From b9f564ff4b0213c90fd89fb65aff5ee18f3f6c3a Mon Sep 17 00:00:00 2001
From: John D in the UK <john.durcan@me.com>
Date: Tue, 10 Mar 2020 15:12:14 +0000
Subject: [PATCH] Updated ViewController to resist Pan interaction below a
 percentage threshold of animation completed.

---
 CardViewAnimation/ViewController.swift | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/CardViewAnimation/ViewController.swift b/CardViewAnimation/ViewController.swift
index 1615c44..b9cfc66 100644
--- a/CardViewAnimation/ViewController.swift
+++ b/CardViewAnimation/ViewController.swift
@@ -21,7 +21,8 @@ class ViewController: UIViewController {
     
     let cardHeight:CGFloat = 600
     let cardHandleAreaHeight:CGFloat = 65
-    
+    var fractionComplete:CGFloat = 0
+
     var cardVisible = false
     var nextState:CardState {
         return cardVisible ? .collapsed : .expanded
@@ -74,10 +75,17 @@ class ViewController: UIViewController {
             startInteractiveTransition(state: nextState, duration: 0.9)
         case .changed:
             let translation = recognizer.translation(in: self.cardViewController.handleArea)
-            var fractionComplete = translation.y / cardHeight
+            fractionComplete = translation.y / cardHeight
             fractionComplete = cardVisible ? fractionComplete : -fractionComplete
             updateInteractiveTransition(fractionCompleted: fractionComplete)
         case .ended:
+            if fractionComplete <  0.25 {
+                for animator in runningAnimations {
+                    animator.isReversed = true
+                }
+                self.cardVisible = !self.cardVisible
+                self.visualEffectView.isUserInteractionEnabled = !self.visualEffectView.isUserInteractionEnabled
+            }
             continueInteractiveTransition()
         default:
             break