php 切取图片代码
function resizethumbnailimage($thumb_image_name, $image, $width, $height, $start_width, $start_height, $scale){
 list($imagewidth, $imageheight, $imagetype) = getimagesize($image);
 $imagetype = image_type_to_mime_type($imagetype);
$newimagewidth = ceil($width * $scale);
 $newimageheight = ceil($height * $scale);
 $newimage = imagecreatetruecolor($newimagewidth,$newimageheight);
 switch($imagetype) {
  case image/gif:
   $source=imagecreatefromgif($image);
   break;
     case image/pjpeg:
  case image/jpeg:
  case image/jpg:
   $source=imagecreatefromjpeg($image);
   break;
     case image/png:
  case image/x-png:
   $source=imagecreatefrompng($image);
   break;
   }
 imagecopyresampled($newimage,$source,0,0,$start_width,$start_height,$newimagewidth,$newimageheight,$width,$height);
 switch($imagetype) {
  case image/gif:
     imagegif($newimage,$thumb_image_name);
   break;
       case image/pjpeg:
  case image/jpeg:
  case image/jpg:
     imagejpeg($newimage,$thumb_image_name,90);
   break;
  case image/png:
  case image/x-png:
   imagepng($newimage,$thumb_image_name); 
   break;
    }
 chmod($thumb_image_name, 0777);
 return $thumb_image_name;
}