iOS开发--微信首页下拉拍摄的眼睛效果（直接拿走）

话不多说直接上图

是不是很爽？
直接上代码：

#import <UIKit/UIKit.h>

@interface ViewController : UIViewController

@property (nonatomic, strong) UITableView *tableView;

@property (strong, nonatomic) CAShapeLayer *eyeFirstLightLayer;
@property (strong, nonatomic) CAShapeLayer *eyeSecondLightLayer;
@property (strong, nonatomic) CAShapeLayer *eyeballLayer;
@property (strong, nonatomic) CAShapeLayer *topEyesocketLayer;
@property (strong, nonatomic) CAShapeLayer *bottomEyesocketLayer;

@end

- (void)viewDidLoad {
    [super viewDidLoad];
    UIView *bg = [[UIView alloc] initWithFrame:CGRectMake(0, 64, width, height)];
    bg.backgroundColor = [[UIColor lightGrayColor] colorWithAlphaComponent:0.5];
    [self.view addSubview:bg];
    [bg addSubview:self.headView];

    self.tableView = [[UITableView alloc] initWithFrame:CGRectMake(0, 64, width, height+64)];
    self.tableView.delegate = self;
    self.tableView.dataSource = self;
    [self.view addSubview:self.tableView];
    self.tableView.backgroundColor = [UIColor clearColor];


    [self.headView.layer addSublayer:self.eyeFirstLightLayer];
    [self.headView.layer addSublayer:self.eyeSecondLightLayer];
    [self.headView.layer addSublayer:self.eyeballLayer];
    [self.headView.layer addSublayer:self.topEyesocketLayer];
    [self.headView.layer addSublayer:self.bottomEyesocketLayer];

    [self setupAnimation];
}

- (UIView *)headView
{
    if (!_headView) {
        CGFloat headViewH = 40.0;
        CGFloat headViewW = 60.0;
        _headView = [[UIView alloc] initWithFrame:CGRectMake((width-headViewW)/2.0, 10, headViewW, headViewH)];
//        _headView.backgroundColor = [UIColor blackColor];
    }
    return _headView;
}

- (CAShapeLayer *)eyeFirstLightLayer {
    if (!_eyeFirstLightLayer) {
        _eyeFirstLightLayer = [CAShapeLayer layer];
        CGPoint center = CGPointMake(CGRectGetWidth(self.headView.frame) / 2, CGRectGetHeight(self.headView.frame) / 2);
        UIBezierPath *path = [UIBezierPath bezierPathWithArcCenter:center
                                                            radius:CGRectGetWidth(self.headView.frame) * 0.2
                                                        startAngle:(230.f / 180.f) * M_PI
                                                          endAngle:(265.f / 180.f) * M_PI
                                                         clockwise:YES];
        _eyeFirstLightLayer.borderColor = [UIColor blackColor].CGColor;
        _eyeFirstLightLayer.lineWidth = 5.f;
        _eyeFirstLightLayer.path = path.CGPath;
        _eyeFirstLightLayer.fillColor = [UIColor clearColor].CGColor;
        _eyeFirstLightLayer.strokeColor = [UIColor whiteColor].CGColor;
    }
    return _eyeFirstLightLayer;
}
- (CAShapeLayer *)eyeSecondLightLayer {
    if (!_eyeSecondLightLayer) {
        _eyeSecondLightLayer = [CAShapeLayer layer];
        CGPoint center = CGPointMake(CGRectGetWidth(self.headView.frame) / 2, CGRectGetHeight(self.headView.frame) / 2);
        UIBezierPath *path = [UIBezierPath bezierPathWithArcCenter:center
                                                            radius:CGRectGetWidth(self.headView.frame) * 0.2
                                                        startAngle:(211.f / 180.f) * M_PI
                                                          endAngle:(220.f / 180.f) * M_PI
                                                         clockwise:YES];
        _eyeSecondLightLayer.borderColor = [UIColor blackColor].CGColor;
        _eyeSecondLightLayer.lineWidth = 5.f;
        _eyeSecondLightLayer.path = path.CGPath;
        _eyeSecondLightLayer.fillColor = [UIColor clearColor].CGColor;
        _eyeSecondLightLayer.strokeColor = [UIColor whiteColor].CGColor;
    }
    return _eyeSecondLightLayer;
}
- (CAShapeLayer *)eyeballLayer {
    if (!_eyeballLayer) {
        _eyeballLayer = [CAShapeLayer layer];
        CGPoint center = CGPointMake(CGRectGetWidth(self.headView.frame) / 2, CGRectGetHeight(self.headView.frame) / 2);
        UIBezierPath *path = [UIBezierPath bezierPathWithArcCenter:center
                                                            radius:CGRectGetWidth(self.headView.frame) * 0.3
                                                        startAngle:(0.f / 180.f) * M_PI
                                                          endAngle:(360.f / 180.f) * M_PI
                                                         clockwise:YES];
        _eyeballLayer.borderColor = [UIColor blackColor].CGColor;
        _eyeballLayer.lineWidth = 1.f;
        _eyeballLayer.path = path.CGPath;
        _eyeballLayer.fillColor = [UIColor clearColor].CGColor;
        _eyeballLayer.strokeColor = [UIColor whiteColor].CGColor;
        _eyeballLayer.anchorPoint = CGPointMake(0.5, 0.5);
    }
    return _eyeballLayer;
}
- (CAShapeLayer *)topEyesocketLayer {
    if (!_topEyesocketLayer) {
        _topEyesocketLayer = [CAShapeLayer layer];
        CGPoint center = CGPointMake(CGRectGetWidth(self.headView.frame) / 2, CGRectGetHeight(self.headView.frame) / 2);
        UIBezierPath *path = [UIBezierPath bezierPath];
        [path moveToPoint:CGPointMake(0, CGRectGetHeight(self.headView.frame) / 2)];
        [path addQuadCurveToPoint:CGPointMake(CGRectGetWidth(self.headView.frame), CGRectGetHeight(self.headView.frame) / 2)
                     controlPoint:CGPointMake(CGRectGetWidth(self.headView.frame) / 2, center.y - center.y - 20)];
        _topEyesocketLayer.borderColor = [UIColor blackColor].CGColor;
        _topEyesocketLayer.lineWidth = 1.f;
        _topEyesocketLayer.path = path.CGPath;
        _topEyesocketLayer.fillColor = [UIColor clearColor].CGColor;
        _topEyesocketLayer.strokeColor = [UIColor whiteColor].CGColor;
    }
    return _topEyesocketLayer;
}

- (CAShapeLayer *)bottomEyesocketLayer {
    if (!_bottomEyesocketLayer) {
        _bottomEyesocketLayer = [CAShapeLayer layer];
        CGPoint center = CGPointMake(CGRectGetWidth(self.headView.frame) / 2, CGRectGetHeight(self.headView.frame) / 2);
        UIBezierPath *path = [UIBezierPath bezierPath];
        [path moveToPoint:CGPointMake(0, CGRectGetHeight(self.headView.frame) / 2)];
        [path addQuadCurveToPoint:CGPointMake(CGRectGetWidth(self.headView.frame), CGRectGetHeight(self.headView.frame) / 2)
                     controlPoint:CGPointMake(CGRectGetWidth(self.headView.frame) / 2, center.y + center.y + 20)];
        _bottomEyesocketLayer.borderColor = [UIColor blackColor].CGColor;
        _bottomEyesocketLayer.lineWidth = 1.f;
        _bottomEyesocketLayer.path = path.CGPath;
        _bottomEyesocketLayer.fillColor = [UIColor clearColor].CGColor;
        _bottomEyesocketLayer.strokeColor = [UIColor whiteColor].CGColor;
    }
    return _bottomEyesocketLayer;
}

- (void)setupAnimation {
    self.eyeFirstLightLayer.lineWidth = 0.f;
    self.eyeSecondLightLayer.lineWidth = 0.f;
    self.eyeballLayer.opacity = 0.f;
    _bottomEyesocketLayer.strokeStart = 0.5f;
    _bottomEyesocketLayer.strokeEnd = 0.5f;
    _topEyesocketLayer.strokeStart = 0.5f;
    _topEyesocketLayer.strokeEnd = 0.5f;
}

- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
    [self animationWith:scrollView.contentOffset.y];
}

- (void)animationWith:(CGFloat)y {
    CGFloat flag = self.view.frame.origin.y * 2.f - 20.f;
    if (y < flag) {
        if (self.eyeFirstLightLayer.lineWidth < 5.f) {
            self.eyeFirstLightLayer.lineWidth += 1.f;
            self.eyeSecondLightLayer.lineWidth += 1.f;
        }
    }
    if(y < flag - 20) {
        if (self.eyeballLayer.opacity <= 1.0f) {
            self.eyeballLayer.opacity += 0.1f;
        }
    }
    if (y < flag - 40) {
        if (self.topEyesocketLayer.strokeEnd < 1.f && self.topEyesocketLayer.strokeStart > 0.f) {
            self.topEyesocketLayer.strokeEnd += 0.1f;
            self.topEyesocketLayer.strokeStart -= 0.1f;
            self.bottomEyesocketLayer.strokeEnd += 0.1f;
            self.bottomEyesocketLayer.strokeStart -= 0.1f;
        }
    }
    if (y > flag - 40) {
        if (self.topEyesocketLayer.strokeEnd > 0.5f && self.topEyesocketLayer.strokeStart < 0.5f) {
            self.topEyesocketLayer.strokeEnd -= 0.1f;
            self.topEyesocketLayer.strokeStart += 0.1f;
            self.bottomEyesocketLayer.strokeEnd -= 0.1f;
            self.bottomEyesocketLayer.strokeStart += 0.1f;
        }
    }
    if (y > flag - 20) {
        if (self.eyeballLayer.opacity >= 0.0f) {
            self.eyeballLayer.opacity -= 0.1f;
        }
    }
    if (y > flag) {
        if (self.eyeFirstLightLayer.lineWidth > 0.f) {
            self.eyeFirstLightLayer.lineWidth -= 1.f;
            self.eyeSecondLightLayer.lineWidth -= 1.f;
        }
    }
}