我想要执行一些旋转动画。现在我这样做:
#define degreesToRadians(x) (M_PI * x / 180.0)
[self.crossButton setTransform:CGAffineTransformRotate(self.crossButton.transform, degreesToRadians(-rotationDegree))];
但是当我通过例如360度时,不会发生。当我将值传递到180以上时,它开始不会很好地运转。你知道我做错了吗?
答案 0 :(得分:1)
你的问题是' setTransformation'适用于矩阵旋转。因此,您将始终获得最终结果的最短路径。当您传递360度旋转时,您的对象在转换后将是相同的。出于这个原因,转换将无所作为,因为它已经在它应该结束的地方。对于180到360度之间的值,您的旋转将再次向后旋转。轮换使用最短的'最终结果的路径。
您可以尝试以下代码:
UIView* toRotate = VIEW_TO_ROTATE;
CGFloat degreesToRotate = DEGREES;
CGFloat animationTime = TOTAL_ANIMATION_TIME;
NSInteger intervals = ((int)degreesToRotate)/179.9;
CGFloat rest = degreesToRotate-(intervals*179.9);
CGFloat radInterval = degreesToRotate>=0?179.9:-179.9;
CGFloat radRest = (M_PI * rest / 180.0);
CGFloat intervalTime = (1-(radRest/M_PI/2))/intervals;
CGFloat restTime = (radRest/M_PI/2)/intervals;
[UIView animateKeyframesWithDuration:animationTime
delay:0.0f
options:UIViewKeyframeAnimationOptionCalculationModeLinear
animations:
^{
for (int i=0; i<intervals; i++) {
[UIView addKeyframeWithRelativeStartTime:intervalTime*i relativeDuration:intervalTime animations:^{
toRotate.transform = CGAffineTransformConcat(toRotate.transform, CGAffineTransformMakeRotation(radInterval));
}];
}
[UIView addKeyframeWithRelativeStartTime:intervalTime*intervals relativeDuration:restTime animations:^{
toRotate.transform = CGAffineTransformConcat(toRotate.transform, CGAffineTransformMakeRotation(radRest));
}];
} completion:^(BOOL finished) {
}];
请务必将VIEW_TO_ROTATE
,DEGREES
和TOTAL_ANIMATION_TIME
替换为您需要的值!