我正在尝试使用仅层功能实现两个UIView的折纸转换。想法是用透视效果折叠两个视图。两个视图都有一个透视，转换由每个视图上的旋转以及对一个视图的平移定义，使得该视图似乎附着在另一个视图上。
问题在于，视图在转换中间互相重叠。我不想使用zPosition来避免这种重叠，我真的希望这两个视图像它们的共享边缘将它们绑定在一起。这是转换的代码。
有什么想法或其他解决方案吗？
为了简化问题，我们可以摆脱任何透视变换。这是一个类似问题的更简单的代码：
问题在于，视图在转换中间互相重叠。我不想使用zPosition来避免这种重叠，我真的希望这两个视图像它们的共享边缘将它们绑定在一起。这是转换的代码。
有什么想法或其他解决方案吗？
- (void)animateWithPerspective
{
CGFloat rotationAngle = 90;
CATransform3D transform = CATransform3DIdentity;
UIView *topView;
UIView *bottomView;
UIView *mainView;
CGRect frame;
CGFloat size = 200;
mainView = [[UIView alloc] initWithFrame:CGRectMake(10,10, size, size*2)];
[self.view addSubview:mainView];
bottomView = [[UIView alloc] initWithFrame:CGRectZero];
bottomView.layer.anchorPoint = CGPointMake(0.5, 1);
bottomView.frame = CGRectMake(0, size, size, size);
bottomView.backgroundColor = [UIColor blueColor];
[mainView addSubview:bottomView];
topView = [[UIView alloc] initWithFrame:CGRectZero];
topView.layer.anchorPoint = CGPointMake(0.5, 0);
topView.frame = CGRectMake(0, 0, size, size);
topView.backgroundColor = [UIColor redColor];
[mainView addSubview:topView];
transform.m34 = 1.0/700.0;
topView.layer.transform = transform;
bottomView.layer.transform = transform;
[UIView beginAnimations:nil context:nil];
[UIView setAnimationDuration:2];
[UIView setAnimationRepeatAutoreverses:YES];
[UIView setAnimationRepeatCount:INFINITY];
[UIView setAnimationCurve:UIViewAnimationCurveLinear];
frame = bottomView.frame;
frame.origin.y = bottomView.frame.origin.y - bottomView.frame.size.height - topView.frame.size.height;
bottomView.frame = frame;
topView.layer.transform = CATransform3DRotate(transform, rotationAngle * M_PI/180, 1, 0, 0);
bottomView.layer.transform = CATransform3DRotate(transform, -rotationAngle * M_PI/180, 1, 0, 0);
[UIView commitAnimations];
}
- (void)viewDidLoad
{
[super viewDidLoad];
[self animate];
}
为了简化问题，我们可以摆脱任何透视变换。这是一个类似问题的更简单的代码：
- (void)animateWithoutPerspective
{
CGFloat rotationAngle = 90;
UIView *topView;
UIView *bottomView;
UIView *mainView;
CGRect frame;
CGFloat size = 200;
mainView = [[UIView alloc] initWithFrame:CGRectMake(10,10, size, size*2)];
[self.view addSubview:mainView];
bottomView = [[UIView alloc] initWithFrame:CGRectMake(0, size, size, size)];
bottomView.backgroundColor = [UIColor blueColor];
[mainView addSubview:bottomView];
topView = [[UIView alloc] initWithFrame:CGRectZero];
topView.layer.anchorPoint = CGPointMake(0.5, 0);
topView.frame = CGRectMake(10, 0, size-20, size);
topView.backgroundColor = [UIColor redColor];
[mainView addSubview:topView];
[UIView beginAnimations:nil context:nil];
[UIView setAnimationDuration:2];
[UIView setAnimationRepeatAutoreverses:YES];
[UIView setAnimationRepeatCount:INFINITY];
[UIView setAnimationCurve:UIViewAnimationCurveLinear];
frame = bottomView.frame;
frame.origin.y = bottomView.frame.origin.y - bottomView.frame.size.height;
bottomView.frame = frame;
topView.layer.transform = CATransform3DMakeRotation(rotationAngle * M_PI/180, 1, 0, 0);
[UIView commitAnimations];
}
