PHP tips for identifying and flipping upside-down pictures taken with iPhone

This article mainly introduces the PHP recognition of upside-down pictures taken by flipping the iPhone. It has certain reference value. Interested friends can refer to it.

Pictures shot and uploaded horizontally with the iPhone are often turned upside down. Displayed 90 degrees to the left or right, this article introduces how to use PHP to identify and flip the picture to the correct position.

ps: This method can only determine that some pictures taken by mobile phone cameras are in reverse position

Code:

// 首先用这个函数读取图片的一些头信息
// 原理就是在头信息中取出图片的位置信息 并且根据位置信息对图片做出调整
// 此函数只能处理jpeg 与 tiff 的图片格式
$exif = exif_read_data ($url,0,true);
 
if(isset($exif['IFD0']['Orientation'])){
 $source = imagecreatefromjpeg($url);//读取图片流
 
 //判断角度翻转
 switch($exif['IFD0']['Orientation']) {
  case 8:
   $image = imagerotate($source, 90, 0);
   break;
  case 3:
   $image = imagerotate($source, 180, 0);
   break;
  case 6:
   $image = imagerotate($source, -90, 0);
   break;
  }
 
 //保存到本地
 imagejpeg($image,'../storage/tmp.jpeg');
 
 //释放内存
 imagedestroy($image);
     
}

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