diff --git a/DTPhotoViewerController/Classes/DTPhotoViewerController.swift b/DTPhotoViewerController/Classes/DTPhotoViewerController.swift
index be2c300..b2a3460 100644
--- a/DTPhotoViewerController/Classes/DTPhotoViewerController.swift
+++ b/DTPhotoViewerController/Classes/DTPhotoViewerController.swift
@@ -309,7 +309,10 @@ open class DTPhotoViewerController: UIViewController {
     }
     
     func _dismiss() {
-        dismiss(animated: true, completion: nil)
+        self.delegate?.photoViewerControllerWillPanDismiss?(self)
+        dismiss(animated: true) {
+            self.delegate?.photoViewerControllerDidPanDismiss?(self)
+        }
     }
     
     @objc func _handleTapGesture(_ gesture: UITapGestureRecognizer) {
diff --git a/DTPhotoViewerController/Classes/DTPhotoViewerControllerDelegate.swift b/DTPhotoViewerController/Classes/DTPhotoViewerControllerDelegate.swift
index a076309..c32a4ca 100644
--- a/DTPhotoViewerController/Classes/DTPhotoViewerControllerDelegate.swift
+++ b/DTPhotoViewerController/Classes/DTPhotoViewerControllerDelegate.swift
@@ -28,4 +28,8 @@ import UIKit
     @objc optional func photoViewerControllerDidEndPresentingAnimation(_ photoViewerController: DTPhotoViewerController)
     
     @objc optional func photoViewerController(_ photoViewerController: DTPhotoViewerController, scrollViewDidScroll: UIScrollView)
+
+    @objc optional func photoViewerControllerWillPanDismiss(_ photoViewerController: DTPhotoViewerController)
+
+    @objc optional func photoViewerControllerDidPanDismiss(_ photoViewerController: DTPhotoViewerController)
 }