From 2a19d7c7cc9823512ddacf06e03e3da90e1d47fc Mon Sep 17 00:00:00 2001
From: Viscmad <viscmadsingh93@gmail.com>
Date: Mon, 13 Nov 2017 11:14:15 +0530
Subject: [PATCH 1/6] Create CardsCollectionViewVerticleLayout.swift

---
 CardsCollectionViewVerticleLayout.swift | 155 ++++++++++++++++++++++++
 1 file changed, 155 insertions(+)
 create mode 100644 CardsCollectionViewVerticleLayout.swift

diff --git a/CardsCollectionViewVerticleLayout.swift b/CardsCollectionViewVerticleLayout.swift
new file mode 100644
index 0000000..32dbf50
--- /dev/null
+++ b/CardsCollectionViewVerticleLayout.swift
@@ -0,0 +1,155 @@
+import UIKit
+ 
+open class CardsCollectionViewLayout: UICollectionViewLayout {
+   
+    // MARK: - Layout configuration
+   
+    //MARK: Size attribute
+    //Using code :
+    //    attributes.size = CGSize(
+    //    width: (collectionView.bounds.width - ((collectionView.bounds.width * 2)/100)) ,
+    //    height: (collectionView.bounds.height - ((collectionView.bounds.height * 4)/100)))
+    //Instead Calling
+    //    public var itemSize: CGSize = CGSize(width: 200, height: 300) {
+    //        didSet{
+    //            invalidateLayout()
+    //        }
+    //    }
+   
+    public var spacing: CGFloat = 10.0 {
+        didSet{
+            invalidateLayout()
+        }
+    }
+   
+    public var maximumVisibleItems: Int = 2 {
+        didSet{
+            invalidateLayout()
+        }
+    }
+   
+    // MARK: UICollectionViewLayout
+   
+    override open var collectionView: UICollectionView {
+        return super.collectionView!
+    }
+   
+    override open var collectionViewContentSize: CGSize {
+        let itemsCount = CGFloat(collectionView.numberOfItems(inSection: 0))
+       
+        return CGSize(width: collectionView.bounds.width,
+                      height: collectionView.bounds.height * itemsCount)
+    }
+   
+    override open func prepare() {
+        super.prepare()
+        assert(collectionView.numberOfSections == 1, "Multiple sections aren't supported!")
+    }
+   
+    override open func layoutAttributesForElements(in rect: CGRect) -> [UICollectionViewLayoutAttributes]? {
+        let totalItemsCount = collectionView.numberOfItems(inSection: 0)
+       
+        let minVisibleIndex = max(Int(collectionView.contentOffset.x) / Int(collectionView.bounds.width), 0)
+        let maxVisibleIndex = min(minVisibleIndex + maximumVisibleItems, totalItemsCount)
+       
+        let contentCenterX = collectionView.contentOffset.x + (collectionView.bounds.width / 2.0)
+       
+        //Converted from contentOffset.x to contentOffset.y
+        //and from collectionView.bounds.widt to collectionView.bounds.heigh
+        let deltaOffset = Int(collectionView.contentOffset.y) % Int( collectionView.bounds.height)
+        let percentageDeltaOffset = CGFloat(deltaOffset) / collectionView.bounds.height
+       
+        let visibleIndices = minVisibleIndex..<maxVisibleIndex
+       
+        let attributes: [UICollectionViewLayoutAttributes] = visibleIndices.map { index in
+            let indexPath = IndexPath(item: index, section: 0)
+            return computeLayoutAttributesForItem(indexPath: indexPath,
+                                                  minVisibleIndex: minVisibleIndex,
+                                                  contentCenterX: contentCenterX,
+                                                  deltaOffset: CGFloat(deltaOffset),
+                                                  percentageDeltaOffset: percentageDeltaOffset)
+        }
+       
+        return attributes
+    }
+   
+    override open func layoutAttributesForItem(at indexPath: IndexPath) -> UICollectionViewLayoutAttributes? {
+        let contentCenterX = collectionView.contentOffset.x + (collectionView.bounds.width / 2.0)
+        let minVisibleIndex = Int(collectionView.contentOffset.x) / Int(collectionView.bounds.width)
+       
+        //Converted from contentOffset.x to contentOffset.y
+        //and from collectionView.bounds.widt to collectionView.bounds.heigh
+        let deltaOffset = Int(collectionView.contentOffset.y) % Int(collectionView.bounds.height)
+        let percentageDeltaOffset = CGFloat(deltaOffset) / collectionView.bounds.height
+       
+        return computeLayoutAttributesForItem(indexPath: indexPath,
+                                              minVisibleIndex: minVisibleIndex,
+                                              contentCenterX: contentCenterX,
+                                              deltaOffset: CGFloat(deltaOffset),
+                                              percentageDeltaOffset: percentageDeltaOffset)
+    }
+   
+    override open func shouldInvalidateLayout(forBoundsChange newBounds: CGRect) -> Bool {
+        return true
+    }
+}
+ 
+ 
+// MARK: - Layout computations
+fileprivate extension CardsCollectionViewLayout {
+   
+    private func scale(at index: Int) -> CGFloat {
+        let translatedCoefficient = CGFloat(index) - CGFloat(self.maximumVisibleItems) / 2
+        return CGFloat(pow(0.95, translatedCoefficient))
+    }
+ 
+    private func transform(atCurrentVisibleIndex visibleIndex: Int, percentageOffset: CGFloat) -> CGAffineTransform {
+        var rawScale = visibleIndex < maximumVisibleItems ? scale(at: visibleIndex) : 1.0
+ 
+        if visibleIndex != 0 {
+            let previousScale = scale(at: visibleIndex - 1)
+            let delta = (previousScale - rawScale) * percentageOffset
+            rawScale += delta
+        }
+        return CGAffineTransform(scaleX: rawScale, y: rawScale)
+    }
+   
+    fileprivate func computeLayoutAttributesForItem(indexPath: IndexPath,
+                                                    minVisibleIndex: Int,
+                                                    contentCenterX: CGFloat,
+                                                    deltaOffset: CGFloat,
+                                                    percentageDeltaOffset: CGFloat) -> UICollectionViewLayoutAttributes {
+        let attributes = UICollectionViewLayoutAttributes(forCellWith:indexPath)
+        let visibleIndex = indexPath.row - minVisibleIndex
+       
+        //Using this to fill up screen with card with fixed % of margin
+        attributes.size = CGSize(
+            width: (collectionView.bounds.width - ((collectionView.bounds.width * 2)/100)) ,
+            height: (collectionView.bounds.height - ((collectionView.bounds.height * 4)/100)))
+       
+        let midY = self.collectionView.bounds.midY
+        attributes.center = CGPoint(x: contentCenterX + spacing * CGFloat(visibleIndex),
+                                    y: midY + spacing * CGFloat(visibleIndex))
+        attributes.zIndex = maximumVisibleItems - visibleIndex
+       
+        attributes.transform = transform(atCurrentVisibleIndex: visibleIndex,
+                                         percentageOffset: percentageDeltaOffset)
+        switch visibleIndex {
+        case 0:
+            attributes.center.y -= deltaOffset
+            break
+        case 1..<maximumVisibleItems:
+            attributes.center.x -= spacing * percentageDeltaOffset
+            attributes.center.y -= spacing * percentageDeltaOffset
+           
+            if visibleIndex == maximumVisibleItems - 1 {
+                attributes.alpha = percentageDeltaOffset
+            }
+            break
+        default:
+            attributes.alpha = 0
+            break
+        }
+        return attributes
+    }
+}

From 9019fc67586d5e0f553388866f07121362004fc0 Mon Sep 17 00:00:00 2001
From: Viscmad <viscmadsingh93@gmail.com>
Date: Mon, 13 Nov 2017 15:05:51 +0530
Subject: [PATCH 2/6] Update CardsCollectionViewVerticleLayout.swift

*Renamed to VerticalCollectionViewLayout
*Fixed issue with scrolling to 1st index (line 58 changed)
---
 CardsCollectionViewVerticleLayout.swift | 82 +++++++++++++------------
 1 file changed, 44 insertions(+), 38 deletions(-)

diff --git a/CardsCollectionViewVerticleLayout.swift b/CardsCollectionViewVerticleLayout.swift
index 32dbf50..9bdd26b 100644
--- a/CardsCollectionViewVerticleLayout.swift
+++ b/CardsCollectionViewVerticleLayout.swift
@@ -1,9 +1,9 @@
 import UIKit
- 
-open class CardsCollectionViewLayout: UICollectionViewLayout {
-   
+
+open class VerticalCollectionViewLayout: UICollectionViewLayout {
+    
     // MARK: - Layout configuration
-   
+    
     //MARK: Size attribute
     //Using code :
     //    attributes.size = CGSize(
@@ -15,52 +15,58 @@ open class CardsCollectionViewLayout: UICollectionViewLayout {
     //            invalidateLayout()
     //        }
     //    }
-   
-    public var spacing: CGFloat = 10.0 {
+    
+    public var spacing: CGFloat = 0.0 {
         didSet{
             invalidateLayout()
         }
     }
-   
+    
     public var maximumVisibleItems: Int = 2 {
         didSet{
             invalidateLayout()
         }
     }
-   
+    
     // MARK: UICollectionViewLayout
-   
+    
     override open var collectionView: UICollectionView {
         return super.collectionView!
     }
-   
+    
     override open var collectionViewContentSize: CGSize {
         let itemsCount = CGFloat(collectionView.numberOfItems(inSection: 0))
-       
+        
+        //Converted from
+        //CGSize(width: collectionView.bounds.width,
+        //height: collectionView.bounds.height * itemsCount)
+        //to
         return CGSize(width: collectionView.bounds.width,
                       height: collectionView.bounds.height * itemsCount)
     }
-   
+    
     override open func prepare() {
         super.prepare()
         assert(collectionView.numberOfSections == 1, "Multiple sections aren't supported!")
     }
-   
+    
     override open func layoutAttributesForElements(in rect: CGRect) -> [UICollectionViewLayoutAttributes]? {
         let totalItemsCount = collectionView.numberOfItems(inSection: 0)
-       
-        let minVisibleIndex = max(Int(collectionView.contentOffset.x) / Int(collectionView.bounds.width), 0)
+        
+        //Converted from contentOffset.x to contentOffset.y
+        //and from collectionView.bounds.widt to collectionView.bounds.heigh
+        let minVisibleIndex = max(Int(collectionView.contentOffset.y) / Int(collectionView.bounds.height), 0)
         let maxVisibleIndex = min(minVisibleIndex + maximumVisibleItems, totalItemsCount)
-       
+        
         let contentCenterX = collectionView.contentOffset.x + (collectionView.bounds.width / 2.0)
-       
+        
         //Converted from contentOffset.x to contentOffset.y
         //and from collectionView.bounds.widt to collectionView.bounds.heigh
         let deltaOffset = Int(collectionView.contentOffset.y) % Int( collectionView.bounds.height)
         let percentageDeltaOffset = CGFloat(deltaOffset) / collectionView.bounds.height
-       
+        
         let visibleIndices = minVisibleIndex..<maxVisibleIndex
-       
+        
         let attributes: [UICollectionViewLayoutAttributes] = visibleIndices.map { index in
             let indexPath = IndexPath(item: index, section: 0)
             return computeLayoutAttributesForItem(indexPath: indexPath,
@@ -69,43 +75,43 @@ open class CardsCollectionViewLayout: UICollectionViewLayout {
                                                   deltaOffset: CGFloat(deltaOffset),
                                                   percentageDeltaOffset: percentageDeltaOffset)
         }
-       
+        
         return attributes
     }
-   
+    
     override open func layoutAttributesForItem(at indexPath: IndexPath) -> UICollectionViewLayoutAttributes? {
         let contentCenterX = collectionView.contentOffset.x + (collectionView.bounds.width / 2.0)
         let minVisibleIndex = Int(collectionView.contentOffset.x) / Int(collectionView.bounds.width)
-       
+        
         //Converted from contentOffset.x to contentOffset.y
         //and from collectionView.bounds.widt to collectionView.bounds.heigh
         let deltaOffset = Int(collectionView.contentOffset.y) % Int(collectionView.bounds.height)
         let percentageDeltaOffset = CGFloat(deltaOffset) / collectionView.bounds.height
-       
+        
         return computeLayoutAttributesForItem(indexPath: indexPath,
                                               minVisibleIndex: minVisibleIndex,
                                               contentCenterX: contentCenterX,
                                               deltaOffset: CGFloat(deltaOffset),
                                               percentageDeltaOffset: percentageDeltaOffset)
     }
-   
+    
     override open func shouldInvalidateLayout(forBoundsChange newBounds: CGRect) -> Bool {
         return true
     }
 }
- 
- 
+
+
 // MARK: - Layout computations
-fileprivate extension CardsCollectionViewLayout {
-   
+fileprivate extension VerticalCollectionViewLayout {
+    
     private func scale(at index: Int) -> CGFloat {
         let translatedCoefficient = CGFloat(index) - CGFloat(self.maximumVisibleItems) / 2
         return CGFloat(pow(0.95, translatedCoefficient))
     }
- 
+
     private func transform(atCurrentVisibleIndex visibleIndex: Int, percentageOffset: CGFloat) -> CGAffineTransform {
         var rawScale = visibleIndex < maximumVisibleItems ? scale(at: visibleIndex) : 1.0
- 
+
         if visibleIndex != 0 {
             let previousScale = scale(at: visibleIndex - 1)
             let delta = (previousScale - rawScale) * percentageOffset
@@ -113,7 +119,7 @@ fileprivate extension CardsCollectionViewLayout {
         }
         return CGAffineTransform(scaleX: rawScale, y: rawScale)
     }
-   
+    
     fileprivate func computeLayoutAttributesForItem(indexPath: IndexPath,
                                                     minVisibleIndex: Int,
                                                     contentCenterX: CGFloat,
@@ -124,16 +130,16 @@ fileprivate extension CardsCollectionViewLayout {
        
         //Using this to fill up screen with card with fixed % of margin
         attributes.size = CGSize(
-            width: (collectionView.bounds.width - ((collectionView.bounds.width * 2)/100)) ,
-            height: (collectionView.bounds.height - ((collectionView.bounds.height * 4)/100)))
-       
+            width: (collectionView.bounds.width - ((collectionView.bounds.width * 8)/100)) ,
+            height: (collectionView.bounds.height - ((collectionView.bounds.height * 8)/100)))
+        
         let midY = self.collectionView.bounds.midY
         attributes.center = CGPoint(x: contentCenterX + spacing * CGFloat(visibleIndex),
                                     y: midY + spacing * CGFloat(visibleIndex))
         attributes.zIndex = maximumVisibleItems - visibleIndex
-       
-        attributes.transform = transform(atCurrentVisibleIndex: visibleIndex,
-                                         percentageOffset: percentageDeltaOffset)
+        
+//        attributes.transform = transform(atCurrentVisibleIndex: visibleIndex,
+//                                         percentageOffset: percentageDeltaOffset)
         switch visibleIndex {
         case 0:
             attributes.center.y -= deltaOffset
@@ -141,7 +147,7 @@ fileprivate extension CardsCollectionViewLayout {
         case 1..<maximumVisibleItems:
             attributes.center.x -= spacing * percentageDeltaOffset
             attributes.center.y -= spacing * percentageDeltaOffset
-           
+            
             if visibleIndex == maximumVisibleItems - 1 {
                 attributes.alpha = percentageDeltaOffset
             }

From 2e631f96077a4bc25ea7d9252594058bf812a885 Mon Sep 17 00:00:00 2001
From: Filipp Fediakov <julik103@mail.ru>
Date: Wed, 3 Jan 2018 21:38:09 +0300
Subject: [PATCH 3/6] Remove redundant comments, change appearance

---
 CardsCollectionViewVerticleLayout.swift       | 57 ++++++-------------
 .../CardsExample.xcodeproj/project.pbxproj    |  8 +++
 .../CardsExample/ViewController.swift         |  1 +
 3 files changed, 26 insertions(+), 40 deletions(-)

diff --git a/CardsCollectionViewVerticleLayout.swift b/CardsCollectionViewVerticleLayout.swift
index 9bdd26b..711db02 100644
--- a/CardsCollectionViewVerticleLayout.swift
+++ b/CardsCollectionViewVerticleLayout.swift
@@ -4,25 +4,19 @@ open class VerticalCollectionViewLayout: UICollectionViewLayout {
     
     // MARK: - Layout configuration
     
-    //MARK: Size attribute
-    //Using code :
-    //    attributes.size = CGSize(
-    //    width: (collectionView.bounds.width - ((collectionView.bounds.width * 2)/100)) ,
-    //    height: (collectionView.bounds.height - ((collectionView.bounds.height * 4)/100)))
-    //Instead Calling
-    //    public var itemSize: CGSize = CGSize(width: 200, height: 300) {
-    //        didSet{
-    //            invalidateLayout()
-    //        }
-    //    }
+    public var itemSize: CGSize = CGSize(width: 200, height: 300) {
+      didSet{
+        invalidateLayout()
+      }
+    }
     
-    public var spacing: CGFloat = 0.0 {
+    public var spacing: CGPoint = CGPoint(x: 10.0, y: 20.0) {
         didSet{
             invalidateLayout()
         }
     }
     
-    public var maximumVisibleItems: Int = 2 {
+    public var maximumVisibleItems: Int = 4 {
         didSet{
             invalidateLayout()
         }
@@ -36,11 +30,6 @@ open class VerticalCollectionViewLayout: UICollectionViewLayout {
     
     override open var collectionViewContentSize: CGSize {
         let itemsCount = CGFloat(collectionView.numberOfItems(inSection: 0))
-        
-        //Converted from
-        //CGSize(width: collectionView.bounds.width,
-        //height: collectionView.bounds.height * itemsCount)
-        //to
         return CGSize(width: collectionView.bounds.width,
                       height: collectionView.bounds.height * itemsCount)
     }
@@ -52,19 +41,13 @@ open class VerticalCollectionViewLayout: UICollectionViewLayout {
     
     override open func layoutAttributesForElements(in rect: CGRect) -> [UICollectionViewLayoutAttributes]? {
         let totalItemsCount = collectionView.numberOfItems(inSection: 0)
-        
-        //Converted from contentOffset.x to contentOffset.y
-        //and from collectionView.bounds.widt to collectionView.bounds.heigh
+
         let minVisibleIndex = max(Int(collectionView.contentOffset.y) / Int(collectionView.bounds.height), 0)
         let maxVisibleIndex = min(minVisibleIndex + maximumVisibleItems, totalItemsCount)
         
         let contentCenterX = collectionView.contentOffset.x + (collectionView.bounds.width / 2.0)
-        
-        //Converted from contentOffset.x to contentOffset.y
-        //and from collectionView.bounds.widt to collectionView.bounds.heigh
-        let deltaOffset = Int(collectionView.contentOffset.y) % Int( collectionView.bounds.height)
+        let deltaOffset = Int(collectionView.contentOffset.y) % Int(collectionView.bounds.height)
         let percentageDeltaOffset = CGFloat(deltaOffset) / collectionView.bounds.height
-        
         let visibleIndices = minVisibleIndex..<maxVisibleIndex
         
         let attributes: [UICollectionViewLayoutAttributes] = visibleIndices.map { index in
@@ -82,12 +65,8 @@ open class VerticalCollectionViewLayout: UICollectionViewLayout {
     override open func layoutAttributesForItem(at indexPath: IndexPath) -> UICollectionViewLayoutAttributes? {
         let contentCenterX = collectionView.contentOffset.x + (collectionView.bounds.width / 2.0)
         let minVisibleIndex = Int(collectionView.contentOffset.x) / Int(collectionView.bounds.width)
-        
-        //Converted from contentOffset.x to contentOffset.y
-        //and from collectionView.bounds.widt to collectionView.bounds.heigh
         let deltaOffset = Int(collectionView.contentOffset.y) % Int(collectionView.bounds.height)
         let percentageDeltaOffset = CGFloat(deltaOffset) / collectionView.bounds.height
-        
         return computeLayoutAttributesForItem(indexPath: indexPath,
                                               minVisibleIndex: minVisibleIndex,
                                               contentCenterX: contentCenterX,
@@ -128,25 +107,23 @@ fileprivate extension VerticalCollectionViewLayout {
         let attributes = UICollectionViewLayoutAttributes(forCellWith:indexPath)
         let visibleIndex = indexPath.row - minVisibleIndex
        
-        //Using this to fill up screen with card with fixed % of margin
-        attributes.size = CGSize(
-            width: (collectionView.bounds.width - ((collectionView.bounds.width * 8)/100)) ,
-            height: (collectionView.bounds.height - ((collectionView.bounds.height * 8)/100)))
+        attributes.size = self.itemSize
         
         let midY = self.collectionView.bounds.midY
-        attributes.center = CGPoint(x: contentCenterX + spacing * CGFloat(visibleIndex),
-                                    y: midY + spacing * CGFloat(visibleIndex))
+        let midX = self.collectionView.bounds.midX
+        attributes.center = CGPoint(x: midX + spacing.x * CGFloat(visibleIndex),
+                                    y: midY + spacing.y * CGFloat(visibleIndex))
         attributes.zIndex = maximumVisibleItems - visibleIndex
         
-//        attributes.transform = transform(atCurrentVisibleIndex: visibleIndex,
-//                                         percentageOffset: percentageDeltaOffset)
+        attributes.transform = transform(atCurrentVisibleIndex: visibleIndex,
+                                         percentageOffset: percentageDeltaOffset)
         switch visibleIndex {
         case 0:
             attributes.center.y -= deltaOffset
             break
         case 1..<maximumVisibleItems:
-            attributes.center.x -= spacing * percentageDeltaOffset
-            attributes.center.y -= spacing * percentageDeltaOffset
+            attributes.center.x -= spacing.x * percentageDeltaOffset
+            attributes.center.y -= spacing.y * percentageDeltaOffset
             
             if visibleIndex == maximumVisibleItems - 1 {
                 attributes.alpha = percentageDeltaOffset
diff --git a/CardsExample/CardsExample.xcodeproj/project.pbxproj b/CardsExample/CardsExample.xcodeproj/project.pbxproj
index 8d29b2e..07dd5a9 100644
--- a/CardsExample/CardsExample.xcodeproj/project.pbxproj
+++ b/CardsExample/CardsExample.xcodeproj/project.pbxproj
@@ -13,6 +13,7 @@
 		365EC0BF1FABCC9200583152 /* Assets.xcassets in Resources */ = {isa = PBXBuildFile; fileRef = 365EC0BE1FABCC9200583152 /* Assets.xcassets */; };
 		365EC0C21FABCC9200583152 /* LaunchScreen.storyboard in Resources */ = {isa = PBXBuildFile; fileRef = 365EC0C01FABCC9200583152 /* LaunchScreen.storyboard */; };
 		365EC0CA1FABCD1500583152 /* CardsCollectionViewLayout.swift in Sources */ = {isa = PBXBuildFile; fileRef = 365EC0C91FABCD1400583152 /* CardsCollectionViewLayout.swift */; };
+		36B5506A1FCE28EB005BBDD5 /* CardsCollectionViewVerticleLayout.swift in Sources */ = {isa = PBXBuildFile; fileRef = 36B550691FCE28EB005BBDD5 /* CardsCollectionViewVerticleLayout.swift */; };
 /* End PBXBuildFile section */
 
 /* Begin PBXFileReference section */
@@ -24,6 +25,7 @@
 		365EC0C11FABCC9200583152 /* Base */ = {isa = PBXFileReference; lastKnownFileType = file.storyboard; name = Base; path = Base.lproj/LaunchScreen.storyboard; sourceTree = "<group>"; };
 		365EC0C31FABCC9200583152 /* Info.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; path = Info.plist; sourceTree = "<group>"; };
 		365EC0C91FABCD1400583152 /* CardsCollectionViewLayout.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; name = CardsCollectionViewLayout.swift; path = ../../CardsCollectionViewLayout.swift; sourceTree = "<group>"; };
+		36B550691FCE28EB005BBDD5 /* CardsCollectionViewVerticleLayout.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; name = CardsCollectionViewVerticleLayout.swift; path = ../../CardsCollectionViewVerticleLayout.swift; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
 /* Begin PBXFrameworksBuildPhase section */
@@ -56,6 +58,7 @@
 		365EC0B61FABCC9200583152 /* CardsExample */ = {
 			isa = PBXGroup;
 			children = (
+				36B550691FCE28EB005BBDD5 /* CardsCollectionViewVerticleLayout.swift */,
 				365EC0C91FABCD1400583152 /* CardsCollectionViewLayout.swift */,
 				365EC0B71FABCC9200583152 /* AppDelegate.swift */,
 				365EC0B91FABCC9200583152 /* ViewController.swift */,
@@ -141,6 +144,7 @@
 			files = (
 				365EC0BA1FABCC9200583152 /* ViewController.swift in Sources */,
 				365EC0CA1FABCD1500583152 /* CardsCollectionViewLayout.swift in Sources */,
+				36B5506A1FCE28EB005BBDD5 /* CardsCollectionViewVerticleLayout.swift in Sources */,
 				365EC0B81FABCC9200583152 /* AppDelegate.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
@@ -278,12 +282,14 @@
 			isa = XCBuildConfiguration;
 			buildSettings = {
 				ASSETCATALOG_COMPILER_APPICON_NAME = AppIcon;
+				"CODE_SIGN_IDENTITY[sdk=iphoneos*]" = "iPhone Developer";
 				CODE_SIGN_STYLE = Automatic;
 				DEVELOPMENT_TEAM = 8CAP6SYJTB;
 				INFOPLIST_FILE = CardsExample/Info.plist;
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks";
 				PRODUCT_BUNDLE_IDENTIFIER = filletofish.CardsExample;
 				PRODUCT_NAME = "$(TARGET_NAME)";
+				PROVISIONING_PROFILE_SPECIFIER = "";
 				SWIFT_VERSION = 3.0;
 				TARGETED_DEVICE_FAMILY = "1,2";
 			};
@@ -293,12 +299,14 @@
 			isa = XCBuildConfiguration;
 			buildSettings = {
 				ASSETCATALOG_COMPILER_APPICON_NAME = AppIcon;
+				"CODE_SIGN_IDENTITY[sdk=iphoneos*]" = "iPhone Developer";
 				CODE_SIGN_STYLE = Automatic;
 				DEVELOPMENT_TEAM = 8CAP6SYJTB;
 				INFOPLIST_FILE = CardsExample/Info.plist;
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks";
 				PRODUCT_BUNDLE_IDENTIFIER = filletofish.CardsExample;
 				PRODUCT_NAME = "$(TARGET_NAME)";
+				PROVISIONING_PROFILE_SPECIFIER = "";
 				SWIFT_VERSION = 3.0;
 				TARGETED_DEVICE_FAMILY = "1,2";
 			};
diff --git a/CardsExample/CardsExample/ViewController.swift b/CardsExample/CardsExample/ViewController.swift
index 429e6b2..540b048 100644
--- a/CardsExample/CardsExample/ViewController.swift
+++ b/CardsExample/CardsExample/ViewController.swift
@@ -19,6 +19,7 @@ class ViewController: UIViewController, UICollectionViewDataSource, UICollection
     collectionView.delegate = self
     collectionView.isPagingEnabled = true
     collectionView.showsHorizontalScrollIndicator = false
+    collectionView.showsVerticalScrollIndicator = false
   }
 
   var colors: [UIColor]  = [

From bd010a0db3ebaad85a37280c9b5fb57c527bf07a Mon Sep 17 00:00:00 2001
From: Filipp Fediakov <julik103@mail.ru>
Date: Wed, 3 Jan 2018 22:22:48 +0300
Subject: [PATCH 4/6] Renamed classes, ident horizontal layout with 4 spaces

---
 CardsCollectionViewHorizontalLayout.swift     | 149 ++++++++++++++++++
 CardsCollectionViewLayout.swift               | 148 -----------------
 CardsCollectionViewVerticleLayout.swift       |  15 +-
 .../CardsExample.xcodeproj/project.pbxproj    |   8 +-
 .../CardsExample/ViewController.swift         |   2 +-
 5 files changed, 167 insertions(+), 155 deletions(-)
 create mode 100644 CardsCollectionViewHorizontalLayout.swift
 delete mode 100644 CardsCollectionViewLayout.swift

diff --git a/CardsCollectionViewHorizontalLayout.swift b/CardsCollectionViewHorizontalLayout.swift
new file mode 100644
index 0000000..0b55105
--- /dev/null
+++ b/CardsCollectionViewHorizontalLayout.swift
@@ -0,0 +1,149 @@
+//
+//  CardsCollectionViewHorizontalLayout.swift
+//  CardsLayout
+//
+//  Created by Filipp Fediakov on 18.08.17.
+//  Copyright © 2017 filletofish. All rights reserved.
+//
+
+import UIKit
+
+open class CardsCollectionViewHorizontalLayout: UICollectionViewLayout {
+
+    // MARK: - Layout configuration
+
+    public var itemSize: CGSize = CGSize(width: 200, height: 300) {
+        didSet {
+            invalidateLayout()
+        }
+    }
+
+    public var spacing: CGFloat = 10.0 {
+        didSet {
+            invalidateLayout()
+        }
+    }
+
+    public var maximumVisibleItems: Int = 4 {
+        didSet {
+            invalidateLayout()
+        }
+    }
+
+    // MARK: UICollectionViewLayout
+
+    override open var collectionView: UICollectionView {
+        return super.collectionView!
+    }
+
+    override open var collectionViewContentSize: CGSize {
+        let itemsCount = CGFloat(collectionView.numberOfItems(inSection: 0))
+        return CGSize(width: collectionView.bounds.width * itemsCount,
+                      height: collectionView.bounds.height)
+    }
+
+    override open func prepare() {
+        super.prepare()
+        assert(collectionView.numberOfSections == 1, "Multiple sections aren't supported!")
+    }
+
+    override open func layoutAttributesForElements(in rect: CGRect) -> [UICollectionViewLayoutAttributes]? {
+        let totalItemsCount = collectionView.numberOfItems(inSection: 0)
+
+        let minVisibleIndex = max(Int(collectionView.contentOffset.x) / Int(collectionView.bounds.width), 0)
+        let maxVisibleIndex = min(minVisibleIndex + maximumVisibleItems, totalItemsCount)
+
+        let contentCenterX = collectionView.contentOffset.x + (collectionView.bounds.width / 2.0)
+
+        let deltaOffset = Int(collectionView.contentOffset.x) % Int(collectionView.bounds.width)
+
+        let percentageDeltaOffset = CGFloat(deltaOffset) / collectionView.bounds.width
+
+        let visibleIndices = minVisibleIndex..<maxVisibleIndex
+
+        let attributes: [UICollectionViewLayoutAttributes] = visibleIndices.map { index in
+            let indexPath = IndexPath(item: index, section: 0)
+            return computeLayoutAttributesForItem(indexPath: indexPath,
+                                                  minVisibleIndex: minVisibleIndex,
+                                                  contentCenterX: contentCenterX,
+                                                  deltaOffset: CGFloat(deltaOffset),
+                                                  percentageDeltaOffset: percentageDeltaOffset)
+        }
+
+        return attributes
+    }
+
+    override open func layoutAttributesForItem(at indexPath: IndexPath) -> UICollectionViewLayoutAttributes? {
+        let contentCenterX = collectionView.contentOffset.x + (collectionView.bounds.width / 2.0)
+        let minVisibleIndex = Int(collectionView.contentOffset.x) / Int(collectionView.bounds.width)
+        let deltaOffset = Int(collectionView.contentOffset.x) % Int(collectionView.bounds.width)
+        let percentageDeltaOffset = CGFloat(deltaOffset) / collectionView.bounds.width
+        return computeLayoutAttributesForItem(indexPath: indexPath,
+                                              minVisibleIndex: minVisibleIndex,
+                                              contentCenterX: contentCenterX,
+                                              deltaOffset: CGFloat(deltaOffset),
+                                              percentageDeltaOffset: percentageDeltaOffset)
+    }
+
+    override open func shouldInvalidateLayout(forBoundsChange newBounds: CGRect) -> Bool {
+        return true
+    }
+}
+
+
+// MARK: - Layout computations
+
+fileprivate extension CardsCollectionViewHorizontalLayout {
+
+    private func scale(at index: Int) -> CGFloat {
+        let translatedCoefficient = CGFloat(index) - CGFloat(self.maximumVisibleItems) / 2
+        return CGFloat(pow(0.95, translatedCoefficient))
+    }
+
+    private func transform(atCurrentVisibleIndex visibleIndex: Int, percentageOffset: CGFloat) -> CGAffineTransform {
+        var rawScale = visibleIndex < maximumVisibleItems ? scale(at: visibleIndex) : 1.0
+
+        if visibleIndex != 0 {
+            let previousScale = scale(at: visibleIndex - 1)
+            let delta = (previousScale - rawScale) * percentageOffset
+            rawScale += delta
+        }
+        return CGAffineTransform(scaleX: rawScale, y: rawScale)
+    }
+
+    fileprivate func computeLayoutAttributesForItem(indexPath: IndexPath,
+                                                    minVisibleIndex: Int,
+                                                    contentCenterX: CGFloat,
+                                                    deltaOffset: CGFloat,
+                                                    percentageDeltaOffset: CGFloat) -> UICollectionViewLayoutAttributes {
+        let attributes = UICollectionViewLayoutAttributes(forCellWith:indexPath)
+        let visibleIndex = indexPath.row - minVisibleIndex
+        attributes.size = itemSize
+        let midY = self.collectionView.bounds.midY
+        attributes.center = CGPoint(x: contentCenterX + spacing * CGFloat(visibleIndex),
+                                    y: midY + spacing * CGFloat(visibleIndex))
+        attributes.zIndex = maximumVisibleItems - visibleIndex
+
+        attributes.transform = transform(atCurrentVisibleIndex: visibleIndex,
+                                         percentageOffset: percentageDeltaOffset)
+        switch visibleIndex {
+        case 0:
+            attributes.center.x -= deltaOffset
+            break
+        case 1..<maximumVisibleItems:
+            attributes.center.x -= spacing * percentageDeltaOffset
+            attributes.center.y -= spacing * percentageDeltaOffset
+
+
+            if visibleIndex == maximumVisibleItems - 1 {
+                attributes.alpha = percentageDeltaOffset
+            }
+            break
+        default:
+            attributes.alpha = 0
+            break
+        }
+        return attributes
+    }
+}
+
diff --git a/CardsCollectionViewLayout.swift b/CardsCollectionViewLayout.swift
deleted file mode 100644
index 82da436..0000000
--- a/CardsCollectionViewLayout.swift
+++ /dev/null
@@ -1,148 +0,0 @@
-//
-//  CardsCollectionViewLayout.swift
-//  CardsExample
-//
-//  Created by Filipp Fediakov on 18.08.17.
-//  Copyright © 2017 filletofish. All rights reserved.
-//
-
-import UIKit
-
-open class CardsCollectionViewLayout: UICollectionViewLayout {
-
-  // MARK: - Layout configuration
-
-  public var itemSize: CGSize = CGSize(width: 200, height: 300) {
-    didSet{
-      invalidateLayout()
-    }
-  }
-
-  public var spacing: CGFloat = 10.0 {
-    didSet{
-      invalidateLayout()
-    }
-  }
-
-  public var maximumVisibleItems: Int = 4 {
-    didSet{
-      invalidateLayout()
-    }
-  }
-
-  // MARK: UICollectionViewLayout
-
-  override open var collectionView: UICollectionView {
-    return super.collectionView!
-  }
-
-  override open var collectionViewContentSize: CGSize {
-    let itemsCount = CGFloat(collectionView.numberOfItems(inSection: 0))
-    return CGSize(width: collectionView.bounds.width * itemsCount,
-                  height: collectionView.bounds.height)
-  }
-
-  override open func prepare() {
-    super.prepare()
-    assert(collectionView.numberOfSections == 1, "Multiple sections aren't supported!")
-  }
-
-  override open func layoutAttributesForElements(in rect: CGRect) -> [UICollectionViewLayoutAttributes]? {
-    let totalItemsCount = collectionView.numberOfItems(inSection: 0)
-
-    let minVisibleIndex = max(Int(collectionView.contentOffset.x) / Int(collectionView.bounds.width), 0)
-    let maxVisibleIndex = min(minVisibleIndex + maximumVisibleItems, totalItemsCount)
-
-    let contentCenterX = collectionView.contentOffset.x + (collectionView.bounds.width / 2.0)
-
-    let deltaOffset = Int(collectionView.contentOffset.x) % Int(collectionView.bounds.width)
-
-    let percentageDeltaOffset = CGFloat(deltaOffset) / collectionView.bounds.width
-
-    let visibleIndices = minVisibleIndex..<maxVisibleIndex
-
-    let attributes: [UICollectionViewLayoutAttributes] = visibleIndices.map { index in
-      let indexPath = IndexPath(item: index, section: 0)
-      return computeLayoutAttributesForItem(indexPath: indexPath,
-                                     minVisibleIndex: minVisibleIndex,
-                                     contentCenterX: contentCenterX,
-                                     deltaOffset: CGFloat(deltaOffset),
-                                     percentageDeltaOffset: percentageDeltaOffset)
-    }
-
-    return attributes
-  }
-
-  override open func layoutAttributesForItem(at indexPath: IndexPath) -> UICollectionViewLayoutAttributes? {
-    let contentCenterX = collectionView.contentOffset.x + (collectionView.bounds.width / 2.0)
-    let minVisibleIndex = Int(collectionView.contentOffset.x) / Int(collectionView.bounds.width)
-    let deltaOffset = Int(collectionView.contentOffset.x) % Int(collectionView.bounds.width)
-    let percentageDeltaOffset = CGFloat(deltaOffset) / collectionView.bounds.width
-    return computeLayoutAttributesForItem(indexPath: indexPath,
-                                   minVisibleIndex: minVisibleIndex,
-                                   contentCenterX: contentCenterX,
-                                   deltaOffset: CGFloat(deltaOffset),
-                                   percentageDeltaOffset: percentageDeltaOffset)
-  }
-
-  override open func shouldInvalidateLayout(forBoundsChange newBounds: CGRect) -> Bool {
-    return true
-  }
-}
-
-
-// MARK: - Layout computations
-
-fileprivate extension CardsCollectionViewLayout {
-
-  private func scale(at index: Int) -> CGFloat {
-    let translatedCoefficient = CGFloat(index) - CGFloat(self.maximumVisibleItems) / 2
-    return CGFloat(pow(0.95, translatedCoefficient))
-  }
-
-  private func transform(atCurrentVisibleIndex visibleIndex: Int, percentageOffset: CGFloat) -> CGAffineTransform {
-    var rawScale = visibleIndex < maximumVisibleItems ? scale(at: visibleIndex) : 1.0
-
-    if visibleIndex != 0 {
-      let previousScale = scale(at: visibleIndex - 1)
-      let delta = (previousScale - rawScale) * percentageOffset
-      rawScale += delta
-    }
-    return CGAffineTransform(scaleX: rawScale, y: rawScale)
-  }
-
-  fileprivate func computeLayoutAttributesForItem(indexPath: IndexPath,
-                                       minVisibleIndex: Int,
-                                       contentCenterX: CGFloat,
-                                       deltaOffset: CGFloat,
-                                       percentageDeltaOffset: CGFloat) -> UICollectionViewLayoutAttributes {
-    let attributes = UICollectionViewLayoutAttributes(forCellWith:indexPath)
-    let visibleIndex = indexPath.row - minVisibleIndex
-    attributes.size = itemSize
-    let midY = self.collectionView.bounds.midY
-    attributes.center = CGPoint(x: contentCenterX + spacing * CGFloat(visibleIndex),
-                                y: midY + spacing * CGFloat(visibleIndex))
-    attributes.zIndex = maximumVisibleItems - visibleIndex
-
-    attributes.transform = transform(atCurrentVisibleIndex: visibleIndex,
-                                          percentageOffset: percentageDeltaOffset)
-    switch visibleIndex {
-    case 0:
-      attributes.center.x -= deltaOffset
-      break
-    case 1..<maximumVisibleItems:
-      attributes.center.x -= spacing * percentageDeltaOffset
-      attributes.center.y -= spacing * percentageDeltaOffset
-
-
-      if visibleIndex == maximumVisibleItems - 1 {
-        attributes.alpha = percentageDeltaOffset
-      }
-      break
-    default:
-      attributes.alpha = 0
-      break
-    }
-    return attributes
-  }
-}
diff --git a/CardsCollectionViewVerticleLayout.swift b/CardsCollectionViewVerticleLayout.swift
index 711db02..642f948 100644
--- a/CardsCollectionViewVerticleLayout.swift
+++ b/CardsCollectionViewVerticleLayout.swift
@@ -1,6 +1,14 @@
+//
+//  CardsCollectionViewVerticleLayout.swift
+//  CardsLayout
+//
+//  Created by Filipp Fediakov on 18.08.17.
+//  Copyright © 2017 filletofish. All rights reserved.
+//
+
 import UIKit
 
-open class VerticalCollectionViewLayout: UICollectionViewLayout {
+open class CardsCollectionViewVerticleLayout: UICollectionViewLayout {
     
     // MARK: - Layout configuration
     
@@ -49,6 +57,7 @@ open class VerticalCollectionViewLayout: UICollectionViewLayout {
         let deltaOffset = Int(collectionView.contentOffset.y) % Int(collectionView.bounds.height)
         let percentageDeltaOffset = CGFloat(deltaOffset) / collectionView.bounds.height
         let visibleIndices = minVisibleIndex..<maxVisibleIndex
+        print("Called layoutAttributesForElements rect = \(rect), delta = \(deltaOffset), percentage = \(percentageDeltaOffset)%")
         
         let attributes: [UICollectionViewLayoutAttributes] = visibleIndices.map { index in
             let indexPath = IndexPath(item: index, section: 0)
@@ -63,10 +72,12 @@ open class VerticalCollectionViewLayout: UICollectionViewLayout {
     }
     
     override open func layoutAttributesForItem(at indexPath: IndexPath) -> UICollectionViewLayoutAttributes? {
+
         let contentCenterX = collectionView.contentOffset.x + (collectionView.bounds.width / 2.0)
         let minVisibleIndex = Int(collectionView.contentOffset.x) / Int(collectionView.bounds.width)
         let deltaOffset = Int(collectionView.contentOffset.y) % Int(collectionView.bounds.height)
         let percentageDeltaOffset = CGFloat(deltaOffset) / collectionView.bounds.height
+        print("Called layoutAttributesForItem IP = \(indexPath), delta = \(deltaOffset), percentage = \(percentageDeltaOffset)%")
         return computeLayoutAttributesForItem(indexPath: indexPath,
                                               minVisibleIndex: minVisibleIndex,
                                               contentCenterX: contentCenterX,
@@ -81,7 +92,7 @@ open class VerticalCollectionViewLayout: UICollectionViewLayout {
 
 
 // MARK: - Layout computations
-fileprivate extension VerticalCollectionViewLayout {
+fileprivate extension CardsCollectionViewVerticleLayout {
     
     private func scale(at index: Int) -> CGFloat {
         let translatedCoefficient = CGFloat(index) - CGFloat(self.maximumVisibleItems) / 2
diff --git a/CardsExample/CardsExample.xcodeproj/project.pbxproj b/CardsExample/CardsExample.xcodeproj/project.pbxproj
index 07dd5a9..f7cede8 100644
--- a/CardsExample/CardsExample.xcodeproj/project.pbxproj
+++ b/CardsExample/CardsExample.xcodeproj/project.pbxproj
@@ -12,7 +12,7 @@
 		365EC0BD1FABCC9200583152 /* Main.storyboard in Resources */ = {isa = PBXBuildFile; fileRef = 365EC0BB1FABCC9200583152 /* Main.storyboard */; };
 		365EC0BF1FABCC9200583152 /* Assets.xcassets in Resources */ = {isa = PBXBuildFile; fileRef = 365EC0BE1FABCC9200583152 /* Assets.xcassets */; };
 		365EC0C21FABCC9200583152 /* LaunchScreen.storyboard in Resources */ = {isa = PBXBuildFile; fileRef = 365EC0C01FABCC9200583152 /* LaunchScreen.storyboard */; };
-		365EC0CA1FABCD1500583152 /* CardsCollectionViewLayout.swift in Sources */ = {isa = PBXBuildFile; fileRef = 365EC0C91FABCD1400583152 /* CardsCollectionViewLayout.swift */; };
+		365EC0CA1FABCD1500583152 /* CardsCollectionViewHorizontalLayout.swift in Sources */ = {isa = PBXBuildFile; fileRef = 365EC0C91FABCD1400583152 /* CardsCollectionViewHorizontalLayout.swift */; };
 		36B5506A1FCE28EB005BBDD5 /* CardsCollectionViewVerticleLayout.swift in Sources */ = {isa = PBXBuildFile; fileRef = 36B550691FCE28EB005BBDD5 /* CardsCollectionViewVerticleLayout.swift */; };
 /* End PBXBuildFile section */
 
@@ -24,7 +24,7 @@
 		365EC0BE1FABCC9200583152 /* Assets.xcassets */ = {isa = PBXFileReference; lastKnownFileType = folder.assetcatalog; path = Assets.xcassets; sourceTree = "<group>"; };
 		365EC0C11FABCC9200583152 /* Base */ = {isa = PBXFileReference; lastKnownFileType = file.storyboard; name = Base; path = Base.lproj/LaunchScreen.storyboard; sourceTree = "<group>"; };
 		365EC0C31FABCC9200583152 /* Info.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; path = Info.plist; sourceTree = "<group>"; };
-		365EC0C91FABCD1400583152 /* CardsCollectionViewLayout.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; name = CardsCollectionViewLayout.swift; path = ../../CardsCollectionViewLayout.swift; sourceTree = "<group>"; };
+		365EC0C91FABCD1400583152 /* CardsCollectionViewHorizontalLayout.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; name = CardsCollectionViewHorizontalLayout.swift; path = ../../CardsCollectionViewHorizontalLayout.swift; sourceTree = "<group>"; };
 		36B550691FCE28EB005BBDD5 /* CardsCollectionViewVerticleLayout.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; name = CardsCollectionViewVerticleLayout.swift; path = ../../CardsCollectionViewVerticleLayout.swift; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
@@ -59,7 +59,7 @@
 			isa = PBXGroup;
 			children = (
 				36B550691FCE28EB005BBDD5 /* CardsCollectionViewVerticleLayout.swift */,
-				365EC0C91FABCD1400583152 /* CardsCollectionViewLayout.swift */,
+				365EC0C91FABCD1400583152 /* CardsCollectionViewHorizontalLayout.swift */,
 				365EC0B71FABCC9200583152 /* AppDelegate.swift */,
 				365EC0B91FABCC9200583152 /* ViewController.swift */,
 				365EC0BB1FABCC9200583152 /* Main.storyboard */,
@@ -143,7 +143,7 @@
 			buildActionMask = 2147483647;
 			files = (
 				365EC0BA1FABCC9200583152 /* ViewController.swift in Sources */,
-				365EC0CA1FABCD1500583152 /* CardsCollectionViewLayout.swift in Sources */,
+				365EC0CA1FABCD1500583152 /* CardsCollectionViewHorizontalLayout.swift in Sources */,
 				36B5506A1FCE28EB005BBDD5 /* CardsCollectionViewVerticleLayout.swift in Sources */,
 				365EC0B81FABCC9200583152 /* AppDelegate.swift in Sources */,
 			);
diff --git a/CardsExample/CardsExample/ViewController.swift b/CardsExample/CardsExample/ViewController.swift
index 540b048..5f8c3a0 100644
--- a/CardsExample/CardsExample/ViewController.swift
+++ b/CardsExample/CardsExample/ViewController.swift
@@ -14,7 +14,7 @@ class ViewController: UIViewController, UICollectionViewDataSource, UICollection
 
   override func viewDidLoad() {
     super.viewDidLoad()
-    collectionView.collectionViewLayout = CardsCollectionViewLayout()
+    collectionView.collectionViewLayout = CardsCollectionViewHorizontalLayout()
     collectionView.dataSource = self
     collectionView.delegate = self
     collectionView.isPagingEnabled = true

From 3f56b5c791e79a695f5dbb7666a5cf14bc6b237e Mon Sep 17 00:00:00 2001
From: Filipp Fediakov <julik103@mail.ru>
Date: Wed, 3 Jan 2018 22:54:53 +0300
Subject: [PATCH 5/6] Refactor code between two layouts

---
 CardsCollectionViewHorizontalLayout.swift | 133 ++++++++++------------
 CardsCollectionViewVerticleLayout.swift   |  93 +++++----------
 2 files changed, 88 insertions(+), 138 deletions(-)

diff --git a/CardsCollectionViewHorizontalLayout.swift b/CardsCollectionViewHorizontalLayout.swift
index 0b55105..def49d2 100644
--- a/CardsCollectionViewHorizontalLayout.swift
+++ b/CardsCollectionViewHorizontalLayout.swift
@@ -2,15 +2,23 @@
 //  CardsCollectionViewHorizontalLayout.swift
 //  CardsLayout
 //
-//  Created by Filipp Fediakov on 18.08.17.
-//  Copyright © 2017 filletofish. All rights reserved.
+//  Created by Filipp Fediakov on 03.01.18.
+//  Copyright © 2018 filletofish. All rights reserved.
 //
 
 import UIKit
 
-open class CardsCollectionViewHorizontalLayout: UICollectionViewLayout {
 
-    // MARK: - Layout configuration
+protocol CardsCollectionViewLayout {
+    var itemSize: CGSize { get set }
+    var spacing: CGPoint { get set }
+    var maximumVisibleItems: Int { get set }
+}
+
+
+open class CardsCollectionViewHorizontalLayout: UICollectionViewLayout, CardsCollectionViewLayout {
+
+    // MARK: Layout configuration
 
     public var itemSize: CGSize = CGSize(width: 200, height: 300) {
         didSet {
@@ -18,7 +26,7 @@ open class CardsCollectionViewHorizontalLayout: UICollectionViewLayout {
         }
     }
 
-    public var spacing: CGFloat = 10.0 {
+    public var spacing: CGPoint = CGPoint(x: 10.0, y: 10.0) {
         didSet {
             invalidateLayout()
         }
@@ -30,7 +38,7 @@ open class CardsCollectionViewHorizontalLayout: UICollectionViewLayout {
         }
     }
 
-    // MARK: UICollectionViewLayout
+    // MARK: - UICollectionViewLayout
 
     override open var collectionView: UICollectionView {
         return super.collectionView!
@@ -49,101 +57,84 @@ open class CardsCollectionViewHorizontalLayout: UICollectionViewLayout {
 
     override open func layoutAttributesForElements(in rect: CGRect) -> [UICollectionViewLayoutAttributes]? {
         let totalItemsCount = collectionView.numberOfItems(inSection: 0)
-
         let minVisibleIndex = max(Int(collectionView.contentOffset.x) / Int(collectionView.bounds.width), 0)
         let maxVisibleIndex = min(minVisibleIndex + maximumVisibleItems, totalItemsCount)
-
-        let contentCenterX = collectionView.contentOffset.x + (collectionView.bounds.width / 2.0)
-
-        let deltaOffset = Int(collectionView.contentOffset.x) % Int(collectionView.bounds.width)
-
-        let percentageDeltaOffset = CGFloat(deltaOffset) / collectionView.bounds.width
-
         let visibleIndices = minVisibleIndex..<maxVisibleIndex
-
-        let attributes: [UICollectionViewLayoutAttributes] = visibleIndices.map { index in
+        let attributes: [UICollectionViewLayoutAttributes?] = visibleIndices.map { index in
             let indexPath = IndexPath(item: index, section: 0)
-            return computeLayoutAttributesForItem(indexPath: indexPath,
-                                                  minVisibleIndex: minVisibleIndex,
-                                                  contentCenterX: contentCenterX,
-                                                  deltaOffset: CGFloat(deltaOffset),
-                                                  percentageDeltaOffset: percentageDeltaOffset)
+            return self.layoutAttributesForItem(at: indexPath)
         }
-
-        return attributes
+        let filteredAttributes = attributes.flatMap { $0 }
+        return filteredAttributes
     }
 
     override open func layoutAttributesForItem(at indexPath: IndexPath) -> UICollectionViewLayoutAttributes? {
-        let contentCenterX = collectionView.contentOffset.x + (collectionView.bounds.width / 2.0)
         let minVisibleIndex = Int(collectionView.contentOffset.x) / Int(collectionView.bounds.width)
-        let deltaOffset = Int(collectionView.contentOffset.x) % Int(collectionView.bounds.width)
+        let deltaOffset = CGFloat(Int(collectionView.contentOffset.x) % Int(collectionView.bounds.width))
         let percentageDeltaOffset = CGFloat(deltaOffset) / collectionView.bounds.width
-        return computeLayoutAttributesForItem(indexPath: indexPath,
-                                              minVisibleIndex: minVisibleIndex,
-                                              contentCenterX: contentCenterX,
-                                              deltaOffset: CGFloat(deltaOffset),
-                                              percentageDeltaOffset: percentageDeltaOffset)
-    }
-
-    override open func shouldInvalidateLayout(forBoundsChange newBounds: CGRect) -> Bool {
-        return true
-    }
-}
-
-
-// MARK: - Layout computations
-
-fileprivate extension CardsCollectionViewHorizontalLayout {
-
-    private func scale(at index: Int) -> CGFloat {
-        let translatedCoefficient = CGFloat(index) - CGFloat(self.maximumVisibleItems) / 2
-        return CGFloat(pow(0.95, translatedCoefficient))
-    }
-
-    private func transform(atCurrentVisibleIndex visibleIndex: Int, percentageOffset: CGFloat) -> CGAffineTransform {
-        var rawScale = visibleIndex < maximumVisibleItems ? scale(at: visibleIndex) : 1.0
-
-        if visibleIndex != 0 {
-            let previousScale = scale(at: visibleIndex - 1)
-            let delta = (previousScale - rawScale) * percentageOffset
-            rawScale += delta
-        }
-        return CGAffineTransform(scaleX: rawScale, y: rawScale)
-    }
+        let visibleIndex = indexPath.row - minVisibleIndex
 
-    fileprivate func computeLayoutAttributesForItem(indexPath: IndexPath,
-                                                    minVisibleIndex: Int,
-                                                    contentCenterX: CGFloat,
-                                                    deltaOffset: CGFloat,
-                                                    percentageDeltaOffset: CGFloat) -> UICollectionViewLayoutAttributes {
         let attributes = UICollectionViewLayoutAttributes(forCellWith:indexPath)
-        let visibleIndex = indexPath.row - minVisibleIndex
         attributes.size = itemSize
         let midY = self.collectionView.bounds.midY
-        attributes.center = CGPoint(x: contentCenterX + spacing * CGFloat(visibleIndex),
-                                    y: midY + spacing * CGFloat(visibleIndex))
+        let midX = self.collectionView.bounds.midX
+        attributes.center = CGPoint(x: midX + spacing.x * CGFloat(visibleIndex),
+                                    y: midY + spacing.y * CGFloat(visibleIndex))
         attributes.zIndex = maximumVisibleItems - visibleIndex
+        attributes.transform = scaleTransform(forVisibleIndex: visibleIndex,
+                                              percentageOffset: percentageDeltaOffset)
+
 
-        attributes.transform = transform(atCurrentVisibleIndex: visibleIndex,
-                                         percentageOffset: percentageDeltaOffset)
         switch visibleIndex {
         case 0:
             attributes.center.x -= deltaOffset
+            attributes.isHidden = false
             break
         case 1..<maximumVisibleItems:
-            attributes.center.x -= spacing * percentageDeltaOffset
-            attributes.center.y -= spacing * percentageDeltaOffset
-
-
+            attributes.center.x -= spacing.x * percentageDeltaOffset
+            attributes.center.y -= spacing.y * percentageDeltaOffset
             if visibleIndex == maximumVisibleItems - 1 {
                 attributes.alpha = percentageDeltaOffset
+            } else {
+                attributes.alpha = 1.0
             }
+
+            attributes.isHidden = false
             break
         default:
             attributes.alpha = 0
+            attributes.isHidden = true
             break
         }
         return attributes
     }
+
+    override open func shouldInvalidateLayout(forBoundsChange newBounds: CGRect) -> Bool {
+        return true
+    }
 }
 
+
+extension CardsCollectionViewLayout {
+    private func scale(at index: Int) -> CGFloat {
+        let translatedCoefficient = CGFloat(index) - CGFloat(self.maximumVisibleItems) / 2
+        return CGFloat(pow(0.95, translatedCoefficient))
+    }
+
+    func scaleTransform(forVisibleIndex visibleIndex: Int, percentageOffset: CGFloat) -> CGAffineTransform {
+        guard visibleIndex != 0 else {
+            let scaleAtZeroIndex = scale(at: visibleIndex)
+            return CGAffineTransform(scaleX: scaleAtZeroIndex, y: scaleAtZeroIndex)
+        }
+
+        guard visibleIndex < maximumVisibleItems else {
+            return CGAffineTransform.identity
+        }
+
+        var rawScale = scale(at: visibleIndex)
+        let previousScale = scale(at: visibleIndex - 1)
+        let delta = (previousScale - rawScale) * percentageOffset
+        rawScale += delta
+        return CGAffineTransform(scaleX: rawScale, y: rawScale)
+    }
+}
diff --git a/CardsCollectionViewVerticleLayout.swift b/CardsCollectionViewVerticleLayout.swift
index 642f948..1b29f47 100644
--- a/CardsCollectionViewVerticleLayout.swift
+++ b/CardsCollectionViewVerticleLayout.swift
@@ -8,9 +8,9 @@
 
 import UIKit
 
-open class CardsCollectionViewVerticleLayout: UICollectionViewLayout {
+open class CardsCollectionViewVerticleLayout: UICollectionViewLayout, CardsCollectionViewLayout {
     
-    // MARK: - Layout configuration
+    // MARK: Layout configuration
     
     public var itemSize: CGSize = CGSize(width: 200, height: 300) {
       didSet{
@@ -30,7 +30,7 @@ open class CardsCollectionViewVerticleLayout: UICollectionViewLayout {
         }
     }
     
-    // MARK: UICollectionViewLayout
+    // MARK: - UICollectionViewLayout
     
     override open var collectionView: UICollectionView {
         return super.collectionView!
@@ -49,101 +49,60 @@ open class CardsCollectionViewVerticleLayout: UICollectionViewLayout {
     
     override open func layoutAttributesForElements(in rect: CGRect) -> [UICollectionViewLayoutAttributes]? {
         let totalItemsCount = collectionView.numberOfItems(inSection: 0)
-
         let minVisibleIndex = max(Int(collectionView.contentOffset.y) / Int(collectionView.bounds.height), 0)
         let maxVisibleIndex = min(minVisibleIndex + maximumVisibleItems, totalItemsCount)
-        
-        let contentCenterX = collectionView.contentOffset.x + (collectionView.bounds.width / 2.0)
-        let deltaOffset = Int(collectionView.contentOffset.y) % Int(collectionView.bounds.height)
-        let percentageDeltaOffset = CGFloat(deltaOffset) / collectionView.bounds.height
         let visibleIndices = minVisibleIndex..<maxVisibleIndex
-        print("Called layoutAttributesForElements rect = \(rect), delta = \(deltaOffset), percentage = \(percentageDeltaOffset)%")
-        
-        let attributes: [UICollectionViewLayoutAttributes] = visibleIndices.map { index in
+        let attributes: [UICollectionViewLayoutAttributes?] = visibleIndices.map { index in
             let indexPath = IndexPath(item: index, section: 0)
-            return computeLayoutAttributesForItem(indexPath: indexPath,
-                                                  minVisibleIndex: minVisibleIndex,
-                                                  contentCenterX: contentCenterX,
-                                                  deltaOffset: CGFloat(deltaOffset),
-                                                  percentageDeltaOffset: percentageDeltaOffset)
+            return self.layoutAttributesForItem(at: indexPath)
         }
-        
-        return attributes
+        let filteredAttributes = attributes.flatMap { $0 }
+        return filteredAttributes
     }
     
     override open func layoutAttributesForItem(at indexPath: IndexPath) -> UICollectionViewLayoutAttributes? {
-
-        let contentCenterX = collectionView.contentOffset.x + (collectionView.bounds.width / 2.0)
-        let minVisibleIndex = Int(collectionView.contentOffset.x) / Int(collectionView.bounds.width)
-        let deltaOffset = Int(collectionView.contentOffset.y) % Int(collectionView.bounds.height)
+        let minVisibleIndex = Int(collectionView.contentOffset.y) / Int(collectionView.bounds.height)
+        let deltaOffset = CGFloat(Int(collectionView.contentOffset.y) % Int(collectionView.bounds.height))
         let percentageDeltaOffset = CGFloat(deltaOffset) / collectionView.bounds.height
-        print("Called layoutAttributesForItem IP = \(indexPath), delta = \(deltaOffset), percentage = \(percentageDeltaOffset)%")
-        return computeLayoutAttributesForItem(indexPath: indexPath,
-                                              minVisibleIndex: minVisibleIndex,
-                                              contentCenterX: contentCenterX,
-                                              deltaOffset: CGFloat(deltaOffset),
-                                              percentageDeltaOffset: percentageDeltaOffset)
-    }
-    
-    override open func shouldInvalidateLayout(forBoundsChange newBounds: CGRect) -> Bool {
-        return true
-    }
-}
-
-
-// MARK: - Layout computations
-fileprivate extension CardsCollectionViewVerticleLayout {
-    
-    private func scale(at index: Int) -> CGFloat {
-        let translatedCoefficient = CGFloat(index) - CGFloat(self.maximumVisibleItems) / 2
-        return CGFloat(pow(0.95, translatedCoefficient))
-    }
-
-    private func transform(atCurrentVisibleIndex visibleIndex: Int, percentageOffset: CGFloat) -> CGAffineTransform {
-        var rawScale = visibleIndex < maximumVisibleItems ? scale(at: visibleIndex) : 1.0
+        let visibleIndex = indexPath.row - minVisibleIndex
 
-        if visibleIndex != 0 {
-            let previousScale = scale(at: visibleIndex - 1)
-            let delta = (previousScale - rawScale) * percentageOffset
-            rawScale += delta
-        }
-        return CGAffineTransform(scaleX: rawScale, y: rawScale)
-    }
-    
-    fileprivate func computeLayoutAttributesForItem(indexPath: IndexPath,
-                                                    minVisibleIndex: Int,
-                                                    contentCenterX: CGFloat,
-                                                    deltaOffset: CGFloat,
-                                                    percentageDeltaOffset: CGFloat) -> UICollectionViewLayoutAttributes {
         let attributes = UICollectionViewLayoutAttributes(forCellWith:indexPath)
-        let visibleIndex = indexPath.row - minVisibleIndex
-       
-        attributes.size = self.itemSize
-        
+        attributes.size = itemSize
         let midY = self.collectionView.bounds.midY
         let midX = self.collectionView.bounds.midX
         attributes.center = CGPoint(x: midX + spacing.x * CGFloat(visibleIndex),
                                     y: midY + spacing.y * CGFloat(visibleIndex))
         attributes.zIndex = maximumVisibleItems - visibleIndex
-        
-        attributes.transform = transform(atCurrentVisibleIndex: visibleIndex,
-                                         percentageOffset: percentageDeltaOffset)
+        attributes.transform = scaleTransform(forVisibleIndex: visibleIndex,
+                                              percentageOffset: percentageDeltaOffset)
+
+
         switch visibleIndex {
         case 0:
             attributes.center.y -= deltaOffset
+            attributes.isHidden = false
             break
         case 1..<maximumVisibleItems:
             attributes.center.x -= spacing.x * percentageDeltaOffset
             attributes.center.y -= spacing.y * percentageDeltaOffset
-            
             if visibleIndex == maximumVisibleItems - 1 {
                 attributes.alpha = percentageDeltaOffset
+            } else {
+                attributes.alpha = 1.0
             }
+
+            attributes.isHidden = false
             break
         default:
             attributes.alpha = 0
+            attributes.isHidden = true
             break
         }
         return attributes
     }
+
+    
+    override open func shouldInvalidateLayout(forBoundsChange newBounds: CGRect) -> Bool {
+        return true
+    }
 }

From 25bec17a60d535693127e856cdd35226d9d75440 Mon Sep 17 00:00:00 2001
From: Filipp Fediakov <julik103@mail.ru>
Date: Wed, 3 Jan 2018 22:57:22 +0300
Subject: [PATCH 6/6] Update pod spec, fix typo in file name

---
 ...ayout.swift => CardsCollectionViewVerticalLayout.swift | 4 ++--
 CardsExample/CardsExample.xcodeproj/project.pbxproj       | 8 ++++----
 CardsLayout.podspec                                       | 2 +-
 3 files changed, 7 insertions(+), 7 deletions(-)
 rename CardsCollectionViewVerticleLayout.swift => CardsCollectionViewVerticalLayout.swift (97%)

diff --git a/CardsCollectionViewVerticleLayout.swift b/CardsCollectionViewVerticalLayout.swift
similarity index 97%
rename from CardsCollectionViewVerticleLayout.swift
rename to CardsCollectionViewVerticalLayout.swift
index 1b29f47..caf96ec 100644
--- a/CardsCollectionViewVerticleLayout.swift
+++ b/CardsCollectionViewVerticalLayout.swift
@@ -1,5 +1,5 @@
 //
-//  CardsCollectionViewVerticleLayout.swift
+//  CardsCollectionViewVerticalLayout.swift
 //  CardsLayout
 //
 //  Created by Filipp Fediakov on 18.08.17.
@@ -8,7 +8,7 @@
 
 import UIKit
 
-open class CardsCollectionViewVerticleLayout: UICollectionViewLayout, CardsCollectionViewLayout {
+open class CardsCollectionViewVerticalLayout: UICollectionViewLayout, CardsCollectionViewLayout {
     
     // MARK: Layout configuration
     
diff --git a/CardsExample/CardsExample.xcodeproj/project.pbxproj b/CardsExample/CardsExample.xcodeproj/project.pbxproj
index f7cede8..3390de5 100644
--- a/CardsExample/CardsExample.xcodeproj/project.pbxproj
+++ b/CardsExample/CardsExample.xcodeproj/project.pbxproj
@@ -13,7 +13,7 @@
 		365EC0BF1FABCC9200583152 /* Assets.xcassets in Resources */ = {isa = PBXBuildFile; fileRef = 365EC0BE1FABCC9200583152 /* Assets.xcassets */; };
 		365EC0C21FABCC9200583152 /* LaunchScreen.storyboard in Resources */ = {isa = PBXBuildFile; fileRef = 365EC0C01FABCC9200583152 /* LaunchScreen.storyboard */; };
 		365EC0CA1FABCD1500583152 /* CardsCollectionViewHorizontalLayout.swift in Sources */ = {isa = PBXBuildFile; fileRef = 365EC0C91FABCD1400583152 /* CardsCollectionViewHorizontalLayout.swift */; };
-		36B5506A1FCE28EB005BBDD5 /* CardsCollectionViewVerticleLayout.swift in Sources */ = {isa = PBXBuildFile; fileRef = 36B550691FCE28EB005BBDD5 /* CardsCollectionViewVerticleLayout.swift */; };
+		36B5506A1FCE28EB005BBDD5 /* CardsCollectionViewVerticalLayout.swift in Sources */ = {isa = PBXBuildFile; fileRef = 36B550691FCE28EB005BBDD5 /* CardsCollectionViewVerticalLayout.swift */; };
 /* End PBXBuildFile section */
 
 /* Begin PBXFileReference section */
@@ -25,7 +25,7 @@
 		365EC0C11FABCC9200583152 /* Base */ = {isa = PBXFileReference; lastKnownFileType = file.storyboard; name = Base; path = Base.lproj/LaunchScreen.storyboard; sourceTree = "<group>"; };
 		365EC0C31FABCC9200583152 /* Info.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; path = Info.plist; sourceTree = "<group>"; };
 		365EC0C91FABCD1400583152 /* CardsCollectionViewHorizontalLayout.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; name = CardsCollectionViewHorizontalLayout.swift; path = ../../CardsCollectionViewHorizontalLayout.swift; sourceTree = "<group>"; };
-		36B550691FCE28EB005BBDD5 /* CardsCollectionViewVerticleLayout.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; name = CardsCollectionViewVerticleLayout.swift; path = ../../CardsCollectionViewVerticleLayout.swift; sourceTree = "<group>"; };
+		36B550691FCE28EB005BBDD5 /* CardsCollectionViewVerticalLayout.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; name = CardsCollectionViewVerticalLayout.swift; path = ../../CardsCollectionViewVerticalLayout.swift; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
 /* Begin PBXFrameworksBuildPhase section */
@@ -58,7 +58,7 @@
 		365EC0B61FABCC9200583152 /* CardsExample */ = {
 			isa = PBXGroup;
 			children = (
-				36B550691FCE28EB005BBDD5 /* CardsCollectionViewVerticleLayout.swift */,
+				36B550691FCE28EB005BBDD5 /* CardsCollectionViewVerticalLayout.swift */,
 				365EC0C91FABCD1400583152 /* CardsCollectionViewHorizontalLayout.swift */,
 				365EC0B71FABCC9200583152 /* AppDelegate.swift */,
 				365EC0B91FABCC9200583152 /* ViewController.swift */,
@@ -144,7 +144,7 @@
 			files = (
 				365EC0BA1FABCC9200583152 /* ViewController.swift in Sources */,
 				365EC0CA1FABCD1500583152 /* CardsCollectionViewHorizontalLayout.swift in Sources */,
-				36B5506A1FCE28EB005BBDD5 /* CardsCollectionViewVerticleLayout.swift in Sources */,
+				36B5506A1FCE28EB005BBDD5 /* CardsCollectionViewVerticalLayout.swift in Sources */,
 				365EC0B81FABCC9200583152 /* AppDelegate.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
diff --git a/CardsLayout.podspec b/CardsLayout.podspec
index 46580b2..5e83a78 100644
--- a/CardsLayout.podspec
+++ b/CardsLayout.podspec
@@ -88,7 +88,7 @@ Pod::Spec.new do |s|
   #  Not including the public_header_files will make all headers public.
   #
 
-  s.source_files  = "CardsCollectionViewLayout.swift"
+  s.source_files  = "CardsCollectionViewHorizontalLayout.swift", "CardsCollectionViewVerticalLayout.swift"
   s.exclude_files = "CardsExample", "CardsOldSource"
 
   # s.public_header_files = "Classes/**/*.h"