旋转UIView (再次)
提问于 2014-08-15 22:23:09
我再次遇到一些旋转uiview的问题。这一次，我试图旋转一个uiview 1/12的速度，我正在以正常速度旋转另一个uiview。然而，当我试图完成这项任务时，我试图移动的uiview移动速度会变得更慢，如下所示：
第一次更新https://www.youtube.com/watch?v=wj3nRJo5CMM&feature=youtu.be
第2次更新https://www.youtube.com/watch?v=YLRkUzXSDtQ&feature=youtu.be
下面是我的代码：
- (void)rotateHand:(UIPanGestureRecognizer *)panGesture {
if ([(UIPanGestureRecognizer*)panGesture state] == UIGestureRecognizerStateBegan) {
CGPoint touchPoint = [panGesture locationInView:[self view]];
float dx = touchPoint.x - minHandContainer.center.x;
float dy = touchPoint.y - minHandContainer.center.y;
arcTanMin = atan2(dy,dx);
arcTanHour = atan2(hourHand.center.x - minHandContainer.center.x, hourHand.center.y - minHandContainer.center.y);
if (arcTanMin < 0) {
arcTanMin = 2 * M_PI + arcTanMin;
}
if (arcTanHour < 0) {
arcTanHour = 2 * M_PI + arcTanMin;
}
NSLog(@"arcTanMin %f", arcTanMin);
startTransformMin = minHandContainer.transform;
startTransformHour = hourHandContainer.transform;
}
if ([(UIPanGestureRecognizer*)panGesture state] == UIGestureRecognizerStateChanged) {
CGPoint pt = [panGesture locationInView:[self view]];
float dx = pt.x - minHandContainer.center.x;
float dy = pt.y - minHandContainer.center.y;
float ang = atan2(dy,dx);
if (ang < 0) {
ang = 2 * M_PI + ang;
}
float angleDifferenceM = arcTanMin - ang;
float angleDifferenceH = arcTanHour + angleDifferenceM * (1.0/12.0);
NSLog(@"angleDiffM %f", angleDifferenceM);
NSLog(@"angleDiffH %f", angleDifferenceH);
minHandContainer.transform = CGAffineTransformRotate(startTransformMin, -angleDifferenceM);
hourHandContainer.transform = CGAffineTransformRotate(startTransformHour, -angleDifferenceH);
}
}
回答 1
Stack Overflow用户
发布于 2014-08-16 19:39:20
看起来您正在使用arcTanMin作为分针和时针的起始参考角。因此，当您跨越x轴进行跳跃时，angleDifferenceM和angleDifferenceH都在进行跳跃(这就是为什么在跳跃的瞬间，时针与y轴的夹角与分针与x轴的夹角相同)，但angleDifferenceH不需要进行跳跃。更改此设置：
float angleDifferenceH = angleDifferenceM * (1.0/12.0); 至
float angleDifferenceH = arcTanHour + angleDifferenceM * (1.0/12.0);具有适当的arcTanHour起始值。
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/25335040
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