Combination of two colors to form a new color entirely using " IF-ELSEIF-ELSE-END" statements

Combination of two colors to form a new color entirely using " IF-ELSEIF-ELSE-END" statements

I have two listboxes (listbox1 and listbox2) each of them contains three strings, namely; “red”, “blue” and “green”; one pushbutton (pushbutton1); and one edittext (edittext1) placed on a figure (figure1).

If I press the pushbutton1, I need It to display the name of the new colour (resultant cikiur) formed in the edittext1, as a result of mixing (combining) the selected colour from listbox1 with the selected colour from listbox2.

The desired outputs are:

red + green = yellow (that is, selection of “red” from listbox1 and selection of “green” from listbox2 will display “yellow” in the edittext1, when the pushbutton1 is pressed).

Similarly:

red + blue = magenta (that is, selection of “red” from listbox1 and selection of “blue” from listbox2 will display “magenta” in the edittext1, when the pushbutton1 is pressed).

blue + green = cyan (that is, selection of “blue” from listbox1 and selection of “green” from listbox2 will display “cyan” in the edittext1, when the pushbutton1 is pressed).

The Callback needs to be implemented using If-elseif-else-end ,statements or the Case-Switch structure to run it.

Many thanks.

Answer 1

[DGM]

Something like this should be a start:

colornames = {'red','green','blue'}; % i assume this order

% placeholder for the listboxes
selection1 = randi([1 3],1,1); 
selection2 = randi([1 3],1,1); 

% display randomly selected input
colornames{selection1}

ans = 'blue'

colornames{selection2}

ans = 'green'

if selection1==selection2
    outcolor = colornames{selection1};
else
    if all(sort([selection1 selection2]) == [1 2])
        outcolor = 'yellow';
    elseif all(sort([selection1 selection2]) == [2 3])
        outcolor = 'cyan';
    elseif all(sort([selection1 selection2]) == [1 3])
        outcolor = 'magenta';
    end	
end

% display the output
outcolor

outcolor = 'cyan'

Which can probably be simplified further.

Obviously, you'll have to adapt this to use the listbox value properties and update the editbox properties and all that.

[Gbola]

Hi DGM,

Thanks for this. The problem has been partially solved as it is displaying a secondary color in edit after pushing a pushbutton, but it is displaying a wrong secondary color in the edit due to error while evaluating UIControl Callback.

You may wish to have a look at the the code below in order to debug the error.

% --- Executes just before Combinationofcolours is made visible.
function Combinationofcolours_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 Combinationofcolours (see VARARGIN)

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

% Update handles structure
guidata(hObject, handles);

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

% --- Outputs from this function are returned to the command line.
function varargout = Combinationofcolours_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 selection change in listbox1.
function listbox1_Callback(hObject, eventdata, handles)
% hObject    handle to listbox1 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)

% Hints: contents = cellstr(get(hObject,'String')) returns listbox1 contents as cell array
%        contents{get(hObject,'Value')} returns selected item from listbox1
colornames = {'red','green','blue'}; % i assume this order
selection1 = randi([1 3],1,1); 
selection2 = randi([1 3],1,1); 
colornames{selection1};
ans = 'blue';
colornames{selection2};
ans = 'green';
if selection1==selection2
    set(handles.colourmixture_name,'String','You have chosen the same color' )
    % ans = colornames{selection1};
else
    if all(sort([selection1 selection2]) == [1 2])
        set(handles.colourmixture_name,'String','YELLOW' )
    elseif all(sort([selection1 selection2]) == [2 3])
        set(handles.colourmixture_name,'String','CYAN' )
    elseif all(sort([selection1 selection2]) == [1 3])
        set(handles.colourmixture_name,'String','MAGENTA' )  
    end	
end

% --- Executes during object creation, after setting all properties.
function listbox1_CreateFcn(hObject, eventdata, handles)
% hObject    handle to listbox1 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    empty - handles not created until after all CreateFcns called

% Hint: listbox controls usually have a white background on Windows.
%       See ISPC and COMPUTER.
if ispc && isequal(get(hObject,'BackgroundColor'), get(0,'defaultUicontrolBackgroundColor'))
    set(hObject,'BackgroundColor','white');
end

% --- Executes on selection change in listbox2.
function listbox2_Callback(hObject, eventdata, handles)
% hObject    handle to listbox2 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)

% Hints: contents = cellstr(get(hObject,'String')) returns listbox2 contents as cell array
%        contents{get(hObject,'Value')} returns selected item from listbox2

% --- Executes during object creation, after setting all properties.
function listbox2_CreateFcn(hObject, eventdata, handles)
% hObject    handle to listbox2 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    empty - handles not created until after all CreateFcns called

% Hint: listbox controls usually have a white background on Windows.
%       See ISPC and COMPUTER.
if ispc && isequal(get(hObject,'BackgroundColor'), get(0,'defaultUicontrolBackgroundColor'))
    set(hObject,'BackgroundColor','white');
end

% --- Executes on button press in pushbutton_display.
function pushbutton_display_Callback(hObject, eventdata, handles)
%hObject    handle to pushbutton_display (see GCBO)
%eventdata  reserved - to be defined in a future version of MATLAB
%handles    structure with handles and user data (see GUIDATA)
val1 = get(handles.listbox1,'Value');
selected_listbox1 = selected_listbox1(string1);
selected_listbox2 = selected_listbox2(string2);
if strcmp( selected_listbox1,'String','red') && strcmp( selected_listbox2,'String','blue') 
    set(handles.colourmixture_name,'String','Magenta' )
elseif strcmp( selected_listbox1,'String','red')&& strcmp( selected_listbox2,'String','green') 
    set(handles.colourmixture_name,'String','Yellow' )
else strcmp( selected_listbox1,'String','blue') && strcmp( selected_listbox2,'String','green'); 
    set(handles.colourmixture_name,'String','Cyan' )
end
guidata(hObject, handles);

Error in

matlab.graphics.internal.figfile.FigFile/read>@(hObject,eventdata)Combinationofcolours('pushbutton_display_Callback',hObject,eventdata,guidata(hObject))

Error while evaluating UIControl Callback.

[DGM]

If this is a relatively simple GUIDE interface, it would probably be easier to make the edit if you attach the .m and .fig files for the GUI so that I can test to make sure it's working.

[DGM]

FWIW, I'm attaching a crude example of how this might be done in a primitive GUI without GUIDE, but I don't know your requirements, so I don't know whether the button is necessary. My approach to writing these things isn't likely optimal, but it's a something to consider if nothing else.

Feel free to attach your own GUI files.

[Gbola]

Hi DGM,

Thank you for the crude example. The buttons (listbox1, listbox2, edit button and pushbutton) are necessary. Find the .m and .fig files for the GUI attached in order for you to test it and make sure it is working.

Cheers.

[DGM]

Attached is a copy of the mfile which should work. Since the listbox callbacks automatically update the output, the pushbutton is redundant. You can choose to disable the automatic update on listbox changes, that way the button has something to do. If the pushbutton is supposed to do something else, let me know.

List boxes should contain valid items. You have a bunch of instructions and empty lines in the list boxes. This creates a bunch of invalid menu items that can be selected. It would be appropriate to remove them. If you want instruction text, use a text object outside of the listboxes.

Currently, the updatecolor() function handles this problem by mapping the locations of the valid menu items and ignoring the rest. If you decide to clean up the listbox contents, the updatecolor() function can be simplified, or you can simply just change the menuidx vector to [1 2 3].

I would have edited the listboxes and added text labels, but that requires editing the .fig file. Since you're using a different version than I am, I would risk breaking the GUI if I edited it. That's one of the limitations of using GUIDE. I'm assuming that the changes made to the mfile shouldn't break anything though.

[DGM]

The recommendations about fixing the menu items is something you'll have to do. If I use GUIDE to edit the .fig file in a different version than you have, chances are that you won't be able to edit it anymore without problems -- at least that's been my experience with trying to deal with GUIDE between versions. You can try the attached files that I edited, but like I said, don't be surprised if they break.

All I did was clean up the list boxes, add static text labels, and change the output box to a static text box. I disabled the update routine on listbox selection so that the redundant pushbutton has something to do. Because I deleted all the invalid listbox entries, the index remapping and checking routine was removed. It's still full of a bunch of superfluous GUIDE clutter, but that's to be expected.

Answer 2

[Gbola]

Dear all,

The following controls: listbox1, listbox2, one edit, and one pushbutton are meant for combining two primary colours to produce a secondary colour and display same inside the edit, e, g., red + green = yellow.

Find the .m and .fig files below for debugging.

• Combinationofcolours.m
• Combinationofcolours.fig

Cheers.

[Rik]

Is this a question, or an anwer?

For general advice and examples for how to create a GUI (and avoid using GUIDE), have look at this thread.

Answer 3

[Gbola]

Hi DGM,

As per your request of 05/01/2022, the UI controls: listbox1, listbox2, one edit, and one pushbutton are meant for combining two primary colours to produce a secondary colour as well as display the name of the secondary colour formed inside the edit, e, g., red + green = yellow; red + blue = magenta; green + blue = cyan. While red + red, green + green or blue + blue will display you have chosen the same colour therefore a new colour cannot be formed.

Find the .m and .fig files below for debugging.

• Combinationofcolours.m
• Combinationofcolours.fig

Cheers.

[Rik]

This looks very similar to your other answer, but, like that previous answer, it looks more like a comment. Are you sure you meant to post them as answers to your question?

Answer 4

[Gbola]

Hi all,

I could not still find a solution to this problem.

Can someone help me out to find what is wrong with the attached .m or / and .fig files? I ran the code in Matlab R2018a using the GUIDE GUIs.

• Combinationofcolours.m
• Combinationofcolours.fig

Alternatively, you may wish to solve the question below using your own approach outrightly to solve it without having to debug the attached .m or .fig file.

THE PROBLEM: Combination of two colors to form a new color entirely using " IF-ELSEIF-ELSE-END" statements

I have two listboxes (listbox1 and listbox2) each of them contains three strings, namely; “red”, “blue” and “green”; one pushbutton (pushbutton1); and one edittext (edittext1) placed on a figure (figure1).

If I press the pushbutton1, I need It to display the name of the new colour (resultant cikiur) formed in the edittext1, as a result of mixing (combining) the selected colour from listbox1 with the selected colour from listbox2.

The desired outputs are:

red + green = yellow (that is, selection of “red” from listbox1 and selection of “green” from listbox2 will display “yellow” in the edittext1, when the pushbutton1 is pressed).

Similarly:

red + blue = magenta (that is, selection of “red” from listbox1 and selection of “blue” from listbox2 will display “magenta” in the edittext1, when the pushbutton1 is pressed).

blue + green = cyan (that is, selection of “blue” from listbox1 and selection of “green” from listbox2 will display “cyan” in the edittext1, when the pushbutton1 is pressed).

While selection of red + red, green + green or blue + blue will display "You have chosen the same colour hence a new colour could not be formed" in the edittext1, when the pushbutton1 is pressed).

The Callback needs to be implemented using If-elseif-else-end statements or the Case-Switch structure to run it.

Many thanks..

[Rik]

Please post this comment as a comment and delete your 3 answers. The order of answers can change.

Is there a reason you want to keep using GUIDE? It generates a lot of code that isn't needed and it requires you to maintain a fig file along with your m file.

[DGM]

These new files are identical to the ones that were posted prior to my last recommendation.