层位置在（核心）动画开始时跳跃

Question

所以，我正在尝试创建一个磁贴翻转效果，就像在 Windows Phone 7 上一样。

到目前为止，我有以下代码，但我有几个查询。

CALayer *layer = self.theRedSquare.layer;
CATransform3D initialTransform = self.theRedSquare.layer.transform;
initialTransform.m34 = 1.0 / -1000;

[UIView beginAnimations:@"Scale" context:nil];
[UIView setAnimationDuration:1];
[UIView setAnimationCurve: UIViewAnimationCurveEaseInOut];
layer.transform = initialTransform;
layer.anchorPoint = CGPointMake(-0.3, 0.5);

CATransform3D rotationAndPerspectiveTransform = self.theRedSquare.layer.transform;

rotationAndPerspectiveTransform = CATransform3DRotate(rotationAndPerspectiveTransform, M_PI , 0 , -self.theRedSquare.bounds.size.height/2, 0);

layer.transform = rotationAndPerspectiveTransform;

[UIView setAnimationDelegate:self];
[UIView commitAnimations];

1.我的红色方块（一个简单的 UI 视图）怎么会在动画开始时向右平移？

2。对于锚点，是否可以在父视图上设置位置？目前我是相对于当前视图任意设置的。

提前感谢您的任何指点。

动画之前

在动画期间（注意方块向右移动）

动画结束后（注意方块向右移动了）

已添加视频：example video

Answer 1

-(void)setAnchorPoint:(CGPoint)anchorPoint forView:(UIView *)view
{
    CGPoint newPoint = CGPointMake(view.bounds.size.width * anchorPoint.x, view.bounds.size.height * anchorPoint.y);
    CGPoint oldPoint = CGPointMake(view.bounds.size.width * view.layer.anchorPoint.x, view.bounds.size.height * view.layer.anchorPoint.y);

    newPoint = CGPointApplyAffineTransform(newPoint, view.transform);
    oldPoint = CGPointApplyAffineTransform(oldPoint, view.transform);

    CGPoint position = view.layer.position;

    position.x -= oldPoint.x;
    position.x += newPoint.x;

    position.y -= oldPoint.y;
    position.y += newPoint.y;

    view.layer.position = position;
    view.layer.anchorPoint = anchorPoint;
}

-(void)animateView:(UIView *)theRedSquare
{
    CALayer *layer = theRedSquare.layer;
    CATransform3D initialTransform = theRedSquare.layer.transform;
    initialTransform.m34 = 1.0 / -1000;

    [self setAnchorPoint:CGPointMake(-0.3, 0.5) forView:theRedSquare];


    [UIView beginAnimations:@"Scale" context:nil];
    [UIView setAnimationDuration:1];
    [UIView setAnimationCurve: UIViewAnimationCurveEaseInOut];
    layer.transform = initialTransform;


    CATransform3D rotationAndPerspectiveTransform = theRedSquare.layer.transform;

    rotationAndPerspectiveTransform = CATransform3DRotate(rotationAndPerspectiveTransform, M_PI , 0 , -theRedSquare.bounds.size.height/2, 0);

    layer.transform = rotationAndPerspectiveTransform;

    [UIView setAnimationDelegate:self];
    [UIView commitAnimations];
}

取自此，稍作调整.. 希望对您有所帮助 Changing my CALayer's anchorPoint moves the view

Answer 2

如果您将正方形设为自己的视图，则翻转是内置的

[UIView beginAnimations:@"flip" context:nil];
[UIView setAnimationDuration:.35f];
[UIView setAnimationCurve:UIViewAnimationCurveEaseIn];
[UIView setAnimationTransition: UIViewAnimationTransitionFlipFromLeft
     forView:self.window cache:YES];

// change to the new view (make this one hidden, the other not)

[UIView commitAnimations];

Answer 3

CALayer 的anchorPoint 的可接受范围是 [0,1]。在您的情况下，您尝试绕 Y 轴翻转，图层的锚点应为 [0, 0.5]。