### 仿微信 头像截取

#import <UIKit/UIKit.h>
@class AvatorImageViewController;

@protocol AvatorImageViewControllerDelegate <NSObject>
- (void)avatorImageViewControllerDidCancel:(AvatorImageViewController *)controller;
- (void)avatorImageViewController:(AvatorImageViewController *)controller didFinishPickingImage:(UIImage *)image;
@end

@interface AvatorImageViewController : UIViewController
@property (nonatomic, strong) UIImage *image;
@property (nonatomic, weak) id<AvatorImageViewControllerDelegate> delegate;
@end

#import "AvatorImageViewController.h"

static CGFloat viewW;
static CGFloat viewH;
static CGFloat newImageW;
static CGFloat newImageH;
static const CGFloat animationTime =  0.3f;
static CGFloat maxScale;

@interface AvatorImageViewController ()
/*! 图片 */
@property (nonatomic, strong) UIImageView *imageView;
/*! 边框 */
@property (nonatomic, strong) UIView *borderView;
/*! 图片旧frame */
@property (nonatomic, assign) CGRect imageViewOldRect;
@end

@implementation AvatorImageViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    
    viewW = self.view.frame.size.width;
    viewH = self.view.frame.size.height;
    
    /*! 初始化图片 */
    [self setupImage];
    /*! 初始化手势 */
    [self setupGesture];
    /*! 初始化遮罩层 */
    [self setupMaskView];
    /*! 初始化按钮 */
    [self setupButtons];
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

#pragma mark - 初始化

- (void)setupImage{
    self.imageView = [[UIImageView alloc] initWithImage:self.image];
    self.imageView.center = self.view.center;
    [self.view addSubview:self.imageView];
    
    newImageW = kScreenW;
    newImageH = self.image.size.height / (self.image.size.width / kScreenW);
    self.imageView.bounds = CGRectMake(0, 0, newImageW, newImageH);
    self.imageViewOldRect = self.imageView.frame;
}

- (void)setupGesture{
    UIPanGestureRecognizer *pan = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(panAvatorImage:)];
    [self.view addGestureRecognizer:pan];
    
    UIPinchGestureRecognizer *pinch = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(pinchAvatorImage:)];
    [self.view addGestureRecognizer:pinch];
}

- (void)setupMaskView{
    UIView *maskView = [[UIView alloc] init];
    maskView.backgroundColor = [UIColor blackColor];
    maskView.alpha = 0.6;
    maskView.frame = self.view.bounds;
    [self.view addSubview:maskView];
    
    //遮罩
    CAShapeLayer *maskLayer = [[CAShapeLayer alloc] init];
    CGMutablePathRef path = CGPathCreateMutable();
    CGPathAddRect(path, nil, CGRectMake(0, 0, viewW, (viewH-viewW)*0.5));
    CGPathAddRect(path, nil, CGRectMake(0, (viewH-viewW)*0.5+viewW, viewW, (viewH-viewW)*0.5));
    maskLayer.path = path;
    maskView.layer.mask = maskLayer;
    
    //框
    self.borderView = [[UIView alloc] init];
    self.borderView.backgroundColor = [UIColor clearColor];
    self.borderView.layer.borderWidth = 1;
    self.borderView.layer.borderColor = [UIColor whiteColor].CGColor;
    self.borderView.frame = CGRectMake(0, (viewH-viewW)*0.5, viewW, viewW);
    [self.view addSubview:self.borderView];
}

- (void)setupButtons{

    UIButton *cancelBtn = [UIButton buttonWithType:UIButtonTypeCustom];
    cancelBtn.frame = CGRectMake(20, kScreenH - 50, 60, 25);
    [cancelBtn setTitle:@"取消" forState:UIControlStateNormal];
    [cancelBtn setTitleColor:[UIColor whiteColor] forState:UIControlStateNormal];
    [cancelBtn addTarget:self action:@selector(cancelBtnDidClick:) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:cancelBtn];

    UIButton *selectBtn = [UIButton buttonWithType:UIButtonTypeCustom];
    selectBtn.frame = CGRectMake(kScreenW-60-20, kScreenH-50, 60, 25);
    [selectBtn setTitle:@"选取" forState:UIControlStateNormal];
    [selectBtn setTitleColor:[UIColor whiteColor] forState:UIControlStateNormal];
    [selectBtn addTarget:self action:@selector(selectBtnDidClick:) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:selectBtn];
    
}

#pragma mark - 按钮
- (void)cancelBtnDidClick:(UIButton *)btn{
    self.imageView.frame = self.imageViewOldRect;
    
    if ([self.delegate respondsToSelector:@selector(avatorImageViewControllerDidCancel:)]) {
        [self.delegate avatorImageViewControllerDidCancel:self];
    }
    
    [self dismissViewControllerAnimated:YES completion:nil];
}

- (void)selectBtnDidClick:(UIButton *)btn{
    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
        UIGraphicsBeginImageContextWithOptions(CGSizeMake(viewW, viewW), YES, [UIScreen mainScreen].scale);
        // 这时候的imagerect要相对这个上下文了
        // y:减掉(viewH-viewW)/2是因为CGSizeMake(viewW, viewW) 高度为viewW
        CGRect imageRect = CGRectMake(self.imageView.frame.origin.x, self.imageView.frame.origin.y - (viewH-viewW)/2, self.imageView.frame.size.width, self.imageView.frame.size.height);
        
        [self.imageView.image drawInRect:imageRect];
        UIImage * tempImage = UIGraphicsGetImageFromCurrentImageContext();
        UIGraphicsEndImageContext();
        
        dispatch_async(dispatch_get_main_queue(), ^{
            // 不做这处理放大很多的情况下会有bug
            self.imageView.frame = self.imageViewOldRect;
            
            if ([self.delegate respondsToSelector:@selector(avatorImageViewController:didFinishPickingImage:)]) {
                [self.delegate avatorImageViewController:self didFinishPickingImage:tempImage];
            }
            
            [self dismissViewControllerAnimated:YES completion:nil];
        });
    });
}

#pragma mark - 手势
- (void)panAvatorImage:(UIPanGestureRecognizer *)gesture{
    if (gesture.state == UIGestureRecognizerStateBegan || gesture.state == UIGestureRecognizerStateChanged) {
        CGPoint transLationPoint = [gesture translationInView:self.view];
        CGFloat newCentX = self.imageView.center.x + transLationPoint.x;
        CGFloat newCentY = self.imageView.center.y + transLationPoint.y;
        self.imageView.center = CGPointMake(newCentX, newCentY);
        [gesture setTranslation:CGPointZero inView:self.view.superview];
    }else if (gesture.state == UIGestureRecognizerStateEnded) {
        [self translateAnimation];
    }
}

- (void)pinchAvatorImage:(UIPinchGestureRecognizer *)gesture{
    if (gesture.state == UIGestureRecognizerStateBegan || gesture.state == UIGestureRecognizerStateChanged) {
        CGFloat newWidth  = self.imageView.frame.size.width * gesture.scale;
        CGFloat newHeight = self.imageView.frame.size.height * gesture.scale;
        self.imageView.bounds = CGRectMake(0, 0, newWidth, newHeight);
        gesture.scale = 1;
    }else if (gesture.state == UIGestureRecognizerStateEnded) {
        // 处理缩放(超过缩放范围则触发弹簧效果)
        [self scaleAnimation];
        // 处理移动(超过边缘则触发弹簧效果)
        [self translateAnimation];
    }
}

- (void)scaleAnimation{
    CGFloat scale = self.imageView.frame.size.width/viewW;
    maxScale = 1.5 + self.image.size.width/kScreenW<1?1:self.image.size.width/kScreenW/2;
    // 缩放比例大于最大比例或者小于最小比例则回到对应比例
    if (scale < 1) {
        [UIView animateWithDuration:animationTime animations:^{
            self.imageView.bounds = CGRectMake(0, 0, newImageW, newImageH);
        }];
    }else if (scale > maxScale) {
        [UIView animateWithDuration:animationTime animations:^{
            self.imageView.bounds = CGRectMake(0, 0, newImageW * maxScale, newImageH * maxScale);
        }];
    }
}

- (void)translateAnimation{
    CGRect borderRect = self.borderView.frame;
    CGRect imageRect  = self.imageView.frame;
    
    //水平方向
    if (imageRect.origin.x > borderRect.origin.x) {
        imageRect.origin.x = borderRect.origin.x;
    }
    if (CGRectGetMaxX(imageRect) < CGRectGetMaxX(borderRect)) {
        imageRect.origin.x = CGRectGetMaxX(borderRect) - imageRect.size.width;
    }
    
    //垂直方向
    if (imageRect.origin.y > borderRect.origin.y) {
        imageRect.origin.y = borderRect.origin.y;
    }
    if (CGRectGetMaxY(imageRect) < CGRectGetMaxY(borderRect)) {
        imageRect.origin.y = CGRectGetMaxY(borderRect) - imageRect.size.height;
    }
    
    //宽度高度
    if (imageRect.size.width < borderRect.size.width || imageRect.size.height < borderRect.size.height){
        [UIView animateWithDuration:animationTime animations:^{
            self.imageView.center = self.borderView.center;
        }];
    }
    else{
        [UIView animateWithDuration:animationTime animations:^{
            self.imageView.frame = imageRect;
        }];
    }
    
}
@end