php+nginx实现动态获取缩略图或放大图并存储

<?php
/**
 * 图像裁剪
 * 需要系统安装 php-imagick 扩展
 */
//ini_set ( "memory_limit", "80M" );

// 请求地址比如  http://xxx.com/resize.php?site=www&width=300&height=200&mode=2&path=uploadfile/helloworld.png
// nginx重写规则  rewrite /s/(.*)/(\d+)x(\d+)-(\d)/(.*) /s/resize.php?site=$1&width=$2&height=$3&mode=$4&path=$5 last;
// 测试 http://localhost/resize.php?site=imgs&width=300&height=300&mode=1&path=22.jpg
// 图片放在resize.php同级的 ./imgs/ 目录下 访问后会创建 ./cache/ 文件夹
// 后期可以考虑

$path = trim ( $_GET ['path'] );
$mode = intval ( $_GET ['mode'] );
$site = trim ( $_GET ['site'] );
$width = intval ( $_GET ['width'] );
$height = intval ( $_GET ['height'] );


//访问文件是否存在
$now_dir = dirname ( __FILE__ );
//缩略图路径(***路径名cache可选修改***)
$zip_dir = "{$now_dir}/cache/{$site}/{$width}x{$height}-{$mode}/";
//原始图片存放目录
$img_dir = "{$now_dir}/{$site}/";
//原始图片文件完整路径
$big_file = "{$img_dir}{$path}";
//缩略图文件完整路径
$save_path = "{$zip_dir}{$path}";


//缩略图存在直接返回，不存在去检测原图
if (file_exists ( $save_path )){
	header ( 'Content-Type: image/jpeg' );
	//header ( 'Last-Modified: ' . gmdate ( 'D, d M Y H:i:s' ) . ' GMT' );
	//读取文件的修改时间
	header ('Modified:'.gmdate("D, d M Y H:i:s",filemtime($save_path)).' GMT');
	//输出图片流
	echo file_get_contents ( $save_path );
	return true;
}else if(! file_exists($big_file)){
	header ( 'HTTP/1.1 404 Not Found' );
	exit ();
}

//检测并创建保存目录
if (! file_exists ( $zip_dir )){
	//wpx_mkdir ( $zip_dir );
	createDir($zip_dir);
}



$target_width = $width;
$target_height = $height;

$new_width = $target_width;
$new_height = $target_height;
$image = new Imagick ( $big_file );
list ( $orig_width, $orig_height, $type, $attr ) = getimagesize ( $big_file );

if ($mode == "0") {
	//等比缩放图像
	$new_height = $orig_height * $new_width / $orig_width;
	if ($new_height > $target_height) {
		$new_width = $orig_width * $target_height / $orig_height;
		$new_height = $target_height;
	}
} else if ($mode == "2") {
	// 放大并裁剪图像
	$desired_aspect = $target_width / $target_height;
	$orig_aspect = $orig_width / $orig_height;

	if ($desired_aspect > $orig_aspect) {
		$trim = $orig_height - ($orig_width / $desired_aspect);
		$image->cropImage ( $orig_width, $orig_height - $trim, 0, $trim / 2 );
		error_log ( "HEIGHT TRIM $trim" );
	} else {
		$trim = $orig_width - ($orig_height * $desired_aspect);
		$image->cropImage ( $orig_width - $trim, $orig_height, $trim / 2, 0 );
	}
}
// 处理图片
$image->resizeImage ( $new_width, $new_height, imagick::FILTER_LANCZOS, 1 );
// 保存处理后的图片
$image->writeImage ( $save_path );
//标记返回头信息
header ( 'Content-Type: image/jpeg' );
header ( 'Last-Modified: ' . gmdate ( 'D, d M Y H:i:s' ) . ' GMT' );
echo file_get_contents ( $save_path );
return true;


// 循环生成目录(不使用)
function wpx_mkdir($dir, $mode = 0777) {
	if (is_dir ( $dir ) || @mkdir ( $dir, $mode ))
		return true;
	if (! wpx_mkdir ( dirname ( $dir ), $mode ))
		return false;
	return @mkdir ( $dir, $mode );
}

//生成目录
function createDir($path){ 
	if (!file_exists($path)){ 
		createDir(dirname($path)); 
		mkdir($path, 0777) or die('create dir fail, NND'); 
	} 
} 

?>

大搬运并修改，原地址
https://www.markdream.com/technologies/programs/how-to-build-a-resizing-image-server-with-imagick.shtml