超级菜解析 osc 注册时图片验证码

function getMostRepeated($array)
{
    $count = array_count_values($array);
    arsort($count);
    $keys = array_keys($count);

    return $keys[1];
}

function fixImg($url)
{
    $img = imagecreatefrompng($url);

    $with = imagesx($img);
    $height = imagesy($img);
    $middle = $height / 2;

    $colors = array();

    for ($i = 0; $i < $with; ++$i) {
        $color = imagecolorat($img, $i, $middle);
        $colors[] = $color;
    }

    $mainColor = getMostRepeated($colors);

    for ($x = 0; $x < $with; ++$x) {
        for ($y = 0; $y < $height; ++$y) {
            $currentColor = imagecolorat($img, $x, $y);

            if ($currentColor !== $mainColor) {
                $white = imagecolorallocate($img, 0xFF, 0xFF, 0xFF);
                imagesetpixel($img, $x, $y, $white);
            }
        }
    }

    return $img;
}

//详情:http://my.oschina.net/gaoshou/blog/126561