php检测图片主要颜色的方法

$i = imagecreatefromjpeg("image.jpg");
for ($x=0;$x<imagesx($i);$x++) {
  for ($y=0;$y<imagesy($i);$y++) {
    $rgb = imagecolorat($i,$x,$y);
    $r  = ($rgb  16) & 0xFF;
    $g  = ($rgb  & 0xFF;
    $b  = $rgb & 0xFF;
    $rTotal += $r;
    $gTotal += $g;
    $bTotal += $b;
    $total++;
  }
}
$rAverage = round($rTotal/$total);
$gAverage = round($gTotal/$total);
$bAverage = round($bTotal/$total);