#cabasicanimation

This code will set CAShapeLayer.path to a BezierPath, and add animation on the layer

// let startPoint = CGPoint(x: 100, y:100) let endPoint = CGPoint(x: 400, y: 400) let controlPoint = CGPoint(x: 100, y: 300) let path = UIBezierPath() path.moveToPoint(startPoint) path.addQuadCurveToPoint(endPoint, controlPoint: controlPoint) let layer = CAShapeLayer() layer.path = path.CGPath layer.fillColor = UIColor.clearColor().CGColor layer.strokeColor = UIColor.redColor().CGColor view.layer.addSublayer(layer) animation1() // func animation1() { let animation1 = CABasicAnimation(keyPath: "lineWidth") animation1.fromValue = animation1.toValue = 10 animation1.duration = 5 animation1.repeatCount = Float(INT_MAX) animation1.autoreverses = true let animation2 = CABasicAnimation(keyPath: "strokeStart") animation2.fromValue = 0 animation2.toValue = 1 animation2.duration = 5 animation2.repeatCount = Float(INT_MAX) animation2.autoreverses = true layer.addAnimation(animation1, forKey: "lineWidth") layer.addAnimation(animation2, forKey: "strokeStart") }

For keyPath "strokeStart", from value 0 to value 1 means the strokeStartPoint will move from StartPoint to EndPoint, which makes it like the line shrinking.

iOS CAShapeLayer 애니메이션 – iOS CAShapeLayer Animation with Auto Layout

CAShapeLayer

오늘은 CAShapeLayer 클래스를 이용하여 애니메이션 효과를 구현해 보겠습니다. CAShapeLayer 클래스를 활용하면 지난 시간 배웠던 마스크(Mask) 효과 이외에도 커스텀 드로잉 (예를 들어 주가 그래프 그리기, 아크(Ark) 그래프 그리기) 효과를 구현하거나, CA(Core Animation)가 의미하듯이 애니메이션 효과도 쉽게 구현할 수 있습니다.

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커스텀 뷰 (Custom View)

먼저 XCode를 열고 File > New > File > iOS…

In this video, four main topics are covered.

Sprint animations

Spring Animation is the base of almost every animation in the iOS8 system, which means almost all of the animations in iOS8 are using spring animation. It was introduced from iOS7 via one single function:

+ animateWithDuration:delay:usingSpringWithDamping:initialSpringVelocity:options:animations:completion:

This function is very similar with ordinary animation function we used to using a lot. The only difference here is two additional parameters: Damping Ratio and Initial Spring Velocity. The damping ratio defines how much the oscillation oscillate at the end state of the animation, ranging from 0.0 to 1.0. 0.0 defines high frequency oscillation, while 1.0 defines no oscillation at all. This is place where can help us make a boucing effect. The initial spring velocity defines how fast the animation starts. The smaller the volecity is, the sooner the animation object will move to the end state, verse vice.

The following demo code imitate the Animation of Opening Folder on iOS Home Screen.

const static CGFloat BOXSIZE = 100.f; - (void)tapped:(UITapGestureRecognizer *)gesture { [self initBox]; [UIView animateWithDuration:1.f delay:0.f usingSpringWithDamping:.75f initialSpringVelocity:.5f options:0 animations:^{ [self endBox]; } completion:^(BOOL finished) { // }]; } - (void)initBox { self.movingBox.frame = CGRectMake(0.f, self.view.bounds.size.height - BOXSIZE, BOXSIZE, BOXSIZE); } - (void)endBox { self.movingBox.frame = CGRectMake(CGRectGetMidX(self.view.bounds) - BOXSIZE * 3.f / 2.f, CGRectGetMidY(self.view.bounds) - BOXSIZE * 3.f / 2.f, BOXSIZE * 3.f, BOXSIZE * 3.f); }

Vibrancy and blur

In iOS8, UIBlurEffect and UIVibrancyEffect are introduced for developers have Dynamic Blur Effect more easily. In the talk, Apple Engineer still recommends using static blur effect code if dynamic blur effect views are not actually what you need, since dynamic blur effect takes a lot of computer power.

The UIBlurEffect gives blur effect to an associated UIView, while UIVibrancyEffect gives the clear part which is not blurred on the blurred view. So, this is a three layer structure. UIView at the bottom, then comes the UIBlurEffect, at last the UIVibrancyEffect comes. The UIVibrancyEffect consumes the computing power most. The UIBlurEffect gives three styles for the developer to use, UIBlurEffectStyleExtraLight, UIBlurEffectStyleLight, UIBlurEffectStyleDark.

The example could be found at Siri User Interface, where user could clearly see the app icons on the Home Screen of the iPhone.

Shape layers

In this section, the engineer talks about the CAShapeLayer. Several things should be mentioned here:

How to use CAShapeLayer back up the UIView as the base layer. In UIView subclass,

+ (Class)layerClass { return [CAShapeLayer Class]; } - (void)awakeFromNib { CAShapeLayer *layer = (CAShapeLayer *)self.layer; // init layer properties here. // Also, everytime to update layer property, convert it to CAShaperLayer and use a local variable for it. }

How to draw part of the path for CAShapeLayer, by setting strokeStart and strokeEnd.

Dyanmic Core Animation behaviors

This is probably the most challenging part for me, so many sample code on CABasicAnimation. I think have a good use of CAAction delegate and CALayer Delegate method could greatly help your custom UIView subclass have great animation effect when UIView’s properties are changed. Also, developer could define customized property, which could be very powerful. By using this technique, developer could not only customize animation behavior, but also disable system’s default animation behaviors.

Today I was browsing through my snippets in CodeBox (by the way - great app for anybody who works with code, saves a lot of time and work, get it here) and I came accross two simple snippets for animating objects using CABasicAnimation that can enhance an app in a great way if used right so I thought I'll share with you.

To begin with you need to add QuartzCore framework to your project. First snippet is animation that moves an element (UIView, UIWhatever...) along the x or y axis and it goes like this.

//Create a CABasicAnimation object CABasicAnimation *move = [CABasicAnimation animationWithKeyPath:@"transform.translation.y" ]; [move setFromValue:[NSNumber numberWithFloat:0.0f]]; [move setToValue:[NSNumber numberWithFloat:100.0f]]; [move setDuration:0.3f]; //Add animation to a specific element's layer. Must be called after the element is displayed. [[element layer] addAnimation:move forKey:@"transform.translation.y"];

Second snippet is a fade transition for whatever UI element.

//Create a CABasicAnimation object. Must be added to the element after it is displayed CATransition *animation = [CATransition animation]; animation.duration = 1.0; animation.type = kCATransitionFade; animation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut]; [myLabel.layer addAnimation:animation forKey:@"changeTextTransition"]; // Change the text and the animation will ocur myLabel.text = @"Changed text";