i labelled as ‘pic1′…when i generate, the picture will be displayed, but when i click the ‘next’ button, and trying to go back to the previous interface, the image gone. i dont understand why…please somebody, i really need help on MATLAB GUI…please email me..thank you very much :(

Doug replied on October 29th, 2008 at 14:42 UTC :

Tasha,

I would recommend this video:

http://blogs.mathworks.com/pick/2008/05/13/accessing-data-from-one-widget-to-another-in-guide/

It will show you how to get data from one uicontrol (like an editbox) and use it as input in the callback of another.

I am sorry, but I am not too clear on your second question. Please contact support@mathworks.com with a more detailed question.

Doug

Ed Helwig replied on December 10th, 2008 at 21:19 UTC :

Doug,

I tried following your set up for putting an image into the axes and I continue to only get the X/Y plot displayed. I have even created a new fig and got the same result. Where should I begin looking for the problem? I am using version 2007b.

Thanks in advance.

dhull replied on December 11th, 2008 at 15:26 UTC :

Ed,

Please post your code for review.
Shorter and simpler is better for us to look at.

thanks,
Doug

mark replied on September 11th, 2009 at 16:58 UTC :

Please can you tell me where you saved the ‘pout.tif’ image. I have saved my image (new.bmp) in the same folder that with the GUI file and the M-File. Below are my codes, but i didn’t get the image in the background. it only showed a numbered x and y axes. Can you help please.

% — 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

axes (hObject)
imshow(’new.bmp’)

dhull replied on September 14th, 2009 at 13:55 UTC :

@mark,

Pout.tif was here:

>> which pout.tif
C:\Program Files\MATLAB\R2009a\toolbox\images\imdemos\pout.tif

In the debugger, put a breakpoint right before imshow, use which as I did above to make sure the file is on your path.

Doug

vasso replied on September 15th, 2009 at 19:59 UTC :

Doug,
is there any way to set a background image for my GUI and, on that, clip another axis in order to display images?
Generelly, can I clip on an axis another axis?
I tried doing it the way you propose, but the images the two axes display (the background image and the image I want to display) get mixed.
Thanks in advance for your reply!

vasso replied on September 15th, 2009 at 20:02 UTC :

sorry for the mixed use of axis and axes! I hope you understood what I meant!

dhull replied on September 16th, 2009 at 15:27 UTC :

@vasso,

I do not understand your question. Please contact http://www.mathworks.com/support

Doug

mark replied on September 16th, 2009 at 17:15 UTC :

Thanks Doug… I got it now. Many Thanks. Doug, do you have tutorials on Plotting graphs using Matlab GUI? I’ve done most of your beginner’s lessons but I can’t find one for plotting graphs

dhull replied on September 16th, 2009 at 17:23 UTC :

@mark,

http://blogs.mathworks.com/videos/2009/07/10/basics-visualizing-a-function-of-two-variables/

This is one of the many videos that cover graphics in some way. Anything specific you would like to see?

Doug

mark replied on September 17th, 2009 at 13:00 UTC :

Thx for the reply Doug. The video was very informative. But I’m after tutorial on plotting graphs. Say I want to plot the values of X against y values using GUI AXES. How do I define X and Y? Give title and axes range to the plot using GUI

dhull replied on September 17th, 2009 at 13:08 UTC :

@mark,

It would be easier to help if I knew what you have already tried. Please e-mail me the details and the code you have tried.

Thanks,
Doug

mark replied on September 17th, 2009 at 13:32 UTC :

Hello Doug i sourced these codes which gave tutorial about diffusion random walker . I don’t really understand some parts. can you clearify some points for me?

% — Executes on slider movement.
function slider_M_Callback(hObject, eventdata, handles)
% hObject handle to slider_M (see GCBO)
% eventdata reserved - to be defined in a future version of MATLAB
% handles structure with handles and user data (see GUIDATA)
M = get(handles.slider_M,’Value’);
set(handles.value_M,’String’,round(max(M,1)));

for the code above what does “round(max(M,1)” means

codes 2

M = round(max(get(handles.slider_M,’Value’),1));
N_max = round(max(get(handles.slider_N,’Value’),1));

part=[zeros(1,M);zeros(1,M)];
move=mod(floor(4*rand(1,M)),4);

N_size=40;
part=[zeros(1,M);zeros(1,M)];
plot(part(1,:),part(2,:),’o',’MarkerFaceColor’,'r’,'MarkerSize’,3,’MarkerEdgeColor’,'none’),…
axis([-N_size N_size -N_size N_size]);
hold on
plot(part(1,1),part(2,1),’o',’MarkerFaceColor’,'b’,'MarkerSize’,3,’MarkerEdgeColor’,'none’);
hold off
datacursormode on

Can you tell me what the above codes does. it was written under this fuction:
function Diffusion_OpeningFcn(hObject, eventdata, handles, varargin)

dhull replied on September 17th, 2009 at 14:06 UTC :

@mark,

The first gets the value of the slider, rounds it off and displays it.

The second code is kind of taken out of context, I know it is getting values from the GUI and rounding them and plotting them.

The best way to understand code like this is to run it with breakpoints at the lines you are trying to understand so that you can inspect each variable as the code is running. Then step through the code seeing what each line does.

-Doug

mark replied on September 17th, 2009 at 19:26 UTC :

Thanks Doug, i have gained some understanding running the code with breakpoint at the lines. Doug do u know what this term does or mean? “isinf” examples of codes are:

ym=isinf(1./move);
xp=isinf(1./(move-1));
yp=isinf(1./(move-2));
xm=isinf(1./(move-3));

And these terms “mod”, “floor” and “rand”. example

move=mod(floor(4*rand(1,M)),4);

Many Thx

dhull replied on September 17th, 2009 at 19:34 UTC :

@Mark,

Where there is a command you do not recognise, you can type:

>>doc ininf

This will bring you to the documentation for that line, in this case to

Doc for isInf
http://www.mathworks.com/access/helpdesk/help/techdoc/ref/isinf.html

Enjoy,
Doug

mark replied on September 17th, 2009 at 19:44 UTC :

Many thanks Doug, You’re a life saver.

mark replied on September 17th, 2009 at 20:12 UTC :

Hello Doug, I am trying to run this code from the command window. But i keep getting this error saying:

??? Random variate function Z(t,X(t)) is invalid.

here are the codes;

>> N = 1; % Dimensions
F = @(t,X) zeros(N,1); % Drift
G = @(t,X) eye(N); % diffusion
S = sde(F,G,’startState’,zeros(N,1));
>> X = S.simByEuler(10000,’ntrials’,1,’Z',@(t,X) RandDir(N));

comet(1:numel(X),X);
plot(1:numel(X),X);
grid on;

??? Random variate function Z(t,X(t)) is invalid.

Please can you identify my mistake for me? Many Thanks

dhull replied on September 18th, 2009 at 16:26 UTC :

@mark,

Please contact http://www.mathworks.com/support as I am not familiar with that toolbox, but we have support engineers who are.

Thanks,
Doug

mark replied on September 18th, 2009 at 18:02 UTC :

Thanks Doug…

mark replied on October 19th, 2009 at 13:44 UTC :

Hello Doug,
I’m trying to plot series of ‘o’ points, But I can’t get the axes correctly. My GUI page has “axes1” and a “push Button” renamed as “start”. I have attached the M-File. How can i tell GUI that when i click on “run figure” from GUI, it should display an empty graph with “Y axes = -40: 40” and X axes = -40: 40”. (Can this code the put in the OpeningFcn?). The callback for the push button will plot series of points. How can get those points to be plot on my initial axes “-40:40” for both X and Y without changing the axes. I want to plot X and Y (as ‘o’) where X = -20:20 and Y = 0:0. Below is the M-File so far. Many thanks.

function varargout = Work2(varargin)
% WORK2 M-file for Work2.fig
% WORK2, by itself, creates a new WORK2 or raises the existing
% singleton*.
%
% H = WORK2 returns the handle to a new WORK2 or the handle to
% the existing singleton*.
%
% WORK2(’CALLBACK’,hObject,eventData,handles,…) calls the local
% function named CALLBACK in WORK2.M with the given input arguments.
%
% WORK2(’Property’,'Value’,…) creates a new WORK2 or raises the
% existing singleton*. Starting from the left, property value pairs are
% applied to the GUI before Work2_OpeningFcn gets called. An
% unrecognized property name or invalid value makes property application
% stop. All inputs are passed to Work2_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 Work2

% Last Modified by GUIDE v2.5 17-Oct-2009 10:42:20

% Begin initialization code - DO NOT EDIT
gui_Singleton = 1;
gui_State = struct(’gui_Name’, mfilename, …
‘gui_Singleton’, gui_Singleton, …
‘gui_OpeningFcn’, @Work2_OpeningFcn, …
‘gui_OutputFcn’, @Work2_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 Work2 is made visible.
function Work2_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 Work2 (see VARARGIN)

% Choose default command line output for Work2
handles.output = hObject;

% Update handles structure
guidata(hObject, handles);

% set(handles.figure1,’Menubar’,'figure’);

% UIWAIT makes Work2 wait for user response (see UIRESUME)
% uiwait(handles.figure1);

% — Outputs from this function are returned to the command line.
function varargout = Work2_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 button press in pushbutton1.
function pushbutton1_Callback(hObject, eventdata, handles)
% hObject handle to pushbutton1 (see GCBO)
% eventdata reserved - to be defined in a future version of MATLAB
% handles structure with handles and user data (see GUIDATA)
axes(handles.axes1)
%create a vector from 0 to 10, [0,1,2,3…10]
x = -20:20;
y = 0:0;
plot(x,y, ‘o’,'MarkerFaceColor’,'r’,'MarkerEdgeColor’,'r’, ‘MarkerSize’,4);

dhull replied on October 19th, 2009 at 17:59 UTC :

@Mark

You might want to try and get the plot working without the GUI first.


x = -20:20;
y = 0:0;
plot(x,y, ‘o’,'MarkerFaceColor’,'r’,'MarkerEdgeColor’,'r’, ‘MarkerSize’,4);

When doing the above, your “y” is a scalar (0). I doubt this is what you want.

-doug

mark replied on October 19th, 2009 at 19:26 UTC :

Yes that’s exactly what I want. I want to get the ‘o’ either vertical (where all X values = 0) or horizontal (where all Y values = 0) Now if you look at the x-axes we have (x = -20:20) and the y-axes (y = -1:1). Is it possible to get both axes the same… say (both x & y will be -20:20). Also if you look at the graph, both the first dot and the last dot touch the boundaries of the graph. Is it possible to make the axes say x & y = -30:30, So that we will have 10 distance gap between the first dot and the boundary and last dots and the boundary. But if you reckon there is another easy way of doing it… please let me know

mark replied on October 19th, 2009 at 23:16 UTC :

Hello Doug,
Many thanks for your reply. Please ignore the above question. I have resolved the problem. I have another question. I want to write a code under the pushbutton2_Callback)
renamed as “RUN” (on GUI). I want to write a code to be able to move the points around. I sourced that I can either use any of these two codes/functions to do it. [V = h.move(position)], [V = move(h, position)].Please can you show me how to write these codes which will be controlled by the “RUN” push botton. The code should move the points to a distance of 0.5 from its original position to the left, right, up and down (just like a random walk). And they should continue to be moving until I click STOP push botton (pushbutton3_Callback). I have attached the M-File. Many Thanks

dhull replied on October 20th, 2009 at 15:49 UTC :

@mark

That is a longer question than should really be answered in the comments to a blog. Let me give some outline:

If you want the point to move until you click again, use a timer object and a toggle button to start and stop the timer.

Use GET and SET to change the xdata and ydata properties of a line (a single point is still a line)

For specifics, please see:

http://www.mathworks.com/support

Thanks,
Doug

mark replied on October 21st, 2009 at 14:33 UTC :

Thank Doug for your respond. I have a question, say I have a dot/point on a graph with coordinates as (x=2, y=3) and I want to used GET and SET to tell GUI to move the point to (x=2.5, y=3.5).How do I write the code for this.

dhull replied on October 21st, 2009 at 14:39 UTC :

@mark

h = line(2,4,'marker','o')
x = get(h,'xdata')
set(h,'xdata',x+0.5)

Enjoy!

Doug

mark replied on October 21st, 2009 at 15:46 UTC :

Many Thanks Doug, that was really helpful. But what does that 2,and 4 in the first line stands for? or what do they do.

dhull replied on October 21st, 2009 at 16:02 UTC :

@mark,

2 and 4? Be adventurous, change them and find out! :) To end the suspense for those playing along at home, they are the x and y coordinates.

Doug

mark replied on October 21st, 2009 at 16:36 UTC :

Thank Doug. You’re right; being adventurous is one of the greatest ways to learn. I’ve changed the code using 3 x values. it works fine. But I get a line joining the new points? i don’t know why. i wanted the old point to be deleted as soon as the new one is plotted. So I added this code (set(h.xdata,’delete’) but it didn’t work.


y = [0,0,0];
x=[0,10,20];
h = line(x,y,'marker','o')
x = get(h,'xdata')
set(h,'xdata',x+4)
set(h.xdata,'delete') %fail

dhull replied on October 21st, 2009 at 17:24 UTC :

@mark

SET ‘lineStyle’ to ‘none’.

There is no need to delete the old line, you are modifying the old line, so it should not be there anymore.

If you really want to delete the old line, do not modify the ‘xdata’ (MATLAB gets confused if ‘xdata’ and ‘ydata’ are not matched up) Instead try this:


set(h.xdata,'delete') %fail
delete(h)             %win

-Doug

mark replied on October 21st, 2009 at 17:31 UTC :

Thanks Doug, Don’t worry about the above question. (Thanks for your adventurous tip). After several trial-and-errors, I got it to work. Many Thanks Doug

mark replied on October 21st, 2009 at 17:46 UTC :

Thanks for your answer. Your suggestion is much easier and simpler than what I did. Thank you.

mark replied on October 23rd, 2009 at 14:05 UTC :

Hello Doug
I have seen your video about creating timer object/function in matlab command window. But please how do you create timer object/function to plot/move a point at (0,0)to any other random position on the graph in gui. I want to use toggle button to start and stop the timer. Please can you give the steps? I’ve seen doc timer note but I still can’t figure it out. Please. Thanks

dhull replied on October 23rd, 2009 at 15:19 UTC :

@mark

I need a more specific question. There are several steps here. Which is giving your problems?

1.) Starting and stopping a timer- can you do this at the command line?

2.) Starting and stopping a timer with a GUI- can you do this?

3.) Moving a point using get and set- Can you do this at the command line?

4.) Putting a callback in a timer- Can you do this to do something simple like displaying “Hello, World!”?

Let me know what you have tried and your specific challenge.

Doug

mark replied on October 23rd, 2009 at 16:18 UTC :

1)Yes, i can start and stop a simple timer function at the command line.
2)NO, i can’t start/stop timer in GUI.
3)Yes, below is an example.
>> size = 40;
>> x = 0;
>> y = 0;
>> axis([-40 40 -40 40]);
>> plot(x,y,’o');
>> axis([-40 40 -40 40]);
>> h = plot(x,y,’o');
>> axis([-40 40 -40 40]);
>> x = get(h,’xdata’)
>> x=0;
>> set(h,’xdata’,x+5);
>>

4)Yes, Make timer display “Hello World at the command line
here is example
>> t = timer

Timer Object: timer-1

Timer Settings
ExecutionMode: singleShot
Period: 1
BusyMode: drop
Running: off

Callbacks
TimerFcn: ”
ErrorFcn: ”
StartFcn: ”
StopFcn: ”

>> set(t,’executionMode’,'FixedRate’)
>> set(t,’TimerFcn’,'disp(”Hello World”)’)
>> start(t)
Hello World
Hello World
Hello World
Hello World
Hello World
Hello World
Hello World
Hello World
Hello World
Hello World
Hello World
Hello World
>> stop(t)

But i don’t know how to Start and stop a timer with a GUI. Many thanks

dhull replied on October 23rd, 2009 at 16:55 UTC :

@mark,

My guess is that you can not find the timer to start and stop it. Have you used TIMERFIND?

http://www.mathworks.com/access/helpdesk/help/techdoc/ref/timerfind.html

Doug

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