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Remove unnecessary calculation

This commit is contained in:
WenchaoD 2017-03-01 21:23:15 +08:00
parent 35691a6f78
commit e4ed35a162
3 changed files with 25 additions and 25 deletions
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24
Sources/FSPageViewLayout.swift
View File

@ -12,7 +12,7 @@ class FSPagerViewLayout: UICollectionViewLayout {
internal var contentSize: CGSize = .zero
internal var leadingSpacing: CGFloat = 0
internal var itemSpan: CGFloat = 0
internal var itemSpacing: CGFloat = 0
internal var needsReprepare = true
open override class var layoutAttributesClass: AnyClass {
@ -83,7 +83,7 @@ class FSPagerViewLayout: UICollectionViewLayout {
return pagerView.interitemSpacing
}()
self.leadingSpacing = (collectionView.frame.width-self.actualItemSize.width)*0.5
self.itemSpan = self.actualItemSize.width+self.actualInteritemSpacing
self.itemSpacing = self.actualItemSize.width+self.actualInteritemSpacing
// Calculate and cache contentSize, rather than calculating each time
self.contentSize = {
@ -107,7 +107,7 @@ class FSPagerViewLayout: UICollectionViewLayout {
override open func layoutAttributesForElements(in rect: CGRect) -> [UICollectionViewLayoutAttributes]? {
var layoutAttributes = [UICollectionViewLayoutAttributes]()
guard self.itemSpan > 0, !rect.isEmpty else {
guard self.itemSpacing > 0, !rect.isEmpty else {
return layoutAttributes
}
let rect = rect.intersection(CGRect(origin: .zero, size: self.contentSize))
@ -115,8 +115,8 @@ class FSPagerViewLayout: UICollectionViewLayout {
return layoutAttributes
}
// Calculate start position and index of certain rects
let numberOfItemsBefore = max(Int((rect.minX-self.leadingSpacing)/self.itemSpan),0)
let startPosition = self.leadingSpacing + CGFloat(numberOfItemsBefore)*self.itemSpan
let numberOfItemsBefore = max(Int((rect.minX-self.leadingSpacing)/self.itemSpacing),0)
let startPosition = self.leadingSpacing + CGFloat(numberOfItemsBefore)*self.itemSpacing
let startIndex = numberOfItemsBefore
// Create layout attributes
var itemIndex = startIndex
@ -128,7 +128,7 @@ class FSPagerViewLayout: UICollectionViewLayout {
self.applyTransform(to: attributes)
layoutAttributes.append(attributes)
itemIndex += 1
x += self.itemSpan
x += self.itemSpacing
}
return layoutAttributes
}
@ -156,12 +156,12 @@ class FSPagerViewLayout: UICollectionViewLayout {
var proposedContentOffset = proposedContentOffset
let proposedContentOffsetX: CGFloat = {
let translation = -collectionView.panGestureRecognizer.translation(in: collectionView).x
var offset: CGFloat = round(proposedContentOffset.x/self.itemSpan)*self.itemSpan
let minFlippingDistance = min(0.5 * self.itemSpan,150)
var offset: CGFloat = round(proposedContentOffset.x/self.itemSpacing)*self.itemSpacing
let minFlippingDistance = min(0.5 * self.itemSpacing,150)
let originalContentOffsetX = collectionView.contentOffset.x - translation
if abs(translation) <= minFlippingDistance {
if abs(velocity.x) >= 0.3 && abs(proposedContentOffset.x-originalContentOffsetX) <= self.itemSpan*0.5 {
offset += self.itemSpan * (velocity.x)/abs(velocity.x)
if abs(velocity.x) >= 0.3 && abs(proposedContentOffset.x-originalContentOffsetX) <= self.itemSpacing*0.5 {
offset += self.itemSpacing * (velocity.x)/abs(velocity.x)
}
}
return offset
@ -188,7 +188,7 @@ class FSPagerViewLayout: UICollectionViewLayout {
internal func frame(for indexPath: IndexPath) -> CGRect {
let numberOfItems = self.numberOfItems*indexPath.section + indexPath.item
let originX = self.leadingSpacing + CGFloat(numberOfItems)*self.itemSpan
let originX = self.leadingSpacing + CGFloat(numberOfItems)*self.itemSpacing
let originY = (self.collectionView!.frame.height-self.actualItemSize.height)/2.0
let origin = CGPoint(x: originX, y: originY)
let frame = CGRect(origin: origin, size: self.actualItemSize)
@ -232,7 +232,7 @@ class FSPagerViewLayout: UICollectionViewLayout {
}
let ruler = collectionView.bounds.midX
attributes.center.x = self.frame(for: attributes.indexPath).midX
attributes.position = (attributes.center.x-ruler)/self.itemSpan
attributes.position = (attributes.center.x-ruler)/self.itemSpacing
attributes.interitemSpacing = self.actualInteritemSpacing
transformer.applyTransform(to: attributes)
}

20
Sources/FSPageViewTransformer.swift
View File

@ -174,20 +174,20 @@ open class FSPagerViewTransformer: NSObject {
attributes.transform = transform
attributes.zIndex = zIndex
case .cubic:
let direction: CGFloat = position < 0 ? 1 : -1
let theta = position * CGFloat(M_PI_2)
let width = attributes.bounds.width
// ForwardX -> RotateY -> BackwardX
attributes.center.x += direction*width*0.5 // ForwardX
var transform3D = CATransform3DIdentity
transform3D.m34 = -0.002
transform3D = CATransform3DRotate(transform3D, theta, 0, 1, 0) // RotateY
transform3D = CATransform3DTranslate(transform3D,-direction*width*0.5, 0, 0) // BackwardX
attributes.transform3D = transform3D
switch position {
case -1...1:
attributes.alpha = 1
attributes.zIndex = Int((1-position) * CGFloat(10))
let direction: CGFloat = position < 0 ? 1 : -1
let theta = position * CGFloat(M_PI_2)
let width = attributes.bounds.width
// ForwardX -> RotateY -> BackwardX
attributes.center.x += direction*width*0.5 // ForwardX
var transform3D = CATransform3DIdentity
transform3D.m34 = -0.002
transform3D = CATransform3DRotate(transform3D, theta, 0, 1, 0) // RotateY
transform3D = CATransform3DTranslate(transform3D,-direction*width*0.5, 0, 0) // BackwardX
attributes.transform3D = transform3D
default:
attributes.zIndex = 0
attributes.alpha = 0

6
Sources/FSPagerView.swift
View File

@ -156,7 +156,7 @@ open class FSPagerView: UIView,UICollectionViewDataSource,UICollectionViewDelega
/// The percentage of x position at which the origin of the content view is offset from the origin of the pagerView view.
open var scrollOffset: CGFloat {
let scrollOffset = Double(self.collectionView.contentOffset.x.divided(by: self.collectionViewLayout.itemSpan))
let scrollOffset = Double(self.collectionView.contentOffset.x.divided(by: self.collectionViewLayout.itemSpacing))
return fmod(CGFloat(scrollOffset), CGFloat(Double(self.numberOfItems)))
}
@ -322,7 +322,7 @@ open class FSPagerView: UIView,UICollectionViewDataSource,UICollectionViewDelega
public func scrollViewDidScroll(_ scrollView: UIScrollView) {
if self.numberOfItems > 0 {
// In case someone is using KVO
let currentIndex = lround(Double(self.scrollOffset))
let currentIndex = lround(Double(self.scrollOffset)) % self.numberOfItems
if (currentIndex != self.currentIndex) {
self.currentIndex = currentIndex
}
@ -344,7 +344,7 @@ open class FSPagerView: UIView,UICollectionViewDataSource,UICollectionViewDelega
public func scrollViewWillEndDragging(_ scrollView: UIScrollView, withVelocity velocity: CGPoint, targetContentOffset: UnsafeMutablePointer<CGPoint>) {
if let function = self.delegate?.pagerViewWillEndDragging(_:targetIndex:) {
let targetItem = lround(Double(targetContentOffset.pointee.x/self.collectionViewLayout.itemSpan))
let targetItem = lround(Double(targetContentOffset.pointee.x/self.collectionViewLayout.itemSpacing))
function(self, targetItem % self.numberOfItems)
}
if self.automaticSlidingInterval > 0 {