Graphing with GUI

Question

Using

x=-10:0.1:10
f=x+2

in basic m-file works fine.

But now I am trying to draw a plot using GUI, and by inputing a function. It gives me bunch of errors. Could anyone explain how I can give values to the y when I have the range of x set?

% --- Executes on button press in zimet.
function zimet_Callback(hObject, eventdata, handles)
% hObject    handle to zimet (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
x=-10:0.1:10;
f=inline(get(handles.vdj,'string'))
y(x)=f

axes(handles.axes)
plot(x,y)







color=get(handles.listbox, 'value')
switch color
    case 2
       set(plot(x,y),'color', 'r')
    case 3
        set(plot(x,y),'color', 'g')
    case 4
        set(plot(x,y),'color', 'b')
end

style=get(handles.popupmenu, 'value')
switch style
    case 2
        set(plot(x,y), 'linestyle','--')
    case 3
        set(plot(x,y), 'linestyle','-.')
    case 4
        set(plot(x,y), 'linestyle',':')
end
rezgis=get(handles.grid, 'value')
switch rezgis
    case 1
        grid on
    case 2
        grid off
end

il_raffa · Accepted Answer · 2017-04-01 16:54:52Z

1

Notice that according to the inline function documentation this function will be removed in future release; you can use, instead, anonymous functions (see below).

The inline function require, as input a string of characters while the get function returns the text of the edit box as a cellarray, therefore you have to convert it using the char function.

Also, once you have generated the inline object, it is you function, so you have to use it directly.

Using inline

You have to change your code this way:

x=-10:0.1:10;
% f=inline(get(handles.vdj,'string'))
% y(x)=f
f=inline(char(get(handles.vdj,'string')))
y=f(x)
axes(handles.axes)
ph=plot(x,y)

Using an anonymous function

You can achieve the same result by using anonymous functions this way:

x=-10:0.1:10;
% Get the function as string
f_str=char(get(handles.vdj,'string'))
% add @(x) to the string you've got
f_str=['@(x) ' f_str ];
% Create the anonymous function
fh = str2func(f_str)
% Evaluate the anonymous function
y=fh(x)

axes(handles.axes)
ph=plot(x,y)

Edit

You can fix the problem with the setting of the line color and style this way:

modify the call to plot by adding the return value (it is the handle to the plot (see above: ph=plot(x,y))
chance the calls to set by replacing the call to plot with the handle of the plot itself (the ph variable as above)

So, to change the color and the line style, in your switch section:

set(ph,'color','r')
set(ph,'linestyle','--')

Hope this helps,

Qapla'

edited Apr 1, 2017 at 16:54

answered Apr 1, 2017 at 15:37

il_raffa

5,175145 gold badges35 silver badges41 bronze badges

Sign up to request clarification or add additional context in comments.

11 Comments

Rihards Over a year ago

Thanks ! But if I , for example, type in x^2 , it doesnt work again. I must get it to understand it as .^2 I assume. is there a way of doing that instead of typing it myself ?

il_raffa Over a year ago

I think the only way is you to take care of define the function in the textbox in the right way. You can add, in the callback some code to perform some checks on the string in order to validate it.

il_raffa Over a year ago

I've also edited the answer: the inline function will be removed in future release of MatLab. I've added a posible solution using anonymous functions.

Rihards Over a year ago

Thanks! If you dont mind.. perhaps you could also know why using listboxes, popupmenus etc.. I have set one to set the style of the graph, the other for color. The last one overwrites the first one. For example I check color green and dotted style. It will be blue (default) and dotted. How can I stop it from overwriting ?

il_raffa Over a year ago

It is not clear what you mean with "overwritting". You should post that part of your code otherwise it is very difficult to identify the possible errors.

|

Collectives™ on Stack Overflow

Graphing with GUI

1 Answer 1

11 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

11 Comments

Your Answer

Sign up or log in

Post as a guest

Related