hryk224 · iamchiwon · Mar 8, 2018 · Mar 8, 2018 · Mar 8, 2018 · Mar 8, 2018
diff --git a/Example/Example.xcodeproj/project.pbxproj b/Example/Example.xcodeproj/project.pbxproj
@@ -18,6 +18,8 @@
 		935BD6E51CE26F0B00E5FDF7 /* Pattern1ViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = 935BD6DE1CE26F0B00E5FDF7 /* Pattern1ViewController.swift */; };
 		935BD6E61CE26F0B00E5FDF7 /* Pattern2.storyboard in Resources */ = {isa = PBXBuildFile; fileRef = 935BD6DF1CE26F0B00E5FDF7 /* Pattern2.storyboard */; };
 		935BD6E71CE26F0B00E5FDF7 /* Pattern2ViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = 935BD6E01CE26F0B00E5FDF7 /* Pattern2ViewController.swift */; };
+		A16472372051129D00A6D53D /* Pattern3ViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = A16472362051129D00A6D53D /* Pattern3ViewController.swift */; };
+		A164723B205117A800A6D53D /* Pattern3.storyboard in Resources */ = {isa = PBXBuildFile; fileRef = A164723A205117A800A6D53D /* Pattern3.storyboard */; };
 		EDA05AD81D92901C00F7C2C5 /* InfiniteCollectionView.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = EDA05AD71D92901900F7C2C5 /* InfiniteCollectionView.framework */; };
 		EDA05AD91D92901C00F7C2C5 /* InfiniteCollectionView.framework in Embed Frameworks */ = {isa = PBXBuildFile; fileRef = EDA05AD71D92901900F7C2C5 /* InfiniteCollectionView.framework */; settings = {ATTRIBUTES = (CodeSignOnCopy, RemoveHeadersOnCopy, ); }; };
 /* End PBXBuildFile section */
@@ -34,7 +36,7 @@
 			isa = PBXContainerItemProxy;
 			containerPortal = EDA05AD21D92901900F7C2C5 /* InfiniteCollectionView.xcodeproj */;
 			proxyType = 1;
-			remoteGlobalIDString = 935BD70C1CE26F8E00E5FDF7;
+			remoteGlobalIDString = OBJ_17;
 			remoteInfo = InfiniteCollectionView;
 		};
 /* End PBXContainerItemProxy section */
@@ -67,6 +69,8 @@
 		935BD6DE1CE26F0B00E5FDF7 /* Pattern1ViewController.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = Pattern1ViewController.swift; sourceTree = "<group>"; };
 		935BD6DF1CE26F0B00E5FDF7 /* Pattern2.storyboard */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = file.storyboard; path = Pattern2.storyboard; sourceTree = "<group>"; };
 		935BD6E01CE26F0B00E5FDF7 /* Pattern2ViewController.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = Pattern2ViewController.swift; sourceTree = "<group>"; };
+		A16472362051129D00A6D53D /* Pattern3ViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Pattern3ViewController.swift; sourceTree = "<group>"; };
+		A164723A205117A800A6D53D /* Pattern3.storyboard */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = file.storyboard; path = Pattern3.storyboard; sourceTree = "<group>"; };
 		EDA05AD21D92901900F7C2C5 /* InfiniteCollectionView.xcodeproj */ = {isa = PBXFileReference; lastKnownFileType = "wrapper.pb-project"; name = InfiniteCollectionView.xcodeproj; path = ../InfiniteCollectionView.xcodeproj; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
@@ -104,6 +108,7 @@
 			children = (
 				ED510E6D1DDD513200470C8B /* Pattern1 */,
 				ED510E6E1DDD513F00470C8B /* Pattern2 */,
+				A16472332051126300A6D53D /* Pattern3 */,
 				935BD6C81CE26EB600E5FDF7 /* AppDelegate.swift */,
 				935BD6CF1CE26EB600E5FDF7 /* Assets.xcassets */,
 				935BD6DA1CE26F0B00E5FDF7 /* ImageCollectionViewCell.swift */,
@@ -116,6 +121,15 @@
 			path = Example;
 			sourceTree = "<group>";
 		};
+		A16472332051126300A6D53D /* Pattern3 */ = {
+			isa = PBXGroup;
+			children = (
+				A164723A205117A800A6D53D /* Pattern3.storyboard */,
+				A16472362051129D00A6D53D /* Pattern3ViewController.swift */,
+			);
+			name = Pattern3;
+			sourceTree = "<group>";
+		};
 		ED510E6D1DDD513200470C8B /* Pattern1 */ = {
 			isa = PBXGroup;
 			children = (
@@ -227,6 +241,7 @@
 			isa = PBXResourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				A164723B205117A800A6D53D /* Pattern3.storyboard in Resources */,
 				935BD6D01CE26EB600E5FDF7 /* Assets.xcassets in Resources */,
 				935BD6E21CE26F0B00E5FDF7 /* ImageCollectionViewCell.xib in Resources */,
 				935BD6D31CE26EB600E5FDF7 /* LaunchScreen.storyboard in Resources */,
@@ -246,6 +261,7 @@
 				935BD6C91CE26EB600E5FDF7 /* AppDelegate.swift in Sources */,
 				935BD6E11CE26F0B00E5FDF7 /* ImageCollectionViewCell.swift in Sources */,
 				935BD6E31CE26F0B00E5FDF7 /* MainViewController.swift in Sources */,
+				A16472372051129D00A6D53D /* Pattern3ViewController.swift in Sources */,
 				935BD6E51CE26F0B00E5FDF7 /* Pattern1ViewController.swift in Sources */,
 				935BD6E71CE26F0B00E5FDF7 /* Pattern2ViewController.swift in Sources */,
 			);
@@ -379,7 +395,7 @@
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks";
 				PRODUCT_BUNDLE_IDENTIFIER = io.github.hryk224.Example;
 				PRODUCT_NAME = "$(TARGET_NAME)";
-				SWIFT_VERSION = 3.0;
+				SWIFT_VERSION = 4.0;
 			};
 			name = Debug;
 		};
@@ -393,7 +409,7 @@
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks";
 				PRODUCT_BUNDLE_IDENTIFIER = io.github.hryk224.Example;
 				PRODUCT_NAME = "$(TARGET_NAME)";
-				SWIFT_VERSION = 3.0;
+				SWIFT_VERSION = 4.0;
 			};
 			name = Release;
 		};

diff --git a/Example/Example/MainViewController.swift b/Example/Example/MainViewController.swift
@@ -13,11 +13,13 @@ final class MainViewController: UIViewController {
     enum Pattern: Int, CustomStringConvertible {
         case pattern1
         case pattern2
-        static var count: Int { return 2 }
+        case pattern3
+        static var count: Int { return 3 }
         var description: String {
             switch self {
             case .pattern1: return "pattern1"
             case .pattern2: return "pattern2"
+            case .pattern3: return "pattern3"
             }
         }
     }
@@ -65,6 +67,9 @@ extension MainViewController: UITableViewDelegate, UITableViewDataSource {
         case .pattern2:
             let controller = Pattern2ViewController.createFromStoryboard()
             navigationController?.pushViewController(controller, animated: true)
+        case .pattern3:
+            let controller = Pattern3ViewController.createFromStoryboard()
+            navigationController?.pushViewController(controller, animated: true)
         }
     }
 }
diff --git a/Example/Example/Pattern1ViewController.swift b/Example/Example/Pattern1ViewController.swift
@@ -39,7 +39,7 @@ final class Pattern1ViewController: UIViewController {
         let storyboard = UIStoryboard(name: "Pattern1", bundle: nil)
         return storyboard.instantiateInitialViewController() as! Pattern1ViewController
     }
-    func rotate(_ notification: Notification) {
+    @objc func rotate(_ notification: Notification) {
         layout.itemSize = UIScreen.main.bounds.size
         layout.invalidateLayout()
         collectionView.rotate(notification)

diff --git a/Example/Example/Pattern2ViewController.swift b/Example/Example/Pattern2ViewController.swift
@@ -81,7 +81,7 @@ final class InfiniteTableViewCell: UITableViewCell {
             pageControl.numberOfPages = 4
         }
     }
-    func rotate(_ notification: Notification) {
+    @objc func rotate(_ notification: Notification) {
         let size = CGSize(width: UIScreen.main.bounds.width, height: 239)
         layout.itemSize = size
         layout.invalidateLayout()
@@ -137,7 +137,7 @@ extension Infinite2TableViewCell: InfiniteCollectionViewDataSource, InfiniteColl
     func infiniteCollectionView(_ collectionView: UICollectionView, didSelectItemAt usableIndexPath: IndexPath) {
         print("didSelectItemAt: \(usableIndexPath.item)")
     }
-    func rotate(_ notification: Notification) {
+    @objc func rotate(_ notification: Notification) {
         collectionView.collectionViewLayout.invalidateLayout()
         collectionView.rotate(notification)
         collectionView.layoutIfNeeded()

diff --git a/Example/Example/Pattern3.storyboard b/Example/Example/Pattern3.storyboard
@@ -0,0 +1,54 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<document type="com.apple.InterfaceBuilder3.CocoaTouch.Storyboard.XIB" version="3.0" toolsVersion="13771" targetRuntime="iOS.CocoaTouch" propertyAccessControl="none" useAutolayout="YES" useTraitCollections="YES" colorMatched="YES" initialViewController="jtB-7l-rQl">
+    <device id="retina4_7" orientation="portrait">
+        <adaptation id="fullscreen"/>
+    </device>
+    <dependencies>
+        <deployment identifier="iOS"/>
+        <plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="13772"/>
+        <capability name="documents saved in the Xcode 8 format" minToolsVersion="8.0"/>
+    </dependencies>
+    <scenes>
+        <!--Pattern3 View Controller-->
+        <scene sceneID="w99-5n-3Mx">
+            <objects>
+                <viewController automaticallyAdjustsScrollViewInsets="NO" id="jtB-7l-rQl" customClass="Pattern3ViewController" customModule="Example" customModuleProvider="target" sceneMemberID="viewController">
+                    <layoutGuides>
+                        <viewControllerLayoutGuide type="top" id="Vix-Nr-Wbb"/>
+                        <viewControllerLayoutGuide type="bottom" id="rTP-xN-QW3"/>
+                    </layoutGuides>
+                    <view key="view" contentMode="scaleToFill" id="fk8-nc-mgC">
+                        <rect key="frame" x="0.0" y="0.0" width="375" height="667"/>
+                        <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
+                        <subviews>
+                            <collectionView clipsSubviews="YES" multipleTouchEnabled="YES" contentMode="scaleToFill" pagingEnabled="YES" showsHorizontalScrollIndicator="NO" showsVerticalScrollIndicator="NO" dataMode="prototypes" translatesAutoresizingMaskIntoConstraints="NO" id="Lwf-cA-VEr" customClass="InfiniteCollectionView" customModule="InfiniteCollectionView">
+                                <rect key="frame" x="0.0" y="0.0" width="375" height="667"/>
+                                <color key="backgroundColor" red="0.0" green="0.0" blue="0.0" alpha="0.0" colorSpace="custom" customColorSpace="sRGB"/>
+                                <collectionViewFlowLayout key="collectionViewLayout" minimumLineSpacing="0.0" minimumInteritemSpacing="0.0" id="9XM-Ng-ou9">
+                                    <size key="itemSize" width="600" height="600"/>
+                                    <size key="headerReferenceSize" width="0.0" height="0.0"/>
+                                    <size key="footerReferenceSize" width="0.0" height="0.0"/>
+                                    <inset key="sectionInset" minX="0.0" minY="0.0" maxX="0.0" maxY="0.0"/>
+                                </collectionViewFlowLayout>
+                                <cells/>
+                            </collectionView>
+                        </subviews>
+                        <color key="backgroundColor" red="1" green="1" blue="1" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
+                        <constraints>
+                            <constraint firstItem="Lwf-cA-VEr" firstAttribute="leading" secondItem="fk8-nc-mgC" secondAttribute="leading" id="NFN-BY-c0F"/>
+                            <constraint firstItem="rTP-xN-QW3" firstAttribute="top" secondItem="Lwf-cA-VEr" secondAttribute="bottom" id="Rm1-Pt-2ET"/>
+                            <constraint firstItem="Lwf-cA-VEr" firstAttribute="top" secondItem="fk8-nc-mgC" secondAttribute="top" id="mQv-aQ-Qp8"/>
+                            <constraint firstAttribute="trailing" secondItem="Lwf-cA-VEr" secondAttribute="trailing" id="o9s-cD-XIp"/>
+                        </constraints>
+                    </view>
+                    <connections>
+                        <outlet property="collectionView" destination="Lwf-cA-VEr" id="Tfg-hy-FJX"/>
+                        <outlet property="layout" destination="9XM-Ng-ou9" id="rvd-rt-iwV"/>
+                    </connections>
+                </viewController>
+                <placeholder placeholderIdentifier="IBFirstResponder" id="6qE-8b-tDF" userLabel="First Responder" sceneMemberID="firstResponder"/>
+            </objects>
+            <point key="canvasLocation" x="-468" y="96"/>
+        </scene>
+    </scenes>
+</document>
diff --git a/Example/Example/Pattern3ViewController.swift b/Example/Example/Pattern3ViewController.swift
@@ -0,0 +1,63 @@
+//
+//  Pattern3ViewController.swift
+//  Example
+//
+//  Created by iamchiwon on 2018. 3. 8..
+//  Copyright © 2018년 hiroyuki yoshida. All rights reserved.
+//
+
+import UIKit
+import InfiniteCollectionView
+
+final class Pattern3ViewController: UIViewController {
+    var itemsCount: Int = 5
+    @IBOutlet weak var collectionView: InfiniteCollectionView! {
+        didSet {
+            collectionView.infiniteDataSource = self
+            collectionView.infiniteDelegate = self
+            collectionView.register(ImageCollectionViewCell.nib, forCellWithReuseIdentifier: ImageCollectionViewCell.identifier)
+        }
+    }
+    @IBOutlet weak var layout: UICollectionViewFlowLayout! {
+        didSet {
+            layout.itemSize = UIScreen.main.bounds.size
+        }
+    }
+    required init?(coder aDecoder: NSCoder) {
+        super.init(coder: aDecoder)
+        NotificationCenter.default.addObserver(self, selector: #selector(Pattern1ViewController.rotate(_:)), name: .UIDeviceOrientationDidChange, object: nil)
+    }
+    deinit {
+        NotificationCenter.default.removeObserver(self, name: .UIDeviceOrientationDidChange, object: nil)
+    }
+    static func createFromStoryboard() -> Pattern3ViewController {
+        let storyboard = UIStoryboard(name: "Pattern3", bundle: nil)
+        return storyboard.instantiateInitialViewController() as! Pattern3ViewController
+    }
+    @objc func rotate(_ notification: Notification) {
+        layout.itemSize = UIScreen.main.bounds.size
+        layout.invalidateLayout()
+        collectionView.rotate(notification)
+        collectionView.layoutIfNeeded()
+        collectionView.setNeedsLayout()
+    }
+}
+
+// MARK: - InfiniteCollectionViewDataSource, InfiniteCollectionViewDelegate
+extension Pattern3ViewController: InfiniteCollectionViewDataSource, InfiniteCollectionViewDelegate {
+    func number(ofItems collectionView: UICollectionView) -> Int {
+        return itemsCount
+    }
+    func collectionView(_ collectionView: UICollectionView, dequeueForItemAt dequeueIndexPath: IndexPath, cellForItemAt usableIndexPath: IndexPath) -> UICollectionViewCell {
+        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: ImageCollectionViewCell.identifier, for: dequeueIndexPath) as! ImageCollectionViewCell
+        cell.configure(indexPath: usableIndexPath)
+        return cell
+    }
+    func infiniteCollectionView(_ collectionView: UICollectionView, didSelectItemAt usableIndexPath: IndexPath) {
+        print("didSelectItemAt: \(usableIndexPath.item)")
+    }
+    func scrollView(_ scrollView: UIScrollView, pageIndex: Int) {
+        print("scrollView: \(pageIndex)")
+    }
+}
+
diff --git a/InfiniteCollectionView.xcodeproj/project.pbxproj b/InfiniteCollectionView.xcodeproj/project.pbxproj
@@ -135,6 +135,7 @@
 				PRODUCT_BUNDLE_IDENTIFIER = InfiniteCollectionView;
 				PRODUCT_MODULE_NAME = "$(TARGET_NAME:c99extidentifier)";
 				PRODUCT_NAME = "$(TARGET_NAME:c99extidentifier)";
+				SWIFT_VERSION = 4.0;
 				TARGET_NAME = InfiniteCollectionView;
 			};
 			name = Debug;
@@ -155,6 +156,7 @@
 				PRODUCT_BUNDLE_IDENTIFIER = InfiniteCollectionView;
 				PRODUCT_MODULE_NAME = "$(TARGET_NAME:c99extidentifier)";
 				PRODUCT_NAME = "$(TARGET_NAME:c99extidentifier)";
+				SWIFT_VERSION = 4.0;
 				TARGET_NAME = InfiniteCollectionView;
 			};
 			name = Release;

diff --git a/Sources/InfiniteCollectionView.swift b/Sources/InfiniteCollectionView.swift
@@ -46,7 +46,7 @@ open class InfiniteCollectionView: UICollectionView {
     deinit {
         NotificationCenter.default.removeObserver(self, name: .UIDeviceOrientationDidChange, object: nil)
     }
-    open func rotate(_ notification: Notification) {
+    @objc open func rotate(_ notification: Notification) {
         setContentOffset(CGPoint(x: CGFloat(pageIndex + indexOffset) * itemWidth, y: contentOffset.y), animated: false)
     }
     open override func selectItem(at indexPath: IndexPath?, animated: Bool, scrollPosition: UICollectionViewScrollPosition) {
@@ -76,10 +76,18 @@ private extension InfiniteCollectionView {
         guard let layout = collectionViewLayout as? UICollectionViewFlowLayout else { return 0 }
         return layout.itemSize.width + layout.minimumInteritemSpacing
     }
+    var itemHeight: CGFloat {
+        guard let layout = collectionViewLayout as? UICollectionViewFlowLayout else { return 0 }
+        return layout.itemSize.height + layout.minimumLineSpacing
+    }
     var totalContentWidth: CGFloat {
         let numberOfCells: CGFloat = CGFloat(infiniteDataSource?.number(ofItems: self) ?? 0)
         return numberOfCells * itemWidth
     }
+    var totalContentHeight: CGFloat {
+        let numberOfCells: CGFloat = CGFloat(infiniteDataSource?.number(ofItems: self) ?? 0)
+        return numberOfCells * itemHeight
+    }
     func configure() {
         delegate = self
         dataSource = self
@@ -103,6 +111,21 @@ private extension InfiniteCollectionView {
             indexOffset += offset
             reloadData()
         }
+        let centerY = (scrollView.contentSize.height - bounds.height) / 2
+        let distFromCenterY = centerY - currentOffset.y
+        if fabs(distFromCenterY) > (totalContentHeight / 4) {
+            let cellcount = distFromCenterY / itemHeight
+            let shiftCells = Int((cellcount > 0) ? floor(cellcount) : ceil(cellcount))
+            let offsetCorrection = (abs(cellcount).truncatingRemainder(dividingBy: 1)) * itemHeight
+            if centerY > contentOffset.y {
+                contentOffset = CGPoint(x: currentOffset.x, y: centerY - offsetCorrection)
+            } else {
+                contentOffset = CGPoint(x: currentOffset.x, y: centerY + offsetCorrection)
+            }
+            let offset = correctedIndex(shiftCells)
+            indexOffset += offset
+            reloadData()
+        }
         let centerPoint = CGPoint(x: scrollView.frame.size.width / 2 + scrollView.contentOffset.x, y: scrollView.frame.size.height / 2 + scrollView.contentOffset.y)
         guard let indexPath = indexPathForItem(at: centerPoint) else { return }
         pageIndex = correctedIndex(indexPath.item - indexOffset)