iOS UIView 动画 CATransform3DMakeRotation 混淆 [英] iOS UIView Animation CATransform3DMakeRotation confusion

问题描述

我有一个 UIView，我正在尝试动画向下翻转，同时将其轴放在视图的底部.例如:

I have a UIView that I am trying to animate flipping down, while having its axis at the bottom of the view. E.g.:

为此，我尝试使用 UIView 动画:

To do this, I am trying to use a UIView animation:

[UIView animateWithDuration:3 delay:0 options:UIViewAnimationCurveEaseOut animations:^{

     // Flip Down
     top3.layer.anchorPoint = CGPointMake(0.5, 1.0);
     top3.layer.transform = CATransform3DMakeRotation(M_PI, 1, 0, 0);

 } completion:^(BOOL finished) {

     // Reset?
     //top3.transform = CGAffineTransformMakeScale(1, 1);

 }];

现在它不能像我想要的那样工作，似乎视图正在远离用户而不是朝向用户进行动画处理.它似乎没有提供 3D 效果，使其在向下旋转时看起来更接近用户，如我的图像所示.我很肯定这是因为我对如何使用 CATransform3DMakeRotation 缺乏了解.

Right now it isn't working how I want, it seems like the view is animating AWAY from the user rather then toward. It does't seem to give a 3D effect that makes it look closer to the user when rotating down, as shown in my image. I am positive that this is because of my lack of understanding how to use CATransform3DMakeRotation.

问题:

• 如何让视图在下降时看起来更接近用户?例如在我的图像示例中倾斜它?
• 当我设置我的 anchorPoint 时，它会将我的视图向下移动，我该如何防止这种情况并仍然设置我的 anchorPoint?
• 使用 UIView 动画，我可以使用缓动设置吗? 在选项中使用 UIViewAnimationCurveEaseOut.
• 我可以使用重力设置吗?

• How can I make the view appear closer to the user as it drops? Such as skewing it as in my image example?
• When I set my anchorPoint it shifts my view down, how can I prevent this and still set my anchorPoint?
• With UIView animation, can I use easing settings? Used UIViewAnimationCurveEaseOut in options.
• Can I use gravity settings?

推荐答案

• 您的问题并不完全清楚，但听起来您在动画过程中没有看到透视失真 - 视图在旋转时保持矩形，对吗?要使 CALayer 以透视图显示，其 transform 需要设置 m34 元素，如此处.
• 为了补偿 anchorPoint 移动你的视图层，你需要改变视图的原始位置.
• 是的.除了您正在使用的动画选项之外，还有几个动画选项，您可以像这样组合它们(例如): UIViewAnimationOptionBeginFromCurrentState |UIViewAnimationOptionCurveEaseInOut |UIViewAnimationOptionAllowUserInteraction.
• Core Animation 并没有真正的物理概念.根据您想要的效果，您可以通过将多个动画与特定的缓动设置链接在一起来实现它——例如，撞击固体表面的下落物体将在其下降过程中使用缓入"动画，然后使用缓入"动画如果它随后反弹，则缓出".
• It’s not completely clear from your question, but it sounds like you’re not seeing a perspective distortion during the animation—the view’s staying rectangular as it rotates, right? For a CALayer to display with perspective, its transform needs to have the m34 element set, as described here.
• To compensate for the anchorPoint moving your view’s layer, you need to change the view’s original position.
• Yes. There are several animation options in addition to the one you’re using, and you can combine them like this (for example): UIViewAnimationOptionBeginFromCurrentState | UIViewAnimationOptionCurveEaseInOut | UIViewAnimationOptionAllowUserInteraction.
• Core Animation doesn’t really have any concept of physics. Depending on the effect you’re going for, you can achieve it by chaining multiple animations together with particular easing settings—for instance, a falling object that hits a solid surface would use an "ease in" animation on its way down, then an "ease out" if it then bounced back up.

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