Question

How to convert RGB to CMYK in PHP

Answer 1

function RGBtoCMYK($R, $G, $B) {
    if ($R == 0 && $G == 0 && $B == 0) {
        return array(0, 0, 0, 1);
    }
    
    $R = $R / 255.0 * 100;
    $G = $G / 255.0 * 100;
    $B = $B / 255.0 * 100;
    $K = 100 - max(array((int)$R, (int)$G, (int)$B)); 
    
    if ($K == 100) {
        return array(0, 0, 0, 100);
    }
    
    $C = abs(round((100 - $R - $K) / (100 - $K) * 100));
    $M = abs(round((100 - $G - $K) / (100 - $K) * 100));
    $Y = abs(round((100 - $B - $K) / (100 - $K) * 100));
    
    return array($C, $M, $Y, $K);
}

$CMYK = RGBtoCMYK(245.0, 213.0, 0.0);

echo json_encode($CMYK);



/*
run:

[0,13,100,4]

*/

 

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