How can I create interactive board?

I have been trying to create interactive board. I want it to change color when I click on it so I can for example write stuff on it. Lets say I have board of 5x5 and click on its pools to write an A. I have been searching for answer to my question in in internet but I was unable to find anything about such thing all I could find is how to make a checkerboard but not how to make empty board that changes colors on click. Can you please give me some information about it and maybe place where I can read how to do this? Here is the board I was able to create:

colors = [0 0 0; 1 1 1];
inds = 1:25;
color_inds = 1+mod(inds,2);
r = colors(color_inds,1);
g = colors(color_inds,2);
b = colors(color_inds,3);
checkers = cat(2,r,g,b);
checkers = reshape(checkers,[5,5,3]);
imagesc(checkers);
axis equal tight;

Answer 1

[Tommy]

It sounds like you want to add a mouse-click callback to your image, which is a function that gets called whenever you click inside the image:

colors = [0 0 0; 1 1 1];
inds = 1:25;
color_inds = 1+mod(inds,2);
r = colors(color_inds,1);
g = colors(color_inds,2);
b = colors(color_inds,3);
checkers = cat(2,r,g,b);
checkers = reshape(checkers,[5,5,3]);
im = imagesc(checkers); % Store the image
axis equal tight;

im.ButtonDownFcn = @clickCallback; % Add the callback

function clickCallback(src, event)
    pos = get(gca,'CurrentPoint'); % You can obtain the coordinates of the click like this
    disp(pos)
end

Then you'll want to determine which square the user clicked inside and update it's color.

More about the mouse-click callback: https://www.mathworks.com/help/matlab/ref/matlab.graphics.primitive.image-properties.html#d120e595216

More about CurrentPoint: https://www.mathworks.com/help/matlab/ref/matlab.graphics.axis.axes-properties.html#d120e60454

Hopefully this helps!