Circular wheel animation implementation in ios - ios

Question

I have to do a animation like :
https://www.flickr.com/photos/134104584#N07/20409116003/in/datetaken/
Currently I am trying to achieve this using custom collection view layout and subclassing UICollectionViewLayout.
Any help or way to achieve this ?

Answer 1

I had the same task and that's what I've found:
You can make your own solution, following great tutorial made by Rounak Jain. The tutorial is available here:
https://www.raywenderlich.com/107687/uicollectionview-custom-layout-tutorial-spinning-wheel
You can reuse the existing code.
Because of time limits I've chosen the second variant, and the best repo I've found was:
https://github.com/sarn/ARNRouletteWheelView
The usage is pretty straightforward, but there are two tips that can be useful:
scrollToItemAtIndexPath was not working and was crashing the app. The Pull Request to fix it: https://github.com/sarn/ARNRouletteWheelView/pull/3/commits/7056e4bac2a04f2c8208d6d43e25d62a848f032d
If you want to make items smaller and disable rotation of the item itself (see gif), you can do the following in your UICollectionViewCell subclass:
#import "ARNRouletteWheelCellScaledAndRotated.h"
#import <ARNRouletteWheelView/ARNRouletteWheelLayoutAttributes.h>
#implementation ARNRouletteWheelCellScaledAndRotated
- (void)applyLayoutAttributes:(UICollectionViewLayoutAttributes *)layoutAttributes {
[super applyLayoutAttributes:layoutAttributes];
if(layoutAttributes != nil && [layoutAttributes isKindOfClass:[ARNRouletteWheelLayoutAttributes class]]) {
ARNRouletteWheelLayoutAttributes *rouletteWheelLayoutAttributes = (ARNRouletteWheelLayoutAttributes *)layoutAttributes;
self.layer.anchorPoint = rouletteWheelLayoutAttributes.anchorPoint;
// update the Y center to reflect the anchor point
CGPoint center = CGPointMake(self.center.x, self.center.y + ((rouletteWheelLayoutAttributes.anchorPoint.y - 0.5) * CGRectGetHeight(self.bounds)));
self.center = center;
// rotate back
CGAffineTransform rotate = CGAffineTransformMakeRotation(-rouletteWheelLayoutAttributes.angle);
// scale
CGFloat scale = 1 - fabs(rouletteWheelLayoutAttributes.angle);
CGAffineTransform translate = CGAffineTransformMakeScale(scale, scale);
// Apply them to a view
self.imageView.transform = CGAffineTransformConcat(translate, rotate);
}
}
#end

Answer 2

Update this tutorial - https://www.raywenderlich.com/1702-uicollectionview-custom-layout-tutorial-a-spinning-wheel. Old version not work. This version good work for Swift 5 + i add pageControl if somebody need.
import UIKit
class CircularCollectionViewLayoutAttributes: UICollectionViewLayoutAttributes {
//1
var anchorPoint = CGPoint(x: 0.5, y: 0.5)
var angle: CGFloat = 0 {
//2
didSet {
zIndex = Int(angle * 1000000)
transform = CGAffineTransform.identity.rotated(by: angle)
}
}
override func copy(with zone: NSZone? = nil) -> Any {
let copiedAttributes: CircularCollectionViewLayoutAttributes = super.copy(with: zone) as! CircularCollectionViewLayoutAttributes
copiedAttributes.anchorPoint = self.anchorPoint
copiedAttributes.angle = self.angle
return copiedAttributes
}
}
protocol CircularViewLayoutDelegate: AnyObject {
func getCurrentIndex(value: Int)
}
class CircularCollectionViewLayout: UICollectionViewLayout {
let itemSize = CGSize(width: 214, height: 339)
let spaceBeetweenItems: CGFloat = 50
var angleAtExtreme: CGFloat {
return collectionView!.numberOfItems(inSection: 0) > 0 ?
-CGFloat(collectionView!.numberOfItems(inSection: 0)) * anglePerItem : 0
}
var angle: CGFloat {
return angleAtExtreme * collectionView!.contentOffset.x / (collectionViewContentSize.width - itemSize.width)
}
var radius: CGFloat = 1000 {
didSet {
invalidateLayout()
}
}
var anglePerItem: CGFloat {
return atan((itemSize.width + spaceBeetweenItems) / radius)
}
weak var delegate: CircularViewLayoutDelegate?
override var collectionViewContentSize: CGSize {
return CGSize(width: (CGFloat(collectionView!.numberOfItems(inSection: 0)) * itemSize.width) + 100, height: collectionView!.bounds.height)
}
override class var layoutAttributesClass: AnyClass {
return CircularCollectionViewLayoutAttributes.self
}
var attributesList = [CircularCollectionViewLayoutAttributes]()
override func prepare() {
super.prepare()
guard let collectionView = collectionView else { return }
let centerX = collectionView.contentOffset.x + collectionView.bounds.width / 2.0
let anchorPointY = (itemSize.height + radius) / itemSize.height
// Add to get current cell index
let theta = atan2(collectionView.bounds.width / 2.0,
radius + (itemSize.height / 2.0) - collectionView.bounds.height / 2.0)
let endIndex = collectionView.numberOfItems(inSection: 0)
let currentIndex = min(endIndex, Int(ceil((theta - angle) / anglePerItem)))
delegate?.getCurrentIndex(value: currentIndex)
attributesList = (0..<collectionView.numberOfItems(inSection: 0)).map {
(i) -> CircularCollectionViewLayoutAttributes in
//1
let attributes = CircularCollectionViewLayoutAttributes.init(forCellWith: IndexPath(item: i, section: 0))
attributes.size = self.itemSize
//2
attributes.center = CGPoint(x: centerX, y: (self.collectionView!.bounds).midY)
//3
attributes.angle = self.angle + (self.anglePerItem * CGFloat(i))
attributes.anchorPoint = CGPoint(x: 0.5, y: anchorPointY)
return attributes
}
}
override func layoutAttributesForElements(in rect: CGRect) -> [UICollectionViewLayoutAttributes]? {
// return an array layout attributes instances for all the views in the given rect
return attributesList
}
override func layoutAttributesForItem(at indexPath: IndexPath) -> UICollectionViewLayoutAttributes? {
return attributesList[indexPath.row]
}
override func shouldInvalidateLayout(forBoundsChange newBounds: CGRect) -> Bool {
return true
}
}
Function in Cell Class:
override func apply(_ layoutAttributes: UICollectionViewLayoutAttributes) {
super.apply(layoutAttributes)
let circularlayoutAttributes = layoutAttributes as! CircularCollectionViewLayoutAttributes
self.layer.anchorPoint = circularlayoutAttributes.anchorPoint
self.center.y += (circularlayoutAttributes.anchorPoint.y - 0.5) * self.bounds.height
}
Add this to controller if you need current cell to add pageControl:
In ViewDidload:
if let layout = collectionView?.collectionViewLayout as? CircularCollectionViewLayout {
layout.delegate = self
}
Extensions:
extension LevelsVC: CircularViewLayoutDelegate {
func getCurrentIndex(value: Int) {
self.pageControl.currentPage = value - 1
}
}