<"无法读取图像文件");
  }
  if(!in_array($this->imgInfo[2], array(2,3))){
   //仅允许jpg和png
   throw Exception("图像格式不支持");
  }
 }
 
 /**
  * 显示图像
  * Enter description here ...
  */
 public function show()
 {
  header("content-type:image/png");
  
  $shadow = $this->createshadow(); //遮罩图片
  
  //创建一个方形图片
  $imgbk = imagecreatetruecolor($this->size, $this->size); //目标图片
  
  switch ($this->imgInfo[2]){
   case 2:
    $imgfk = imagecreatefromjpeg($this->fileName); //原素材图片
    break;
   case 3:
    $imgfk = imagecreatefrompng($this->fileName); //原素材图片
   default:
    return ;
    break;
  }
  
  
  $realSize = $this->imgInfo[0]<$this->imgInfo[1]? $this->imgInfo[0] : $this->imgInfo[1];
  
  imagecopyresized($imgbk, $imgfk, 0, 0, 0, 0, $this->size, $this->size, $realSize, $realSize);
  imagecopymerge($imgbk, $shadow, 0, 0, 0, 0, $this->size, $this->size, 100);
  
  //创建图像
  imagepng($imgbk);
  
  //销毁资源
  imagedestroy($imgbk);
  imagedestroy($imgfk);
  imagedestroy($shadow);
 }
 
 /**
  * 创建一个圆形遮罩
  * Enter description here ...
  * @param array 10进制颜色数组
  */
 private function createshadow()
 {
  
  $img = imagecreatetruecolor($this->size, $this->size);
  
  imageantialias($img, true); //开启抗锯齿
  
  $color_bg = imagecolorallocate($img, $this->rgb[0], $this->rgb[1], $this->rgb[2]); //背景色
  $color_fg = imagecolorallocate($img, 0, 0, 0); //前景色，主要用来创建圆形
  
  imagefilledrectangle($img, 0, 0, 200, 200, $color_bg);
  imagefilledarc($img, 100, 100, 200, 200, 0, 0, $color_fg, IMG_ARC_PIE);
  
  imagecolortransparent($img, $color_fg); //将前景色转换为透明
  
  
  return $img;
 }
 
 /**
  * 将字符形式16进制串转为10进制
  * Enter description here ...
  * @param $str
  */
 private function getIntFromHexStr($str)
 {
  $format = '0123456789abcdef';
  
  $sum = 0;
  
  for($i=strlen($str)-1, $c=0, $j=0; $i>=$c; $i--,$j++){
   $index = strpos($format, $str[$i]);//strpos从0计算
   $sum+=$index * pow(16,$j);
  }
  
  return $sum;
 }
 
 /**
  * 将16进制颜色转为10进制颜色值数组（RGB）
  * Enter description here ...
  * @param $str 16进制串（如：ff9900）
  */
 private function createRGB($str)
 {
  $rgb = array();
  if(strlen($str) != 6){
   $rgb[] = 0xff;
   $rgb[] = 0xff;
   $rgb[] = 0xff;
   return $rgb; //默认白色
  }
 
  $rgb[] = $this->getIntFromHexStr(substr($str, 0, 2));
  $rgb[] = $this->getIntFromHexStr(substr($str, 2, 2));
  $rgb[] = $this->getIntFromHexStr(substr($str, 4, 2));
  
  return $rgb;
  
 }
}