Php function hex or rgb color to color name

Question

Is there a php function that return the closest colorname by give the rgb or hex color as parameter? I have seared a lot but can\'t find a function that does that job.

P

Answer 1

there is no such function,

you will need to write your own function that fetches the R, G and B value induvidualy, and loops them to each value and find out wat the closest is ( total of R and G and B ofset the smallest)

you can find all HTML colornames here: http://www.w3.org/TR/SVG/types.html#ColorKeywords

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ex:

user gives in [250,1,2] (olwost red). you have a array:

$input = [255,1,2]
$colors = array("red" => [255,0,0],"green"=>[0,255,0]) // used JS array to be quiker

foreach( $ .. as .. $color){ // or a sort function?
// get diff, key 0 is red key 2 is blue
$diff = abs($input[0] - $color[0]) + ... + abs($input[2] - $color[2]); 
}

red will have a diff of: 5 + 1 + 2 green will have: 250 + 254 + 2 blue is : 250 + 1 + 253

red has the lowest sum, so it must be colsest to red. blue is the next, and then comes green

Answer 2

See my Code below. I use it to copy Logo Color to change the site theme automatically at run-time. Hope it works!

Simply pass the image URL as parameter in the function.

function CopyLogoColor($logo_path){
    $i = imagecreatefromjpeg($logo_path);

    $rTotal = 0;
    $gTotal =0;
    $bTotal = 0;
    $total = 0;

    for ( $x=0 ; $x<imagesx($i) ; $x++){
        for ( $y=0 ; $y<imagesy($i) ; $y++ ) {
            $rgb = imagecolorat($i,$x,$y);
            $r   = ($rgb >> 16) & 0xFF;
            $g   = ($rgb >> 8)& 0xFF;
            $b   = $rgb & 0xFF;

            $rTotal += $r;
            $gTotal += $g;
            $bTotal += $b;
            $total++;

        }
    }

    $rAverage = round($rTotal/$total);
    $gAverage = round($gTotal/$total);
    $bAverage = round($bTotal/$total);



    $r = intval($rAverage); 
    $g = intval($gAverage);
    $b = intval($bAverage);

    $r = dechex($r<0?0:($r>255?255:$r));
    $g = dechex($g<0?0:($g>255?255:$g));
    $b = dechex($b<0?0:($b>255?255:$b));

    $color = (strlen($r) < 2?'0':'').$r;
    $color .= (strlen($g) < 2?'0':'').$g;
    $color .= (strlen($b) < 2?'0':'').$b;

    return '#'.$color;

}