//核心代码
首先用composer在项目里安装Grafika 在composer.json require里加入 “kosinix/grafika”: “dev-master”,然后composer update即可;类里use Grafika\Grafika;
$root = $_SERVER['DOCUMENT_ROOT'];
$num = strrpos($root,'/');
$rootdir = substr($root,0,$num);
$num = strrpos($rootdir,'/');
$rootdir = substr($root,0,$num);
if(count($goodsThumb)<=0){return json_encode(['code'=>-101,'message'=>'未接收到图片','data'=>'']);}
$editor = Grafika::createEditor();
$imageBack = Grafika::createBlankImage(1200, count($goodsThumb)*1200);//创建一个750*750的空白图像
$backurl =$rootdir . '/backend/web/';
foreach ($goodsThumb as $k=>$pic_path) {
$dir_name =$backurl . $pic_path;
$editor->open($image,$dir_name );//打开1.jpeg并且存放到$image1
$editor->resizeFill($image, '1200','1200');//居中剪裁。就是把较短的变缩放到200px,然后将长边的大于200px的部分居中剪裁掉,图片不会变形
$editor->blend($imageBack, $image, 'normal', 1, 'top-center',0,$k*1200);//将两个图像合成在一起,第一个图像作为基础,第二个图像在顶部。支持多种混合模式
$num = strrpos($dir_name,'/');
$savedir = substr($dir_name,0,$num);
$savedir = $savedir . '/all_'.$ids.'.jpg';
$file = $editor->save($imageBack, $savedir );//imageBack保存为all.jpg
}
if($file){
// $shorturl = str_replace($backurl,"",$savedir);
$httpurl = $savedir;
// var_dump($httpurl);die;
$files = file_get_contents($httpurl);
header("Content-type:application/octet-stream");
$filename = pathinfo($httpurl, PATHINFO_BASENAME);
header("Content-Disposition:attachment;filename=" . $filename);
header("Accept-ranges:bytes");
exit($files);