ios - CAKeyframeAnimation 对于 CGPathAddArc 的某些角度值停止
<p><p>我正在尝试制作动画，
其中一个圆圈围绕 View 中心旋转。</p>
<p>我希望圆圈出现在点击手势的位置下方，因此我计算 View 中心与圆圈之间的距离和角度。</p>
<p>然后我在 <code>CGPathAddArc</code> 中为动画路径设置这些值。</p>
<p>这似乎工作得很好，但有时，在执行整个旋转后，圆圈会停止一会儿，然后重新启动。
玩了一圈，发现这一定和<code>CGPathAddArc</code>函数的起止角度有关，因为设置-M_PI到M_PI这样的标准值不会导致问题。</p>
<p>我的代码是:</p>
<pre><code>CAKeyframeAnimation *pathAnimation = ;
pathAnimation.fillMode = kCAFillModeRemoved;
pathAnimation.removedOnCompletion = YES;
pathAnimation.duration = 4.0;
pathAnimation.repeatCount = HUGE_VALF;
CGMutablePathRef curvedPath = CGPathCreateMutable();
//get the angle and dinstance of location in relation to center of view (mathematics)
CGFloat angle = atan2f(location.y -self.view.center.y, location.x - self.view.center.x);
CGFloat distance = hypotf(location.x - self.view.center.x, location.y - self.view.center.y);
NSLog(@"angle: %f", angle);
CGPathAddArc(curvedPath, NULL, self.view.center.x, self.view.center.y, distance, angle, angle + 2 * M_PI, NO);
//Now we have the path, we tell the animation we want to use this path - then we release the path
pathAnimation.path = curvedPath;
CGPathRelease(curvedPath);
//Add the animation to the circleView - once you add the animation to the layer, the animation starts
;
;
</code></pre>
<p>location 保存触摸事件的坐标，圆对象是在此代码段之前创建的。任何帮助将不胜感激。</p></p>
<br><hr><h1><strong>Best Answer-推荐答案</ strong></h1><br>
<p><p>添加它会使动画均匀平滑:</p>
<pre><code>pathAnimation.calculationMode = kCAAnimationPaced;
</code></pre>
<p>刚刚测试过。</p>
<p>顺便说一句，计算不错。 </p>
<p>希望这会有所帮助。</p></p>
<p style="font-size: 20px;">关于ios - CAKeyframeAnimation 对于 CGPathAddArc 的某些角度值停止，我们在Stack Overflow上找到一个类似的问题：
<a href="https://stackoverflow.com/questions/23330329/" rel="noreferrer noopener nofollow" style="color: red;">
https://stackoverflow.com/questions/23330329/
</a>
</p>
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