iOS核心动画-汽车爬坡小动画

前言

今天看到一个汽车爬坡的小动画，觉得挺好玩的，记录一下实现过程。

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实现过程

主要代码

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    self.view.backgroundColor = [UIColor brownColor];
    self.title = @"汽车爬坡";
    
    UIBezierPath *bezierPath = [UIBezierPath bezierPath];
    [bezierPath moveToPoint:CGPointMake(20, 200)];
    [bezierPath addCurveToPoint:CGPointMake(300, 200) controlPoint1:CGPointMake(100, 0) controlPoint2:CGPointMake(200, 400)];
    
    CAShapeLayer *pathLayer = [CAShapeLayer layer];
    pathLayer.path = bezierPath.CGPath;
    pathLayer.fillColor = nil;
    pathLayer.strokeColor = [UIColor redColor].CGColor;
    [self.view.layer addSublayer:pathLayer];
    
    CALayer *carLayer = [CALayer layer];
    carLayer.frame = CGRectMake(0, 0, 36, 36);
    carLayer.anchorPoint = CGPointMake(0.5, 0.8);
    carLayer.position = CGPointMake(20, 210);
    carLayer.contents = (id)[UIImage imageNamed:@"car"].CGImage;
    [self.view.layer addSublayer:carLayer];
    
    CAKeyframeAnimation *anim = [CAKeyframeAnimation animation];
    anim.keyPath = @"position";
    anim.path = bezierPath.CGPath;
    anim.duration = 4.0;
    anim.rotationMode = kCAAnimationRotateAuto;
    [carLayer addAnimation:anim forKey:nil];
}

实现效果

20190709_153127.GIF

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