iOS-星球沿椭圆轨迹旋转

先看效果：

QQ20171222-170814-HD.gif

什么？太模糊！
来一张高清无码

图片.png

背景旋转

    CABasicAnimation *animation =  [CABasicAnimation animationWithKeyPath:@"transform.rotation.z"];
    //默认是顺时针效果，若将fromValue和toValue的值互换，则为逆时针效果
    animation.fromValue = [NSNumber numberWithFloat:0.f];
    animation.toValue =  [NSNumber numberWithFloat: M_PI *2];
    animation.duration  = 200;
    animation.autoreverses = NO;
    animation.fillMode =kCAFillModeForwards;
    animation.repeatCount = MAXFLOAT; //如果这里想设置成一直自旋转，可以设置为MAXFLOAT，否则设置具体的数值则代表执行多少次
    [ self.bgImaegview.layer addAnimation:animation forKey:nil];

星星的闪烁

-(CABasicAnimation *)opacityForever_Animation:(float)time
{
    CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:@"opacity"];//必须写opacity才行。
    animation.fromValue = [NSNumber numberWithFloat:1.0f];
    animation.toValue = [NSNumber numberWithFloat:0.0f];
    animation.autoreverses = YES;
    animation.duration = time;
    animation.repeatCount = MAXFLOAT;
    animation.removedOnCompletion = NO;
    animation.fillMode = kCAFillModeForwards;
    animation.timingFunction=[CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseIn];///没有的话是均匀的动画。
    return animation;
}

轨迹动画

   CAKeyframeAnimation *pathAnimation = [CAKeyframeAnimation animationWithKeyPath:@"position"];
        pathAnimation.calculationMode = kCAAnimationPaced;
        pathAnimation.fillMode = kCAFillModeForwards;
        pathAnimation.removedOnCompletion = NO;
        pathAnimation.repeatCount = CGFLOAT_MAX;
        pathAnimation.duration = 30.0;
        CGMutablePathRef ovalfromarc = CGPathCreateMutable();
        CGAffineTransform t2 = CGAffineTransformConcat(CGAffineTransformConcat(                                                                 CGAffineTransformMakeTranslation(-origin_x,-origin_y),                                                                             CGAffineTransformMakeScale(1, radiuscale)),                                                      CGAffineTransformMakeTranslation(origin_x, origin_y));
        CGPathAddArc(ovalfromarc, &t2, origin_x, origin_y, radiusX,beginAng,endAng, 0);
        pathAnimation.path = ovalfromarc;
        CGPathRelease(ovalfromarc);

绘制椭圆

    CGContextRef context = UIGraphicsGetCurrentContext();
    CGContextSaveGState(context);
    UIBezierPath *arc = [UIBezierPath bezierPathWithOvalInRect:CGRectMake(20+40, 25, SCREEN_WIDTH-40,SCREEN_WIDTH/2-50)];
    [COLOR(147.f, 151.f, 157.f,0.5f)  setStroke];
    [arc stroke];
    CGContextRestoreGState(context);

下面是demo地址
链接: https://pan.baidu.com/s/1bp4jHWr 密码: 5mt6

感谢作者：秋雨W
https://www.jianshu.com/p/d8cc02e7efa7