I want to create an animation where an object animates its position along a path. The trouble I am having is making this path dynamic meaning that it works on all screen sizes.
The spaceship in the gif above follows a "U" shape path initially.
I use this "U" shape path and it works, here is the code:
func animateAlongPath() {
// Create and add image to view
let myImage = UIImage(named: "myImage")!
let myImageView = UIImageView(image: myImage)
myImageView.frame = CGRect(x: 100, y: 100, width: myImage.size.width, height: myImage.size.height)
holderView.addSubview(myImageView)
// Create "U" shape path for animation (path code created in PaintCode)
let path = UIBezierPath()
path.moveToPoint(CGPointMake(59.5, 81.5))
path.addCurveToPoint(CGPointMake(66.5, 91.5), controlPoint1: CGPointMake(63.64, 84.13), controlPoint2: CGPointMake(62.62, 85.9))
path.addCurveToPoint(CGPointMake(81.5, 110.5), controlPoint1: CGPointMake(72.31, 99.88), controlPoint2: CGPointMake(75.91, 103.08))
path.addCurveToPoint(CGPointMake(109.5, 142.5), controlPoint1: CGPointMake(88.44, 119.71), controlPoint2: CGPointMake(102.39, 135.23))
path.addCurveToPoint(CGPointMake(145.5, 156.5), controlPoint1: CGPointMake(122.47, 155.76), controlPoint2: CGPointMake(129.15, 157.54))
path.addCurveToPoint(CGPointMake(237.5, 81.5), controlPoint1: CGPointMake(185.04, 153.99), controlPoint2: CGPointMake(237.5, 81.5))
let pathAnimation = CAKeyframeAnimation(keyPath: "position")
pathAnimation.path = path.CGPath // Use "U" shape path for animation
pathAnimation.calculationMode = kCAAnimationPaced
pathAnimation.timingFunctions = [CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseOut)]
pathAnimation.duration = 1
pathAnimation.removedOnCompletion = false
pathAnimation.fillMode = kCAFillModeForwards
myImageView.layer.addAnimation(pathAnimation, forKey: nil)
myImageView.layer.position = path.currentPoint
}
The problem is that the UIBezierPath is not dynamic. It works great on the iPhone 6 device screen size, but does not work great on any other device size since it is static. I tried using PaintCode to create dynamic paths with variables, but just can't get it to work.
Any ideas?
PaintCode can generate code for resizable UIBezierPaths using Frames.
Put the Bezier inside a Frame object and then set desired autoresizing springs (all flexible). The resulting code will be parametrized with CGRect/NSRect and will use relative coefficients to calculate bezier points.
There’s also a video tutorial about Dynamic Shapes if you want to get more into depth.
Related
I'm trying to make a Gauge UIView to mimic the following image as close as possible
func gradientBezierPath(percent: CGFloat) -> UIBezierPath {
// vary this to move the start of the arc
let startAngle = CGFloat(180).toRadians()//-CGFloat.pi / 2 // This corresponds to 12 0'clock
// vary this to vary the size of the segment, in per cent
let proportion = CGFloat(50 * percent)
let centre = CGPoint (x: self.frame.size.width / 2, y: self.frame.size.height / 2)
let radius = self.frame.size.height/4//self.frame.size.width / (CGFloat(130).toRadians())
let arc = CGFloat.pi * 2 * proportion / 100 // i.e. the proportion of a full circle
// Start a mutable path
let cPath = UIBezierPath()
// Move to the centre
cPath.move(to: centre)
// Draw a line to the circumference
cPath.addLine(to: CGPoint(x: centre.x + radius * cos(startAngle), y: centre.y + radius * sin(startAngle)))
// NOW draw the arc
cPath.addArc(withCenter: centre, radius: radius, startAngle: startAngle, endAngle: arc + startAngle, clockwise: true)
// Line back to the centre, where we started (or the stroke doesn't work, though the fill does)
cPath.addLine(to: CGPoint(x: centre.x, y: centre.y))
return cPath
}
override func draw(_ rect: CGRect) {
// let endAngle = percent == 1.0 ? 0 : (percent * 180) + 180
path = UIBezierPath(arcCenter: CGPoint(x: self.frame.size.width/2, y: self.frame.size.height/2),
radius: self.frame.size.height/4,
startAngle: CGFloat(180).toRadians(),
endAngle: CGFloat(0).toRadians(),
clockwise: true)
percentPath = UIBezierPath(arcCenter: CGPoint(x: self.frame.size.width/2, y: self.frame.size.height/2),
radius: self.frame.size.height/4,
startAngle: CGFloat(180).toRadians(),
endAngle: CGFloat(0).toRadians(),
clockwise: true)
let shapeLayer = CAShapeLayer()
shapeLayer.path = self.path.cgPath
shapeLayer.strokeColor = UIColor(red: 110 / 255, green: 78 / 255, blue: 165 / 255, alpha: 1.0).cgColor
shapeLayer.fillColor = UIColor.clear.cgColor
shapeLayer.lineWidth = 5.0
shapeLayer.lineCap = .round
self.layer.addSublayer(shapeLayer)
percentLayer.path = self.percentPath.cgPath
percentLayer.strokeColor = UIColor(red: 255 / 255, green: 93 / 255, blue: 41 / 255, alpha: 1.0).cgColor
percentLayer.fillColor = UIColor.clear.cgColor
percentLayer.lineWidth = 8.0
// percentLayer.strokeEnd = CGFloat(percent)
percentLayer.lineCap = .round
self.layer.addSublayer(percentLayer)
// n.b. as #MartinR points out `cPath.close()` does the same!
// circle shape
circleShape.path = gradientBezierPath(percent: 1.0).cgPath//cPath.cgPath
circleShape.strokeColor = UIColor.clear.cgColor
circleShape.fillColor = UIColor.green.cgColor
self.layer.addSublayer(circleShape)
gradient.frame = frame
gradient.mask = circleShape
gradient.type = .radial
gradient.colors = [UIColor(red: 255 / 255, green: 93 / 255, blue: 41 / 255, alpha: 0.0).cgColor,
UIColor(red: 255 / 255, green: 93 / 255, blue: 41 / 255, alpha: 0.0).cgColor,
UIColor(red: 255 / 255, green: 93 / 255, blue: 41 / 255, alpha: 0.4).cgColor]
gradient.locations = [0, 0.35, 1]
gradient.startPoint = CGPoint(x: 0.49, y: 0.55) // increase Y adds more orange from top to bottom
gradient.endPoint = CGPoint(x: 0.98, y: 1) // increase x pushes orange out more to edges
self.layer.addSublayer(gradient)
//myTextLayer.string = "\(Int(percent * 100))"
myTextLayer.backgroundColor = UIColor.clear.cgColor
myTextLayer.foregroundColor = UIColor.white.cgColor
myTextLayer.fontSize = 85.0
myTextLayer.frame = CGRect(x: (self.frame.size.width / 2) - (self.frame.size.width/8), y: (self.frame.size.height / 2) - self.frame.size.height/8, width: 120, height: 120)
self.layer.addSublayer(myTextLayer)
}
This produces the following in a playground which is pretty close to what i'm aiming for:
The problem comes when trying to animate the change in the gauge value. I can animate the percentLayer pretty easy with modifying strokeEnd, but animating the circleShape.path for the gradient results in some non-smooth animations if there's a large change in the percent value of the gauge. Here's the function i use to animate both layers (it's called on a timer every 2 seconds right now to simulate gauge value changes).
func randomPercent() {
let random = CGFloat.random(in: 0.0...1.0)
// Animate the percent layer
let animation = CABasicAnimation(keyPath: "strokeEnd")
animation.fromValue = percentLayer.strokeEnd
animation.toValue = random
animation.duration = 1.5
percentLayer.strokeEnd = random
percentLayer.add(animation, forKey: nil)
// Animate the gradient layer
let newShapePath = gradientBezierPath(percent: random)
let gradientAnimation = CABasicAnimation(keyPath: "path")
gradientAnimation.duration = 1.5
gradientAnimation.toValue = newShapePath
gradientAnimation.fromValue = circleShape.path
circleShape.path = newShapePath.cgPath
self.circleShape.add(gradientAnimation, forKey: nil)
myTextLayer.string = "\(Int(random * 100))"
}
Notice how when the animation is done with small changes in the value, the animation looks good. However when there's a large change the gradient animation doesn't look natural at all. Any ideas on how to improve this? Or maybe is it possible to animate a different keyPath for better performance? Any help would be greatly appreciated!
You can't use the Bezier path addArc() function to animate an arc and change the arc distance.
The problem is control points. In order for an animation to work smoothly, the starting and ending shape must have the same number and type of control points. Under the covers, the UIBezierPath (and CGPath) objects create arcs approximating a circle by combining Bezier curves (I don't remember if it uses Quadratic or Cubic Bezier curves.) The entire circle is made up of multiple connected Bezier curves ("Bezier" the mathematical spline function, not UIBeizerPath, which is a UIKit function that creates shapes that can include Bezier paths.) I seem to remember a Bezier approximation of a circle is made up of 4 linked cubic Bezier curves. (See this SO answer for a discussion of what that looks like, if you're interested.)
Here is my understanding of how it works. (I might have the details wrong, but it illustrates the problem in any case.) As you move from <= 1/4 of a full circle to > 1/4 of a full circle, the arc function will use first 1 cubic Bezier section, then 2. At the transition from <= 1/2 of a circle to > 1/2 of a circle, it will shift to 3 Bezier curves, and at the transition from <= 3/4 of a circle to > 3/4 of a circle, it will switch to 4 Bezier curves.
The solution:
You are on the right track with using strokeEnd. Always create your shape as the full circle, and set strokeEnd to something less than 1. That will give you a part of a circle, but in a way that you can animate smoothly. (You can animate strokeStart as well.)
I've animated circles just like you describe using CAShapeLayer and strokeEnd (It was a number of years ago, so it was in Objective-C.) I wrote an article here on OS on using the approach to animate a mask on a UIImageView and create a "clock wipe" animation. If you have an image of your full shaded circle you could use that exact approach here. (You should be able to add a mask layer to any UIView's content layer or other layer, and animate that layer as in my clock wipe demo. Let me know if you need help deciphering the Objective-C.
Here is the sample clock wipe animation I created:
Note that you can use this effect to mask any layer, not just an image view.
EDIT: I posted an update to my clock wipe animation question and answer with a Swift version of the project.
You can get to the new repo directly at https://github.com/DuncanMC/ClockWipeSwift.
For your application I would set up the parts of your gauge that you need to animate as a composite of layers. You'd then attach a CAShapeLayer based mask layer to that composite layer and add a circle arc path to that shape layer and animate the strokeEnd as shown in my sample project. My clock wipe animation reveals the image like the sweep of a clock hand from the center of the layer. In your case you'd center the arc on the bottom center of your layer, and only use a half-circle arc in your shape layer. Using a mask that way would give you a sharp-edged crop to your composited layer. you'd lose the round end caps on your red arc. To fix that you'd have to animate the red arc as it's own shape layer (using strokeEnd) and animate the gradient fill's arc strokeEnd separately.
I'm trying to get this effect in Swift, tried many ways, UIBezierPath and so on, but nothing gets even closer to what I want to achieve. I'm interested in the bottom part of the image, that curve + shadow.
The best result I got with a UIBezierPath that cuts a view I placed on the bottom of the image. But then I can't put the shadow in there. So, any other ideas ? Thanks !
PS: I didn't like the approach I took with my code so I didn't want to post it, but anyway, here it is:
I put a white UIView on top of the image, on the bottom of it and 'cut' through it like this:
let freeform = UIBezierPath()
freeform.move(to: .zero)
freeform.addQuadCurve(to: CGPoint(x: viewArch.width / 2, y: viewArch.height), controlPoint: CGPoint(x: viewArch.width / 4, y: viewArch.height))
freeform.addQuadCurve(to: CGPoint(x: viewArch.width, y: 0), controlPoint: CGPoint(x: viewArch.width * 0.75, y: viewArch.height))
freeform.addLine(to: CGPoint(x: viewArch.width, y: viewArch.height))
freeform.addLine(to: CGPoint(x: 0, y: viewArch.height))
freeform.addLine(to: .zero)
freeform.close()
let maskLayerA = CAShapeLayer()
maskLayerA.path = freeform.cgPath
viewArch.layer.mask = maskLayerA
This results in something like:
But I used the path on my white view, not on the image, so no idea how to put now a shadow.
I outlined the viewArch here, just to be clear:
let centerPointX = colorSizeGuide.bounds.midX / 2
let centerPointY = colorSizeGuide.bounds.midY / 2
let circleWidth: CGFloat = 10
let circleHeight: CGFloat = 10
shape.path = UIBezierPath(ovalIn: CGRect(x: centerPointX + circleWidth / 4, y: centerPointY + circleHeight / 4, width: circleWidth, height: circleHeight)).cgPath
shape.strokeColor = UIColor(r: 160, g: 150, b: 180).cgColor
shape.fillColor = UIColor(r: 160, g: 150, b: 180).cgColor
shape.anchorPoint = CGPoint(x: 0.5, y: 0.5)
shape.lineWidth = 0.1
shape.transform = CATransform3DMakeScale(4.0, 4.0, 1.0)
colorSizeGuide.layer.addSublayer(shape)
Here's what's happening. I need the CAShapeLayer to stay in the middle of the small gray area:
I struggle with affine transforms a little myself, but here's what I think is going on:
The scale takes place centered around 0,0, so it will grow out from that point. That means it will "push away" from the origin.
In order to grow from the center, you should shift the origin to the center point of your shape, scale, and then shift the origin back, by the now-scaled amount:
var transform = CATransform3DMakeTranslation(centerPointX, centerPointY, 0)
transform = CATransformScale(transform, 4.0, 4.0, 1.0)
var transform = CATransform3DTranslate(
transform,
-4.0 * centerPointX,
-4.0 * centerPointY,
0)
shape.transform = transform
BTW, I can't make any sense of the image you posted with your question. You say "I need the CAShapeLayer to stay in the middle of the small gray area" I gather your shape layer is one of the circles, but it isn't clear what you mean by "the small gray area." It looks like there might be an outline that got cropped somehow.
I have this inside my GameScene which is called in the didMove()
for i in 1...5 {
// path to create the circle
let path = UIBezierPath(arcCenter: CGPoint(x: center.x, y: center.y), radius: CGFloat(((43 * i) + 140)), startAngle: CGFloat(GLKMathDegreesToRadians(-50)), endAngle: CGFloat(M_PI * 2), clockwise: false)
// the inside edge of the circle used for creating its physics body
let innerPath = UIBezierPath(arcCenter: CGPoint(x: center.x, y: center.y), radius: CGFloat(((43 * i) + 130)), startAngle: CGFloat(GLKMathDegreesToRadians(-50)), endAngle: CGFloat(M_PI * 2), clockwise: false)
// create a shape from the path and customize it
let shape = SKShapeNode(path: path.cgPath)
shape.lineWidth = 20
shape.strokeColor = UIColor(red:0.98, green:0.99, blue:0.99, alpha:1.00)
// create a texture and apply it to the sprite
let trackViewTexture = self.view!.texture(from: shape)
let trackViewSprite = SKSpriteNode(texture: trackViewTexture)
trackViewSprite.physicsBody = SKPhysicsBody(edgeChainFrom: innerPath.cgPath)
self.addChild(trackViewSprite)
}
It uses UIBezierPaths to make a few circles. It converts the path into a SKShapeNode then a SKTexture and then applies it to the final SKSpriteNode.
When I do this, the SKSpriteNode is not where it should be, it is a few to the right:
But when I add the SKShapeNode I created, it is set perfectly fine to where it should be:
Even doing this does not center it!
trackViewSprite.position = CGPoint(x: 0, y: 0)
No matter what I try it just will not center.
Why is this happening? Some sort of bug when converting to a texture?
P.S - This has something to do with this also Keep relative positions of SKSpriteNode from SKShapeNode from CGPath
But there is also no response :(
Edit, When I run this:
let testSprite = SKSpriteNode(color: UIColor.yellow, size: trackViewSprite.size)
self.addChild(testSprite)
It shows it has the same frame also:
After a long discussion, we determined that the problem is due to the frame size not being the expected size of the shape.
To combat this, the OP created an outer path of his original path, and calculated the frame that would surround this. Now this approach may not work for everybody.
If anybody else comes across this issue, they will need to do these things:
1) Check the frame of the SKShapeNode to make sure that it is correct
2) Determine what method is best to calculate the correct desired frame
3) Use this new frame when getting textureFromNode to extract only the desired texture size
I am experimenting with PaintCode. As an example, I've imported an abstract Illustrator drawing file, which has produced the below bezier Swift code.
On my storyboard I have an UIImageView named exampleImageView that I want to display the PaintCode code and have the ability to scale the resulting image like a vector graphic at different sizes, e.g. 1x, 2.5x 5x etc (i.e. smooth non pixellated lines and curves).
Questions:
1 - How do I display the below code as an image in an UIImageView named exampleImageView in Xcode?
2 - How do I display the below code in an UIView named exampleView in Xcode?
3 - Is it possible to scale up or down the below code (i.e. like a vector graphic), and if so, how in Xcode?
Expected image:
PaintCode code:
//// General Declarations
let context = UIGraphicsGetCurrentContext()
//// Color Declarations
let fillColor = UIColor(red: 0.087, green: 0.086, blue: 0.083, alpha: 1.000)
//// Group 2
CGContextSaveGState(context)
CGContextSetAlpha(context, 0.75)
CGContextBeginTransparencyLayer(context, nil)
//// Bezier Drawing
let bezierPath = UIBezierPath()
bezierPath.moveToPoint(CGPointMake(26.08, 23.65))
bezierPath.addCurveToPoint(CGPointMake(61.71, 12.5), controlPoint1: CGPointMake(38.43, 23.65), controlPoint2: CGPointMake(54.42, 18.61))
bezierPath.addCurveToPoint(CGPointMake(52.65, 1.35), controlPoint1: CGPointMake(69, 6.38), controlPoint2: CGPointMake(64.99, 1.35))
bezierPath.addCurveToPoint(CGPointMake(16.91, 12.5), controlPoint1: CGPointMake(40.2, 1.35), controlPoint2: CGPointMake(24.2, 6.38))
bezierPath.addCurveToPoint(CGPointMake(26.08, 23.65), controlPoint1: CGPointMake(9.63, 18.61), controlPoint2: CGPointMake(13.63, 23.65))
bezierPath.closePath()
bezierPath.moveToPoint(CGPointMake(48.14, 25))
bezierPath.addLineToPoint(CGPointMake(0.79, 25))
bezierPath.addCurveToPoint(CGPointMake(0.24, 24.35), controlPoint1: CGPointMake(-0.02, 25), controlPoint2: CGPointMake(-0.21, 24.73))
bezierPath.addCurveToPoint(CGPointMake(2.41, 23.65), controlPoint1: CGPointMake(0.76, 23.92), controlPoint2: CGPointMake(1.59, 23.65))
bezierPath.moveToPoint(CGPointMake(14.36, 12.5))
bezierPath.addCurveToPoint(CGPointMake(54.26, 0), controlPoint1: CGPointMake(22.62, 5.57), controlPoint2: CGPointMake(40.59, 0))
bezierPath.addCurveToPoint(CGPointMake(64.36, 12.5), controlPoint1: CGPointMake(67.93, 0), controlPoint2: CGPointMake(72.62, 5.57))
bezierPath.addCurveToPoint(CGPointMake(37.3, 23.65), controlPoint1: CGPointMake(58.56, 17.37), controlPoint2: CGPointMake(47.81, 21.59))
bezierPath.addLineToPoint(CGPointMake(49.75, 23.65))
fillColor.setFill()
bezierPath.fill()
CGContextEndTransparencyLayer(context)
CGContextRestoreGState(context)
1 - How do I display the below code as an image in an UIImageView named exampleImageView?
Image can be created in PaintCode, but I don't think it is the right fit here. For starters create a drawing method in PaintCode.
2 - Is it possible to scale up or down the below code (i.e. like a vector graphic), and if so, how?
In PaintCode you can make the thing resizable by using frames.
Look at the Dynamic Shapes tutorial that addresses both.