PHP image scaling and cutting functions

/**

 * 图片缩放函数（可设置高度固定，宽度固定或者最大宽高，支持gif/jpg/png三种类型）

 * Author : Specs

 *

 * @param string $source_path 源图片

 * @param int $target_width 目标宽度

 * @param int $target_height 目标高度

 * @param string $fixed_orig 锁定宽高（可选参数 width、height或者空值）

 * @return string

 */

function myImageResize($source_path, $target_width = 200, $target_height = 200, $fixed_orig = ''){

  $source_info = getimagesize($source_path);

  $source_width = $source_info[0];

  $source_height = $source_info[1];

  $source_mime = $source_info['mime'];

  $ratio_orig = $source_width / $source_height;

  if ($fixed_orig == 'width'){

    //宽度固定

    $target_height = $target_width / $ratio_orig;

  }elseif ($fixed_orig == 'height'){

    //高度固定

    $target_width = $target_height * $ratio_orig;

  }else{

    //最大宽或最大高

    if ($target_width / $target_height > $ratio_orig){

      $target_width = $target_height * $ratio_orig;

    }else{

      $target_height = $target_width / $ratio_orig;

    }

  }

  switch ($source_mime){

    case 'image/gif':

      $source_image = imagecreatefromgif($source_path);

      break;

    case 'image/jpeg':

      $source_image = imagecreatefromjpeg($source_path);

      break;

    case 'image/png':

      $source_image = imagecreatefrompng($source_path);

      break;

    default:

      return false;

      break;

  }

  $target_image = imagecreatetruecolor($target_width, $target_height);

  imagecopyresampled($target_image, $source_image, 0, 0, 0, 0, $target_width, $target_height, $source_width, $source_height);

  //header('Content-type: image/jpeg');

  $imgArr = explode('.', $source_path);

  $target_path = $imgArr[0] . '_new.' . $imgArr[1];

  imagejpeg($target_image, $target_path, 100);

}

function imagecropper($source_path, $target_width, $target_height){

  $source_info = getimagesize($source_path);

  $source_width = $source_info[0];

  $source_height = $source_info[1];

  $source_mime = $source_info['mime'];

  $source_ratio = $source_height / $source_width;

  $target_ratio = $target_height / $target_width;

  // 源图过高

  if ($source_ratio > $target_ratio){

    $cropped_width = $source_width;

    $cropped_height = $source_width * $target_ratio;

    $source_x = 0;

    $source_y = ($source_height - $cropped_height) / 2;

  }elseif ($source_ratio < $target_ratio){ // 源图过宽

    $cropped_width = $source_height / $target_ratio;

    $cropped_height = $source_height;

    $source_x = ($source_width - $cropped_width) / 2;

    $source_y = 0;

  }else{ // 源图适中

    $cropped_width = $source_width;

    $cropped_height = $source_height;

    $source_x = 0;

    $source_y = 0;

  }

  switch ($source_mime){

    case 'image/gif':

      $source_image = imagecreatefromgif($source_path);

      break;

    case 'image/jpeg':

      $source_image = imagecreatefromjpeg($source_path);

      break;

    case 'image/png':

      $source_image = imagecreatefrompng($source_path);

      break;

    default:

      return false;

      break;

  }

  $target_image = imagecreatetruecolor($target_width, $target_height);

  $cropped_image = imagecreatetruecolor($cropped_width, $cropped_height);

  // 裁剪

  imagecopy($cropped_image, $source_image, 0, 0, $source_x, $source_y, $cropped_width, $cropped_height);

  // 缩放

  imagecopyresampled($target_image, $cropped_image, 0, 0, 0, 0, $target_width, $target_height, $cropped_width, $cropped_height);

  $dotpos = strrpos($source_path, '.');

  $imgName = substr($source_path, 0, $dotpos);

  $suffix = substr($source_path, $dotpos);

  $imgNew = $imgName . '_small' . $suffix;

  imagejpeg($target_image, $imgNew, 100);

  imagedestroy($source_image);

  imagedestroy($target_image);

  imagedestroy($cropped_image);

}