我正在尝试旋转NS
ImageView的CALayer.我的问题是anchorPoint默认显示为(0.0,0.0),但我希望它是图像的中心(Apple的文档表明默认值应该是中心(0.5,0.5),但它不在我的系统操作系统上X 10.7),当我修改锚点时,图像中心的原点移动到左下角.
这是我用来旋转图层的代码：
CALayer *myLayer = [imageView layer]; CGFloat myRotationAngle = -M_PI_2; NSNumber *rotationAtStart = [myLayer valueForKeyPath:@"transform.rotation"]; CATransform3D myRotationTransform = CATransform3DRotate(myLayer.transform,myRotationAngle,0.0,1.0); myLayer.transform = myRotationTransform; CABasicAnimation *myAnimation = [CABasicAnimation animationWithKeyPath:@"transform.rotation"]; myAnimation.duration = 1.0; myAnimation.fromValue = rotationAtStart; myAnimation.toValue = [NSNumber numberWithFloat:([rotationAtStart floatValue] + myRotationAngle)]; [myLayer addAnimation:myAnimation forKey:@"transform.rotation"]; myLayer.anchorPoint = CGPointMake(0.5,0.5); [myLayer addAnimation:myAnimation forKey:@"transform.rotation"];
解决方法
似乎改变某些东西的锚点也会改变它的位置.以下代码段修复了此问题：
CGPoint anchorPoint = CGPointMake(0.5,0.5); CGPoint newPoint = CGPointMake(disclosureTriangle.bounds.size.width * anchorPoint.x,disclosureTriangle.bounds.size.height * anchorPoint.y); CGPoint oldPoint = CGPointMake(disclosureTriangle.bounds.size.width * disclosureTriangle.layer.anchorPoint.x,disclosureTriangle.bounds.size.height * disclosureTriangle.layer.anchorPoint.y); newPoint = CGPointApplyAffineTransform(newPoint,[disclosureTriangle.layer affineTransform]); oldPoint = CGPointApplyAffineTransform(oldPoint,[disclosureTriangle.layer affineTransform]); CGPoint position = disclosureTriangle.layer.position; position.x -= oldPoint.x; position.x += newPoint.x; position.y -= oldPoint.y; position.y += newPoint.y; disclosureTriangle.layer.position = position; disclosureTriangle.layer.anchorPoint = anchorPoint;