GMSGroundOverlay 动画-我应该使用 CATiledLayer 吗？

I got this answer from pressinganswer.com, i think it may helps you.

As currently I cannot use the "position" keypath for animating, I ended up animating it using the "latitude" and "longitude" keypaths separately.

First calculate the points and add them to 2 separate arrays, one for latitude value (y) and one for longitude (x) and then use the values property in CAKeyFrameAnimation to animate. Create 2 CAKeyFrameAnimation objects (1 for each axis) and group them together using CAAnimationGroup and animate them together to form a circle.

In my equation I vary the length of the radius on each axis so that I can also generate an oval path.

NSMutableArray *latitudes = [NSMutableArray arrayWithCapacity:21];
NSMutableArray *longitudes = [NSMutableArray arrayWithCapacity:21];
for (int i = 0; i <= 20; i++) {
CGFloat radians = (float)i * ((2.0f * M_PI) / 20.0f);


// Calculate the x,y coordinate using the angle
CGFloat x = hDist * cosf(radians);
CGFloat y = vDist * sinf(radians);


// Calculate the real lat and lon using the
// current lat and lon as center points.
y = marker.position.latitude + y;
x = marker.position.longitude + x;




[longitudes addObject:[NSNumber numberWithFloat:x]];
[latitudes addObject:[NSNumber numberWithFloat:y]];
}


CAKeyframeAnimation *horizontalAnimation = [CAKeyframeAnimation animationWithKeyPath:@"longitude"];
horizontalAnimation.values = longitudes;
horizontalAnimation.duration = duration;


CAKeyframeAnimation *verticleAnimation = [CAKeyframeAnimation animationWithKeyPath:@"latitude"];
verticleAnimation.values = latitudes;
verticleAnimation.duration = duration;


CAAnimationGroup *group = [[CAAnimationGroup alloc] init];
group.animations = @[horizontalAnimation, verticleAnimation];
group.duration = duration;
group.repeatCount = HUGE_VALF;
[marker.layer addAnimation:group forKey:[NSString stringWithFormat:@"circular-%@",marker.description]];