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(, , , );
     ship.position = self.view.center;
 //    透明度 设置
     ship.opacity = 0.5;
     [self.view.layer addSublayer:ship];

     NSLog(@"锚点y:%f\n锚点x:%f", ship.anchorPoint.y, ship.anchorPoint.x);

     APLayer = [[CALayer alloc] init];
     APLayer.bounds = CGRectMake(, , , );
 //    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\n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 (*M_PI/, , , );

 }

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

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

 @end