Swoole\Image::thumbnail PHP Method

    static function thumbnail($pic, $dst_pic, $max_width, $max_height = null, $qulitity = 100, $copy = true)
    {
        $im = self::readfile($pic);
        if ($im === false) {
            return false;
        }
        $old_w = imagesx($im);
        $old_h = imagesy($im);
        if ($max_height == null) {
            $max_height = $max_width;
        }
        if ($old_w > $max_width or $old_h > $max_height) {
            $w_h = $old_w / $old_h;
            $h_w = $old_h / $old_w;
            if ($w_h > $h_w) {
                $width = $max_width;
                $height = $width * $h_w;
            } else {
                $height = $max_height;
                $width = $height * $w_h;
            }
            $newim = imagecreatetruecolor($width, $height);
            imagecopyresampled($newim, $im, 0, 0, 0, 0, $width, $height, $old_w, $old_h);
            imagejpeg($newim, $dst_pic, $qulitity);
            imagedestroy($im);
            return true;
        } elseif ($pic != $dst_pic and $copy) {
            return copy($pic, $dst_pic);
        } else {
            return false;
        }
    }