使用PHP进行高效图片批量处理与优化技巧详解

使用PHP进行高效图片批量处理与优化技巧详解

一、准备工作

安装GD库：

• 在Linux环境下，可以使用包管理器安装：

  
  sudo apt-get install php-gd
  

• 在Windows环境下，需要在PHP配置文件php.ini中启用extension=php_gd.dll。

检查GD库是否安装成功：

• 创建一个PHP文件，写入以下代码并运行：

  
  phpinfo();
  

• 查看输出信息中是否有GD库的相关信息。

二、批量裁剪图片

创建裁剪函数：

function cropImage($source, $destination, $x, $y, $width, $height) {
   $info = getimagesize($source);
   switch ($info['mime']) {
       case 'image/jpeg':
           $image = imagecreatefromjpeg($source);
           break;
       case 'image/gif':
           $image = imagecreatefromgif($source);
           break;
       case 'image/png':
           $image = imagecreatefrompng($source);
           break;
       default:
           return false;
   }
   $croppedImage = imagecrop($image, ['x' => $x, 'y' => $y, 'width' => $width, 'height' => $height]);
   if ($croppedImage !== false) {
       switch ($info['mime']) {
           case 'image/jpeg':
               imagejpeg($croppedImage, $destination);
               break;
           case 'image/gif':
               imagegif($croppedImage, $destination);
               break;
           case 'image/png':
               imagepng($croppedImage, $destination);
               break;
       }
       imagedestroy($image);
       imagedestroy($croppedImage);
       return true;
   }
   return false;
}

1. $directory = 'path/to/your/images';
   $files = scandir($directory);
   foreach ($files as $file) {
      if (in_array(pathinfo($file, PATHINFO_EXTENSION), ['jpg', 'jpeg', 'gif', 'png'])) {
          $source = $directory . '/' . $file;
          $destination = $directory . '/cropped_' . $file;
          cropImage($source, $destination, 100, 100, 300, 300);
      }
   }
   

三、批量缩放图片

创建缩放函数：

function resizeImage($source, $destination, $width, $height, $quality = 90) {
   $info = getimagesize($source);
   switch ($info['mime']) {
       case 'image/jpeg':
           $image = imagecreatefromjpeg($source);
           break;
       case 'image/gif':
           $image = imagecreatefromgif($source);
           break;
       case 'image/png':
           $image = imagecreatefrompng($source);
           break;
       default:
           return false;
   }
   $newImage = imagescale($image, $width, $height);
   if ($newImage !== false) {
       switch ($info['mime']) {
           case 'image/jpeg':
               imagejpeg($newImage, $destination, $quality);
               break;
           case 'image/gif':
               imagegif($newImage, $destination);
               break;
           case 'image/png':
               imagepng($newImage, $destination, round($quality / 10));
               break;
       }
       imagedestroy($image);
       imagedestroy($newImage);
       return true;
   }
   return false;
}

1. $directory = 'path/to/your/images';
   $files = scandir($directory);
   foreach ($files as $file) {
      if (in_array(pathinfo($file, PATHINFO_EXTENSION), ['jpg', 'jpeg', 'gif', 'png'])) {
          $source = $directory . '/' . $file;
          $destination = $directory . '/resized_' . $file;
          resizeImage($source, $destination, 500, 500);
      }
   }
   

四、批量转换图片格式

创建转换格式函数：

function convertImageFormat($source, $destination, $format) {
   $info = getimagesize($source);
   switch ($info['mime']) {
       case 'image/jpeg':
           $image = imagecreatefromjpeg($source);
           break;
       case 'image/gif':
           $image = imagecreatefromgif($source);
           break;
       case 'image/png':
           $image = imagecreatefrompng($source);
           break;
       default:
           return false;
   }
   switch ($format) {
       case 'jpg':
           imagejpeg($image, $destination);
           break;
       case 'gif':
           imagegif($image, $destination);
           break;
       case 'png':
           imagepng($image, $destination);
           break;
       default:
           return false;
   }
   imagedestroy($image);
   return true;
}

1. $directory = 'path/to/your/images';
   $files = scandir($directory);
   foreach ($files as $file) {
      if (in_array(pathinfo($file, PATHINFO_EXTENSION), ['jpg', 'jpeg', 'gif', 'png'])) {
          $source = $directory . '/' . $file;
          $destination = $directory . '/' . pathinfo($file, PATHINFO_FILENAME) . '.png';
          convertImageFormat($source, $destination, 'png');
      }
   }
   

五、批量添加水印

创建添加水印函数：

function addWatermark($source, $destination, $watermark, $position = 'bottom-right') {
   $info = getimagesize($source);
   switch ($info['mime']) {
       case 'image/jpeg':
           $image = imagecreatefromjpeg($source);
           break;
       case 'image/gif':
           $image = imagecreatefromgif($source);
           break;
       case 'image/png':
           $image = imagecreatefrompng($source);
           break;
       default:
           return false;
   }
   $watermarkInfo = getimagesize($watermark);
   switch ($watermarkInfo['mime']) {
       case 'image/jpeg':
           $watermarkImage = imagecreatefromjpeg($watermark);
           break;
       case 'image/gif':
           $watermarkImage = imagecreatefromgif($watermark);
           break;
       case 'image/png':
           $watermarkImage = imagecreatefrompng($watermark);
           break;
       default:
           return false;
   }
   $x = $info[0] - $watermarkInfo[0];
   $y = $info[1] - $watermarkInfo[1];
   switch ($position) {
       case 'top-left':
           $x = 0;
           $y = 0;
           break;
       case 'top-right':
           $x = $info[0] - $watermarkInfo[0];
           $y = 0;
           break;
       case 'bottom-left':
           $x = 0;
           $y = $info[1] - $watermarkInfo[1];
           break;
       case 'bottom-right':
           $x = $info[0] - $watermarkInfo[0];
           $y = $info[1] - $watermarkInfo[1];
           break;
   }
   imagecopy($image, $watermarkImage, $x, $y, 0, 0, $watermarkInfo[0], $watermarkInfo[1]);
   switch ($info['mime']) {
       case 'image/jpeg':
           imagejpeg($image, $destination);
           break;
       case 'image/gif':
           imagegif($image, $destination);
           break;
       case 'image/png':
           imagepng($image, $destination);
           break;
   }
   imagedestroy($image);
   imagedestroy($watermarkImage);
   return true;
}

1. $directory = 'path/to/your/images';
   $watermark = 'path/to/your/watermark.png';
   $files = scandir($directory);
   foreach ($files as $file) {
      if (in_array(pathinfo($file, PATHINFO_EXTENSION), ['jpg', 'jpeg', 'gif', 'png'])) {
          $source = $directory . '/' . $file;
          $destination = $directory . '/watermarked_' . $file;
          addWatermark($source, $destination, $watermark, 'bottom-right');
      }
   }
   

六、总结