sudo apt-get install libpng-dev
sudo apt-get install libjpeg-dev

wget https://fukuchi.org/works/qrencode/qrencode-3.4.4.tar.gz
tar zxvf qrencode-3.4.4.tar.gz
cd qrencode-3.4.4/
./configure
make&make install

sudo apt-get install libgd-dev

git clone https://github.com/Leon2012/php-qrencode
cd php-qrencode
phpize
./configure
make&sudo make install

vi php.ini
extension=qrencode.so

<?php
$resource = qrencode_create("test", 2, 2);
if (!is_null($resource)){
	//qrencode_save($resource, "./test.png");//保存文件
	qrencode_output($resource);//直接输出到浏览器
}
echo qrencode_version()."\n";//查看版本号

?>

<?php
$t1 = microtime(true);
$qrcode_image = "/Users/kentchen/Downloads/qrencode1.png";
$content = "hello world";
$resource = qrencode_create($content, QRENCODE_QRECLEVEL_Q, QRENCODE_MODE_8);
qrencode_save($resource, $qrcode_image);
$t2 = microtime(true);
echo (($t2-$t1)*1000).':ms';
?>

<?php
include('./phpqrcode/phpqrcode.php'); 
$t1 = microtime(true);
$qrcode_image = "/Users/kentchen/Downloads/qrencode2.png";
$content = "hello world";
QRcode::png($content, $qrcode_image, QR_ECLEVEL_Q, 12);
$t2 = microtime(true);
echo (($t2-$t1)*1000).':ms';
?>