iOS开发之锚点anchorPoint

效果图如下：我们可以看到，不管棕色的方块怎么运动，总是以绿色的店作为中心来移动的，这就和船只的锚点是一样的道理一、简介：anchorPoint 锚点以锚点为中心，执行动画（与渔夫固定船的点一致）anchorPoint 默认是 0.5 0.5锚点是一个比例anchorPoint 锚点在左上角的时候，为（0，0）右上角（1，0）左下角（0，1）右下角（1，1）二、代码1、定义两个全局变量

<span style="color:#009900;">{
CALayer *ship;
CALayer *APLayer;
}</span>

2、代码实现两个layer

ship = [[CALayer alloc]init];
ship.backgroundColor = [UIColor brownColor].CGColor;
ship.bounds = CGRectMake(0, 0, 100, 100);
ship.position = self.view.center;  // CALayer的 中心点
ship.opacity = 0.5;  //  CALayer的透明度 shadowOpacity

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

[self.view.layer addSublayer:ship];

APLayer = [[CALayer alloc]init];APLayer.backgroundColor = [UIColor greenColor].CGColor;APLayer.bounds = CGRectMake(0, 0, 10, 10);CGFloat x = CGRectGetWidth(ship.bounds)*ship.anchorPoint.x;CGFloat y = CGRectGetHeight(ship.bounds)*ship.anchorPoint.y;APLayer.position = CGPointMake(x, y);[ship addSublayer:APLayer];

3、触摸屏幕和触屏结束调用

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{UITouch *touch = [touches anyObject];CGPoint touchPoint = [touch locationInView:self.view];//    APLayer.position = touchPoint;//    得到锚点CGFloat x1 = touchPoint.x/CGRectGetWidth(self.view.frame);CGFloat y1 = touchPoint.y/CGRectGetHeight(self.view.frame);ship.anchorPoint = CGPointMake(x1, y1);NSLog(@"%f  %f",x1,y1);//    得到APlayer的位置CGFloat x = CGRectGetWidth(ship.bounds)*ship.anchorPoint.x;CGFloat y = CGRectGetHeight(ship.bounds)*ship.anchorPoint.y;APLayer.position = CGPointMake(x, y);//    角度值经计算转化为弧度值。要把角度值转化为弧度值，可以使用一个简单的公式Mπ/180//    xyz 是三个轴 0 1ship.transform = CATransform3DMakeRotation(45*M_PI/180, 0, 0, 1);}- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event{ship.transform = CATransform3DIdentity;}