#import <UIKit/UIKit.h>

#import "ViewController.h"

//window窗口

#define WINDOW  [[UIApplication sharedApplication]keyWindow]

@interface MyNavigationViewController : UINavigationController

@end

#define D_screenWidth 568

#define D_leastOffset 50

#import "MyNavigationViewController.h"

#import <QuartzCore/QuartzCore.h>

@interface MyNavigationViewController ()

{

    CGPoint startTouch;//拖动时的开始坐标

    BOOL isMoving;//是否在拖动中

    UIView *blackMask;//那层黑面罩

    UIImageView *lastScreenShotView;//截图

}

@property (nonatomic,retain) UIView *backgroundView;//背景

@property (nonatomic,retain) NSMutableArray *screenShotsList;//存截图

@end

@implementation MyNavigationViewController

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil

{

    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];

    if (self) {

        // 只少2个 头一个肯定是*的界面

        self.screenShotsList = [[NSMutableArray alloc]initWithCapacity:];

    }

    return self;

}

- (void)viewDidLoad

{

    [super viewDidLoad];

    //拖动手势

    UIPanGestureRecognizer *panGesture=[[UIPanGestureRecognizer alloc]initWithTarget:self action:@selector(handlePanGesture:)];

    //添加手势

    [self.view addGestureRecognizer:panGesture];

    //是否开始拖动

    isMoving = NO;

}

//拖动手势

-(IBAction)handlePanGesture:(UIGestureRecognizer*)sender{

    //如果是*viewcontroller，结束

    if (self.viewControllers.count <= ) return;

    //得到触摸中在window上拖动的过程中的xy坐标

    CGPoint translation=[sender locationInView:WINDOW];

    //状态结束，保存数据

    if(sender.state == UIGestureRecognizerStateEnded){

        NSLog(@"结束%f,%f",translation.x,translation.y);

        isMoving = NO;

        self.backgroundView.hidden = NO;

        //如果结束坐标大于开始坐标D_leastOffset像素就动画效果移动

        if (translation.x - startTouch.x > D_leastOffset) {

            [UIView animateWithDuration:0.3 animations:^{

                //动画效果，移动

                [self moveViewWithX:D_screenWidth];

            } completion:^(BOOL finished) {

                //返回上一层

                [self popViewControllerAnimated:NO];

                //并且还原坐标

                CGRect frame = self.view.frame;

                frame.origin.x = ;

                self.view.frame = frame;

            }];

        }else{

            //不大于D_leastOffset时就移动原位

            [UIView animateWithDuration:0.3 animations:^{

                //动画效果

                [self moveViewWithX:];

            } completion:^(BOOL finished) {

                //背景隐藏

                self.backgroundView.hidden = YES;

            }];

        }

        return;

    }else if(sender.state == UIGestureRecognizerStateBegan){

        NSLog(@"开始%f,%f",translation.x,translation.y);

        //开始坐标

        startTouch = translation;

        //是否开始移动

        isMoving = YES;

        if (!self.backgroundView)

        {

            //添加背景

            CGRect frame = self.view.frame;

            self.backgroundView = [[UIView alloc]initWithFrame:CGRectMake(, , frame.size.width , frame.size.height)];

            //把backgroundView插入到Window视图上，并below低于self.view层

            [WINDOW insertSubview:self.backgroundView belowSubview:self.view];

            //在backgroundView添加黑色的面罩

            blackMask = [[UIView alloc]initWithFrame:CGRectMake(, , frame.size.width , frame.size.height)];

            blackMask.backgroundColor = [UIColor blackColor];

            [self.backgroundView addSubview:blackMask];

        }

        self.backgroundView.hidden = NO;

        if (lastScreenShotView) [lastScreenShotView removeFromSuperview];

        //数组中最后截图

        UIImage *lastScreenShot = [self.screenShotsList lastObject];

        //并把截图插入到backgroundView上，并黑色的背景下面

        lastScreenShotView = [[UIImageView alloc]initWithImage:lastScreenShot];

        [self.backgroundView insertSubview:lastScreenShotView belowSubview:blackMask];

    }

    if (isMoving) {

        [self moveViewWithX:translation.x - startTouch.x];

    }

}

- (void)moveViewWithX:(float)x

{

    NSLog(@"Move to:%f",x);

    x = x>D_screenWidth?D_screenWidth:x;

    x = x<?:x;

    CGRect frame = self.view.frame;

    frame.origin.x = x;

    self.view.frame = frame;

   // float scale = (x/6400)+0.95;//缩放大小

    float alpha = 0.4 - (x/(D_screenWidth *));//透明值

    //缩放scale

    //lastScreenShotView.transform = CGAffineTransformMakeScale(scale, scale);

    //背景颜色透明值

    blackMask.alpha = alpha;

}

//把UIView转化成UIImage，实现截屏

- (UIImage *)ViewRenderImage

{

    //创建基于位图的图形上下文 Creates a bitmap-based graphics context with the specified options.:UIGraphicsBeginImageContextWithOptions(CGSize size, BOOL opaque, CGFloat scale),size大小，opaque是否透明，不透明（YES），scale比例缩放

    UIGraphicsBeginImageContextWithOptions(self.view.bounds.size, self.view.opaque, 0.0);

    //当前层渲染到上下文

    [self.view.layer renderInContext:UIGraphicsGetCurrentContext()];

    //上下文形成图片

    UIImage * img = UIGraphicsGetImageFromCurrentImageContext();

    //结束并删除当前基于位图的图形上下文。

    UIGraphicsEndImageContext();

    //反回图片

    return img;

}

#pragma Navagation 覆盖方法

-(void)pushViewController:(UIViewController *)viewController animated:(BOOL)animated

{

    //图像数组中存放一个当前的界面图像，然后再push

    [self.screenShotsList addObject:[self ViewRenderImage]];

    [super pushViewController:viewController animated:animated];

}

-(UIViewController *)popViewControllerAnimated:(BOOL)animated

{

    //移除最后一个

    [self.screenShotsList removeLastObject];

    return [super popViewControllerAnimated:animated];

}

- (void)didReceiveMemoryWarning

{

    [super didReceiveMemoryWarning];

    // Dispose of any resources that can be recreated.

}

@end