ios - RotationMode 在 CAKeyframeAnimation(线性路径)中不起作用

Question

只要 View 通过路径(线性路径)，我就会尝试让 View 旋转，但它不会旋转。

这是我的代码:

 CAKeyframeAnimation *animKF = [CAKeyframeAnimation animationWithKeyPath:@"position"];
animKF.values = [NSArray arrayWithObjects:[NSValue valueWithCGPoint:CGPointMake(100, 100)], [NSValue valueWithCGPoint:CGPointMake(400, 400)], [NSValue valueWithCGPoint:CGPointMake(700, 100)], [NSValue valueWithCGPoint:CGPointMake(1000, 400)], nil];

animKF.keyTimes = [NSArray arrayWithObjects:[NSNumber numberWithFloat:0.0], [NSNumber numberWithFloat:0.25], [NSNumber numberWithFloat:0.5], [NSNumber numberWithFloat:1.0], nil];

animKF.duration = 6;

animKF.rotationMode =  kCAAnimationRotateAuto;

[imageView.layer addAnimation:animKF forKey:@"keyframe"];

但是imageView(图中蓝色的脸)并没有沿着path(图中红色的线)旋转

非常感谢。

Answer 1

来自 rotationMode 的文档:

The effect of setting this property to a non-nil value when no path object is supplied is undefined.

在您的代码中，您正在设置关键帧动画的 values 属性，但您需要设置一个 path相反。

---

您应该根据您的值创建一个 CGPath 并将其设置为您的关键帧的路径。

UIBezierPath *animationPath = [UIBezierPath bezierPath];
[animationPath moveToPoint:CGPointMake(100, 100)];
[animationPath addLineToPoint:CGPointMake(400, 400)];
[animationPath addLineToPoint:CGPointMake(700, 100)];
[animationPath addLineToPoint:CGPointMake(1000, 400)];

animKF.path = animationPath.CGPath;