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;
}
?>