php 将颜色值转换为16进制数字，将16进制数字转换为颜色值

下面两个函数将颜色值转换为16进制数字，将16进制数字转换为颜色值。

<?php
function toHex($N) {
    if ($N==NULL) return "00";
    if ($N==0) return "00";
    $N=max(0,$N); 
    $N=min($N,255); 
    $N=round($N);
    $string = "0123456789ABCDEF";
    $val = (($N-$N%16)/16);
    $s1 = $string{$val};
    $val = ($N%16);
    $s2 = $string{$val};
    return $s1.$s2;
}

function rgb2hex($r,$g,$b){
    return toHex($r).toHex($g).toHex($b);
}

function hex2rgb($N){
    $dou = str_split($N,2);
    return array(
        "R" => hexdec($dou[0]), 
        "G" => hexdec($dou[1]), 
        "B" => hexdec($dou[2])
    );
}

echo rgb2hex(106,48,48);
echo '<p> </p>';
print_r(hex2rgb("6A3030"));
?>