iphone上电子书翻页效果的实现

// // LeavesView.h // Leaves // // Created by Tom Brow on 4/18/10. // Copyright 2010 Tom Brow. All rights reserved. // #import <UIKit/UIKit.h> #import <QuartzCore/QuartzCore.h> #import "LeavesCache.h" @protocol LeavesViewDataSource; @protocol LeavesViewDelegate; @interface LeavesView : UIView { CALayer *topPage; CALayer *topPageOverlay; CAGradientLayer *topPageShadow; CALayer *topPageReverse; CALayer *topPageReverseImage; CALayer *topPageReverseOverlay; CAGradientLayer *topPageReverseShading; CALayer *bottomPage; CAGradientLayer *bottomPageShadow; CGFloat leafEdge; NSUInteger currentPageIndex; NSUInteger numberOfPages; id<LeavesViewDelegate> delegate; CGSize pageSize; LeavesCache *pageCache; CGFloat preferredTargetWidth; BOOL backgroundRendering; CGPoint touchBeganPoint; BOOL touchIsActive; CGRect nextPageRect, prevPageRect; BOOL interactionLocked; } @property (assign) id<LeavesViewDataSource> dataSource; @property (assign) id<LeavesViewDelegate> delegate; // the automatically determined width of the interactive areas on either side of the page @property (readonly) CGFloat targetWidth; // set this to a nonzero value to get a targetWidth other than the default @property (assign) CGFloat preferredTargetWidth; // the zero-based index of the page currently being displayed. @property (assign) NSUInteger currentPageIndex; // If backgroundRendering is YES, some pages not currently being displayed will be pre-rendered in background threads. // The default value is NO. Only set this to YES if your implementation of the data source methods is thread-safe. @property (assign) BOOL backgroundRendering; // refreshes the contents of all pages via the data source methods, much like -[UITableView reloadData] - (void) reloadData; @end @protocol LeavesViewDataSource <NSObject> - (NSUInteger) numberOfPagesInLeavesView:(LeavesView*)leavesView; - (void) renderPageAtIndex:(NSUInteger)index inContext:(CGContextRef)ctx; @end @protocol LeavesViewDelegate <NSObject> @optional // called when the user touches up on the left or right side of the page, or finishes dragging the page - (void) leavesView:(LeavesView *)leavesView willTurnToPageAtIndex:(NSUInteger)pageIndex; // called when the page-turn animation (following a touch-up or drag) completes - (void) leavesView:(LeavesView *)leavesView didTurnToPageAtIndex:(NSUInteger)pageIndex; @end