iPhone - How to make a circle path for a CAKeyframeAnimation?

iphone animation cakeyframeanimation
Chris picture Chris · Sep 27, 2010 · Viewed 7.1k times · Source

I'm trying to make an key frame animation that lets a image view fly around a circle. I'm using CGPathAddCurveToPoint to make the key frame points. The problem is that the image view always uses the shortest (linear) route.

I would like to have some kind of function that builds a circle path for a given radius.

Thanks a lot for any help.

Answer

Ilker Baltaci picture Ilker Baltaci · Oct 9, 2012 
CGMutablePathRef path = CGPathCreateMutable();
CGPathMoveToPoint(path, NULL, startPoint.x, startPoint.y);
CGPathAddQuadCurveToPoint(path, NULL,middlePoint.x, middlePoint.y,endPoint.x,endPoint.y);

CAKeyframeAnimation *pathAnimation = [CAKeyframeAnimation animationWithKeyPath:@"position"];
pathAnimation.removedOnCompletion = NO;
pathAnimation.path = path;
[pathAnimation setCalculationMode:kCAAnimationCubic];
[pathAnimation setFillMode:kCAFillModeForwards];
pathAnimation.duration = 2.0;

[viewTobemoved.layer addAnimation:pathAnimation forKey:nil];

This animation uses only one bezier point and makes a soft circle from beginning point to end point.If you want to define the curve exactly by also defining the radius of the circle you can refer to the following link

http://blog.shoguniphicus.com/2011/05/19/keyframe-animation-ios-cakeyframeanimation-objective-c/

Related questions

How to animate the change of image in an UIImageView?

I have an UIImageView with an image. Now I have a completely new image (graphic file), and want to display that in this UIImageView. If I just set myImageView.image = newImage; the new image is visible immediately. Not animatable. I …

Read More
How to create a UIView bounce animation?

I have the following CATransition for a UIView called finalScoreView, which makes it enter the screen from the top: CATransition *animation = [CATransition animation]; animation.duration = 0.2; animation.type = kCATransitionPush; animation.subtype = kCATransitionFromBottom; animation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseIn]; [gameOver.layer addAnimation:animation …

Read More
iPhone WebKit CSS animations cause flicker

This is the iphone site: http://www.thevisionairegroup.com/projects/accessorizer/site/ After you click "play now" you'll get to a game. The guns will scroll in. You can scroll the purse and accessories up and down. You can see …

Read More