简介
iCarousel是一个类，它继承自UIView。用于简化实现各种类型的旋转木马(分页滚动视图)iPhone、iPad和Mac OS。iCarousel实现一些常见的影响如圆柱、平面式的旋转木马。经过 iCarousel类的封装，使iCarousel类的使用方式类似于UITableView的使用，每一个界面类似于一个单元格。 iCarousel类为我们提供了十几种分页效果，我们还可以使用 iCarousel类中的 (BOOL) vertical属性设置显示效果是垂直显示还是水平显示。
iCarousel类的实现方式，先通过（ iCarouselDataSource）协议方法确定需要显示视图的个数，和创建需要显示的视图。 iCarousel内先创建一个可变字典，用于存储需要显示的单元格视图。创建一个父视图用于显示单元格视图，从字典中取出需要显示的单元格视图添加到创建父视图上，用于显示需要创建的单元格视图，在iCarousel类的内部对这些需要显示的单元格视图进行布局。
源码分析
iCarousel.h
//
// iCarousel.h
//
// Version 1.8.3
//
// Created by Nick Lockwood on 01/04/2011.
// Copyright 2011 Charcoal Design
//
// Distributed under the permissive zlib License
// Get the latest version from here:
//
// https://github.com/nicklockwood/iCarousel
//
// This software is provided 'as-is', without any express or implied
// warranty. In no event will the authors be held liable for any damages
// arising from the use of this software.
//
// Permission is granted to anyone to use this software for any purpose,
// including commercial applications, and to alter it and redistribute it
// freely, subject to the following restrictions:
//
// 1. The origin of this software must not be misrepresented; you must not
// claim that you wrote the original software. If you use this software
// in a product, an acknowledgment in the product documentation would be
// appreciated but is not required.
//
// 2. Altered source versions must be plainly marked as such, and must not be
// misrepresented as being the original software.
//
// 3. This notice may not be removed or altered from any source distribution.
//
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wunknown-pragmas"
#pragma clang diagnostic ignored "-Wreserved-id-macro"
#pragma clang diagnostic ignored "-Wobjc-missing-property-synthesis"
#import <Availability.h>
#undef weak_delegate
#undef __weak_delegate
#if __has_feature(objc_arc) && __has_feature(objc_arc_weak) && \
(!(defined __MAC_OS_X_VERSION_MIN_REQUIRED) || \
__MAC_OS_X_VERSION_MIN_REQUIRED >= __MAC_10_8)
#define weak_delegate weak
#else
#define weak_delegate unsafe_unretained
#endif
#import <QuartzCore/QuartzCore.h>
#if defined USING_CHAMELEON || defined __IPHONE_OS_VERSION_MAX_ALLOWED
#define ICAROUSEL_IOS
#else
#define ICAROUSEL_MACOS
#endif
#ifdef ICAROUSEL_IOS
#import <UIKit/UIKit.h>
#else
#import <Cocoa/Cocoa.h>
typedef NSView UIView;
#endif
// 视图的显示类型
typedef NS_ENUM(NSInteger, iCarouselType)
{
iCarouselTypeLinear = 0, // 线性的
iCarouselTypeRotary, // 可旋转的
iCarouselTypeInvertedRotary, // 反向旋转
iCarouselTypeCylinder, // 圆柱式
iCarouselTypeInvertedCylinder, // 反向圆柱式
iCarouselTypeWheel, // 车轮式
iCarouselTypeInvertedWheel, // 反向车轮
iCarouselTypeCoverFlow, // 封面流
iCarouselTypeCoverFlow2, // 封面流样式2
iCarouselTypeTimeMachine, // 时光机
iCarouselTypeInvertedTimeMachine, // 反向时光机
iCarouselTypeCustom // 自定义
};
typedef NS_ENUM(NSInteger, iCarouselOption)
{
iCarouselOptionWrap = 0,
iCarouselOptionShowBackfaces,
iCarouselOptionOffsetMultiplier,
iCarouselOptionVisibleItems,
iCarouselOptionCount,
iCarouselOptionArc,
iCarouselOptionAngle,
iCarouselOptionRadius,
iCarouselOptionTilt,
iCarouselOptionSpacing,
iCarouselOptionFadeMin,
iCarouselOptionFadeMax,
iCarouselOptionFadeRange,
iCarouselOptionFadeMinAlpha
};
NS_ASSUME_NONNULL_BEGIN
@protocol iCarouselDataSource, iCarouselDelegate;
@interface iCarousel : UIView
@property (nonatomic, weak_delegate) IBOutlet __nullable id<iCarouselDataSource> dataSource;
@property (nonatomic, weak_delegate) IBOutlet __nullable id<iCarouselDelegate> delegate;
// 视图的显示类型
@property (nonatomic, assign) iCarouselType type;
@property (nonatomic, assign) CGFloat perspective;
@property (nonatomic, assign) CGFloat decelerationRate;
@property (nonatomic, assign) CGFloat scrollSpeed;
@property (nonatomic, assign) CGFloat bounceDistance;
// 设置是否能滑动 默认YES
@property (nonatomic, assign, getter = isScrollEnabled) BOOL scrollEnabled;
// 是否按页滑动
@property (nonatomic, assign, getter = isPagingEnabled) BOOL pagingEnabled;
// 设置单元格显示是水平或竖直，默认NO（水平）
@property (nonatomic, assign, getter = isVertical) BOOL vertical;
// 设置是否启动旋转木马效果, readonly 外部无法直接设置，默认为NO
@property (nonatomic, readonly, getter = isWrapEnabled) BOOL wrapEnabled;
// 与scrollView 相同
@property (nonatomic, assign) BOOL bounces;
@property (nonatomic, assign) CGFloat scrollOffset;
@property (nonatomic, readonly) CGFloat offsetMultiplier;
// 用于设置滚动视图的水平位置
@property (nonatomic, assign) CGSize contentOffset;
@property (nonatomic, assign) CGSize viewpointOffset;
// 代理设置 item number
@property (nonatomic, readonly) NSInteger numberOfItems;
@property (nonatomic, readonly) NSInteger numberOfPlaceholders;
// 当前index
@property (nonatomic, assign) NSInteger currentItemIndex;
// 当前 itemView 只读
@property (nonatomic, strong, readonly) UIView * __nullable currentItemView;
@property (nonatomic, strong, readonly) NSArray *indexesForVisibleItems;
@property (nonatomic, readonly) NSInteger numberOfVisibleItems;
@property (nonatomic, strong, readonly) NSArray *visibleItemViews;
@property (nonatomic, readonly) CGFloat itemWidth;
@property (nonatomic, strong, readonly) UIView *contentView;
@property (nonatomic, readonly) CGFloat toggle;
@property (nonatomic, assign) CGFloat autoscroll;
@property (nonatomic, assign) BOOL stopAtItemBoundary;
@property (nonatomic, assign) BOOL scrollToItemBoundary;
@property (nonatomic, assign) BOOL ignorePerpendicularSwipes;
// 用于设置被选中的单元格在否在中心显示，默认YES
@property (nonatomic, assign) BOOL centerItemWhenSelected;
// 当前手势状态
@property (nonatomic, readonly, getter = isDragging) BOOL dragging;
@property (nonatomic, readonly, getter = isDecelerating) BOOL decelerating;
@property (nonatomic, readonly, getter = isScrolling) BOOL scrolling;
// 滑动相关
- (void)scrollByOffset:(CGFloat)offset duration:(NSTimeInterval)duration;
- (void)scrollToOffset:(CGFloat)offset duration:(NSTimeInterval)duration;
- (void)scrollByNumberOfItems:(NSInteger)itemCount duration:(NSTimeInterval)duration;
- (void)scrollToItemAtIndex:(NSInteger)index duration:(NSTimeInterval)duration;
- (void)scrollToItemAtIndex:(NSInteger)index animated:(BOOL)animated;
// 视图设置
- (nullable UIView *)itemViewAtIndex:(NSInteger)index;
- (NSInteger)indexOfItemView:(UIView *)view;
- (NSInteger)indexOfItemViewOrSubview:(UIView *)view;
- (CGFloat)offsetForItemAtIndex:(NSInteger)index;
- (nullable UIView *)itemViewAtPoint:(CGPoint)point;
// 视图操作
- (void)removeItemAtIndex:(NSInteger)index animated:(BOOL)animated;
- (void)insertItemAtIndex:(NSInteger)index animated:(BOOL)animated;
- (void)reloadItemAtIndex:(NSInteger)index animated:(BOOL)animated;
- (void)reloadData;
@end
// datasource
@protocol iCarouselDataSource <NSObject>
// 返回显示界面的个数
- (NSInteger)numberOfItemsInCarousel:(iCarousel *)carousel;
// 返回每个需要显示的视图
- (UIView *)carousel:(iCarousel *)carousel viewForItemAtIndex:(NSInteger)index reusingView:(nullable UIView *)view;
@optional
- (NSInteger)numberOfPlaceholdersInCarousel:(iCarousel *)carousel;
- (UIView *)carousel:(iCarousel *)carousel placeholderViewAtIndex:(NSInteger)index reusingView:(nullable UIView *)view;
@end
// delegate
@protocol iCarouselDelegate <NSObject>
@optional
- (void)carouselWillBeginScrollingAnimation:(iCarousel *)carousel;
- (void)carouselDidEndScrollingAnimation:(iCarousel *)carousel;
- (void)carouselDidScroll:(iCarousel *)carousel;
- (void)carouselCurrentItemIndexDidChange:(iCarousel *)carousel;
- (void)carouselWillBeginDragging:(iCarousel *)carousel;
- (void)carouselDidEndDragging:(iCarousel *)carousel willDecelerate:(BOOL)decelerate;
- (void)carouselWillBeginDecelerating:(iCarousel *)carousel;
- (void)carouselDidEndDecelerating:(iCarousel *)carousel;
- (BOOL)carousel:(iCarousel *)carousel shouldSelectItemAtIndex:(NSInteger)index;
- (void)carousel:(iCarousel *)carousel didSelectItemAtIndex:(NSInteger)index;
// 设置width
- (CGFloat)carouselItemWidth:(iCarousel *)carousel;
// 设置transform 的 offset
- (CATransform3D)carousel:(iCarousel *)carousel itemTransformForOffset:(CGFloat)offset baseTransform:(CATransform3D)transform;
// 此协议方法可以设置每个视图之间的间隙的各种位置属性，还可以通过此协议方法设置是否采用旋转木马效果
- (CGFloat)carousel:(iCarousel *)carousel valueForOption:(iCarouselOption)option withDefault:(CGFloat)value;
@end
NS_ASSUME_NONNULL_END
#pragma clang diagnostic pop
iCarousel.m
//
// iCarousel.m
//
// Version 1.8.3
//
// Created by Nick Lockwood on 01/04/2011.
// Copyright 2011 Charcoal Design
#import "iCarousel.h"
#import <objc/message.h>
#import <tgmath.h>
#import <Availability.h>
#if !__has_feature(objc_arc)
#error This class requires automatic reference counting
#endif
#if !defined(__has_warning) || __has_warning("-Wreceiver-is-weak")
# pragma GCC diagnostic ignored "-Wreceiver-is-weak"
#endif
#pragma clang diagnostic ignored "-Warc-repeated-use-of-weak"
#pragma clang diagnostic ignored "-Wobjc-missing-property-synthesis"
#pragma clang diagnostic ignored "-Wdirect-ivar-access"
#pragma clang diagnostic ignored "-Wunused-macros"
#pragma clang diagnostic ignored "-Wconversion"
#pragma clang diagnostic ignored "-Wformat-nonliteral"
#pragma clang diagnostic ignored "-Wpartial-availability"
#pragma clang diagnostic ignored "-Wdouble-promotion"
#pragma clang diagnostic ignored "-Wselector"
#pragma clang diagnostic ignored "-Wgnu"
#define MIN_TOGGLE_DURATION 0.2
#define MAX_TOGGLE_DURATION 0.4
#define SCROLL_DURATION 0.4
#define INSERT_DURATION 0.4
#define DECELERATE_THRESHOLD 0.1
#define SCROLL_SPEED_THRESHOLD 2.0
#define SCROLL_DISTANCE_THRESHOLD 0.1
#define DECELERATION_MULTIPLIER 30.0
#define FLOAT_ERROR_MARGIN 0.000001
#ifdef ICAROUSEL_MACOS
#define MAX_VISIBLE_ITEMS 50
#else
#define MAX_VISIBLE_ITEMS 30
#endif
@implementation NSObject (iCarousel)
- (NSUInteger)numberOfPlaceholdersInCarousel:(__unused iCarousel *)carousel { return 0; }
- (void)carouselWillBeginScrollingAnimation:(__unused iCarousel *)carousel {}
- (void)carouselDidEndScrollingAnimation:(__unused iCarousel *)carousel {}
- (void)carouselDidScroll:(__unused iCarousel *)carousel {}
- (void)carouselCurrentItemIndexDidChange:(__unused iCarousel *)carousel {}
- (void)carouselWillBeginDragging:(__unused iCarousel *)carousel {}
- (void)carouselDidEndDragging:(__unused iCarousel *)carousel willDecelerate:(__unused BOOL)decelerate {}
- (void)carouselWillBeginDecelerating:(__unused iCarousel *)carousel {}
- (void)carouselDidEndDecelerating:(__unused iCarousel *)carousel {}
- (BOOL)carousel:(__unused iCarousel *)carousel shouldSelectItemAtIndex:(__unused NSInteger)index { return YES; }
- (void)carousel:(__unused iCarousel *)carousel didSelectItemAtIndex:(__unused NSInteger)index {}
- (CGFloat)carouselItemWidth:(__unused iCarousel *)carousel { return 0; }
- (CATransform3D)carousel:(__unused iCarousel *)carousel
itemTransformForOffset:(__unused CGFloat)offset
baseTransform:(CATransform3D)transform { return transform; }
- (CGFloat)carousel:(__unused iCarousel *)carousel
valueForOption:(__unused iCarouselOption)option
withDefault:(CGFloat)value { return value; }
@end
@interface iCarousel ()
@property (nonatomic, strong) UIView *contentView;
@property (nonatomic, strong) NSMutableDictionary *itemViews;
@property (nonatomic, strong) NSMutableSet *itemViewPool;
@property (nonatomic, strong) NSMutableSet *placeholderViewPool;
@property (nonatomic, assign) CGFloat previousScrollOffset;
@property (nonatomic, assign) NSInteger previousItemIndex;
@property (nonatomic, assign) NSInteger numberOfPlaceholdersToShow;
@property (nonatomic, assign) NSInteger numberOfVisibleItems;
@property (nonatomic, assign) CGFloat itemWidth;
@property (nonatomic, assign) CGFloat offsetMultiplier;
@property (nonatomic, assign) CGFloat startOffset;
@property (nonatomic, assign) CGFloat endOffset;
@property (nonatomic, assign) NSTimeInterval scrollDuration;
@property (nonatomic, assign, getter = isScrolling) BOOL scrolling;
@property (nonatomic, assign) NSTimeInterval startTime;
@property (nonatomic, assign) NSTimeInterval lastTime;
@property (nonatomic, assign) CGFloat startVelocity;
@property (nonatomic, strong) NSTimer *timer;
@property (nonatomic, assign, getter = isDecelerating) BOOL decelerating;
@property (nonatomic, assign) CGFloat previousTranslation;
@property (nonatomic, assign, getter = isWrapEnabled) BOOL wrapEnabled;
@property (nonatomic, assign, getter = isDragging) BOOL dragging;
@property (nonatomic, assign) BOOL didDrag;
@property (nonatomic, assign) NSTimeInterval toggleTime;
NSComparisonResult compareViewDepth(UIView *view1, UIView *view2, iCarousel *self);
@end
@implementation iCarousel
#pragma mark -
#pragma mark Initialisation
// 初始化
- (void)setUp
{
_decelerationRate = 0.95;
_scrollEnabled = YES;
_bounces = YES;
_offsetMultiplier = 1.0;
_perspective = -1.0/500.0;
_contentOffset = CGSizeZero;
_viewpointOffset = CGSizeZero;
_scrollSpeed = 1.0;
_bounceDistance = 1.0;
_stopAtItemBoundary = YES;
_scrollToItemBoundary = YES;
_ignorePerpendicularSwipes = YES;
_centerItemWhenSelected = YES;
_contentView = [[UIView alloc] initWithFrame:self.bounds];
#ifdef ICAROUSEL_IOS
_contentView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
//add pan gesture recogniser
UIPanGestureRecognizer *panGesture = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(didPan:)];
panGesture.delegate = (id <UIGestureRecognizerDelegate>)self;
[_contentView addGestureRecognizer:panGesture];
//add tap gesture recogniser
UITapGestureRecognizer *tapGesture = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(didTap:)];
tapGesture.delegate = (id <UIGestureRecognizerDelegate>)self;
[_contentView addGestureRecognizer:tapGesture];
//set up accessibility
self.accessibilityTraits = UIAccessibilityTraitAllowsDirectInteraction;
self.isAccessibilityElement = YES;
#else
[_contentView setWantsLayer:YES];
#endif
[self addSubview:_contentView];
if (_dataSource)
{
[self reloadData];
}
}
#ifndef USING_CHAMELEON
- (id)initWithCoder:(NSCoder *)aDecoder
{
if ((self = [super initWithCoder:aDecoder]))
{
[self setUp];
if (self.superview)
{
[self startAnimation];
}
}
return self;
}
#endif
#ifdef ICAROUSEL_IOS
// iOS
- (id)initWithFrame:(CGRect)frame
#else
// Mac
- (id)initWithFrame:(NSRect)frame
#endif
{
if ((self = [super initWithFrame:frame]))
{
[self setUp];
}
return self;
}
- (void)dealloc
{
[self stopAnimation];
}
// setDatasource 时刷新
- (void)setDataSource:(id<iCarouselDataSource>)dataSource
{
if (_dataSource != dataSource)
{
_dataSource = dataSource;
if (_dataSource)
{
[self reloadData];
}
}
}
// setDelegate 时 setNeedsLayout 重新布局
- (void)setDelegate:(id<iCarouselDelegate>)delegate
{
if (_delegate != delegate)
{
_delegate = delegate;
if (_delegate && _dataSource)
{
[self setNeedsLayout];
}
}
}
- (void)setType:(iCarouselType)type
{
if (_type != type)
{
_type = type;
[self layOutItemViews];
}
}
- (void)setVertical:(BOOL)vertical
{
if (_vertical != vertical)
{
_vertical = vertical;
[self layOutItemViews];
}
}
- (void)setScrollOffset:(CGFloat)scrollOffset
{
_scrolling = NO;
_decelerating = NO;
_startOffset = scrollOffset;
_endOffset = scrollOffset;
if (fabs(_scrollOffset - scrollOffset) > 0.0)
{
_scrollOffset = scrollOffset;
[self depthSortViews];
[self didScroll];
}
}
- (void)setCurrentItemIndex:(NSInteger)currentItemIndex
{
[self setScrollOffset:currentItemIndex];
}
- (void)setPerspective:(CGFloat)perspective
{
_perspective = perspective;
[self transformItemViews];
}
- (void)setViewpointOffset:(CGSize)viewpointOffset
{
if (!CGSizeEqualToSize(_viewpointOffset, viewpointOffset))
{
_viewpointOffset = viewpointOffset;
[self transformItemViews];
}
}
- (void)setContentOffset:(CGSize)contentOffset
{
if (!CGSizeEqualToSize(_contentOffset, contentOffset))
{
_contentOffset = contentOffset;
[self layOutItemViews];
}
}
- (void)setAutoscroll:(CGFloat)autoscroll
{
_autoscroll = autoscroll;
if (autoscroll != 0.0) [self startAnimation];
}
- (void)pushAnimationState:(BOOL)enabled
{
[CATransaction begin];
[CATransaction setDisableActions:!enabled];
}
- (void)popAnimationState
{
[CATransaction commit];
}
#pragma mark -
#pragma mark View management
- (NSArray *)indexesForVisibleItems
{
return [[_itemViews allKeys] sortedArrayUsingSelector:@selector(compare:)];
}
- (NSArray *)visibleItemViews
{
NSArray *indexes = [self indexesForVisibleItems];
return [_itemViews objectsForKeys:indexes notFoundMarker:[NSNull null]];
}
- (UIView *)itemViewAtIndex:(NSInteger)index
{
return _itemViews[@(index)];
}
- (UIView *)currentItemView
{
return [self itemViewAtIndex:self.currentItemIndex];
}
- (NSInteger)indexOfItemView:(UIView *)view
{
NSInteger index = [[_itemViews allValues] indexOfObject:view];
if (index != NSNotFound)
{
return [[_itemViews allKeys][index] integerValue];
}
return NSNotFound;
}
- (NSInteger)indexOfItemViewOrSubview:(UIView *)view
{
NSInteger index = [self indexOfItemView:view];
if (index == NSNotFound && view.superview && view != _contentView)
{
return [self indexOfItemViewOrSubview:(UIView *__nonnull)view.superview];
}
return index;
}
- (UIView *)itemViewAtPoint:(CGPoint)point
{
for (UIView *view in [[[_itemViews allValues] sortedArrayUsingFunction:(NSInteger (*)(id, id, void *))compareViewDepth context:(__bridge void *)self] reverseObjectEnumerator])
{
if ([view.superview.layer hitTest:point])
{
return view;
}
}
return nil;
}
- (void)setItemView:(UIView *)view forIndex:(NSInteger)index
{
_itemViews[@(index)] = view;
}
- (void)removeViewAtIndex:(NSInteger)index
{
NSMutableDictionary *newItemViews = [NSMutableDictionary dictionaryWithCapacity:[_itemViews count] - 1];
for (NSNumber *number in [self indexesForVisibleItems])
{
NSInteger i = [number integerValue];
if (i < index)
{
newItemViews[number] = _itemViews[number];
}
else if (i > index)
{
newItemViews[@(i - 1)] = _itemViews[number];
}
}
self.itemViews = newItemViews;
}
- (void)insertView:(UIView *)view atIndex:(NSInteger)index
{
NSMutableDictionary *newItemViews = [NSMutableDictionary dictionaryWithCapacity:[_itemViews count] + 1];
for (NSNumber *number in [self indexesForVisibleItems])
{
NSInteger i = [number integerValue];
if (i < index)
{
newItemViews[number] = _itemViews[number];
}
else
{
newItemViews[@(i + 1)] = _itemViews[number];
}
}
if (view)
{
[self setItemView:view forIndex:index];
}
self.itemViews = newItemViews;
}
#pragma mark -
#pragma mark View layout
// 随着偏移改变透明度
- (CGFloat)alphaForItemWithOffset:(CGFloat)offset
{
CGFloat fadeMin = (CGFloat)-INFINITY;
CGFloat fadeMax = (CGFloat)INFINITY;
CGFloat fadeRange = 1.0;
CGFloat fadeMinAlpha = 0.0;
switch (_type)
{
case iCarouselTypeTimeMachine:
{
fadeMax = 0.0;
break;
}
case iCarouselTypeInvertedTimeMachine:
{
fadeMin = 0.0;
break;
}
case iCarouselTypeCoverFlow:
case iCarouselTypeCoverFlow2:
case iCarouselTypeCustom:
case iCarouselTypeCylinder:
case iCarouselTypeInvertedCylinder:
case iCarouselTypeRotary:
case iCarouselTypeInvertedRotary:
case iCarouselTypeWheel:
case iCarouselTypeInvertedWheel:
case iCarouselTypeLinear:
{
//do nothing
}
}
fadeMin = [self valueForOption:iCarouselOptionFadeMin withDefault:fadeMin];
fadeMax = [self valueForOption:iCarouselOptionFadeMax withDefault:fadeMax];
fadeRange = [self valueForOption:iCarouselOptionFadeRange withDefault:fadeRange];
fadeMinAlpha = [self valueForOption:iCarouselOptionFadeMinAlpha withDefault:fadeMinAlpha];
#ifdef ICAROUSEL_MACOS
if (_vertical)
{
//invert
offset = -offset;
}
#endif
CGFloat factor = 0.0;
if (offset > fadeMax)
{
factor = offset - fadeMax;
}
else if (offset < fadeMin)
{
factor = fadeMin - offset;
}
return 1.0 - MIN(factor, fadeRange) / fadeRange * (1.0 - fadeMinAlpha);
}
- (CGFloat)valueForOption:(iCarouselOption)option withDefault:(CGFloat)value
{
return _delegate? [_delegate carousel:self valueForOption:option withDefault:value]: value;
}
- (CATransform3D)transformForItemViewWithOffset:(CGFloat)offset
{
//set up base transform
CATransform3D transform = CATransform3DIdentity;
transform.m34 = _perspective;
transform = CATransform3DTranslate(transform, -_viewpointOffset.width, -_viewpointOffset.height, 0.0);
//perform transform
switch (_type)
{
case iCarouselTypeCustom:
{
return [_delegate carousel:self itemTransformForOffset:offset baseTransform:transform];
}
case iCarouselTypeLinear:
{
CGFloat spacing = [self valueForOption:iCarouselOptionSpacing withDefault:1.0];
if (_vertical)
{
return CATransform3DTranslate(transform, 0.0, offset * _itemWidth * spacing, 0.0);
}
else
{
return CATransform3DTranslate(transform, offset * _itemWidth * spacing, 0.0, 0.0);
}
}
case iCarouselTypeRotary:
case iCarouselTypeInvertedRotary:
{
CGFloat count = [self circularCarouselItemCount];
CGFloat spacing = [self valueForOption:iCarouselOptionSpacing withDefault:1.0];
CGFloat arc = [self valueForOption:iCarouselOptionArc withDefault:M_PI * 2.0];
CGFloat radius = [self valueForOption:iCarouselOptionRadius withDefault:MAX(_itemWidth * spacing / 2.0, _itemWidth * spacing / 2.0 / tan(arc/2.0/count))];
CGFloat angle = [self valueForOption:iCarouselOptionAngle withDefault:offset / count * arc];
if (_type == iCarouselTypeInvertedRotary)
{
radius = -radius;
angle = -angle;
}
if (_vertical)
{
return CATransform3DTranslate(transform, 0.0, radius * sin(angle), radius * cos(angle) - radius);
}
else
{
return CATransform3DTranslate(transform, radius * sin(angle), 0.0, radius * cos(angle) - radius);
}
}
case iCarouselTypeCylinder:
case iCarouselTypeInvertedCylinder:
{
CGFloat count = [self circularCarouselItemCount];
CGFloat spacing = [self valueForOption:iCarouselOptionSpacing withDefault:1.0];
CGFloat arc = [self valueForOption:iCarouselOptionArc withDefault:M_PI * 2.0];
CGFloat radius = [self valueForOption:iCarouselOptionRadius withDefault:MAX(0.01, _itemWidth * spacing / 2.0 / tan(arc/2.0/count))];
CGFloat angle = [self valueForOption:iCarouselOptionAngle withDefault:offset / count * arc];
if (_type == iCarouselTypeInvertedCylinder)
{
radius = -radius;
angle = -angle;
}
if (_vertical)
{
transform = CATransform3DTranslate(transform, 0.0, 0.0, -radius);
transform = CATransform3DRotate(transform, angle, -1.0, 0.0, 0.0);
return CATransform3DTranslate(transform, 0.0, 0.0, radius + 0.01);
}
else
{
transform = CATransform3DTranslate(transform, 0.0, 0.0, -radius);
transform = CATransform3DRotate(transform, angle, 0.0, 1.0, 0.0);
return CATransform3DTranslate(transform, 0.0, 0.0, radius + 0.01);
}
}
case iCarouselTypeWheel:
case iCarouselTypeInvertedWheel:
{
CGFloat count = [self circularCarouselItemCount];
CGFloat spacing = [self valueForOption:iCarouselOptionSpacing withDefault:1.0];
CGFloat arc = [self valueForOption:iCarouselOptionArc withDefault:M_PI * 2.0];
CGFloat radius = [self valueForOption:iCarouselOptionRadius withDefault:_itemWidth * spacing * count / arc];
CGFloat angle = [self valueForOption:iCarouselOptionAngle withDefault:arc / count];
if (_type == iCarouselTypeInvertedWheel)
{
radius = -radius;
angle = -angle;
}
if (_vertical)
{
transform = CATransform3DTranslate(transform, -radius, 0.0, 0.0);
transform = CATransform3DRotate(transform, angle * offset, 0.0, 0.0, 1.0);
return CATransform3DTranslate(transform, radius, 0.0, offset * 0.01);
}
else
{
transform = CATransform3DTranslate(transform, 0.0, radius, 0.0);
transform = CATransform3DRotate(transform, angle * offset, 0.0, 0.0, 1.0);
return CATransform3DTranslate(transform, 0.0, -radius, offset * 0.01);
}
}
case iCarouselTypeCoverFlow:
case iCarouselTypeCoverFlow2:
{
CGFloat tilt = [self valueForOption:iCarouselOptionTilt withDefault:0.9];
CGFloat spacing = [self valueForOption:iCarouselOptionSpacing withDefault:0.25];
CGFloat clampedOffset = MAX(-1.0, MIN(1.0, offset));
if (_type == iCarouselTypeCoverFlow2)
{
if (_toggle > 0.0)
{
if (offset <= -0.5)
{
clampedOffset = -1.0;
}
else if (offset <= 0.5)
{
clampedOffset = -_toggle;
}
else if (offset <= 1.5)
{
clampedOffset = 1.0 - _toggle;
}
}
else
{
if (offset > 0.5)
{
clampedOffset = 1.0;
}
else if (offset > -0.5)
{
clampedOffset = -_toggle;
}
else if (offset > -1.5)
{
clampedOffset = - 1.0 - _toggle;
}
}
}
CGFloat x = (clampedOffset * 0.5 * tilt + offset * spacing) * _itemWidth;
CGFloat z = fabs(clampedOffset) * -_itemWidth * 0.5;
if (_vertical)
{
transform = CATransform3DTranslate(transform, 0.0, x, z);
return CATransform3DRotate(transform, -clampedOffset * M_PI_2 * tilt, -1.0, 0.0, 0.0);
}
else
{
transform = CATransform3DTranslate(transform, x, 0.0, z);
return CATransform3DRotate(transform, -clampedOffset * M_PI_2 * tilt, 0.0, 1.0, 0.0);
}
}
case iCarouselTypeTimeMachine:
case iCarouselTypeInvertedTimeMachine:
{
CGFloat tilt = [self valueForOption:iCarouselOptionTilt withDefault:0.3];
CGFloat spacing = [self valueForOption:iCarouselOptionSpacing withDefault:1.0];
if (_type == iCarouselTypeInvertedTimeMachine)
{
tilt = -tilt;
offset = -offset;
}
if (_vertical)
{
#ifdef ICAROUSEL_MACOS
//invert again
tilt = -tilt;
offset = -offset;
#endif
return CATransform3DTranslate(transform, 0.0, offset * _itemWidth * tilt, offset * _itemWidth * spacing);
}
else
{
return CATransform3DTranslate(transform, offset * _itemWidth * tilt, 0.0, offset * _itemWidth * spacing);
}
}
}
}
NSComparisonResult compareViewDepth(UIView *view1, UIView *view2, iCarousel *self)
{
//compare depths
CATransform3D t1 = view1.superview.layer.transform;
CATransform3D t2 = view2.superview.layer.transform;
CGFloat z1 = t1.m13 + t1.m23 + t1.m33 + t1.m43;
CGFloat z2 = t2.m13 + t2.m23 + t2.m33 + t2.m43;
CGFloat difference = z1 - z2;
//if depths are equal, compare distance from current view
if (difference == 0.0)
{
CATransform3D t3 = [self currentItemView].superview.layer.transform;
if (self.vertical)
{
CGFloat y1 = t1.m12 + t1.m22 + t1.m32 + t1.m42;
CGFloat y2 = t2.m12 + t2.m22 + t2.m32 + t2.m42;
CGFloat y3 = t3.m12 + t3.m22 + t3.m32 + t3.m42;
difference = fabs(y2 - y3) - fabs(y1 - y3);
}
else
{
CGFloat x1 = t1.m11 + t1.m21 + t1.m31 + t1.m41;
CGFloat x2 = t2.m11 + t2.m21 + t2.m31 + t2.m41;
CGFloat x3 = t3.m11 + t3.m21 + t3.m31 + t3.m41;
difference = fabs(x2 - x3) - fabs(x1 - x3);
}
}
return (difference < 0.0)? NSOrderedAscending: NSOrderedDescending;
}
#ifdef ICAROUSEL_IOS
- (void)depthSortViews
{
for (UIView *view in [[_itemViews allValues] sortedArrayUsingFunction:(NSInteger (*)(id, id, void *))compareViewDepth context:(__bridge void *)self])
{
[_contentView bringSubviewToFront:(UIView *__nonnull)view.superview];
}
}
#else
- (void)setNeedsLayout
{
[self setNeedsLayout:YES];
}
- (void)depthSortViews
{
//does nothing on Mac OS
}
#endif
- (CGFloat)offsetForItemAtIndex:(NSInteger)index
{
//calculate relative position
CGFloat offset = index - _scrollOffset;
if (_wrapEnabled)
{
if (offset > _numberOfItems/2.0)
{
offset -= _numberOfItems;
}
else if (offset < -_numberOfItems/2.0)
{
offset += _numberOfItems;
}
}
#ifdef ICAROUSEL_MACOS
if (_vertical)
{
//invert transform
offset = -offset;
}
#endif
return offset;
}
- (UIView *)containView:(UIView *)view
{
//set item width
if (!_itemWidth)
{
_itemWidth = _vertical? view.bounds.size.height: view.bounds.size.width;
}
//set container frame
CGRect frame = view.bounds;
frame.size.width = _vertical? frame.size.width: _itemWidth;
frame.size.height = _vertical? _itemWidth: frame.size.height;
UIView *containerView = [[UIView alloc] initWithFrame:frame];
#ifdef ICAROUSEL_MACOS
//clipping works differently on Mac OS
[containerView setBoundsSize:view.frame.size];
#endif
//set view frame
frame = view.frame;
frame.origin.x = (containerView.bounds.size.width - frame.size.width) / 2.0;
frame.origin.y = (containerView.bounds.size.height - frame.size.height) / 2.0;
view.frame = frame;
[containerView addSubview:view];
containerView.layer.opacity = 0;
return containerView;
}
- (void)transformItemView:(UIView *)view atIndex:(NSInteger)index
{
// 计算偏移量
//calculate offset
CGFloat offset = [self offsetForItemAtIndex:index];
// 透明度
//update alpha
view.superview.layer.opacity = [self alphaForItemWithOffset:offset];
#ifdef ICAROUSEL_IOS
//center view
view.superview.center = CGPointMake(self.bounds.size.width/2.0 + _contentOffset.width,
self.bounds.size.height/2.0 + _contentOffset.height);
//enable/disable interaction
view.superview.userInteractionEnabled = (!_centerItemWhenSelected || index == self.currentItemIndex);
//account for retina
view.superview.layer.rasterizationScale = [UIScreen mainScreen].scale;
// 重新布局
[view layoutIfNeeded];
#else
//center view
[view.superview setFrameOrigin:NSMakePoint(self.bounds.size.width/2.0 + _contentOffset.width,
self.bounds.size.height/2.0 + _contentOffset.height)];
view.superview.layer.anchorPoint = CGPointMake(0.5, 0.5);
//account for retina
view.superview.layer.rasterizationScale = view.window.screen.backingScaleFactor;
#endif
//special-case logic for iCarouselTypeCoverFlow2
CGFloat clampedOffset = MAX(-1.0, MIN(1.0, offset));
if (_decelerating || (_scrolling && !_dragging && !_didDrag) || (_autoscroll && !_dragging) ||
(!_wrapEnabled && (_scrollOffset < 0 || _scrollOffset >= _numberOfItems - 1)))
{
if (offset > 0)
{
_toggle = (offset <= 0.5)? -clampedOffset: (1.0 - clampedOffset);
}
else
{
_toggle = (offset > -0.5)? -clampedOffset: (- 1.0 - clampedOffset);
}
}
//calculate transform
CATransform3D transform = [self transformForItemViewWithOffset:offset];
//transform view
view.superview.layer.transform = transform;
//backface culling
BOOL showBackfaces = view.layer.doubleSided;
if (showBackfaces)
{
switch (_type)
{
case iCarouselTypeInvertedCylinder:
{
showBackfaces = NO;
break;
}
case iCarouselTypeCoverFlow:
case iCarouselTypeCoverFlow2:
case iCarouselTypeCustom:
case iCarouselTypeCylinder:
case iCarouselTypeRotary:
case iCarouselTypeInvertedRotary:
case iCarouselTypeWheel:
case iCarouselTypeInvertedWheel:
case iCarouselTypeLinear:
case iCarouselTypeTimeMachine:
case iCarouselTypeInvertedTimeMachine:
{
showBackfaces = YES;
break;
}
}
}
showBackfaces = !![self valueForOption:iCarouselOptionShowBackfaces withDefault:showBackfaces];
//we can't just set the layer.doubleSided property because it doesn't block interaction
//instead we'll calculate if the view is front-facing based on the transform
view.superview.hidden = !(showBackfaces ?: (transform.m33 > 0.0));
}
#ifdef ICAROUSEL_MACOS
- (void)resizeSubviewsWithOldSize:(__unused NSSize)oldSize
{
[self pushAnimationState:NO];
_contentView.frame = self.bounds;
[self layOutItemViews];
[self popAnimationState];
}
#else
- (void)layoutSubviews
{
[super layoutSubviews];
_contentView.frame = self.bounds;
[self layOutItemViews];
}
#endif
- (void)transformItemViews
{
for (NSNumber *number in _itemViews)
{
NSInteger index = [number integerValue];
UIView *view = _itemViews[number];
[self transformItemView:view atIndex:index];
}
}
// 更新item的宽度
- (void)updateItemWidth
{
_itemWidth = [_delegate carouselItemWidth:self] ?: _itemWidth;
if (_numberOfItems > 0)
{
if ([_itemViews count] == 0)
{
[self loadViewAtIndex:0];
}
}
else if (_numberOfPlaceholders > 0)
{
if ([_itemViews count] == 0)
{
[self loadViewAtIndex:-1];
}
}
}
// 更新可见item的数量
- (void)updateNumberOfVisibleItems
{
//get number of visible items
switch (_type)
{
case iCarouselTypeLinear:
{
//exact number required to fill screen
CGFloat spacing = [self valueForOption:iCarouselOptionSpacing withDefault:1.0];
CGFloat width = _vertical ? self.bounds.size.height: self.bounds.size.width;
CGFloat itemWidth = _itemWidth * spacing;
_numberOfVisibleItems = ceil(width / itemWidth) + 2;
break;
}
case iCarouselTypeCoverFlow:
case iCarouselTypeCoverFlow2:
{
//exact number required to fill screen
CGFloat spacing = [self valueForOption:iCarouselOptionSpacing withDefault:0.25];
CGFloat width = _vertical ? self.bounds.size.height: self.bounds.size.width;
CGFloat itemWidth = _itemWidth * spacing;
_numberOfVisibleItems = ceil(width / itemWidth) + 2;
break;
}
case iCarouselTypeRotary:
case iCarouselTypeCylinder:
{
//based on count value
_numberOfVisibleItems = [self circularCarouselItemCount];
break;
}
case iCarouselTypeInvertedRotary:
case iCarouselTypeInvertedCylinder:
{
//TODO: improve this
_numberOfVisibleItems = ceil([self circularCarouselItemCount] / 2.0);
break;
}
case iCarouselTypeWheel:
case iCarouselTypeInvertedWheel:
{
//TODO: improve this
CGFloat count = [self circularCarouselItemCount];
CGFloat spacing = [self valueForOption:iCarouselOptionSpacing withDefault:1.0];
CGFloat arc = [self valueForOption:iCarouselOptionArc withDefault:M_PI * 2.0];
CGFloat radius = [self valueForOption:iCarouselOptionRadius withDefault:_itemWidth * spacing * count / arc];
if (radius - _itemWidth / 2.0 < MIN(self.bounds.size.width, self.bounds.size.height) / 2.0)
{
_numberOfVisibleItems = count;
}
else
{
_numberOfVisibleItems = ceil(count / 2.0) + 1;
}
break;
}
case iCarouselTypeTimeMachine:
case iCarouselTypeInvertedTimeMachine:
case iCarouselTypeCustom:
{
//slightly arbitrary number, chosen for performance reasons
_numberOfVisibleItems = MAX_VISIBLE_ITEMS;
break;
}
}
_numberOfVisibleItems = MIN(MAX_VISIBLE_ITEMS, _numberOfVisibleItems);
_numberOfVisibleItems = [self valueForOption:iCarouselOptionVisibleItems withDefault:_numberOfVisibleItems];
_numberOfVisibleItems = MAX(0, MIN(_numberOfVisibleItems, _numberOfItems + _numberOfPlaceholdersToShow));
}
- (NSInteger)circularCarouselItemCount
{
NSInteger count = 0;
switch (_type)
{
case iCarouselTypeRotary:
case iCarouselTypeInvertedRotary:
case iCarouselTypeCylinder:
case iCarouselTypeInvertedCylinder:
case iCarouselTypeWheel:
case iCarouselTypeInvertedWheel:
{
//slightly arbitrary number, chosen for aesthetic reasons
CGFloat spacing = [self valueForOption:iCarouselOptionSpacing withDefault:1.0];
CGFloat width = _vertical ? self.bounds.size.height: self.bounds.size.width;
count = MIN(MAX_VISIBLE_ITEMS, MAX(12, ceil(width / (spacing * _itemWidth)) * M_PI));
count = MIN(_numberOfItems + _numberOfPlaceholdersToShow, count);
break;
}
case iCarouselTypeCoverFlow:
case iCarouselTypeCoverFlow2:
case iCarouselTypeTimeMachine:
case iCarouselTypeInvertedTimeMachine:
case iCarouselTypeLinear:
case iCarouselTypeCustom:
{
//not used for non-circular carousels
return _numberOfItems + _numberOfPlaceholdersToShow;
}
}
return [self valueForOption:iCarouselOptionCount withDefault:count];
}
- (void)layOutItemViews
{
//bail out if not set up yet
if (!_dataSource || !_contentView)
{
return;
}
//update wrap
switch (_type)
{
case iCarouselTypeRotary:
case iCarouselTypeInvertedRotary:
case iCarouselTypeCylinder:
case iCarouselTypeInvertedCylinder:
case iCarouselTypeWheel:
case iCarouselTypeInvertedWheel:
{
_wrapEnabled = YES;
break;
}
case iCarouselTypeCoverFlow:
case iCarouselTypeCoverFlow2:
case iCarouselTypeTimeMachine:
case iCarouselTypeInvertedTimeMachine:
case iCarouselTypeLinear:
case iCarouselTypeCustom:
{
_wrapEnabled = NO;
break;
}
}
_wrapEnabled = !![self valueForOption:iCarouselOptionWrap withDefault:_wrapEnabled];
//no placeholders on wrapped carousels
_numberOfPlaceholdersToShow = _wrapEnabled? 0: _numberOfPlaceholders;
//set item width
[self updateItemWidth];
//update number of visible items
[self updateNumberOfVisibleItems];
//prevent false index changed event
_previousScrollOffset = self.scrollOffset;
//update offset multiplier
switch (_type)
{
case iCarouselTypeCoverFlow:
case iCarouselTypeCoverFlow2:
{
_offsetMultiplier = 2.0;
break;
}
case iCarouselTypeCylinder:
case iCarouselTypeInvertedCylinder:
case iCarouselTypeWheel:
case iCarouselTypeInvertedWheel:
case iCarouselTypeRotary:
case iCarouselTypeInvertedRotary:
case iCarouselTypeTimeMachine:
case iCarouselTypeInvertedTimeMachine:
case iCarouselTypeLinear:
case iCarouselTypeCustom:
{
_offsetMultiplier = 1.0;
break;
}
}
_offsetMultiplier = [self valueForOption:iCarouselOptionOffsetMultiplier withDefault:_offsetMultiplier];
//align
if (!_scrolling && !_decelerating && !_autoscroll)
{
if (_scrollToItemBoundary && self.currentItemIndex != -1)
{
[self scrollToItemAtIndex:self.currentItemIndex animated:YES];
}
else
{
_scrollOffset = [self clampedOffset:_scrollOffset];
}
}
//update views
[self didScroll];
}
#pragma mark -
#pragma mark View queing
- (void)queueItemView:(UIView *)view
{
if (view)
{
[_itemViewPool addObject:view];
}
}
- (void)queuePlaceholderView:(UIView *)view
{
if (view)
{
[_placeholderViewPool addObject:view];
}
}
- (UIView *)dequeueItemView
{
UIView *view = [_itemViewPool anyObject];
if (view)
{
[_itemViewPool removeObject:view];
}
return view;
}
- (UIView *)dequeuePlaceholderView
{
UIView *view = [_placeholderViewPool anyObject];
if (view)
{
[_placeholderViewPool removeObject:view];
}
return view;
}
#pragma mark -
#pragma mark View loading
- (UIView *)loadViewAtIndex:(NSInteger)index withContainerView:(UIView *)containerView
{
[self pushAnimationState:NO];
// 获取代理中的新视图
UIView *view = nil;
if (index < 0)
{
view = [_dataSource carousel:self placeholderViewAtIndex:(NSInteger)(ceil((CGFloat)_numberOfPlaceholdersToShow/2.0)) + index reusingView:[self dequeuePlaceholderView]];
}
else if (index >= _numberOfItems)
{
view = [_dataSource carousel:self placeholderViewAtIndex:_numberOfPlaceholdersToShow/2.0 + index - _numberOfItems reusingView:[self dequeuePlaceholderView]];
}
else
{
view = [_dataSource carousel:self viewForItemAtIndex:index reusingView:[self dequeueItemView]];
}
if (view == nil)
{
view = [[UIView alloc] init];
}
[self setItemView:view forIndex:index];
if (containerView)
{
// 移除旧视图， 用 containerView 添加新视图
// 获取旧的 view
//get old item view
UIView *oldItemView = [containerView.subviews lastObject];
if (index < 0 || index >= _numberOfItems)
{
[self queuePlaceholderView:oldItemView];
}
else
{
[self queueItemView:oldItemView];
}
// 设置容器的frame
//set container frame
CGRect frame = containerView.bounds;
if(_vertical)
{
frame.size.width = view.frame.size.width;
frame.size.height = MIN(_itemWidth, view.frame.size.height);
}
else
{
frame.size.width = MIN(_itemWidth, view.frame.size.width);
frame.size.height = view.frame.size.height;
}
containerView.bounds = frame;
#ifdef ICAROUSEL_MACOS
//clipping works differently on Mac OS
[containerView setBoundsSize:view.frame.size];
#endif
//set view frame
frame = view.frame;
frame.origin.x = (containerView.bounds.size.width - frame.size.width) / 2.0;
frame.origin.y = (containerView.bounds.size.height - frame.size.height) / 2.0;
view.frame = frame;
// 更新视图坐标
//switch views
[oldItemView removeFromSuperview];
[containerView addSubview:view];
}
else
{
[_contentView addSubview:[self containView:view]];
}
view.superview.layer.opacity = 0.0;
[self transformItemView:view atIndex:index];
[self popAnimationState];
return view;
}
- (UIView *)loadViewAtIndex:(NSInteger)index
{
return [self loadViewAtIndex:index withContainerView:nil];
}
- (void)loadUnloadViews
{
//set item width
[self updateItemWidth];
//update number of visible items
[self updateNumberOfVisibleItems];
// 维护可见视图的下部数据
//calculate visible view indices
NSMutableSet *visibleIndices = [NSMutableSet setWithCapacity:_numberOfVisibleItems];
NSInteger min = -(NSInteger)(ceil((CGFloat)_numberOfPlaceholdersToShow/2.0));
NSInteger max = _numberOfItems - 1 + _numberOfPlaceholdersToShow/2;
NSInteger offset = self.currentItemIndex - _numberOfVisibleItems/2;
if (!_wrapEnabled)
{
offset = MAX(min, MIN(max - _numberOfVisibleItems + 1, offset));
}
for (NSInteger i = 0; i < _numberOfVisibleItems; i++)
{
NSInteger index = i + offset;
if (_wrapEnabled)
{
index = [self clampedIndex:index];
}
CGFloat alpha = [self alphaForItemWithOffset:[self offsetForItemAtIndex:index]];
if (alpha)
{
//only add views with alpha > 0
[visibleIndices addObject:@(index)];
}
}
// 移除视野范围外的视图
//remove offscreen views
for (NSNumber *number in [_itemViews allKeys])
{
if (![visibleIndices containsObject:number])
{
UIView *view = _itemViews[number];
if ([number integerValue] < 0 || [number integerValue] >= _numberOfItems)
{
[self queuePlaceholderView:view];
}
else
{
[self queueItemView:view];
}
[view.superview removeFromSuperview];
[(NSMutableDictionary *)_itemViews removeObjectForKey:number];
}
}
// 新增视野内的全部视图
//add onscreen views
for (NSNumber *number in visibleIndices)
{
UIView *view = _itemViews[number];
if (view == nil)
{
// 加载代理视图
[self loadViewAtIndex:[number integerValue]];
}
}
}
- (void)reloadData
{
//remove old views
for (UIView *view in [_itemViews allValues])
{
[view.superview removeFromSuperview];
}
//bail out if not set up yet
if (!_dataSource || !_contentView)
{
return;
}
//get number of items and placeholders
_numberOfVisibleItems = 0;
_numberOfItems = [_dataSource numberOfItemsInCarousel:self];
_numberOfPlaceholders = [_dataSource numberOfPlaceholdersInCarousel:self];
//reset view pools
self.itemViews = [NSMutableDictionary dictionary];
self.itemViewPool = [NSMutableSet set];
self.placeholderViewPool = [NSMutableSet setWithCapacity:_numberOfPlaceholders];
//layout views
[self setNeedsLayout];
//fix scroll offset
if (_numberOfItems > 0 && _scrollOffset < 0.0)
{
[self scrollToItemAtIndex:0 animated:(_numberOfPlaceholders > 0)];
}
}
#pragma mark -
#pragma mark Scrolling
- (NSInteger)clampedIndex:(NSInteger)index
{
if (_numberOfItems == 0)
{
return -1;
}
else if (_wrapEnabled)
{
return index - floor((CGFloat)index / (CGFloat)_numberOfItems) * _numberOfItems;
}
else
{
return MIN(MAX(0, index), MAX(0, _numberOfItems - 1));
}
}
- (CGFloat)clampedOffset:(CGFloat)offset
{
if (_numberOfItems == 0)
{
return -1.0;
}
else if (_wrapEnabled)
{
return offset - floor(offset / (CGFloat)_numberOfItems) * _numberOfItems;
}
else
{
return MIN(MAX(0.0, offset), MAX(0.0, (CGFloat)_numberOfItems - 1.0));
}
}
- (NSInteger)currentItemIndex
{
return [self clampedIndex:round(_scrollOffset)];
}
- (NSInteger)minScrollDistanceFromIndex:(NSInteger)fromIndex toIndex:(NSInteger)toIndex
{
NSInteger directDistance = toIndex - fromIndex;
if (_wrapEnabled)
{
NSInteger wrappedDistance = MIN(toIndex, fromIndex) + _numberOfItems - MAX(toIndex, fromIndex);
if (fromIndex < toIndex)
{
wrappedDistance = -wrappedDistance;
}
return (ABS(directDistance) <= ABS(wrappedDistance))? directDistance: wrappedDistance;
}
return directDistance;
}
- (CGFloat)minScrollDistanceFromOffset:(CGFloat)fromOffset toOffset:(CGFloat)toOffset
{
CGFloat directDistance = toOffset - fromOffset;
if (_wrapEnabled)
{
CGFloat wrappedDistance = MIN(toOffset, fromOffset) + _numberOfItems - MAX(toOffset, fromOffset);
if (fromOffset < toOffset)
{
wrappedDistance = -wrappedDistance;
}
return (fabs(directDistance) <= fabs(wrappedDistance))? directDistance: wrappedDistance;
}
return directDistance;
}
- (void)scrollByOffset:(CGFloat)offset duration:(NSTimeInterval)duration
{
if (duration > 0.0)
{
_decelerating = NO;
_scrolling = YES;
_startTime = CACurrentMediaTime();
_startOffset = _scrollOffset;
_scrollDuration = duration;
_endOffset = _startOffset + offset;
if (!_wrapEnabled)
{
_endOffset = [self clampedOffset:_endOffset];
}
[_delegate carouselWillBeginScrollingAnimation:self];
[self startAnimation];
}
else
{
self.scrollOffset += offset;
}
}
- (void)scrollToOffset:(CGFloat)offset duration:(NSTimeInterval)duration
{
[self scrollByOffset:[self minScrollDistanceFromOffset:_scrollOffset toOffset:offset] duration:duration];
}
- (void)scrollByNumberOfItems:(NSInteger)itemCount duration:(NSTimeInterval)duration
{
if (duration > 0.0)
{
CGFloat offset = 0.0;
if (itemCount > 0)
{
offset = (floor(_scrollOffset) + itemCount) - _scrollOffset;
}
else if (itemCount < 0)
{
offset = (ceil(_scrollOffset) + itemCount) - _scrollOffset;
}
else
{
offset = round(_scrollOffset) - _scrollOffset;
}
[self scrollByOffset:offset duration:duration];
}
else
{
self.scrollOffset = [self clampedIndex:_previousItemIndex + itemCount];
}
}
- (void)scrollToItemAtIndex:(NSInteger)index duration:(NSTimeInterval)duration
{
[self scrollToOffset:index duration:duration];
}
- (void)scrollToItemAtIndex:(NSInteger)index animated:(BOOL)animated
{
[self scrollToItemAtIndex:index duration:animated? SCROLL_DURATION: 0];
}
- (void)removeItemAtIndex:(NSInteger)index animated:(BOOL)animated
{
index = [self clampedIndex:index];
UIView *itemView = [self itemViewAtIndex:index];
if (animated)
{
#ifdef ICAROUSEL_IOS
[UIView beginAnimations:nil context:nil];
[UIView setAnimationDuration:0.1];
[UIView setAnimationDelegate:itemView.superview];
[UIView setAnimationDidStopSelector:@selector(removeFromSuperview)];
[self performSelector:@selector(queueItemView:) withObject:itemView afterDelay:0.1];
itemView.superview.layer.opacity = 0.0;
[UIView commitAnimations];
[UIView beginAnimations:nil context:nil];
[UIView setAnimationDelay:0.1];
[UIView setAnimationDuration:INSERT_DURATION];
[UIView setAnimationDelegate:self];
[UIView setAnimationDidStopSelector:@selector(depthSortViews)];
[self removeViewAtIndex:index];
_numberOfItems --;
_wrapEnabled = !![self valueForOption:iCarouselOptionWrap withDefault:_wrapEnabled];
[self updateNumberOfVisibleItems];
_scrollOffset = self.currentItemIndex;
[self didScroll];
[UIView commitAnimations];
#else
[NSAnimationContext beginGrouping];
[[NSAnimationContext currentContext] setAllowsImplicitAnimation:YES];
[CATransaction begin];
[CATransaction setAnimationDuration:0.1];
[CATransaction setCompletionBlock:^{
[self queueItemView:itemView];
[itemView.superview removeFromSuperview];
}];
itemView.superview.layer.opacity = 0.0;
[CATransaction commit];
[CATransaction begin];
[CATransaction setAnimationDuration:INSERT_DURATION];
[CATransaction setCompletionBlock:^{
[self depthSortViews];
}];
[self removeViewAtIndex:index];
_numberOfItems --;
_wrapEnabled = !![self valueForOption:iCarouselOptionWrap withDefault:_wrapEnabled];
_scrollOffset = self.currentItemIndex;
[self didScroll];
[CATransaction commit];
[NSAnimationContext endGrouping];
#endif
}
else
{
[self pushAnimationState:NO];
[self queueItemView:itemView];
[itemView.superview removeFromSuperview];
[self removeViewAtIndex:index];
_numberOfItems --;
_wrapEnabled = !![self valueForOption:iCarouselOptionWrap withDefault:_wrapEnabled];
_scrollOffset = self.currentItemIndex;
[self didScroll];
[self depthSortViews];
[self popAnimationState];
}
}
- (void)insertItemAtIndex:(NSInteger)index animated:(BOOL)animated
{
_numberOfItems ++;
_wrapEnabled = !![self valueForOption:iCarouselOptionWrap withDefault:_wrapEnabled];
[self updateNumberOfVisibleItems];
index = [self clampedIndex:index];
[self insertView:nil atIndex:index];
[self loadViewAtIndex:index];
if (fabs(_itemWidth) < FLOAT_ERROR_MARGIN)
{
[self updateItemWidth];
}
if (animated)
{
#ifdef ICAROUSEL_IOS
[UIView beginAnimations:nil context:nil];
[UIView setAnimationDuration:INSERT_DURATION];
[UIView setAnimationDelegate:self];
[UIView setAnimationDidStopSelector:@selector(didScroll)];
[self transformItemViews];
[UIView commitAnimations];
#else
[NSAnimationContext beginGrouping];
[[NSAnimationContext currentContext] setAllowsImplicitAnimation:YES];
[CATransaction begin];
[CATransaction setAnimationDuration:INSERT_DURATION];
[CATransaction setCompletionBlock:^{
[self didScroll];
}];
[self transformItemViews];
[CATransaction commit];
[NSAnimationContext endGrouping];
#endif
}
else
{
[self pushAnimationState:NO];
[self didScroll];
[self popAnimationState];
}
if (_scrollOffset < 0.0)
{
[self scrollToItemAtIndex:0 animated:(animated && _numberOfPlaceholders)];
}
}
- (void)reloadItemAtIndex:(NSInteger)index animated:(BOOL)animated
{
//get container view
UIView *containerView = [[self itemViewAtIndex:index] superview];
if (containerView)
{
if (animated)
{
//fade transition
CATransition *transition = [CATransition animation];
transition.duration = INSERT_DURATION;
transition.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];
transition.type = kCATransitionFade;
[containerView.layer addAnimation:transition forKey:nil];
}
//reload view
[self loadViewAtIndex:index withContainerView:containerView];
}
}
#pragma mark -
#pragma mark Animation
- (void)startAnimation
{
if (!_timer)
{
self.timer = [NSTimer timerWithTimeInterval:1.0/60.0
target:self
selector:@selector(step)
userInfo:nil
repeats:YES];
[[NSRunLoop mainRunLoop] addTimer:_timer forMode:NSDefaultRunLoopMode];
#ifdef ICAROUSEL_IOS
[[NSRunLoop mainRunLoop] addTimer:_timer forMode:UITrackingRunLoopMode];
#endif
// 每秒执行60次step方法
// step的主要怕任务是 通过计算下一步的事物执行流程
// 最后会执行didScroll来执行最后的视图变更
}
}
// 停止动画
- (void)stopAnimation
{
[_timer invalidate];
_timer = nil;
}
- (CGFloat)decelerationDistance
{
CGFloat acceleration = -_startVelocity * DECELERATION_MULTIPLIER * (1.0 - _decelerationRate);
return -pow(_startVelocity, 2.0) / (2.0 * acceleration);
}
- (BOOL)shouldDecelerate
{
return (fabs(_startVelocity) > SCROLL_SPEED_THRESHOLD) &&
(fabs([self decelerationDistance]) > DECELERATE_THRESHOLD);
}
- (BOOL)shouldScroll
{
return (fabs(_startVelocity) > SCROLL_SPEED_THRESHOLD) &&
(fabs(_scrollOffset - self.currentItemIndex) > SCROLL_DISTANCE_THRESHOLD);
}
- (void)startDecelerating
{
CGFloat distance = [self decelerationDistance];
_startOffset = _scrollOffset;
_endOffset = _startOffset + distance;
if (_pagingEnabled)
{
if (distance > 0.0)
{
_endOffset = ceil(_startOffset);
}
else
{
_endOffset = floor(_startOffset);
}
}
else if (_stopAtItemBoundary)
{
if (distance > 0.0)
{
_endOffset = ceil(_endOffset);
}
else
{
_endOffset = floor(_endOffset);
}
}
if (!_wrapEnabled)
{
if (_bounces)
{
_endOffset = MAX(-_bounceDistance, MIN(_numberOfItems - 1.0 + _bounceDistance, _endOffset));
}
else
{
_endOffset = [self clampedOffset:_endOffset];
}
}
distance = _endOffset - _startOffset;
_startTime = CACurrentMediaTime();
_scrollDuration = fabs(distance) / fabs(0.5 * _startVelocity);
if (distance != 0.0)
{
_decelerating = YES;
[self startAnimation];
}
}
- (CGFloat)easeInOut:(CGFloat)time
{
return (time < 0.5)? 0.5 * pow(time * 2.0, 3.0): 0.5 * pow(time * 2.0 - 2.0, 3.0) + 1.0;
}
- (void)step
{
[self pushAnimationState:NO];
NSTimeInterval currentTime = CACurrentMediaTime();
double delta = currentTime - _lastTime;
_lastTime = currentTime;
if (_scrolling && !_dragging)
{
NSTimeInterval time = MIN(1.0, (currentTime - _startTime) / _scrollDuration);
delta = [self easeInOut:time];
_scrollOffset = _startOffset + (_endOffset - _startOffset) * delta;
[self didScroll];
if (time >= 1.0)
{
_scrolling = NO;
[self depthSortViews];
[self pushAnimationState:YES];
[_delegate carouselDidEndScrollingAnimation:self];
[self popAnimationState];
}
}
else if (_decelerating)
{
CGFloat time = MIN(_scrollDuration, currentTime - _startTime);
CGFloat acceleration = -_startVelocity/_scrollDuration;
CGFloat distance = _startVelocity * time + 0.5 * acceleration * pow(time, 2.0);
_scrollOffset = _startOffset + distance;
[self didScroll];
if (fabs(time - _scrollDuration) < FLOAT_ERROR_MARGIN)
{
_decelerating = NO;
[self pushAnimationState:YES];
[_delegate carouselDidEndDecelerating:self];
[self popAnimationState];
if ((_scrollToItemBoundary || fabs(_scrollOffset - [self clampedOffset:_scrollOffset]) > FLOAT_ERROR_MARGIN) && !_autoscroll)
{
if (fabs(_scrollOffset - self.currentItemIndex) < FLOAT_ERROR_MARGIN)
{
//call scroll to trigger events for legacy support reasons
//even though technically we don't need to scroll at all
[self scrollToItemAtIndex:self.currentItemIndex duration:0.01];
}
else
{
[self scrollToItemAtIndex:self.currentItemIndex animated:YES];
}
}
else
{
CGFloat difference = round(_scrollOffset) - _scrollOffset;
if (difference > 0.5)
{
difference = difference - 1.0;
}
else if (difference < -0.5)
{
difference = 1.0 + difference;
}
_toggleTime = currentTime - MAX_TOGGLE_DURATION * fabs(difference);
_toggle = MAX(-1.0, MIN(1.0, -difference));
}
}
}
else if (_autoscroll && !_dragging)
{
//autoscroll goes backwards from what you'd expect, for historical reasons
self.scrollOffset = [self clampedOffset:_scrollOffset - delta * _autoscroll];
}
else if (fabs(_toggle) > FLOAT_ERROR_MARGIN)
{
NSTimeInterval toggleDuration = _startVelocity? MIN(1.0, MAX(0.0, 1.0 / fabs(_startVelocity))): 1.0;
toggleDuration = MIN_TOGGLE_DURATION + (MAX_TOGGLE_DURATION - MIN_TOGGLE_DURATION) * toggleDuration;
NSTimeInterval time = MIN(1.0, (currentTime - _toggleTime) / toggleDuration);
delta = [self easeInOut:time];
_toggle = (_toggle < 0.0)? (delta - 1.0): (1.0 - delta);
[self didScroll];
}
else if (!_autoscroll)
{
[self stopAnimation];
}
[self popAnimationState];
}
#ifdef ICAROUSEL_IOS
- (void)didMoveToSuperview
#else
- (void)viewDidMoveToSuperview
#endif
{
if (self.superview)
{
[self startAnimation];
}
else
{
[self stopAnimation];
}
}
// 应该是模仿系统
/*
关键流程
----- 检查视图index是否改变
----- loadUnloadViews 新旧视图的更新和维护
----- transformItemView 视图变更过程
----- 通知代理执行相关代理方法进行重新绘制或数据变更
----- 更新控件相关数据参数
*/
- (void)didScroll
{
if (_wrapEnabled || !_bounces)
{
_scrollOffset = [self clampedOffset:_scrollOffset];
}
else
{
CGFloat min = -_bounceDistance;
CGFloat max = MAX(_numberOfItems - 1, 0.0) + _bounceDistance;
if (_scrollOffset < min)
{
_scrollOffset = min;
_startVelocity = 0.0;
}
else if (_scrollOffset > max)
{
_scrollOffset = max;
_startVelocity = 0.0;
}
}
//check if index has changed
NSInteger difference = [self minScrollDistanceFromIndex:self.currentItemIndex toIndex:self.previousItemIndex];
if (difference)
{
_toggleTime = CACurrentMediaTime();
_toggle = MAX(-1, MIN(1, difference));
#ifdef ICAROUSEL_MACOS
if (_vertical)
{
//invert toggle
_toggle = -_toggle;
}
#endif
[self startAnimation];
}
[self loadUnloadViews];
[self transformItemViews];
//notify delegate of offset change
if (fabs(_scrollOffset - _previousScrollOffset) > FLOAT_ERROR_MARGIN)
{
[self pushAnimationState:YES];
[_delegate carouselDidScroll:self];
[self popAnimationState];
}
//notify delegate of index change
if (_previousItemIndex != self.currentItemIndex)
{
[self pushAnimationState:YES];
[_delegate carouselCurrentItemIndexDidChange:self];
[self popAnimationState];
}
//update previous index
_previousScrollOffset = _scrollOffset;
_previousItemIndex = self.currentItemIndex;
}
#ifdef ICAROUSEL_IOS
#pragma mark -
#pragma mark Gestures and taps
- (NSInteger)viewOrSuperviewIndex:(UIView *)view
{
if (view == nil || view == _contentView)
{
return NSNotFound;
}
NSInteger index = [self indexOfItemView:view];
if (index == NSNotFound)
{
return [self viewOrSuperviewIndex:view.superview];
}
return index;
}
- (BOOL)viewOrSuperview:(UIView *)view implementsSelector:(SEL)selector
{
if (!view || view == self.contentView)
{
return NO;
}
//thanks to @mattjgalloway and @shaps for idea
//https://gist.github.com/mattjgalloway/6279363
//https://gist.github.com/shaps80/6279008
Class viewClass = [view class];
while (viewClass && viewClass != [UIView class])
{
unsigned int numberOfMethods;
Method *methods = class_copyMethodList(viewClass, &numberOfMethods);
for (unsigned int i = 0; i < numberOfMethods; i++)
{
if (method_getName(methods[i]) == selector)
{
free(methods);
return YES;
}
}
if (methods) free(methods);
viewClass = [viewClass superclass];
}
return [self viewOrSuperview:view.superview implementsSelector:selector];
}
- (id)viewOrSuperview:(UIView *)view ofClass:(Class)class
{
if (!view || view == self.contentView)
{
return nil;
}
else if ([view isKindOfClass:class])
{
return view;
}
return [self viewOrSuperview:view.superview ofClass:class];
}
// 手势的代理
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gesture shouldReceiveTouch:(UITouch *)touch
{
if (_scrollEnabled)
{
_dragging = NO;
_scrolling = NO;
_decelerating = NO;
}
if ([gesture isKindOfClass:[UITapGestureRecognizer class]])
{
//handle tap
NSInteger index = [self viewOrSuperviewIndex:touch.view];
if (index == NSNotFound && _centerItemWhenSelected)
{
//view is a container view
index = [self viewOrSuperviewIndex:[touch.view.subviews lastObject]];
}
if (index != NSNotFound)
{
if ([self viewOrSuperview:touch.view implementsSelector:@selector(touchesBegan:withEvent:)])
{
return NO;
}
}
}
else if ([gesture isKindOfClass:[UIPanGestureRecognizer class]])
{
if (!_scrollEnabled)
{
return NO;
}
else if ([self viewOrSuperview:touch.view implementsSelector:@selector(touchesMoved:withEvent:)])
{
UIScrollView *scrollView = [self viewOrSuperview:touch.view ofClass:[UIScrollView class]];
if (scrollView)
{
return !scrollView.scrollEnabled ||
(self.vertical && scrollView.contentSize.height <= scrollView.frame.size.height) ||
(!self.vertical && scrollView.contentSize.width <= scrollView.frame.size.width);
}
if ([self viewOrSuperview:touch.view ofClass:[UIButton class]] ||
[self viewOrSuperview:touch.view ofClass:[UIBarButtonItem class]])
{
return YES;
}
return NO;
}
}
return YES;
}
// 坚挺手势开始的代理方法
- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gesture
{
// 如果是拖拽手势
if ([gesture isKindOfClass:[UIPanGestureRecognizer class]])
{
// 忽略竖直方向的滑动
//ignore vertical swipes
UIPanGestureRecognizer *panGesture = (UIPanGestureRecognizer *)gesture;
CGPoint translation = [panGesture translationInView:self];
if (_ignorePerpendicularSwipes)
{
if (_vertical)
{
return fabs(translation.x) <= fabs(translation.y);
}
else
{
return fabs(translation.x) >= fabs(translation.y);
}
}
}
return YES;
}
// 轻击
- (void)didTap:(UITapGestureRecognizer *)tapGesture
{
//check for tapped view
UIView *itemView = [self itemViewAtPoint:[tapGesture locationInView:_contentView]];
NSInteger index = itemView? [self indexOfItemView:itemView]: NSNotFound;
if (index != NSNotFound)
{
if (!_delegate || [_delegate carousel:self shouldSelectItemAtIndex:index])
{
if ((index != self.currentItemIndex && _centerItemWhenSelected) ||
(index == self.currentItemIndex && _scrollToItemBoundary))
{
[self scrollToItemAtIndex:index animated:YES];
}
[_delegate carousel:self didSelectItemAtIndex:index];
}
else if (_scrollEnabled && _scrollToItemBoundary && _autoscroll)
{
[self scrollToItemAtIndex:self.currentItemIndex animated:YES];
}
}
else
{
[self scrollToItemAtIndex:self.currentItemIndex animated:YES];
}
}
// 拖拽
- (void)didPan:(UIPanGestureRecognizer *)panGesture
{
if (_scrollEnabled && _numberOfItems)
{
switch (panGesture.state)
{
case UIGestureRecognizerStateBegan:
{
_dragging = YES;
_scrolling = NO;
_decelerating = NO;
_previousTranslation = _vertical? [panGesture translationInView:self].y: [panGesture translationInView:self].x;
#if defined(USING_CHAMELEON) && USING_CHAMELEON
_previousTranslation = -_previousTranslation;
#endif
[_delegate carouselWillBeginDragging:self];
break;
}
case UIGestureRecognizerStateEnded:
case UIGestureRecognizerStateCancelled:
case UIGestureRecognizerStateFailed:
{
_dragging = NO;
_didDrag = YES;
if ([self shouldDecelerate])
{
_didDrag = NO;
[self startDecelerating];
}
[self pushAnimationState:YES];
[_delegate carouselDidEndDragging:self willDecelerate:_decelerating];
[self popAnimationState];
if (!_decelerating)
{
if ((_scrollToItemBoundary || fabs(_scrollOffset - [self clampedOffset:_scrollOffset]) > FLOAT_ERROR_MARGIN) && !_autoscroll)
{
if (fabs(_scrollOffset - self.currentItemIndex) < FLOAT_ERROR_MARGIN)
{
//call scroll to trigger events for legacy support reasons
//even though technically we don't need to scroll at all
[self scrollToItemAtIndex:self.currentItemIndex duration:0.01];
}
else if ([self shouldScroll])
{
NSInteger direction = (int)(_startVelocity / fabs(_startVelocity));
[self scrollToItemAtIndex:self.currentItemIndex + direction animated:YES];
}
else
{
[self scrollToItemAtIndex:self.currentItemIndex animated:YES];
}
}
else
{
[self depthSortViews];
}
}
else
{
[self pushAnimationState:YES];
[_delegate carouselWillBeginDecelerating:self];
[self popAnimationState];
}
break;
}
case UIGestureRecognizerStateChanged:
{
CGFloat translation = _vertical? [panGesture translationInView:self].y: [panGesture translationInView:self].x;
CGFloat velocity = _vertical? [panGesture velocityInView:self].y: [panGesture velocityInView:self].x;
#if defined(USING_CHAMELEON) && USING_CHAMELEON
translation = -translation;
velocity = -velocity;
#endif
CGFloat factor = 1.0;
if (!_wrapEnabled && _bounces)
{
factor = 1.0 - MIN(fabs(_scrollOffset - [self clampedOffset:_scrollOffset]),
_bounceDistance) / _bounceDistance;
}
_startVelocity = -velocity * factor * _scrollSpeed / _itemWidth;
_scrollOffset -= (translation - _previousTranslation) * factor * _offsetMultiplier / _itemWidth;
_previousTranslation = translation;
[self didScroll];
break;
}
case UIGestureRecognizerStatePossible:
{
//do nothing
break;
}
}
}
}
#else
#pragma mark -
#pragma mark Mouse control
- (void)mouseDown:(__unused NSEvent *)theEvent
{
_didDrag = NO;
_startVelocity = 0.0;
}
- (void)mouseDragged:(NSEvent *)theEvent
{
_didDrag = YES;
if (_scrollEnabled)
{
if (!_dragging)
{
_dragging = YES;
[_delegate carouselWillBeginDragging:self];
}
_scrolling = NO;
_decelerating = NO;
CGFloat translation = _vertical? [theEvent deltaY]: [theEvent deltaX];
CGFloat factor = 1.0;
if (!_wrapEnabled && _bounces)
{
factor = 1.0 - MIN(fabs(_scrollOffset - [self clampedOffset:_scrollOffset]), _bounceDistance) / _bounceDistance;
}
NSTimeInterval thisTime = [theEvent timestamp];
_startVelocity = -(translation / (thisTime - _startTime)) * factor * _scrollSpeed / _itemWidth;
_startTime = thisTime;
_scrollOffset -= translation * factor * _offsetMultiplier / _itemWidth;
[self pushAnimationState:NO];
[self didScroll];
[self popAnimationState];
}
}
- (void)mouseUp:(NSEvent *)theEvent
{
if (!_didDrag)
{
//convert position to view
CGPoint position = [theEvent locationInWindow];
position = [self convertPoint:position fromView:self.window.contentView];
//check for tapped view
UIView *itemView = [self itemViewAtPoint:position];
NSInteger index = itemView? [self indexOfItemView: itemView]: NSNotFound;
if (index != NSNotFound)
{
if (_centerItemWhenSelected && index != self.currentItemIndex)
{
[self scrollToItemAtIndex:index animated:YES];
}
if (!_delegate || [_delegate carousel:self shouldSelectItemAtIndex:index])
{
[self pushAnimationState:YES];
[_delegate carousel:self didSelectItemAtIndex:index];
[self popAnimationState];
}
}
}
else if (_scrollEnabled)
{
_dragging = NO;
if ([self shouldDecelerate])
{
_didDrag = NO;
[self startDecelerating];
}
[self pushAnimationState:YES];
[_delegate carouselDidEndDragging:self willDecelerate:_decelerating];
[self popAnimationState];
if (!_decelerating && !_autoscroll)
{
if ([self shouldScroll])
{
NSInteger direction = (int)(_startVelocity / fabs(_startVelocity));
[self scrollToItemAtIndex:self.currentItemIndex + direction animated:YES];
}
else
{
[self scrollToItemAtIndex:self.currentItemIndex animated:YES];
}
}
else
{
[self pushAnimationState:YES];
[_delegate carouselWillBeginDecelerating:self];
[self popAnimationState];
}
}
}
#pragma mark -
#pragma mark Keyboard control
- (BOOL)acceptsFirstResponder
{
return YES;
}
- (void)keyDown:(NSEvent *)theEvent
{
NSString *characters = [theEvent charactersIgnoringModifiers];
if (_scrollEnabled && !_scrolling && [characters length])
{
if (_vertical)
{
switch ([characters characterAtIndex:0])
{
case NSUpArrowFunctionKey:
{
[self scrollToItemAtIndex:self.currentItemIndex-1 animated:YES];
break;
}
case NSDownArrowFunctionKey:
{
[self scrollToItemAtIndex:self.currentItemIndex+1 animated:YES];
break;
}
}
}
else
{
switch ([characters characterAtIndex:0])
{
case NSLeftArrowFunctionKey:
{
[self scrollToItemAtIndex:self.currentItemIndex-1 animated:YES];
break;
}
case NSRightArrowFunctionKey:
{
[self scrollToItemAtIndex:self.currentItemIndex+1 animated:YES];
break;
}
}
}
}
}
#endif
@end