iphone - CAKeyFrameAnimation中的keyTime是什么样的值？

例如，我有以下CAKeyFrameAnimation:

CALayer* theLayer = myView.layer;
    CAKeyframeAnimation* animation;
    animation = [CAKeyframeAnimation animationWithKeyPath:@"transform.rotation.z"];

    animation.duration = 1.6;
    //animation.cumulative = YES;
    animation.repeatCount = 1;
    animation.removedOnCompletion = NO;
    animation.fillMode = kCAFillModeForwards;

    animation.values = [NSArray arrayWithObjects:
                        [NSNumber numberWithFloat:0.0 * M_PI],
                        [NSNumber numberWithFloat:(15.0/180.0) * M_PI],
                        [NSNumber numberWithFloat:(30.0/180.0) * M_PI], // animation stops here...
                        [NSNumber numberWithFloat:(45.0/180.0) * M_PI], // ignored!
                        [NSNumber numberWithFloat:(190.0/180.0) * M_PI], nil]; // ignored!

    animation.keyTimes = [NSArray arrayWithObjects:
                          [NSNumber numberWithFloat:0.0],
                          [NSNumber numberWithFloat:0.2],
                          [NSNumber numberWithFloat:0.4], // ignored!
                          [NSNumber numberWithFloat:0.8], // ignored!
                          [NSNumber numberWithFloat:1.6], nil]; // ignored!

    animation.timingFunctions = [NSArray arrayWithObjects:
                                 [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionLinear],
                                 [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionLinear],
                                 [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionLinear],
                                 [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionLinear],
                                 [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionLinear], nil];

    [theLayer addAnimation:animation forKey:@"transform.rotation.z"];

我不明白的是:

A)自动画开始以来，关键时间值是绝对的耗时吗？

B)关键时间值仅表示该特定关键帧要使用多少时间？

最佳答案

docs在这里有点奇怪，但很准确:



基本上，每个值都指示给定关键帧出现在动画的哪个标准化点。因此，如果关键帧占动画的25％，则该值为0.25。文档中令人困惑的部分是它们指示持续时间，而实际上这是标准化的时间点。

关于iphone - CAKeyFrameAnimation中的keyTime是什么样的值？，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/2184803/