MATLAB: How to make a select-able grid

guimatlab gui

I need some guidance on how to make a selectable grid. I need to make a GUI that allows people to select a box on a grid over an image and make it change colors. So say I have a 25×25 grid over an image. if a person clicks on box 13,20 that box should change to blue. How do i do that?

Best Answer

    N = 25 ;
    x = linspace(0,1,N) ;
    y = linspace(0,1,N) ;
    [X,Y] = meshgrid(x,y) ;
    coor = [X(:) Y(:)] ;
I = imread('cameraman.tif');
image([0 1],[0 1],I) 
hold on
plot(X,Y,'k') ; 
plot(X',Y','k') ;
    count = 0 ;
    while count == 0
        [x,y] = ginput(1) ;
        idx = knnsearch(coor,[x y],'k',4) ;
        % form bounding box
        x0 = min(coor(idx,1)) ;x1 = max(coor(idx,1)) ;
        y0 = min(coor(idx,2)) ;y1 = max(coor(idx,2)) ;
        % square points
        coori = [x0 y0 ; x0 y1 ; x1 y1 ; x1 y0 ; x0 y0] ;
        patch(coori(:,1),coori(:,2),'b') ;
    end
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