Merge pull request #14 from superpeteblaze/psmith/Swift4

Psmith/swift4

.gitattributes

@@ -0,0 +1 @@
+Example/Pods/* linguist-vendored

.swift-version

@@ -0,0 +1 @@
+4.0

.travis.yml

@@ -3,12 +3,12 @@
 # * https://github.com/supermarin/xcpretty#usage
 
 language: objective-c
-osx_image: xcode8
+osx_image: xcode9
 # cache: cocoapods
 # podfile: Example/Podfile
 before_install:
 - gem install cocoapods # Since Travis is not always on latest version
 # - pod install --project-directory=Example
 script:
-- set -o pipefail && xcodebuild -workspace Example/ScalingCarousel.xcworkspace -scheme ScalingCarousel-Example -sdk iphonesimulator -destination 'platform=iOS Simulator,OS=10.0,name=iPhone 7' ONLY_ACTIVE_ARCH=NO | xcpretty
+- set -o pipefail && xcodebuild -workspace Example/ScalingCarousel.xcworkspace -scheme ScalingCarousel-Example -sdk iphonesimulator -destination 'platform=iOS Simulator,OS=11.0,name=iPhone 7' ONLY_ACTIVE_ARCH=NO | xcpretty
 - pod lib lint

Example/Pods/Pods.xcodeproj/project.pbxproj

@@ -139,9 +139,9 @@
 		2AF1556C49363C2BA1C10796E1C93F58 /* Classes */ = {
 			isa = PBXGroup;
 			children = (
+				BA88835C545DBDE8A6A6984912DA1E88 /* ScalingCarouselView.swift */,
 				0F029A4B46297C4E659645069518366C /* ScalingCarouselCell.swift */,
 				BFA8691AE35E197F6C1CFAD0EC691EE2 /* ScalingCarouselLayout.swift */,
-				BA88835C545DBDE8A6A6984912DA1E88 /* ScalingCarouselView.swift */,
 			);
 			path = Classes;
 			sourceTree = "<group>";
@@ -317,7 +317,15 @@
 			isa = PBXProject;
 			attributes = {
 				LastSwiftUpdateCheck = 0730;
-				LastUpgradeCheck = 0700;
+				LastUpgradeCheck = 0900;
+				TargetAttributes = {
+					479882F85D2E213BDCC80F17AAAA8A63 = {
+						LastSwiftMigration = "";
+					};
+					E9582E7E712D7CD7A32DF86E8120CBC5 = {
+						LastSwiftMigration = 0900;
+					};
+				};
 			};
 			buildConfigurationList = 2D8E8EC45A3A1A1D94AE762CB5028504 /* Build configuration list for PBXProject "Pods" */;
 			compatibilityVersion = "Xcode 3.2";
@@ -382,6 +390,7 @@
 			isa = XCBuildConfiguration;
 			baseConfigurationReference = 2CAFE40C0C16F348A480291448686E57 /* Pods-ScalingCarousel_Example.release.xcconfig */;
 			buildSettings = {
+				ALWAYS_EMBED_SWIFT_STANDARD_LIBRARIES = YES;
 				"CODE_SIGN_IDENTITY[sdk=appletvos*]" = "";
 				"CODE_SIGN_IDENTITY[sdk=iphoneos*]" = "";
 				"CODE_SIGN_IDENTITY[sdk=watchos*]" = "";
@@ -407,6 +416,8 @@
 				PRODUCT_NAME = Pods_ScalingCarousel_Example;
 				SDKROOT = iphoneos;
 				SKIP_INSTALL = YES;
+				SWIFT_SWIFT3_OBJC_INFERENCE = On;
+				SWIFT_VERSION = 4.0;
 				TARGETED_DEVICE_FAMILY = "1,2";
 				VERSIONING_SYSTEM = "apple-generic";
 				VERSION_INFO_PREFIX = "";
@@ -473,7 +484,8 @@
 				PRODUCT_NAME = ScalingCarousel;
 				SDKROOT = iphoneos;
 				SKIP_INSTALL = YES;
-				SWIFT_VERSION = 3.0;
+				SWIFT_SWIFT3_OBJC_INFERENCE = Off;
+				SWIFT_VERSION = 4.0;
 				TARGETED_DEVICE_FAMILY = "1,2";
 				VERSIONING_SYSTEM = "apple-generic";
 				VERSION_INFO_PREFIX = "";
@@ -489,19 +501,29 @@
 				CLANG_CXX_LIBRARY = "libc++";
 				CLANG_ENABLE_MODULES = YES;
 				CLANG_ENABLE_OBJC_ARC = YES;
+				CLANG_WARN_BLOCK_CAPTURE_AUTORELEASING = YES;
 				CLANG_WARN_BOOL_CONVERSION = YES;
+				CLANG_WARN_COMMA = YES;
 				CLANG_WARN_CONSTANT_CONVERSION = YES;
 				CLANG_WARN_DIRECT_OBJC_ISA_USAGE = YES;
 				CLANG_WARN_EMPTY_BODY = YES;
 				CLANG_WARN_ENUM_CONVERSION = YES;
+				CLANG_WARN_INFINITE_RECURSION = YES;
 				CLANG_WARN_INT_CONVERSION = YES;
+				CLANG_WARN_NON_LITERAL_NULL_CONVERSION = YES;
+				CLANG_WARN_OBJC_LITERAL_CONVERSION = YES;
 				CLANG_WARN_OBJC_ROOT_CLASS = YES;
+				CLANG_WARN_RANGE_LOOP_ANALYSIS = YES;
+				CLANG_WARN_STRICT_PROTOTYPES = YES;
+				CLANG_WARN_SUSPICIOUS_MOVE = YES;
 				CLANG_WARN_UNREACHABLE_CODE = YES;
 				CLANG_WARN__DUPLICATE_METHOD_MATCH = YES;
 				CODE_SIGNING_REQUIRED = NO;
 				COPY_PHASE_STRIP = YES;
 				ENABLE_NS_ASSERTIONS = NO;
+				ENABLE_STRICT_OBJC_MSGSEND = YES;
 				GCC_C_LANGUAGE_STANDARD = gnu99;
+				GCC_NO_COMMON_BLOCKS = YES;
 				GCC_PREPROCESSOR_DEFINITIONS = (
 					"POD_CONFIGURATION_RELEASE=1",
 					"$(inherited)",
@@ -515,6 +537,7 @@
 				IPHONEOS_DEPLOYMENT_TARGET = 9.0;
 				PROVISIONING_PROFILE_SPECIFIER = NO_SIGNING/;
 				STRIP_INSTALLED_PRODUCT = NO;
+				SWIFT_OPTIMIZATION_LEVEL = "-Owholemodule";
 				SYMROOT = "${SRCROOT}/../build";
 				VALIDATE_PRODUCT = YES;
 			};
@@ -529,20 +552,30 @@
 				CLANG_CXX_LIBRARY = "libc++";
 				CLANG_ENABLE_MODULES = YES;
 				CLANG_ENABLE_OBJC_ARC = YES;
+				CLANG_WARN_BLOCK_CAPTURE_AUTORELEASING = YES;
 				CLANG_WARN_BOOL_CONVERSION = YES;
+				CLANG_WARN_COMMA = YES;
 				CLANG_WARN_CONSTANT_CONVERSION = YES;
 				CLANG_WARN_DIRECT_OBJC_ISA_USAGE = YES;
 				CLANG_WARN_EMPTY_BODY = YES;
 				CLANG_WARN_ENUM_CONVERSION = YES;
+				CLANG_WARN_INFINITE_RECURSION = YES;
 				CLANG_WARN_INT_CONVERSION = YES;
+				CLANG_WARN_NON_LITERAL_NULL_CONVERSION = YES;
+				CLANG_WARN_OBJC_LITERAL_CONVERSION = YES;
 				CLANG_WARN_OBJC_ROOT_CLASS = YES;
+				CLANG_WARN_RANGE_LOOP_ANALYSIS = YES;
+				CLANG_WARN_STRICT_PROTOTYPES = YES;
+				CLANG_WARN_SUSPICIOUS_MOVE = YES;
 				CLANG_WARN_UNREACHABLE_CODE = YES;
 				CLANG_WARN__DUPLICATE_METHOD_MATCH = YES;
 				CODE_SIGNING_REQUIRED = NO;
 				COPY_PHASE_STRIP = NO;
+				ENABLE_STRICT_OBJC_MSGSEND = YES;
 				ENABLE_TESTABILITY = YES;
 				GCC_C_LANGUAGE_STANDARD = gnu99;
 				GCC_DYNAMIC_NO_PIC = NO;
+				GCC_NO_COMMON_BLOCKS = YES;
 				GCC_OPTIMIZATION_LEVEL = 0;
 				GCC_PREPROCESSOR_DEFINITIONS = (
 					"POD_CONFIGURATION_DEBUG=1",
@@ -568,6 +601,7 @@
 			isa = XCBuildConfiguration;
 			baseConfigurationReference = 6820F178C5F5E9638CACA2814BABA73E /* Pods-ScalingCarousel_Example.debug.xcconfig */;
 			buildSettings = {
+				ALWAYS_EMBED_SWIFT_STANDARD_LIBRARIES = YES;
 				"CODE_SIGN_IDENTITY[sdk=appletvos*]" = "";
 				"CODE_SIGN_IDENTITY[sdk=iphoneos*]" = "";
 				"CODE_SIGN_IDENTITY[sdk=watchos*]" = "";
@@ -594,6 +628,8 @@
 				SDKROOT = iphoneos;
 				SKIP_INSTALL = YES;
 				SWIFT_OPTIMIZATION_LEVEL = "-Onone";
+				SWIFT_SWIFT3_OBJC_INFERENCE = On;
+				SWIFT_VERSION = 4.0;
 				TARGETED_DEVICE_FAMILY = "1,2";
 				VERSIONING_SYSTEM = "apple-generic";
 				VERSION_INFO_PREFIX = "";
@@ -626,7 +662,8 @@
 				SDKROOT = iphoneos;
 				SKIP_INSTALL = YES;
 				SWIFT_OPTIMIZATION_LEVEL = "-Onone";
-				SWIFT_VERSION = 3.0;
+				SWIFT_SWIFT3_OBJC_INFERENCE = Off;
+				SWIFT_VERSION = 4.0;
 				TARGETED_DEVICE_FAMILY = "1,2";
 				VERSIONING_SYSTEM = "apple-generic";
 				VERSION_INFO_PREFIX = "";

Example/Pods/Target Support Files/ScalingCarousel/Info.plist

@@ -2,25 +2,25 @@
 <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
 <plist version="1.0">
 <dict>
-  <key>CFBundleDevelopmentRegion</key>
-  <string>en</string>
-  <key>CFBundleExecutable</key>
-  <string>${EXECUTABLE_NAME}</string>
-  <key>CFBundleIdentifier</key>
-  <string>${PRODUCT_BUNDLE_IDENTIFIER}</string>
-  <key>CFBundleInfoDictionaryVersion</key>
-  <string>6.0</string>
-  <key>CFBundleName</key>
-  <string>${PRODUCT_NAME}</string>
-  <key>CFBundlePackageType</key>
-  <string>FMWK</string>
-  <key>CFBundleShortVersionString</key>
-  <string>0.1.0</string>
-  <key>CFBundleSignature</key>
-  <string>????</string>
-  <key>CFBundleVersion</key>
-  <string>${CURRENT_PROJECT_VERSION}</string>
-  <key>NSPrincipalClass</key>
-  <string></string>
+	<key>CFBundleDevelopmentRegion</key>
+	<string>en</string>
+	<key>CFBundleExecutable</key>
+	<string>${EXECUTABLE_NAME}</string>
+	<key>CFBundleIdentifier</key>
+	<string>${PRODUCT_BUNDLE_IDENTIFIER}</string>
+	<key>CFBundleInfoDictionaryVersion</key>
+	<string>6.0</string>
+	<key>CFBundleName</key>
+	<string>${PRODUCT_NAME}</string>
+	<key>CFBundlePackageType</key>
+	<string>FMWK</string>
+	<key>CFBundleShortVersionString</key>
+	<string>2.0</string>
+	<key>CFBundleSignature</key>
+	<string>????</string>
+	<key>CFBundleVersion</key>
+	<string>${CURRENT_PROJECT_VERSION}</string>
+	<key>NSPrincipalClass</key>
+	<string></string>
 </dict>
 </plist>

Example/ScalingCarousel.xcodeproj/project.pbxproj

@@ -245,16 +245,16 @@
 			isa = PBXProject;
 			attributes = {
 				LastSwiftUpdateCheck = 0720;
-				LastUpgradeCheck = 0720;
+				LastUpgradeCheck = 0900;
 				ORGANIZATIONNAME = CocoaPods;
 				TargetAttributes = {
 					607FACCF1AFB9204008FA782 = {
 						CreatedOnToolsVersion = 6.3.1;
-						LastSwiftMigration = 0820;
+						LastSwiftMigration = 0900;
 					};
 					607FACE41AFB9204008FA782 = {
 						CreatedOnToolsVersion = 6.3.1;
-						LastSwiftMigration = 0820;
+						LastSwiftMigration = 0900;
 						TestTargetID = 607FACCF1AFB9204008FA782;
 					};
 				};
@@ -448,13 +448,21 @@
 				CLANG_CXX_LIBRARY = "libc++";
 				CLANG_ENABLE_MODULES = YES;
 				CLANG_ENABLE_OBJC_ARC = YES;
+				CLANG_WARN_BLOCK_CAPTURE_AUTORELEASING = YES;
 				CLANG_WARN_BOOL_CONVERSION = YES;
+				CLANG_WARN_COMMA = YES;
 				CLANG_WARN_CONSTANT_CONVERSION = YES;
 				CLANG_WARN_DIRECT_OBJC_ISA_USAGE = YES_ERROR;
 				CLANG_WARN_EMPTY_BODY = YES;
 				CLANG_WARN_ENUM_CONVERSION = YES;
+				CLANG_WARN_INFINITE_RECURSION = YES;
 				CLANG_WARN_INT_CONVERSION = YES;
+				CLANG_WARN_NON_LITERAL_NULL_CONVERSION = YES;
+				CLANG_WARN_OBJC_LITERAL_CONVERSION = YES;
 				CLANG_WARN_OBJC_ROOT_CLASS = YES_ERROR;
+				CLANG_WARN_RANGE_LOOP_ANALYSIS = YES;
+				CLANG_WARN_STRICT_PROTOTYPES = YES;
+				CLANG_WARN_SUSPICIOUS_MOVE = YES;
 				CLANG_WARN_UNREACHABLE_CODE = YES;
 				CLANG_WARN__DUPLICATE_METHOD_MATCH = YES;
 				"CODE_SIGN_IDENTITY[sdk=iphoneos*]" = "iPhone Developer";
@@ -493,13 +501,21 @@
 				CLANG_CXX_LIBRARY = "libc++";
 				CLANG_ENABLE_MODULES = YES;
 				CLANG_ENABLE_OBJC_ARC = YES;
+				CLANG_WARN_BLOCK_CAPTURE_AUTORELEASING = YES;
 				CLANG_WARN_BOOL_CONVERSION = YES;
+				CLANG_WARN_COMMA = YES;
 				CLANG_WARN_CONSTANT_CONVERSION = YES;
 				CLANG_WARN_DIRECT_OBJC_ISA_USAGE = YES_ERROR;
 				CLANG_WARN_EMPTY_BODY = YES;
 				CLANG_WARN_ENUM_CONVERSION = YES;
+				CLANG_WARN_INFINITE_RECURSION = YES;
 				CLANG_WARN_INT_CONVERSION = YES;
+				CLANG_WARN_NON_LITERAL_NULL_CONVERSION = YES;
+				CLANG_WARN_OBJC_LITERAL_CONVERSION = YES;
 				CLANG_WARN_OBJC_ROOT_CLASS = YES_ERROR;
+				CLANG_WARN_RANGE_LOOP_ANALYSIS = YES;
+				CLANG_WARN_STRICT_PROTOTYPES = YES;
+				CLANG_WARN_SUSPICIOUS_MOVE = YES;
 				CLANG_WARN_UNREACHABLE_CODE = YES;
 				CLANG_WARN__DUPLICATE_METHOD_MATCH = YES;
 				"CODE_SIGN_IDENTITY[sdk=iphoneos*]" = "iPhone Developer";
@@ -518,6 +534,7 @@
 				IPHONEOS_DEPLOYMENT_TARGET = 9.0;
 				MTL_ENABLE_DEBUG_INFO = NO;
 				SDKROOT = iphoneos;
+				SWIFT_OPTIMIZATION_LEVEL = "-Owholemodule";
 				VALIDATE_PRODUCT = YES;
 			};
 			name = Release;
@@ -526,6 +543,7 @@
 			isa = XCBuildConfiguration;
 			baseConfigurationReference = 54ACDAF6D64CCC3389CF9744 /* Pods-ScalingCarousel_Example.debug.xcconfig */;
 			buildSettings = {
+				ALWAYS_EMBED_SWIFT_STANDARD_LIBRARIES = YES;
 				ASSETCATALOG_COMPILER_APPICON_NAME = AppIcon;
 				INFOPLIST_FILE = ScalingCarousel/Info.plist;
 				IPHONEOS_DEPLOYMENT_TARGET = 9.0;
@@ -533,7 +551,8 @@
 				MODULE_NAME = ExampleApp;
 				PRODUCT_BUNDLE_IDENTIFIER = "org.cocoapods.demo.$(PRODUCT_NAME:rfc1034identifier)";
 				PRODUCT_NAME = "$(TARGET_NAME)";
-				SWIFT_VERSION = 3.0;
+				SWIFT_SWIFT3_OBJC_INFERENCE = Off;
+				SWIFT_VERSION = 4.0;
 			};
 			name = Debug;
 		};
@@ -541,6 +560,7 @@
 			isa = XCBuildConfiguration;
 			baseConfigurationReference = C076B0D8341FA770E7E1424B /* Pods-ScalingCarousel_Example.release.xcconfig */;
 			buildSettings = {
+				ALWAYS_EMBED_SWIFT_STANDARD_LIBRARIES = YES;
 				ASSETCATALOG_COMPILER_APPICON_NAME = AppIcon;
 				INFOPLIST_FILE = ScalingCarousel/Info.plist;
 				IPHONEOS_DEPLOYMENT_TARGET = 9.0;
@@ -548,7 +568,8 @@
 				MODULE_NAME = ExampleApp;
 				PRODUCT_BUNDLE_IDENTIFIER = "org.cocoapods.demo.$(PRODUCT_NAME:rfc1034identifier)";
 				PRODUCT_NAME = "$(TARGET_NAME)";
-				SWIFT_VERSION = 3.0;
+				SWIFT_SWIFT3_OBJC_INFERENCE = Off;
+				SWIFT_VERSION = 4.0;
 			};
 			name = Release;
 		};
@@ -568,7 +589,8 @@
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks @loader_path/Frameworks";
 				PRODUCT_BUNDLE_IDENTIFIER = "org.cocoapods.$(PRODUCT_NAME:rfc1034identifier)";
 				PRODUCT_NAME = "$(TARGET_NAME)";
-				SWIFT_VERSION = 3.0;
+				SWIFT_SWIFT3_OBJC_INFERENCE = Off;
+				SWIFT_VERSION = 4.0;
 			};
 			name = Debug;
 		};
@@ -584,7 +606,8 @@
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks @loader_path/Frameworks";
 				PRODUCT_BUNDLE_IDENTIFIER = "org.cocoapods.$(PRODUCT_NAME:rfc1034identifier)";
 				PRODUCT_NAME = "$(TARGET_NAME)";
-				SWIFT_VERSION = 3.0;
+				SWIFT_SWIFT3_OBJC_INFERENCE = Off;
+				SWIFT_VERSION = 4.0;
 			};
 			name = Release;
 		};

Example/ScalingCarousel.xcodeproj/xcshareddata/xcschemes/ScalingCarousel-Example.xcscheme

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <Scheme
-   LastUpgradeVersion = "0720"
+   LastUpgradeVersion = "0900"
    version = "1.3">
    <BuildAction
       parallelizeBuildables = "YES"
@@ -40,6 +40,7 @@
       buildConfiguration = "Debug"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      language = ""
       shouldUseLaunchSchemeArgsEnv = "YES">
       <Testables>
          <TestableReference
@@ -69,6 +70,7 @@
       buildConfiguration = "Debug"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      language = ""
       launchStyle = "0"
       useCustomWorkingDirectory = "NO"
       ignoresPersistentStateOnLaunch = "NO"

Example/ScalingCarousel/Base.lproj/Main.storyboard

@@ -1,10 +1,11 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<document type="com.apple.InterfaceBuilder3.CocoaTouch.Storyboard.XIB" version="3.0" toolsVersion="11762" systemVersion="16B2555" targetRuntime="iOS.CocoaTouch" propertyAccessControl="none" useAutolayout="YES" useTraitCollections="YES" colorMatched="YES" initialViewController="jed-5q-J52">
+<document type="com.apple.InterfaceBuilder3.CocoaTouch.Storyboard.XIB" version="3.0" toolsVersion="13122.19" systemVersion="16F73" targetRuntime="iOS.CocoaTouch" propertyAccessControl="none" useAutolayout="YES" useTraitCollections="YES" colorMatched="YES" initialViewController="jed-5q-J52">
     <device id="retina4_7" orientation="portrait">
         <adaptation id="fullscreen"/>
     </device>
     <dependencies>
-        <plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="11757"/>
+        <deployment identifier="iOS"/>
+        <plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="13104.16"/>
         <capability name="documents saved in the Xcode 8 format" minToolsVersion="8.0"/>
     </dependencies>
     <scenes>
@@ -74,19 +75,29 @@
                                     <action selector="showHideButtonPressed:" destination="vXZ-lx-hvc" eventType="touchUpInside" id="Jsy-vc-cWp"/>
                                 </connections>
                             </button>
+                            <label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="" textAlignment="natural" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="UYO-rO-XuZ">
+                                <rect key="frame" x="187" y="143" width="0.0" height="0.0"/>
+                                <fontDescription key="fontDescription" type="system" pointSize="17"/>
+                                <nil key="textColor"/>
+                                <nil key="highlightedColor"/>
+                            </label>
                         </subviews>
                         <color key="backgroundColor" red="1" green="1" blue="1" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
                         <constraints>
                             <constraint firstItem="Mq8-SH-Mx8" firstAttribute="width" secondItem="kh9-bI-dsS" secondAttribute="width" id="4Ux-ib-2uZ"/>
+                            <constraint firstItem="UYO-rO-XuZ" firstAttribute="centerX" secondItem="KAz-De-GJ8" secondAttribute="centerX" id="8U2-jX-Aw6"/>
                             <constraint firstItem="KAz-De-GJ8" firstAttribute="top" secondItem="jyV-Pf-zRb" secondAttribute="bottom" constant="85" id="Ffh-uk-Qnl"/>
                             <constraint firstItem="2fi-mo-0CV" firstAttribute="top" secondItem="Mq8-SH-Mx8" secondAttribute="bottom" constant="15" id="Kee-s5-jSC"/>
                             <constraint firstItem="KAz-De-GJ8" firstAttribute="centerX" secondItem="kh9-bI-dsS" secondAttribute="centerX" id="M5E-lE-5Pp"/>
                             <constraint firstItem="Mq8-SH-Mx8" firstAttribute="leading" secondItem="kh9-bI-dsS" secondAttribute="leading" id="NPp-qY-rgM"/>
+                            <constraint firstItem="UYO-rO-XuZ" firstAttribute="top" secondItem="KAz-De-GJ8" secondAttribute="bottom" constant="8" id="nfn-SZ-h6K"/>
                         </constraints>
                     </view>
                     <tabBarItem key="tabBarItem" title="Storyboard" id="7Ol-Hv-b1V"/>
                     <connections>
+                        <outlet property="carousel" destination="Mq8-SH-Mx8" id="PYK-cv-2wb"/>
                         <outlet property="carouselBottomConstraint" destination="Kee-s5-jSC" id="HnZ-jP-gpN"/>
+                        <outlet property="output" destination="UYO-rO-XuZ" id="v8Z-xt-lyT"/>
                     </connections>
                 </viewController>
                 <placeholder placeholderIdentifier="IBFirstResponder" id="x5A-6p-PRh" sceneMemberID="firstResponder"/>
@@ -118,6 +129,7 @@
                 <tabBarController automaticallyAdjustsScrollViewInsets="NO" id="jed-5q-J52" sceneMemberID="viewController">
                     <toolbarItems/>
                     <tabBar key="tabBar" contentMode="scaleToFill" id="Xg8-GK-uv2">
+                        <rect key="frame" x="0.0" y="0.0" width="1000" height="1000"/>
                         <autoresizingMask key="autoresizingMask"/>
                         <color key="backgroundColor" white="0.0" alpha="0.0" colorSpace="calibratedWhite"/>
                     </tabBar>

Example/ScalingCarousel/CodeViewController.swift

@@ -24,6 +24,9 @@ class CodeCell: ScalingCarouselCell {
 }
 
 class CodeViewController: UIViewController {
+    
+    // MARK: - Properties (Private)
+    fileprivate var scalingCarousel: ScalingCarouselView!
 
     // MARK: - Lifecycle
     
@@ -43,8 +46,9 @@ class CodeViewController: UIViewController {
     private func addCarousel() {
         
         let frame = CGRect(x: 0, y: 0, width: 0, height: 0)
-        let scalingCarousel = ScalingCarouselView(withFrame: frame, andInset: 20)
+        scalingCarousel = ScalingCarouselView(withFrame: frame, andInset: 20)
         scalingCarousel.dataSource = self
+        scalingCarousel.delegate = self
         scalingCarousel.translatesAutoresizingMaskIntoConstraints = false
         scalingCarousel.backgroundColor = .white
         
@@ -76,3 +80,10 @@ extension CodeViewController: UICollectionViewDataSource {
         return cell
     }
 }
+
+extension CodeViewController: UICollectionViewDelegate {
+    
+    func scrollViewDidScroll(_ scrollView: UIScrollView) {
+        scalingCarousel.didScroll()
+    }
+}

Example/ScalingCarousel/Info.plist

@@ -15,7 +15,7 @@
 	<key>CFBundlePackageType</key>
 	<string>APPL</string>
 	<key>CFBundleShortVersionString</key>
-	<string>1.0</string>
+	<string>2.0</string>
 	<key>CFBundleSignature</key>
 	<string>????</string>
 	<key>CFBundleVersion</key>

Example/ScalingCarousel/StoryboardViewController.swift

@@ -18,6 +18,7 @@ class StoryboardViewController: UIViewController {
     // MARK: - IBOutlets
     @IBOutlet weak var carousel: ScalingCarouselView!
     @IBOutlet weak var carouselBottomConstraint: NSLayoutConstraint!
+    @IBOutlet weak var output: UILabel!
     
     private struct Constants {
         static let carouselHideConstant: CGFloat = -250
@@ -59,3 +60,15 @@ extension CarouselDatasource: UICollectionViewDataSource {
         return cell
     }
 }
+
+typealias CarouselDelegate = StoryboardViewController
+extension StoryboardViewController: UICollectionViewDelegate {
+    
+    func scrollViewDidScroll(_ scrollView: UIScrollView) {
+        carousel.didScroll()
+        
+        guard let currentCenterIndex = carousel.currentCenterCellIndex?.row else { return }
+        
+        output.text = String(describing: currentCenterIndex)
+    }
+}

README.md

@@ -8,7 +8,9 @@
 ScalingCarousel provides a simple carousel-style collection view.
 It takes care of cell presentation, scaling each cell as the collection view is scrolled.
 
-It is used in [Bikey](https://itunes.apple.com/ie/app/bikey/id1048962300?mt=8) to present bike station information.
+It is used in [Bikey](https://itunes.apple.com/ie/app/bikey/id1048962300?mt=8) to present bike station information, as seen below;
+
+![Bikey ScalingCarousel example](Images/BikeyExample.gif)
 
 ## Usage
 
@@ -16,20 +18,22 @@ ScalingCarousel can be added via both storyboard/xib and code, as described belo
 
 ### Storyboard
 
-1. Add a UICollectionView to your view, and change the type to ScalingCarouselView
+* Add a UICollectionView to your view, and change the type to ScalingCarouselView
 
-2. In the attributes inspector, set the desired carousel inset
+* In the attributes inspector, set the desired carousel inset
 
-3. Set your UIViewController as the collection view datasource and implement the standard UICollectionViewDatasource methods in your view controller
+* Set your UIViewController as the collection view datasource and implement the standard UICollectionViewDatasource methods in your view controller
 
-4. Create a custom UICollectionViewCell which inherits from ScalingCarouselCell, and set the cell type to your custom cell type in the storyboard
+* Set your UIViewController as the collection view delegate and implement the UIScrollViewDelegate method scrollViewDidScroll(:). In this method, call the didScroll() method of ScalingCarouselView
 
-5. Add a view to the cell's content view, and connect this via the Connections Inspector (in Interface builder) to the cell's mainView IBOutlet.
+* Create a custom UICollectionViewCell which inherits from ScalingCarouselCell, and set the cell type to your custom cell type in the storyboard
+
+* Add a view to the cell's content view, and connect this via the Connections Inspector (in Interface builder) to the cell's mainView IBOutlet.
 This property is declared in ScalingCarouselCell. You should add any cell content to this view.
 
 ### Code
 
-1. Create a custom UICollectionViewCell which inherits from ScalingCarouselCell. Initialize the mainView property, which is declared in ScalingCarouselCell;
+* Create a custom UICollectionViewCell which inherits from ScalingCarouselCell. Initialize the mainView property, which is declared in ScalingCarouselCell;
 
 ```
 override init(frame: CGRect) {
@@ -41,7 +45,7 @@ override init(frame: CGRect) {
 }
 ```
 
-2. Create and add a ScalingCarouselView to your view, and implement the standard UICollectionViewDatasource methods in your view controller;
+* Create and add a ScalingCarouselView to your view, and implement the standard UICollectionViewDatasource methods in your view controller;
 
 ```
 // Create our carousel
@@ -62,6 +66,8 @@ scalingCarousel.leadingAnchor.constraint(equalTo: view.leadingAnchor).isActive =
 scalingCarousel.topAnchor.constraint(equalTo: view.topAnchor, constant: 50).isActive = true
 ```
 
+* Set your UIViewController as the collection view delegate and implement the UIScrollViewDelegate method scrollViewDidScroll(:). In this method, call the didScroll() method of ScalingCarouselView
+
 ## Example
 
 To run the example project, clone the repo, and run `pod install` from the Example directory first.

ScalingCarousel.podspec

@@ -8,7 +8,7 @@
 
 Pod::Spec.new do |s|
   s.name             = 'ScalingCarousel'
-  s.version          = '1.0'
+  s.version          = '2.0'
   s.summary          = 'A super simple carousel view with scaling transitions written in Swift'
 
   s.description      = <<-DESC

ScalingCarousel/Classes/ScalingCarouselCell.swift

@@ -51,22 +51,38 @@ open class ScalingCarouselCell: UICollectionViewCell {
     /// - parameter carouselInset: The inset of the related SPBCarousel view
     /// - parameter scaleMinimum:  The minimun % a cell should scale to,
     ///             expressed as a value between 0.0 and 1.0
-    open func scale(withCarouselInset carouselInset: CGFloat, scaleMinimum: CGFloat = 0.9) {
-        guard let superview = superview, let mainView = mainView else { return }
+    open func scale(withCarouselInset carouselInset: CGFloat,
+                    scaleMinimum: CGFloat = 0.9) {
         
+        // Ensure we have a superView, and mainView
+        guard let superview = superview,
+            let mainView = mainView else { return }
+        
+        // Get our absolute origin value
         let originX = superview.convert(frame, to: nil).origin.x
+        
+        // Calculate our actual origin.x value using our inset
         let originXActual = originX - carouselInset
         
         let width = frame.size.width
         
+        // Calculate our scale values
         let scaleCalculator = fabs(width - fabs(originXActual))
         let percentageScale = (scaleCalculator/width)
         
-        let scaleValue = scaleMinimum + (percentageScale/InternalConstants.scaleDivisor)
-        let alphaValue = InternalConstants.alphaSmallestValue + (percentageScale/InternalConstants.scaleDivisor)
+        let scaleValue = scaleMinimum
+            + (percentageScale/InternalConstants.scaleDivisor)
         
-        mainView.transform = CGAffineTransform.identity.scaledBy(x: scaleValue, y: scaleValue)
+        let alphaValue = InternalConstants.alphaSmallestValue
+            + (percentageScale/InternalConstants.scaleDivisor)
+        
+        let affineIdentity = CGAffineTransform.identity
+        
+        // Scale our mainView and set it's alpha value
+        mainView.transform = affineIdentity.scaledBy(x: scaleValue, y: scaleValue)
         mainView.alpha = alphaValue
+        
+        // ..also..round the corners
         mainView.layer.cornerRadius = 20
     }
 }

ScalingCarousel/Classes/ScalingCarouselLayout.swift

@@ -30,11 +30,14 @@ open class ScalingCarouselLayout: UICollectionViewFlowLayout {
     }
     
     override open func prepare() {
+        
         guard let collectionViewSize = collectionView?.frame.size else { return }
         
+        // Set itemSize based on total width and inset
         itemSize = collectionViewSize
         itemSize.width = itemSize.width - (inset * 2)
         
+        // Set scrollDirection and paging
         scrollDirection = .horizontal
         collectionView?.isPagingEnabled = true
         

ScalingCarousel/Classes/ScalingCarouselView.swift

@@ -19,33 +19,80 @@ open class ScalingCarouselView: UICollectionView {
     
     // MARK: - Properties (Public)
     
-    /// Inset of the main, central cell
+    /// Inset of the main, center cell
     @IBInspectable public var inset: CGFloat = 0.0 {
         didSet {
-            collectionViewLayout = ScalingCarouselLayout(withCarouselInset: inset)
+            /*
+             Configure our layout, and add more
+             constraints to our invisible UIScrollView
+            */
+            configureLayout()
         }
     }
     
+    /// Returns the current center cell of the carousel if it can be calculated
+    public var currentCenterCell: UICollectionViewCell? {
+        
+        let lowerBound = inset - 20
+        let upperBound = inset + 20
+        
+        for cell in visibleCells {
+            
+            let cellRect = convert(cell.frame, to: nil)
+            
+            if cellRect.origin.x > lowerBound && cellRect.origin.x < upperBound {
+                return cell
+            }
+            
+        }
+        
+        return nil
+    }
+    
+    /// Returns the IndexPath of the current center cell if it can be calculated
+    public var currentCenterCellIndex: IndexPath? {
+        guard let currentCenterCell = self.currentCenterCell else { return nil }
+        
+        return indexPath(for: currentCenterCell)
+    }
+    
     /// Override of the collection view content size to add an observer
     override open var contentSize: CGSize {
         didSet {
-            invisibleScrollView.contentSize = contentSize
+            
+            guard let dataSource = dataSource,
+                let invisibleScrollView = invisibleScrollView else { return }
+            
+            let numberSections = dataSource.numberOfSections?(in: self) ?? 1
+            
+            // Calculate total number of items in collection view
+            var numberItems = 0
+            
+            for i in 0..<numberSections {
+                
+                let numberSectionItems = dataSource.collectionView(self, numberOfItemsInSection: i)
+                numberItems += numberSectionItems
+            }
+            
+            // Set the invisibleScrollView contentSize width based on number of items
+            let contentWidth = invisibleScrollView.frame.width * CGFloat(numberItems)
+            invisibleScrollView.contentSize = CGSize(width: contentWidth, height: invisibleScrollView.frame.height)
         }
     }
     
     // MARK: - Properties (Private)
     fileprivate var invisibleScrollView: UIScrollView!
+    fileprivate var invisibleWidthConstraint: NSLayoutConstraint?
+    fileprivate var invisibleLeftConstraint: NSLayoutConstraint?
     
     // MARK: - Lifecycle
     
     override public init(frame: CGRect, collectionViewLayout layout: UICollectionViewLayout) {
         super.init(frame: frame, collectionViewLayout: layout)
-        configure()
     }
     
     required public init?(coder aDecoder: NSCoder) {
         super.init(coder: aDecoder)
-        configure()
     }
     
     /// Convenience initializer allowing setting of the carousel inset
@@ -61,16 +108,6 @@ open class ScalingCarouselView: UICollectionView {
     
     // MARK: - Overrides
     
-    override open func updateConstraints() {
-        
-        invisibleScrollView.heightAnchor.constraint(equalTo: heightAnchor).isActive = true
-        invisibleScrollView.widthAnchor.constraint(equalTo: widthAnchor, constant: -(2 * inset)).isActive = true
-        invisibleScrollView.leftAnchor.constraint(equalTo: leftAnchor, constant: inset).isActive = true
-        invisibleScrollView.topAnchor.constraint(equalTo: topAnchor).isActive = true
-        
-        super.updateConstraints()
-    }
-    
     override open func scrollRectToVisible(_ rect: CGRect, animated: Bool) {
         invisibleScrollView.setContentOffset(rect.origin, animated: animated)
     }
@@ -83,23 +120,104 @@ open class ScalingCarouselView: UICollectionView {
         scrollRectToVisible(rect, animated: animated)
     }
     
-    // MARK: - Configuration
-    
-    private func configure() {
+    override open func didMoveToSuperview() {
+        super.didMoveToSuperview()
         
-        // Add our invisible scrollview
-        invisibleScrollView = UIScrollView(frame: self.bounds)
+        addInvisibleScrollView(to: superview)
+    }
+    
+    // MARK: - Public API
+    
+    /*
+     This method should ALWAYS be called from the ScalingCarousel delegate when
+     the UIScrollViewDelegate scrollViewDidScroll(_:) method is called
+     
+     e.g In the ScalingCarousel delegate, implement:
+     
+     func scrollViewDidScroll(_ scrollView: UIScrollView) {
+        carousel.didScroll()
+     }
+    */
+    public func didScroll() {
+        scrollViewDidScroll(self)
+    }
+}
+
+private typealias PrivateAPI = ScalingCarouselView
+fileprivate extension PrivateAPI {
+    
+    fileprivate func addInvisibleScrollView(to superview: UIView?) {
+        guard let superview = superview else { return }
+        
+        /// Add our 'invisible' scrollview
+        invisibleScrollView = UIScrollView(frame: bounds)
         invisibleScrollView.translatesAutoresizingMaskIntoConstraints = false
         invisibleScrollView.isPagingEnabled = true
         invisibleScrollView.showsHorizontalScrollIndicator = false
         
-        // Turn off interaction on the overlay so touch events fall through to the main scroll view
+        /*
+         Disable user interaction on the 'invisible' scrollview,
+         This means touch events will fall through to the underlying UICollectionView
+         */
         invisibleScrollView.isUserInteractionEnabled = false
+        
+        /// Set the scroll delegate to be the ScalingCarouselView
         invisibleScrollView.delegate = self
         
-        // Add the disabled invisible scrollviews pan gesture recognizer to our collection view
+        /*
+         Now add the invisible scrollview's pan 
+         gesture recognizer to the ScalingCarouselView
+         */
         addGestureRecognizer(invisibleScrollView.panGestureRecognizer)
-        addSubview(invisibleScrollView)
+        
+        /*
+         Finally, add the 'invisible' scrollview as a subview 
+         of the ScalingCarousel's superview
+        */
+        superview.addSubview(invisibleScrollView)
+        
+        /*
+         Add constraints for height and top, relative to the
+         ScalingCarouselView
+        */
+        invisibleScrollView.heightAnchor.constraint(equalTo: heightAnchor).isActive = true
+        invisibleScrollView.topAnchor.constraint(equalTo: topAnchor).isActive = true
+        
+        /*
+         Further configure our layout and add more constraints
+         for width and left position
+        */
+        configureLayout()
+    }
+    
+    fileprivate func configureLayout() {
+        
+        // Create a ScalingCarouselLayout using our inset
+        collectionViewLayout = ScalingCarouselLayout(
+            withCarouselInset: inset)
+        
+        /*
+         Only continue if we have a reference to
+         our 'invisible' UIScrollView
+        */
+        guard let invisibleScrollView = invisibleScrollView else { return }
+    
+        // Remove constraints if they already exist
+        invisibleWidthConstraint?.isActive = false
+        invisibleLeftConstraint?.isActive = false
+        
+        /* 
+         Add constrants for width and left postion 
+         to our 'invisible' UIScrollView
+        */
+        invisibleWidthConstraint = invisibleScrollView.widthAnchor.constraint(
+            equalTo: widthAnchor, constant: -(2 * inset))
+        invisibleLeftConstraint =  invisibleScrollView.leftAnchor.constraint(
+            equalTo: leftAnchor, constant: inset)
+        
+        // Activate the constraints
+        invisibleWidthConstraint?.isActive = true
+        invisibleLeftConstraint?.isActive = true
     }
 }
 
@@ -111,12 +229,13 @@ extension InvisibleScrollDelegate: UIScrollViewDelegate {
     
     public func scrollViewDidScroll(_ scrollView: UIScrollView) {
         
-        delegate?.scrollViewDidScroll?(scrollView)
-        
-        // Only move the collection view by an amount based on the invisible scrollview
+        /*
+         Move the ScalingCarousel base d on the
+         contentOffset of the 'invisible' UIScrollView
+        */
         updateOffSet()
         
-        // Scale Visible cells
+        // Also, this is where we scale our cells
         for cell in visibleCells {
             if let infoCardCell = cell as? ScalingCarouselCell {
                 infoCardCell.scale(withCarouselInset: inset)