/**
* 图像的裁剪、缩放、加水印
* @param string $path    路径
* @param int $width   裁剪的宽度/限制的高度或宽度，当有$height值时此值为图片的宽度，否则为限制的宽度或高度
* @param int $height   [可选]裁剪的高度
* @param boolean $water   [可选]是否加水印
* @param int $word    [可选]水印文字
*/
function zoom_image($path,$width = 300,$height = null,$water = null,$word = 'water'){
  $image = new \Think\Image();
  $image->open($path);
  $imgWidth = $image->width();
  $imgHeight = $image->height();
  // 限制尺寸
  if($width and !$height){
    $maxSize = $width;
    // 宽度或高度大于规定尺寸时
    if($imgWidth > $maxSize or $imgHeight > $maxSize){
      $size = image_min_width($imgWidth,$imgHeight,$maxSize);
      $image->thumb($size['width'], $size['height']);
      $do = true;
      $dowater = true;
    }
  // 裁剪固定尺寸
  }else if($width and $height){
    $size = image_min_width($imgWidth,$imgHeight,$width);
    $image->thumb($size['width'], $size['height'])->crop($width, $height);
    $do = true;
    $dowater = true;
  }
  if($dowater and $water and $word){
    $image->text($word,'./Public/images/arial.ttf',20,'#dddddd', \Think\Image::IMAGE_WATER_SOUTHEAST,-10);
  }
  // 未操作则不保存
  if($do){
    $image->save($path);
  }
}