How do I animate position of red ball from A to B starting from C ?
i.e. It should first animate from C to B and then animate indefinately between A & B
I have following code snippet
animation.fromValue = A
animation.toValue = B
animation.removedOnCompletion = false
animation.autoreverses = true
animation.repeatCount = Float.infinity
animation.duration = 2.0
The problem with this code snippet is that resets the position to A before starting the animation.
I want the animation to start from C to B and then animate between A and C
you will probably need to use 2 different animations: One from position C to position B, and then a repeating, auto-reversing animation from B back to A. If you can use it, UIView animations are much easier to use than CAAnimations. I'd try UIView animations first before diving into CAAnimation objects.
You can try to do something like:
UIView.animateWithDuration(0.2, animations: { () -> Void in
var frame = self.circleView.frame
frame.origin = A
self.circleView.frame = frame
}) { (finished) -> Void in
let animation = CABasicAnimation(keyPath: "position")
animation.fromValue = NSValue(CGPoint: CGPoint(x: A, y: self.circleView.frame.origin.y))
animation.toValue = NSValue(CGPoint: CGPoint(x: B, y: self.circleView.frame.origin.y))
animation.removedOnCompletion = false
animation.repeatCount = Float.infinity
animation.duration = 2.0
self.circleView.layer.addAnimation(animation, forKey: "position")
}
If you want to have it reversible instead of jumping to A point whenever it reaches to B, you can also add animation.autoreverses = true
Related
I am working on a looping animation that can be cancelled when desired. When the animation is cancelled another animation is called to animate the Presentation Layer back to the fromValue of the previous animation.
The looping animation:
var toBounds = layer.bounds
toBounds.size.height = 12
let animation = CABasicAnimation(keyPath: "bounds")
animation.fromValue = layer.bounds
animation.toValue = toBounds
animation.repeatCount = HUGE
animation.autoreverses = true
animation.duration = 0.3
animation.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseIn)
layer.removeAllAnimations()
layer.add(animation, forKey: "oscillation")
The cancel animation:
if let presentationLayer = layer.presentation() {
let animation = CABasicAnimation(keyPath: "bounds")
animation.fromValue = presentationLayer.bounds
animation.toValue = layer.bounds
animation.duration = 0.3
animation.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseOut)
layer.removeAllAnimations()
layer.add(animation, forKey: "decay")
}
This makes the animation look smooth when returning to it's original state. However, when the animation gets restarted while the cancel animation is still busy, the animation has this stuttering effect. What I tried to do is change the fromValue in the looping animation but this means that the animation doesn't return to the desired fromValue. How can I make this restart smooth again? Is there a way to set the animation's current value?
I am trying to animate the position of a UIView object with CABasicAnimation on a button Tap. The object animated and moves to the 'to' position, but returns back to the original position after the animation ends. I want to retain the position of the view object even after the animation ends. This the code snippet that performs the animation. viewObject is the object which I'm trying to animate.
let animation = CABasicAnimation(keyPath: "position")
animation.timingFunction = CAMediaTimingFunction(controlPoints: 0.86, 0, 0.07, 1.0)
animation.duration = 0.5
animation.fromValue = NSValue(cgPoint: CGPoint(x: viewObject.center.x, y: viewObject.center.y))
animation.toValue = NSValue(cgPoint: CGPoint(x: viewObject.center.x + 64, y: viewObject.center.y))
viewObject.layer.add(animation, forKey: "position")
add following lines before adding animation
animation.isRemovedOnCompletion = false
animation.fillMode = kCAFillModeForwards
Swift
animation.fillMode = .forwards
animation.isRemovedOnCompletion = false
Please add the following code:
Objective-C:
animation.fillMode = kCAFillModeForwards;
animation.removedOnCompletion = NO;
Swift 4:
animation.fillMode = .forwards
animation.isRemovedOnCompletion = false
I think you need to give frame again on completion. So, this can be a nice approach
UIView.animate(withDuration: 0.7, delay: 1.0, options: .curveLinear, animations: {
let animation = CABasicAnimation(keyPath: "position")
animation.timingFunction = CAMediaTimingFunction(controlPoints: 0.86, 0, 0.07, 1.0)
animation.duration = 0.5
animation.fromValue = NSValue(cgPoint: CGPoint(x: self.viewObject.center.x, y: self.viewObject.center.y))
animation.toValue = NSValue(cgPoint: CGPoint(x: self.viewObject.center.x + 64, y: self.viewObject.center.y))
self.viewObject.layer.add(animation, forKey: "position")
}, completion: { finished in
self.viewObject.frame.origin.x = self.viewObject.frame.origin.x + 64
})
Try this. It will work perfectly
UIView.animateWithDuration(0.7, delay: 1.0, options: .CurveEaseOut, animations:
{
Code
}, completion:
{
finished in
println("Nothing to do!")
})
Just do animation inside a block and when it finishes. hold that position and do not revert back. It should stay at same position
and add this line inside code
cabasicanimation.removedOnCompletion = false;
This line will make it do not go back in the same state
If you want keep your position, you should put your code same my structure
CATransaction.begin()
CATransaction.setDisableActions(true)
CATransaction.setCompletionBlock {
// Input code set new position at here
}
// Intput code animation
CATransaction.commit()
I am having some trouble to understand why an animation isn't working like expected.
What I am doing is this:
Create a UIBezierPath with an arc to move a Label along this path and animate the paths stroke.
//Start Point is -.pi /2 to let the Arc start at the top.
//self.progress = Value between 0.0 and 1.0
let path : UIBezierPath = UIBezierPath.init(arcCenter: CGPoint.init(x: self.bounds.width * 0.5, y: self.bounds.height * 0.5),
radius: self.bounds.width * 0.5, startAngle: -.pi / 2, endAngle: (2 * self.progress * .pi) - (.pi / 2), clockwise: true)
return path
Add this path to a CAShapeLayer
circlePathLayer.frame = bounds
circlePathLayer.path = self.path.cgPath
circlePathLayer.strokeStart = 0
circlePathLayer.strokeEnd = 1
Animate the strokeEnd property with a CABasicAnimation
let animation = CABasicAnimation(keyPath: "strokeEnd")
animation.repeatCount = HUGE
animation.fromValue = 0.0
animation.toValue = 1.0
animation.duration = self.animationDuration
animation.isRemovedOnCompletion = false
animation.fillMode = kCAFillModeBoth
Animate the position property of my label with a CAKeyFrameAnimation
let animationScore = CAKeyframeAnimation(keyPath: "position")
//some things I tried to fix
//animationScore.timingFunctions = [CAMediaTimingFunction(controlPoints: 0.250, 0.250, 0.750, 0.750)]
//animationScore.timingFunction = CAMediaTimingFunction.init(name: kCAMediaTimingFunctionLinear)
animationScore.path = self.path.cgPath
animationScore.duration = self.animationDuration
animationScore.isRemovedOnCompletion = false
animationScore.fillMode = kCAFillModeBoth
animationScore.repeatCount = HUGE
Add my animations to layer and label
self.circlePathLayer.add(animation, forKey: nil)
self.scoreLabel.layer.add(animationScore, forKey: nil)
My Problem: For ProgressValues greater than 0.75 my label is not moving in linear speed. Values greater than 0.75 mean that my arc is greater than PI.
For values less than 0.75 my animation works fine and label and strokeend have the same speed and are on top of each other.
GIF :
Please ignore the 100% in the Label in this gif my progress was at a value of 0.76.
You see my Label slows down after three quarters of my circle.
I hope someone can help me.
Many thanks
The keyframe animation introduces an unnecessary complication. Simply rotate the label around the center with the same duration as the shape layer's stroke animation:
(I apologize that my animation starts at the bottom, not the top, but I wasn't looking at your question when I wrote the code and now I'm too lazy to change it!)
So, how is that done? It's three animations, all with the same duration:
The shape layer's strokeEnd, like your animation.
An "arm" running thru the center of the circle, with the label as a sublayer at one end (so that the label appears at the radius of the circle). The arm does a rotation transform animation.
The label does a rotation transform animation in the opposite direction. If it didn't, it would rotate along with its superlayer. (Think of how a Ferris wheel works; your chair is on the end of the arm, but it remains upright with respect to the earth.)
This is the entire animation code:
let anim = CABasicAnimation(keyPath: "transform.rotation.z")
anim.fromValue = 0
anim.toValue = 5
anim.duration = 10
self.arm.layer.add(anim, forKey:nil)
let anim2 = CABasicAnimation(keyPath: "transform.rotation.z")
anim2.fromValue = 0
anim2.toValue = -5
anim2.duration = 10
self.lab.layer.add(anim2, forKey:nil)
let anim3 = CABasicAnimation(keyPath: "strokeEnd")
anim3.fromValue = 0
anim3.toValue = 1
anim3.duration = 10
self.shape.add(anim3, forKey:nil)
I'm trying to implement two consecutive transformation animations. When the first animation ends, the second animation is called through the completion handler. Because this is a transformation animation, my issue is that when the first animation finishes, the layer resizes back to the original size, and then the second animation begins. I'd like for the second animation to begin with the new layer size after the first transformation animation. This post Objective-C - CABasicAnimation applying changes after animation? says I have to resize/transform the layer before beginning the first animation, so that when the first animation ends, the layer is actually the new size. I've tried to do that by changing the bounds or actually applying the transform to the layer but its still not working.
override func viewDidAppear(_ animated: Bool) {
buildBar()
}
func buildBar(){
progressBar1.bounds = CGRect(x: 0, y: 0, width: 20, height: 5)
progressBar1.position = CGPoint(x: 0, y: 600)
progressBar1.backgroundColor = UIColor.white.cgColor
view.layer.addSublayer(progressBar1)
extendBar1()
}
func extendBar1(){
CATransaction.begin()
let transform1 = CATransform3DMakeScale(10, 1, 1)
let anim = CABasicAnimation(keyPath: "transform")
// self.progressBar1.bounds = CGRect(x: 0, y: 0, width: 200, height: 5)
// self.progressBar1.transform = transform1
anim.isRemovedOnCompletion = false
anim.fillMode = kCAFillModeForwards
anim.toValue = NSValue(caTransform3D:transform1)
anim.duration = 5.00
CATransaction.setCompletionBlock {
self.extendBar2()
}
progressBar1.add(anim, forKey: "transform")
CATransaction.commit()
}
func extendBar2(){
let transform1 = CATransform3DMakeScale(2, 1, 1)
let anim = CABasicAnimation(keyPath: "transform")
anim.isRemovedOnCompletion = false
anim.fillMode = kCAFillModeForwards
anim.toValue = NSValue(caTransform3D:transform1)
anim.duration = 5.00
progressBar1.add(anim, forKey: "transform")
}
Because you are modifying the transform property of the layer in both animation, it will be easier here to use CAKeyframeAnimation, which will handle the chaining of the animations for you.
func extendBar(){
let transform1 = CATransform3DMakeScale(10, 1, 1)
let transform2 = CATransform3DMakeScale(2, 1, 1)
let anim = CAKeyframeAnimation()
anim.keyPath = "transform"
anim.values = [progressBar1.transform, transform1, transform2] // the stages of the animation
anim.keyTimes = [0, 0.5, 1] // when they occurs, 0 being the very begining, 1 the end
anim.duration = 10.00
progressBar1.add(anim, forKey: "transform")
progressBar1.transform = transform2 // we set the transform property to the final animation's value
}
A word about the content of values and keyTimes:
We set the first value to be the current transform of progressBar1. This will make sure we start in the current layer's state.
In keyTimes, we say that at the begining, the first value in the values array should be used. We then say at animation's half time, the layer should be transformed in values second value. Hence, the animation between the initial state and the second one will occurs during that time. Then, between 0.5 to 1, we'll go from tranform1 to transform2.
You can read more about animations in this very nice article from objc.io.
If you really need two distinct animations (because maybe you want to add subviews to progressBar1 in between, here's the code that will do it
func extendBar1() {
CATransaction.begin()
CATransaction.setCompletionBlock {
print("side effects")
extendBar2()
}
let transform1 = CATransform3DMakeScale(5, 1, 1)
let anim = CABasicAnimation(keyPath: "transform")
anim.fromValue = progressBar1.transform
anim.toValue = transform1
anim.duration = 2.00
progressBar1.add(anim, forKey: "transform")
CATransaction.setDisableActions(true)
progressBar1.transform = transform1
CATransaction.commit()
}
func extendBar2() {
CATransaction.begin()
let transform2 = CATransform3DMakeScale(2, 1, 1)
let anim = CABasicAnimation(keyPath: "transform")
anim.fromValue = progressBar1.transform
anim.toValue = transform2
anim.duration = 2.00
progressBar1.add(anim, forKey: "transform")
CATransaction.setDisableActions(true)
progressBar1.transform = transform2
CATransaction.commit()
}
What happens here? Basically, we setup a first "normal animation". So we create the animation, that will modify the presentation layer and set the actual layer to the final first animation's transform.
Then, when the first animation completes, we call extendBar2 which will in turn queue a normal animation.
You also want to call CATransaction.setDisableActions(true) before explicitly updating the transform, otherwise, core animation will create an implicit one, which will override the one created just before.
I have a UIView called viewProgress. It is the white box in the image. I want a circular progress bar, which is the green circle in the image. The progress bar should stay within the white box, but as you can see it is way off.
How do I make it stay inside the viewProgress?
Here you have my animation function:
func animateView() {
let circle = viewProgress // viewProgress is a UIView
var progressCircle = CAShapeLayer()
let circlePath = UIBezierPath(arcCenter: circle.center, radius: circle.bounds.midX, startAngle: -CGFloat(M_PI_2), endAngle: CGFloat(3.0 * M_PI_2), clockwise: true)
progressCircle = CAShapeLayer ()
progressCircle.path = circlePath.CGPath
progressCircle.strokeColor = UIColor.whiteColor().CGColor
progressCircle.fillColor = UIColor.clearColor().CGColor
progressCircle.lineWidth = 10.0
circle.layer.addSublayer(progressCircle)
let animation = CABasicAnimation(keyPath: "strokeEnd")
animation.fromValue = 0
animation.toValue = 0.4
animation.duration = 1
animation.fillMode = kCAFillModeForwards
animation.removedOnCompletion = false
progressCircle.addAnimation(animation, forKey: "ani")
}
And I'm just calling the function inside viewDidLoad()
Basically u have few problems:
incorrect position of your layer - frame should be equal to bounds of parent layer in parentView
you animation will play only once - if u want to make it infinite add something like animation.repeatCount = MAXFLOAT
to make sure that all size correct - in layoutSubviews recreate layers, with removing previously created one
UIBezierPath(arcCenter... will start path from rightSide, u can also use simpler variant like UIBezierPath(ovalInRect. With this in mind u also need to rotate layer for M_PI_2 if u want to make start of drawing in the very top of circle
U should also take in mind that with line width 10, half of u'r circle path will be catted by clipSubviews of parentView. To prevent this use modified parentLayer rect
U can also maybe want to improve visualization of lineCap, buy setting it to "round" style
progressCircle.addAnimation(animation, forKey: "ani") key for anim not required if u dont want to get completion event from animation - i your case i see there is no delegate and no removeOnCompletion flag setted to false, so make assumption that u don`t actually need it
Keeping this all in mind code can be like :
let circle = UIView(frame: CGRectMake(100, 100, 100, 100)) // viewProgress is a UIView
circle.backgroundColor = UIColor.greenColor()
view.addSubview(circle)
var progressCircle = CAShapeLayer()
progressCircle.frame = view.bounds
let lineWidth:CGFloat = 10
let rectFofOval = CGRectMake(lineWidth / 2, lineWidth / 2, circle.bounds.width - lineWidth, circle.bounds.height - lineWidth)
let circlePath = UIBezierPath(ovalInRect: rectFofOval)
progressCircle = CAShapeLayer ()
progressCircle.path = circlePath.CGPath
progressCircle.strokeColor = UIColor.whiteColor().CGColor
progressCircle.fillColor = UIColor.clearColor().CGColor
progressCircle.lineWidth = 10.0
progressCircle.frame = view.bounds
progressCircle.lineCap = "round"
circle.layer.addSublayer(progressCircle)
circle.transform = CGAffineTransformRotate(circle.transform, CGFloat(-M_PI_2))
let animation = CABasicAnimation(keyPath: "strokeEnd")
animation.fromValue = 0
animation.toValue = 1.1
animation.duration = 1
animation.repeatCount = MAXFLOAT
animation.fillMode = kCAFillModeForwards
animation.removedOnCompletion = false
animation.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseIn)
progressCircle.addAnimation(animation, forKey: nil)
and result actually like:
Note:
If u want to animate rotation of animated layer u should also add additional animation in to anim group