From 56d12295bab1de34b70ad83d04cd2d615432e3b6 Mon Sep 17 00:00:00 2001
From: Shadowfacts <me@shadowfacts.net>
Date: Sun, 24 Nov 2024 23:58:39 -0500
Subject: [PATCH] Don't dismiss gallery if pan distance/velocity is low

See #520
---
 .../GalleryVC/GalleryDismissInteraction.swift | 33 ++++++++++++++++---
 1 file changed, 28 insertions(+), 5 deletions(-)

diff --git a/Packages/GalleryVC/Sources/GalleryVC/GalleryDismissInteraction.swift b/Packages/GalleryVC/Sources/GalleryVC/GalleryDismissInteraction.swift
index e7d1ee364..3bff7aef2 100644
--- a/Packages/GalleryVC/Sources/GalleryVC/GalleryDismissInteraction.swift
+++ b/Packages/GalleryVC/Sources/GalleryVC/GalleryDismissInteraction.swift
@@ -53,12 +53,35 @@ class GalleryDismissInteraction: NSObject {
             let translation = recognizer.translation(in: viewController.view)
             let velocity = recognizer.velocity(in: viewController.view)
             
-            dismissVelocity = velocity
-            dismissTranslation = translation
-            viewController.dismiss(animated: true)
+            let translationMagnitude = sqrt(translation.x.magnitudeSquared + translation.y.magnitudeSquared)
+            let velocityMagnitude = sqrt(velocity.x.magnitudeSquared + velocity.y.magnitudeSquared)
+            
+            if translationMagnitude < 150 && velocityMagnitude < 500 {
+                isActive = false
+                
+                let spring = UISpringTimingParameters(mass: 1, stiffness: 439, damping: 42, initialVelocity: .zero)
+                let animator = UIViewPropertyAnimator(duration: 0.2, timingParameters: spring)
+                animator.addAnimations {
+                    self.content!.view.frame = self.origContentFrameInGallery!
+                    self.viewController.currentItemViewController.setControlsVisible(self.origControlsVisible!, animated: false, dueToUserInteraction: false)
+                }
+                animator.addCompletion { _ in
+                    self.content!.view.removeFromSuperview()
+                    self.viewController.currentItemViewController.addContent()
+                    self.content = nil
+                    self.origContentFrameInGallery = nil
+                    self.origControlsVisible = nil
+                }
+                animator.startAnimation()
 
-            // don't unset this until after dismiss is called, so that the dismiss animation controller can read it
-            isActive = false
+            } else {
+                dismissVelocity = velocity
+                dismissTranslation = translation
+                viewController.dismiss(animated: true)
+                
+                // don't unset this until after dismiss is called, so that the dismiss animation controller can read it
+                isActive = false
+            }
             
         default:
             break