php Hex RGB颜色值互换的使用

function HexToRGB($colour) {    if ($colour [0] == '#') {        $colour = substr ( $colour, 1 );    }    if (strlen ( $colour ) == 6) {        list ( $r, $g, $b ) = array (                $colour [0] . $colour [1],                $colour [2] . $colour [3],                $colour [4] . $colour [5]         );    } elseif (strlen ( $colour ) == 3) {        list ( $r, $g, $b ) = array (                $colour [0] . $colour [0],                $colour [1] . $colour [1],                $colour [2] . $colour [2]         );    } else {        return false;    }    $r = hexdec ( $r );    $g = hexdec ( $g );    $b = hexdec ( $b );    return array (            'red' => $r,            'green' => $g,            'blue' => $b     );}function RGBToHex($rgb) {    $regexp = "/^rgb\(([0-9]{0,3})\,\s*([0-9]{0,3})\,\s*([0-9]{0,3})\)/";    $re = preg_match ( $regexp, $rgb, $match );    $re = array_shift ( $match );    $hexColor = "#";    $hex = array (            '0',            '1',            '2',            '3',            '4',            '5',            '6',            '7',            '8',            '9',            'A',            'B',            'C',            'D',            'E',            'F'     );    for($i = 0; $i < 3; $i ++) {        $r = null;        $c = $match [$i];        $hexAr = array ();        while ( $c > 16 ) {            $r = $c % 16;            $c = ($c / 16) >> 0;            array_push ( $hexAr, $hex [$r] );        }        array_push ( $hexAr, $hex [$c] );        $ret = array_reverse ( $hexAr );        $item = implode ( '', $ret );        $item = str_pad ( $item, 2, '0', STR_PAD_LEFT );        $hexColor .= $item;    }    return $hexColor;}?>