PHP FileField::normalize示例

 /**
  * {@inheritDoc}
  */
 protected function normalize()
 {
     parent::normalize();
     $val = $this->base['value'];
     if ($val) {
         switch ($this->base['return_format']) {
             case 'array':
                 $this->atWidth = $val['width'];
                 $this->atHeight = $val['height'];
                 break;
             case 'id':
                 $src = wp_get_attachment_image_src($this->id(), 'full');
                 $this->atWidth = $src[1];
                 $this->atHeight = $src[2];
                 break;
             case 'url':
                 $this->atWidth = 0;
                 $this->atHeight = 0;
                 break;
             default:
                 throw new Exception("Field format {$this->base['return_format']} not valid");
         }
     } else {
         $this->atWidth = 0;
         $this->atHeight = 0;
     }
 }