Hi guys. How can I have display a color from RGB coordinates?

What I'd like to do is to print a color starting from its RGB coordinates. Like MS Paint tool, more or less. There already exists a tool in Matlab? Thanks

Answer 1

[KSSV]

Red = [255 0 0] ;
Lime = [0 255 0] ;

x = [0 1 1 0] ; y = [0 0 1 1] ;

figure
fill(x,y,Red/255)
figure
fill(x,y,Lime/255)

[Luigi Treccozzi]

Thanks! This is what I was looking for!

Answer 2

[Robert Watson]

Its an older thread, but I made a utility function to help me do this more cleanly in future. This will take both normalised floats and 8-bit RGB values, throwing errors on invalid input.

Figured I should share, so its also on File Exchange.

function showColor(rgb)
    %SHOWCOLOR Display a colorswatch of the given rgb value
    arguments
        rgb (1,3) {mustBeNonnegative, mustBeLessThanOrEqual(rgb, 255)} % 1x3 vector of RGB values.
    end

    % Validate & handle colors in 8-bit format 
    max_val = max(rgb);
    float_tol = 1e-12;
    if max_val > 1

        % Error if not integer values 
        is_ints = all(mod(rgb,1) <= float_tol);
        assert(is_ints, "Invalid color format supplied. Must be 1x3 vector of floats in range [0,1] or integers in range [0,255]");
        
        % Scale to floats for consistent processing
        rgb = rgb./ 255;
    end
    
    % Make color swatch
    color(1,1,:) = rgb;
    color = repmat (color, 128,128,1);

    % Display color swatch
    % (Want a small figure with minimal whitespace)
    f = figure();
    tiledlayout(1,1,"TileSpacing","tight","Padding","compact");
    nexttile;
    imshow(color);
    daspect([1 1 1]);
    f.Units = "normalized";
    f.Position(3:4) = [0.125, 0.125];
end

% Example 1: Basic 8-bit colors
showColor([128,230,45])

% Example 2: Basic Normalized Float Colors
showColor([0.5,0.7,0.8])

●

% Example 3: Show part of a color map
cmap = lines(3);
showColor(cmap(2,:))