iphone Animation:为什么围绕 X 轴旋转 UILabel 会切断它的下半部分? [英] iphone Animation: why does rotating a UILabel around X axis cut off its bottom half?

问题描述

我想围绕 X 轴旋转 UILabel，并为其设置动画.但是当动画开始时，标签的文本被水平切成两半.下半部分消失，上半部分在旋转.为什么?

I want to rotate a UILabel around the X axis, and animating it. But when the animation starts, the text of the label is cut in two, horizontally. The bottom half disappears, the upper half is rotating. Why?

代码如下:

CATransform3D _3Dt = CATransform3DMakeRotation(radians(90.0f), 1.0, 0.0, 0.0);

CABasicAnimation *transformAnimation = [CABasicAnimation animationWithKeyPath:@"transform"];

transformAnimation.removedOnCompletion = NO;

transformAnimation.toValue = [NSValue valueWithCATransform3D:_3Dt];

transformAnimation.fillMode = kCAFillModeForwards;

(sdk 3.0)

推荐答案

X轴?这意味着在 UILabel 的旋转一半期间将有 z >0(在屏幕前面)和一半将有 z <0(在屏幕后面).

X axis? That means during the rotation half of the UILabel will have z > 0 (in front of the screen) and half will have z < 0 (behind the screen).

如果 z == 0 有其他层，它们将覆盖您的 UILabel 的 z <0一半.

If there's other layers at z == 0 they will cover your UILabel's z < 0 half.

尝试增加标签层的zPosition.

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