I am trying to create a basic animation that makes an image pulse from colored to grey however when I set it up it blinks way too fast even though my .duration attribute of the animation is set to 5 seconds Here is my code:
public func beginBlinking(){
blinking = true
let pulseAnimation = CABasicAnimation(keyPath: "opacity")
pulseAnimation.duration = 5
pulseAnimation.fromValue = 0
pulseAnimation.toValue = 1
pulseAnimation.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseInEaseOut)
pulseAnimation.autoreverses = true
pulseAnimation.repeatCount = FLT_MAX
DispatchQueue.main.async() {
self.layer.add(pulseAnimation, forKey: "animateOpacity")
}
}
Thanks for any assistance.
Edit: Just to add, the code does work but the problem is that the animation does not follow the duration set by the duration attribute. It animates extremely fast. I am also programming in the swift playgrounds app for iPad and it does work in the xcode simulator so it may be a bug there.
Related
I have a button in a view controller that has a shadow. This shadow is applied with an animation, in viewWillAppear.
The button is inside an empty view called 'buttonContainer'.
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
CATransaction.begin()
CATransaction.setCompletionBlock {
self.buttonContainer.layer.shadowOpacity = 1
}
let animation = CABasicAnimation(keyPath: "shadowOpacity")
animation.fromValue = buttonContainer.layer.shadowOpacity
animation.toValue = 1
animation.duration = 0.6
buttonContainer.layer.add(animation, forKey: animation.keyPath)
CATransaction.commit()
}
I want the shadow to animate with the push animation of the view controller. I started implementing 'UIViewControllerAnimatedTransitioning' and I couldn't find a way to tie in the animation duration with CABasicAnimation.
func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {
let containerView = transitionContext.containerView
let button = containerView.viewWithTag(68) as! UIButton
let animation = CABasicAnimation(keyPath: "shadowOpacity")
animation.fromValue = ?
animation.toValue = ?
}
And I suppose I would need to implement UIViewControllerInteractiveTransitioning but I can't think of a way to tie in CABasicAnimation. Any help appreciated
After doing some reading around it looks like someone has implemented a bridge between lower level CALayer animations and 'UIViewControllerInteractiveTransitioning'
https://github.com/stringcode86/UIPercentDrivenInteractiveTransitionWithCABasicAnimation/blob/master/InteractiveTransition/SCPercentDrivenInteractiveTransition.m
But it was done a long time ago and I haven't had time to verify it. One thing for sure is that it looks pretty ugly.
The UIViewPropertyAnimator class was released in iOS 10 and was meant to help out with this bridging by providing coordination with functions like 'addAnimation' and 'addCompletion'.
These guys have managed to implement a clean solution for bridging animations of 'CALayer' with 'UIViewControllerInteractiveTransitioning' via UIViewPropertyAnimator.
https://github.com/hedjirog/CustomPresentation
In summary
It's too hard. Don't bother.
I have some UIButtons that I'm animating indefinitely. The buttons all have 3 sublayers that are added, each of which have their own animation. I'm initializing these animations on viewDidAppear which works great - they fade in and start rotating. The problem is that when I transition to a new view, the animations seem to "snap" back to their initial state, then back to some other state right before the transition occurs. I've tried explicitly removing all of the animations on viewWillDisappear, even tried hiding the entire UIButton itself, but nothing seems to prevent this weird snapping behavior from occurring.
Here's a gif of what's happening (this is me transitioning back and forth between two views):
func animateRotation() {
// Gets called on viewDidAppear
let rotationRight: CABasicAnimation = CABasicAnimation(keyPath: "transform.rotation.z")
rotationRight.toValue = Double.pi * 2
rotationRight.duration = 4
rotationRight.isCumulative = true
rotationRight.repeatCount = Float.greatestFiniteMagnitude
rotationRight.isRemovedOnCompletion = false
rotationRight.fillMode = .forwards
let rotationLeft: CABasicAnimation = CABasicAnimation(keyPath: "transform.rotation.z")
rotationLeft.toValue = Double.pi * -2
rotationLeft.duration = 3
rotationLeft.isCumulative = true
rotationLeft.repeatCount = Float.greatestFiniteMagnitude
rotationLeft.isRemovedOnCompletion = false
rotationLeft.fillMode = .forwards
let circleImage1 = UIImage(named: "circle_1")?.cgImage
circleLayer1.frame = self.bounds
circleLayer1.contents = circleImage1
circleLayer1.add(rotationRight, forKey: "rotationAnimation")
layer.addSublayer(circleLayer1)
let circleImage2 = UIImage(named: "circle_2")?.cgImage
circleLayer2.frame = self.bounds
circleLayer2.contents = circleImage2
circleLayer2.add(rotationLeft, forKey: "rotationAnimation")
layer.addSublayer(circleLayer2)
let circleImage3 = UIImage(named: "circle_3")?.cgImage
circleLayer3.frame = self.bounds
circleLayer3.contents = circleImage3
circleLayer3.add(rotationRight, forKey: "rotationAnimation")
layer.addSublayer(circleLayer3)
}
I would think something as simple as this would hide the button completely as soon as it knows it's going away:
override func viewWillDisappear(_ animated: Bool) {
animatedButton.isHidden = true
}
What's also interesting is that this seems to stop happening if I let it run for a couple minutes. This tells me that it might be some sort of race condition. Just not sure what that race might be...
When you use the UIView set of animations they set the actual state to the final state and then start the animation, ie:
UIView.animate(withDuration: 1) { view.alpha = 0 }
If you check alpha right after the animation starts, it's already 0.
This is a convenience that UIView does for you but that CALayer does not. When you set a CALayer animation you are only setting the animation value, not the actual value of the variable, so when the animation is done, the layer snaps back to its original value. Check the layer value while you are in the middle of the animation and you will see the real value has not changed; only the animated value in the presentation layer has changed.
If you want to replicate the UIView behavior you need to either set the actual final value not he layer when the animation begins or in the use the delegate to set it when the animation ends.
I have a progress circle that animates. I can hit a button and it animates to 20%, if I hit the button again it animates to 40%. I am setting isRemovedOnCompletion to false. However each time I perform an animation a new animation is added to the CAShapelayer. I imagine this is not good for performance. Is there a better way to do this?
Dummy code:
#IBAction func didTapAnimate(_ sender: Any) {
let animateStroke = CABasicAnimation(keyPath: "strokeEnd")
animateStroke.fromValue = index > 0 ? progressPts[index - 1] : 0
animateStroke.toValue = progressPts[index]
animateStroke.duration = 2.0
animateStroke.fillMode = .forwards
animateStroke.isRemovedOnCompletion = false
circleLayer.add(animateStroke, forKey: "MyAnimation")
index+=1
}
I think no need to remove previous animation as per my knowledge only one animation layer is used for single key so animation automatically replace with previous one.
A string that identifies the animation. Only one animation per unique
key is added to the layer. The special key kCATransition is
automatically used for transition animations. You may specify nil for
this parameter.
So only the last animation occupies the memory previous animation automatically deallocated.
Just remove previous animation from circleLayer by calling removeAnimation(forKey:"yourkey")
#IBAction func didTapAnimate(_ sender: Any) {
circleLayer.removeAnimation(forKey: "MyAnimation")
let animateStroke = CABasicAnimation(keyPath: "strokeEnd")
animateStroke.fromValue = index > 0 ? progressPts[index - 1] : 0
animateStroke.toValue = progressPts[index]
animateStroke.duration = 2.0
animateStroke.fillMode = .forwards
animateStroke.isRemovedOnCompletion = false
circleLayer.add(animateStroke, forKey: "MyAnimation")
index+=1
}
Update: The NSTimer approach works now, but comes with a huge performance hit. The question is now narrowed down to an approach without NSTimers.
I'm trying to animate a 'Press and hold' interactive animation. After following a load of SO answers, I've mostly followed the approach in Controlling Animation Timing by #david-rönnqvist. And it works, if I use a Slider to pass the layer.timeOffset.
However, I can't seem to find a good way to continuously update the same animation on a press and hold gesture. The animation either doesn't start, only shows the beginning frame or at some points finishes and refuses to start again.
Can anyone help with achieving the following effect, without the horrible NSTimer approach I'm currently experimenting with?
On user press, animation starts, circle fills up.
While user holds (not necessarily moving the finger), the animation should continue until the end and stay on that frame.
When user lifts finger, the animation should reverse, so the circle is empties again.
If the user lifts his finger during the animation or presses down again during the reverse, the animation should respond accordingly and either fill or empty from the current frame.
Here's a Github repo with my current efforts.
As mentioned, the following code works well. It's triggered by a slider and does its job great.
func animationTimeOffsetToPercentage(percentage: Double) {
if fillShapeLayer == nil {
fillShapeLayer = constructFillShapeLayer()
}
guard let fillAnimationLayer = fillShapeLayer, let _ = fillAnimationLayer.animationForKey("animation") else {
print("Animation not found")
return
}
let timeOffset = maximumDuration * percentage
print("Set animation to percentage \(percentage) with timeOffset: \(timeOffset)")
fillAnimationLayer.timeOffset = timeOffset
}
However, the following approach with NSTimers works, but has an incredible performance hit. I'm looking for an approach which doesn't use the NSTimer.
func beginAnimation() {
if fillShapeLayer == nil {
fillShapeLayer = constructFillShapeLayer()
}
animationTimer?.invalidate()
animationTimer = NSTimer.schedule(interval: 0.1, repeats: true, block: { [unowned self] () -> Void in
if self.layer.timeOffset >= 1.0 {
self.layer.timeOffset = self.maximumDuration
}
else {
self.layer.timeOffset += 0.1
}
})
}
func reverseAnimation() {
guard let fillAnimationLayer = fillShapeLayer, let _ = fillAnimationLayer.animationForKey("animation") else {
print("Animation not found")
return
}
animationTimer?.invalidate()
animationTimer = NSTimer.schedule(interval: 0.1, repeats: true, block: { [unowned self] () -> Void in
if self.layer.timeOffset <= 0.0 {
self.layer.timeOffset = 0.0
}
else {
self.layer.timeOffset -= 0.1
}
})
}
When you use slider you use fillAnimationLayer layer for animation
fillAnimationLayer.timeOffset = timeOffset
However, in beginAnimation and reverseAnimation functions you are using self.layer.
Try to replace self.layer.timeOffset with self.fillShapeLayer!.timeOffset in your timer blocks.
The solution is two-fold;
Make sure the animation doesn't remove itself on completion and keeps its final frame. Easily accomplished with the following lines of code;
animation.fillMode = kCAFillModeForwards
animation.removedOnCompletion = false
The hard part; you have to remove the original animation and start a new, fresh reverse animation that begins at the correct point. Doing this, gives me the following code;
func setAnimation(layer: CAShapeLayer, startPath: AnyObject, endPath: AnyObject, duration: Double)
{
// Always create a new animation.
let animation: CABasicAnimation = CABasicAnimation(keyPath: "path")
if let currentAnimation = layer.animationForKey("animation") as? CABasicAnimation {
// If an animation exists, reverse it.
animation.fromValue = currentAnimation.toValue
animation.toValue = currentAnimation.fromValue
let pauseTime = layer.convertTime(CACurrentMediaTime(), fromLayer: nil)
// For the timeSinceStart, we take the minimum from the duration or the time passed.
// If not, holding the animation longer than its duration would cause a delay in the reverse animation.
let timeSinceStart = min(pauseTime - startTime, currentAnimation.duration)
// Now convert for the reverse animation.
let reversePauseTime = currentAnimation.duration - timeSinceStart
animation.beginTime = pauseTime - reversePauseTime
// Remove the old animation
layer.removeAnimationForKey("animation")
// Reset startTime, to be when the reverse WOULD HAVE started.
startTime = animation.beginTime
}
else {
// This happens when there is no current animation happening.
startTime = layer.convertTime(CACurrentMediaTime(), fromLayer: nil)
animation.fromValue = startPath
animation.toValue = endPath
}
animation.duration = duration
animation.fillMode = kCAFillModeForwards
animation.removedOnCompletion = false
layer.addAnimation(animation, forKey: "animation")
}
This Apple article explains how to do a proper pause and resume animation, which is converted to use with the reverse animation.
I have a CABasicAnimation animating the strokeEnd property of a CAShapeLayer. Every time I add the animation, it quickly jumps through the animation and then goes and does the real animation (as seen in the image above). If I add the animation in the viewDidLoad, this doesn't happen.
Here's my animation code:
let progressAnim = CABasicAnimation(keyPath: "strokeEnd")
progressAnim.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionDefault)
progressAnim.duration = 4.5
progressAnim.fromValue = 0.0
progressAnim.toValue = 1.0
progressAnim.removedOnCompletion = false
progressLayer.addAnimation(progressAnim, forKey: "progressAnimation")
progressLayer.strokeEnd = 1.0
I'm not sure what exactly I'm doing wrong, any help would be highly appreciated. Thanks!
My problem was with the line progressLayer.strokeEnd = 1.0. The reason I had that in my code was to stop the animation from going back to it's original values when it finished animating.
The next solution would be to set the fillMode to progressAnim.fillMode = kCAFillModeForwards and removedOnCompletion to progressAnim.removedOnCompletion = false. This sort of fixed my problem. But it created another. In my code, this solution doesn't update the strokeEnd property to the toValue.
My final solution was to set the toValue to the strokeEnd inside override func animationDidStop(anim: CAAnimation, finished flag: Bool).
My animation code:
let progressAnim = CABasicAnimation(keyPath: "strokeEnd")
progressAnim.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionDefault)
progressAnim.duration = animationDuration
progressAnim.fromValue = 0.0
progressAnim.toValue = 0.5
progressAnim.delegate = self
progressLayer.addAnimation(progressAnim, forKey: "progressAnimation")
Code for when animation is complete:
override func animationDidStop(anim: CAAnimation, finished flag: Bool) {
progressLayer.strokeEnd = 0.5
progressLayer.removeAllAnimations()
}