CoreAnimation 核心动画二 锚点

 锚点： anchorPoint     以锚点为中心 执行动画 （与 渔夫固定船的点时一致的）

       anchorPoint 默认是 0.5，0.5  （注意： 锚点 是一个比例）

     anchorPoint 在左上角的时候 为 0，0

     anchorPoint 在右上角的时候 为 1，0

     anchorPoint 在左下角的时候 为 0，1

     anchorPoint 在右下角的时候 为 1，1

#import "ViewController.h"

@interface ViewController ()
{
    CALayer *APLayer;
    CALayer *ship;
}
@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    self.view.backgroundColor = [UIColor whiteColor];
    UIImageView *imageView = [[UIImageView alloc] initWithFrame:self.view.frame];
    imageView.image = [UIImage imageNamed:@"网格.jpg"];
    [self.view addSubview:imageView];
    
    [self addShipLayer];

}

- (void)addShipLayer {
    
    ship = [[CALayer alloc] init];
    ship.backgroundColor = [UIColor brownColor].CGColor;
    ship.bounds = CGRectMake(0, 0, 100, 100);
    ship.position = self.view.center;
//    透明度 设置
    ship.opacity = 0.5;
    [self.view.layer addSublayer:ship];
    
    NSLog(@"锚点y:%f
锚点x:%f", ship.anchorPoint.y, ship.anchorPoint.x);
    
    
    APLayer = [[CALayer alloc] init];
    APLayer.bounds = CGRectMake(0, 0, 5, 5);
//    通过ship的尺寸  设置 APLayer 的中心点
//   position.x = ship的宽*锚点的X     position.y = ship的高*锚点的Y
    CGFloat x = CGRectGetWidth(ship.bounds)*(ship.anchorPoint.x);
    CGFloat y = CGRectGetHeight(ship.bounds)*(ship.anchorPoint.y);
    APLayer.position = CGPointMake(x, y);
    APLayer.backgroundColor = [UIColor cyanColor].CGColor;
    [ship addSublayer:APLayer];
}

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    UITouch *touch = [touches anyObject];
    CGPoint touchPoint = [touch locationInView:self.view];
    
//    通过点击屏幕的x点/屏幕的宽度 得到点击的点 与屏幕一个比例
    CGFloat x = touchPoint.x/CGRectGetWidth([UIScreen mainScreen].bounds);
//    通过点击屏幕的y点/屏幕的高度 得到点击的点 与屏幕一个比例
    CGFloat y = touchPoint.y/CGRectGetHeight([UIScreen mainScreen].bounds);
//    改变ship 的锚点
    ship.anchorPoint = CGPointMake(x, y);
    
    
    CGFloat cx = CGRectGetWidth(ship.bounds)*ship.anchorPoint.x;
    CGFloat cy = CGRectGetHeight(ship.bounds)*ship.anchorPoint.y;
    APLayer.position = CGPointMake(cx, cy);
    NSLog(@"锚点y:%f
锚点x:%f", ship.anchorPoint.y, ship.anchorPoint.x);
//    角度值经计算转化为幅度值。要把角度值转化为弧度制，可以使用一个简单的公式Mπ/180
    ship.transform = CATransform3DMakeRotation (90*M_PI/180, 0, 0, 1);
    
}

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
    ship.transform = CATransform3DIdentity;
}

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

@end