图片压缩

• 将图片压缩成jpg或png

  $type = explode('/', $file->type);
  $mainType = $type[0];
  $subType = $type[1];
  $isImage = $mainType == 'image';
  $isGif = $subType == 'gif';//gif压缩会变静态的，所以过滤掉
  if ($isImage) {
      $maxSize = 1024 * 1024;
      if (!$isGif) {
          //图片进行压缩
          $file->data = $this->compressImage($file->data, $maxSize);
      }
      //生成文件
  }
  
  function compressImage($data, $maxSize, $percent = 1) {
      $size = strlen($data);
      if ($size <= $maxSize) {
          return $data;
      }
  
      $img = imagecreatefromstring($data);
      $width = imagesx($img);
      $height = imagesy($img);
  
      $newWidth = $width * $percent;
      $newHeight = $height * $percent;
  
      $newImg = imagecreatetruecolor($newWidth, $newHeight);
      imagecopyresampled($newImg, $img, 0, 0, 0, 0, floor($newWidth), floor($newHeight), $width, $height);
  
      ob_start(); //Turn on output buffering
      imagepng($newImg); //Generate your image
      //imagejpeg($newImg); 
      $data = $output = ob_get_contents(); // get the image as a string in a variable
      ob_end_clean(); //Turn off output buffering and clean it
      imagedestroy($newImg);
      $percent -= 0.1;
      print_r("
  percent={$percent},size={$size}");
      return self::compressImage($data, $maxSize,$percent);
  }

• jpg
  • 4.58M：（1）710KB[4]
  • 3.78M：（2）267KB[1]
  • 1.38M：（3）718KB[1]
• png
  • 4.58M：（1）997.29[6]
  • 3.78M：（2）982.2KB[4]
  • 1.38M：（3）928KB[5]