From 94b0f4348ccf9a267027418198342033e620afd3 Mon Sep 17 00:00:00 2001
From: James Magahern <jmagahern@apple.com>
Date: Thu, 11 Feb 2021 20:25:16 -0800
Subject: [PATCH] TabBarView: animations!

---
 .../DocumentControlViewController.swift       |  5 ++++
 App/Tabs/TabBarView.swift                     | 30 +++++++++++++++----
 2 files changed, 29 insertions(+), 6 deletions(-)

diff --git a/App/Document Controls UI/DocumentControlViewController.swift b/App/Document Controls UI/DocumentControlViewController.swift
index 01963dc..dd6102c 100644
--- a/App/Document Controls UI/DocumentControlViewController.swift	
+++ b/App/Document Controls UI/DocumentControlViewController.swift	
@@ -13,6 +13,7 @@ class DocumentControlViewController: UIViewController
     let fontSizeAdjustView = FontSizeAdjustView()
     let findOnPageControlView = DocumentControlView()
     let navigationControlView = NavigationControlsView()
+    let settingsView = DocumentControlView()
     
     var observations: [NSKeyValueObservation] = []
     
@@ -24,9 +25,13 @@ class DocumentControlViewController: UIViewController
         findOnPageControlView.label.text = "Find On Page"
         findOnPageControlView.imageView.image = UIImage(systemName: "magnifyingglass")
         
+        settingsView.label.text = "Settings"
+        settingsView.imageView.image = UIImage(systemName: "gear")
+        
         documentControlView.addArrangedSubview(navigationControlView)
         documentControlView.addArrangedSubview(fontSizeAdjustView)
         documentControlView.addArrangedSubview(findOnPageControlView)
+        documentControlView.addArrangedSubview(settingsView)
         
         for (i, view) in documentControlView.arrangedSubviews.enumerated() {
             view.drawsBottomSeparator = (i < documentControlView.arrangedSubviews.count - 1)
diff --git a/App/Tabs/TabBarView.swift b/App/Tabs/TabBarView.swift
index 6ebc987..6a72097 100644
--- a/App/Tabs/TabBarView.swift
+++ b/App/Tabs/TabBarView.swift
@@ -10,6 +10,7 @@ import UIKit
 class TabView: UIControl
 {
     var active: Bool = false { didSet { setNeedsLayout() } }
+    var collapsed: Bool = false
     let label = UILabel(frame: .zero)
     let closeButton = UIButton(frame: .zero)
     let imageView = UIImageView(image: nil)
@@ -139,7 +140,7 @@ class TabBarView: UIView
         bottomSeparatorView.backgroundColor = .systemFill
     }
     
-    public func reloadTabs() {
+    public func reloadTabs(animated: Bool = true) {
         guard let dataSource = self.dataSource else { return }
         
         let numberOfTabs = dataSource.numberOfTabs(forTabBarView: self)
@@ -149,14 +150,27 @@ class TabBarView: UIView
         }
         
         while numberOfTabs > tabViews.count {
-            tabViews.append(makeTabView())
+            let newTabView = makeTabView()
+            if animated { newTabView.collapsed = true }
+            tabViews.append(newTabView)
         }
         
         for (i, _) in tabViews.enumerated() {
             self.reloadTab(atIndex: i)
         }
         
-        setNeedsLayout()
+        layoutSubviews()
+        
+        if animated {
+            tabViews.forEach { $0.collapsed = false }
+            UIView.animate(withDuration: 0.3) { [unowned self] in
+                layoutSubviews()
+            }
+        }
+        
+        // Adjust scroll offset
+        let contentEnd = CGPoint(x: tabContainerView.contentSize.width - tabContainerView.bounds.width, y: 0.0)
+        tabContainerView.setContentOffset(contentEnd, animated: animated)
     }
     
     public func reloadTab(atIndex index: Int) {
@@ -209,7 +223,7 @@ class TabBarView: UIView
         
         let minimumTabWidth = { (traitCollection: UITraitCollection) -> CGFloat in
             if traitCollection.horizontalSizeClass == .compact {
-                return tabContainerBounds.width / 3.0
+                return (tabContainerBounds.width / 3.0) + 15.0
             } else {
                 return 140.0
             }
@@ -217,8 +231,10 @@ class TabBarView: UIView
         
         let maximumTabWidth = tabContainerBounds.width
         
+        let visibleTabCount = tabViews.filter({ $0.collapsed == false }).count
+        
         var xOffset = CGFloat(0.0)
-        var tabWidth: CGFloat = (tabContainerBounds.width / CGFloat(tabViews.count))
+        var tabWidth: CGFloat = (tabContainerBounds.width / CGFloat(visibleTabCount))
         if tabWidth < minimumTabWidth {
             tabWidth = minimumTabWidth
         } else if tabWidth > maximumTabWidth {
@@ -231,7 +247,7 @@ class TabBarView: UIView
             tabView.frame = CGRect(
                 x: xOffset,
                 y: tabContainerBounds.minY,
-                width: tabWidth,
+                width: tabView.collapsed ? 1.0 : tabWidth,
                 height: tabContainerBounds.height
             )
             
@@ -242,6 +258,8 @@ class TabBarView: UIView
             } else {
                 tabView.active = false
             }
+            
+            tabView.layoutIfNeeded()
         }
         
         tabContainerView.contentSize = CGSize(