This question already has answers here:
How to rotate UIBezierPath around center of its own bounds?
(3 answers)
Closed 4 years ago.
I wanted to rotate my ellipse but I don't manage to do it.
I tried to make a CGAffineTransform, but my rectangle disappeared and I also tried a to do a CATransformRotate or something like this on note, but didn't managed to use it properly
let ovalPath = UIBezierPath(ovalIn: CGRect(x: 100, y: 100, width: 10, height: 15))
UIColor.gray.setFill()
ovalPath.fill()
let rotation = CGAffineTransform(rotationAngle: CGFloat(M_PI / 3.0))
ovalPath.apply(rotation)
let note = CAShapeLayer()
note.path = ovalPath.cgPath
note.fillColor = UIColor.black.cgColor
view.layer.addSublayer(note)
You're rotating the path off the screen because of the x/y offset in the cgrect (it's rotating around (0,0)). try this and rotate ccw a bit to see the rotation behavior work correctly. If you want the layer to be at coordinate 100,100 you can use another transform to move it:
let ovalPath = UIBezierPath(ovalIn: CGRect(x: 0, y: 0, width: 10, height: 15))
UIColor.gray.setFill()
ovalPath.fill()
let rotation = CGAffineTransform(rotationAngle: -CGFloat(M_PI / 3.0))
ovalPath.apply(rotation)
let note = CAShapeLayer()
note.path = ovalPath.cgPath
note.fillColor = UIColor.black.cgColor
view.layer.addSublayer(note)
Related
This question already has answers here:
UIView animateWithDuration doesn't animate cornerRadius variation
(8 answers)
Closed 2 years ago.
I created simple path for tooltip of a slider. I wanted it to animate as it appears so a user would know that he can drag it.
But it does not animate:
let upperToolTipPath: CAShapeLayer = CAShapeLayer()
var path = UIBezierPath(roundedRect: CGRect(x: 0,y: 0, width: 65, height: 30), cornerRadius: 3)
path.stroke()
path.move(to: CGPoint(x: 50, y: 10))
path.addLine(to: CGPoint(x: 40, y: 30))
path.addLine(to: CGPoint(x: 15, y: 10))
upperToolTipPath.path = path.cgPath
self.layer.insertSublayer(upperToolTipPath, at: 0)
UIView.animate(
withDuration: 5,
delay: 3,
options: [.repeat, .autoreverse, .curveEaseIn],
animations: {
self.upperToolTipPath.transform = CATransform3DMakeScale(2, 2, 1)
})
Could you help me with the animation?
UIView.animate is for view animation. But upperToolTipPath is a layer; it is not a view's primary layer, so it can be animated only with layer animation. That means Core Animation, i.e. CABasicAnimation.
So to make the animation you wish to make, you will need to use Core Animation.
Alternatively, you could make a view that hosts the shape layer as its primary layer. Then you would be able to use view animation.
But I think it's better in this case to use Core Animation. Here's an example of the sort of thing I think you are trying to do:
let upperToolTipPath = CAShapeLayer()
upperToolTipPath.frame = CGRect(x: 0,y: 0, width: 65, height: 30)
let path = UIBezierPath(roundedRect: CGRect(x: 0,y: 0, width: 65, height: 30),
cornerRadius: 3)
upperToolTipPath.fillColor = UIColor.clear.cgColor
upperToolTipPath.strokeColor = UIColor.black.cgColor
upperToolTipPath.path = path.cgPath
self.layer.insertSublayer(upperToolTipPath, at: 0)
let b = CABasicAnimation(keyPath: #keyPath(CALayer.transform))
b.duration = 5
b.beginTime = CACurrentMediaTime() + 3
b.toValue = CATransform3DMakeScale(2, 2, 1)
b.repeatCount = .greatestFiniteMagnitude
b.autoreverses = true
upperToolTipPath.add(b, forKey:nil)
I'm trying to understand CAShapeLayer and where it shines. It seems like the main advantage is the shape style properties that you can conveniently access:
let shapeLayer = CAShapeLayer()
shapeLayer.frame = CGRect(origin: CGPoint(x: 100, y: 100), size: .init(width: 200, height: 200))
shapeLayer.fillColor = .none
shapeLayer.lineWidth = 5
shapeLayer.strokeColor = UIColor.blue.cgColor
let path = UIBezierPath()
let withCenter = CGPoint(x: 100, y: 100)
let radius = CGFloat(100)
let startAngle = CGFloat(0.0)
let endAngle = CGFloat(CGFloat.pi * 2)
path.addArc(withCenter: withCenter, radius: radius, startAngle: startAngle, endAngle: endAngle, clockwise: true)
shapeLayer.path = path.cgPath
But, I think the advantage ends there. It rather limits your ability set the context to multiple states like colors for different paths and requires a new CAShapeLayer. I can override the drawing method or use the delegate, but that's be doing the same thing as CALayer in that case.
On the other hand, with CALayer:
let layer = CALayer()
layer.frame = CGRect(origin: CGPoint(x: 100, y: 300), size: .init(width: 200, height: 200))
let renderer = UIGraphicsImageRenderer(size: CGSize(width: 200, height: 200))
let image = renderer.image { (_) in
let path = UIBezierPath()
let withCenter = CGPoint(x: 100, y: 100)
let radius = CGFloat(100)
let startAngle = CGFloat(0.0)
let endAngle = CGFloat(CGFloat.pi * 2)
path.lineWidth = 5
UIColor.blue.setStroke()
path.addArc(withCenter: withCenter, radius: radius, startAngle: startAngle, endAngle: endAngle, clockwise: true)
path.stroke()
}
layer.contents = image.cgImage
you can set multiple stroke colors for different paths. Obviously, you can set the CAShapeLayer's contents in a similar manner, but I want to take advantage of CAShapeLayer's API's that CALayer doesn't offer.
Are the shape style properties the main reason for CAShapeLayer?
For me, the big advantage to CAShapeLayer is animation. As Matt says, you can animate strokeStart and/or strokeEnd to cause a shape to either appear like it's being drawn with a pen, or disappear. You can also use animate strokeStart and/or strokeEnd to create a variety of different "wipe" animations.
Here is a link to a post I wrote using animations to strokeEnd to create a "clock wipe" animation:
How do you achieve a "clock wipe"/ radial wipe effect in iOS?
You can also animate the path that's installed into the shape layer. As long as the starting and ending paths have the same number of control points, the system creates a smooth, elegant looking animation. There are some tricks to making this work correctly however. Arc animations don't work as expected if you change the arc angle during an animation, because internally arcs are composed of different numbers of cubic Bezier curves.
Check out my projects RandomBlobs and TrochoidDemo on Github for examples of animating a path's control points.
class AttributedView: UIView {
private let gradient = CAGradientLayer()
var cornerRadius: CGFloat = 3 {
didSet {
layer.cornerRadius = cornerRadius
}
}
}
I simply use it for both: button view (corner radius: 20) and background circle (corner radius: 600).
Why button is smooth, and background is not?
With iOS 13.0 you can simple do, in addition to setting corner radius
yourView.layer.cornerCurve = .continuous
You should use bezzier paths and draw circle. After that you will receive nice, smooth edges.
let context = UIGraphicsGetCurrentContext()!
let gradient = CGGradient(colorsSpace: nil, colors: [UIColor.red.cgColor, UIColor.white.cgColor] as CFArray, locations: [0, 1])!
let ovalPath = UIBezierPath(ovalIn: CGRect(x: 64, y: 9, width: 111, height: 93))
context.saveGState()
ovalPath.addClip()
context.drawLinearGradient(gradient, start: CGPoint(x: 119.5, y: 9), end: CGPoint(x: 119.5, y: 102), options: [])
context.restoreGState()
UIBezierPath is a simple and efficient class for drawing shapes using Swift, which you can then put into CAShapeLayer, SKShapeNode, or other places. It comes with various shapes built in, so you can write code like this to create a rounded rectangle or a circle:
let rect = CGRect(x: 0, y: 0, width: 256, height: 256)
let roundedRect = UIBezierPath(roundedRect: rect, cornerRadius: 50)
let circle = UIBezierPath(ovalIn: rect)
You can also create custom shapes by moving a pen to a starting position then adding lines:
let freeform = UIBezierPath()
freeform.move(to: .zero)
freeform.addLine(to: CGPoint(x: 50, y: 50))
freeform.addLine(to: CGPoint(x: 50, y: 150))
freeform.addLine(to: CGPoint(x: 150, y: 50))
freeform.addLine(to: .zero)
If your end result needs a CGPath, you can get one by accessing the cgPath property of your UIBezierPath.
You probably should clip bounds of this view:
attributedView.clipsToBounds = true
I added a subview (with a black border) in a view and centered it.
Then I generate 2 identical triangles with CAShapeLayer and add one to the subview and the other to the main view.
Here is the visual result in Playground where we can see that the green triangle is totally off and should have been centered.
And here is the code:
let view = UIView()
let borderedView = UIView()
var containedFrame = CGRect(x: 0, y: 0, width: 100, height: 100)
func setupUI() {
view.frame = CGRect(x: 0, y: 0, width: 300, height: 600)
view.backgroundColor = .white
borderedView.frame = containedFrame
borderedView.center = view.center
borderedView.backgroundColor = .clear
borderedView.layer.borderColor = UIColor.black.cgColor
borderedView.layer.borderWidth = 1
view.addSubview(borderedView)
setupTriangles()
}
private func setupTriangles() {
view.layer.addSublayer(createTriangle(color: .red)) // RED triangle
borderedView.layer.addSublayer(createTriangle(color: .green)) // GREEN triangle
}
private func createTriangle(color: UIColor) -> CAShapeLayer {
let layer = CAShapeLayer()
let bezierPath = UIBezierPath()
bezierPath.move(to: CGPoint(x: 0, y: 0))
bezierPath.addLine(to: CGPoint(x: -containedFrame.width, y: 0))
bezierPath.addLine(to: CGPoint(x: 0, y: -containedFrame.height))
bezierPath.close()
layer.position = borderedView.center
layer.path = bezierPath.cgPath
layer.fillColor = color.cgColor
return layer
}
Note: All position (of view, the borderedView and both triangles) are the same (150.0, 300.0)
Question: Why is the green layer not in the right position?
#DuncanC is right that each view has its own coordinate system. Your problem is this line:
layer.position = borderedView.center
That sets the layer's position to the center of the frame for the borderedView which is in the coordinate system of view. When you create the green triangle, it needs to use the coordinate system of borderedView.
You can fix this by passing the view to your createTriangle function, and then use the center of the bounds of that view as the layer position:
private func setupTriangles() {
view.layer.addSublayer(createTriangle(color: .red, for: view)) // RED triangle
borderedView.layer.addSublayer(createTriangle(color: .green, for: borderedView)) // GREEN triangle
}
private func createTriangle(color: UIColor, for view: UIView) -> CAShapeLayer {
let layer = CAShapeLayer()
let bezierPath = UIBezierPath()
bezierPath.move(to: CGPoint(x: 0, y: 0))
bezierPath.addLine(to: CGPoint(x: -containedFrame.width, y: 0))
bezierPath.addLine(to: CGPoint(x: 0, y: -containedFrame.height))
bezierPath.close()
layer.position = CGPoint(x: view.bounds.midX, y: view.bounds.midY)
layer.path = bezierPath.cgPath
layer.fillColor = color.cgColor
return layer
}
Note: When you do this, the green triangle appears directly below the red one, so it isn't visible.
Every view/layer uses the coordinate system of it's superview/superlayer. If you add a layer to self.view.layer, it will be positioned in self.view.layer's coordinate system. If you add a layer to borderedView.layer, it will be in borderedView.layer's coordinate system.
Think of the view/layer hierarchy as stacks of pieces of graph paper. You place a new piece of paper on the current piece (the superview/layer) in the current piece's coordinates system, but then if you draw on the new view/layer, or add new views/layer inside that one, you use the new view/layer's coordinate system.
I want to shrink a triangle downward as below:
But the triangle shrink upward as below:
The transform code is below:
layer.setAffineTransform(CGAffineTransformMakeScale(1.0, 0.5))
I tried to use anchorPoint but I can't scceed.
//: Playground - noun: a place where people can play
import UIKit
let view = UIView(frame: CGRectMake(0, 0, 200, 150))
let layer = CAShapeLayer()
let triangle = UIBezierPath()
triangle.moveToPoint (CGPointMake( 50, 150))
triangle.addLineToPoint(CGPointMake(100, 50))
triangle.addLineToPoint(CGPointMake(150, 150))
triangle.closePath()
layer.path = triangle.CGPath
layer.strokeColor = UIColor.blueColor().CGColor
layer.lineWidth = 3.0
view.layer.addSublayer(layer)
view
layer.setAffineTransform(CGAffineTransformMakeScale(1.0, 0.5))
view
Anish gave me a advice but doesn't work well:
layer.setAffineTransform(CGAffineTransformMakeScale(2.0, 0.5))
Transforms operate around the layer's anchorPoint, which by default is at the center of the layer. Thus, you shrink by collapsing inwards, not by collapsing downwards.
If you want to shrink downward, you will need to scale down and change the view's position (or use a translate transform in addition to your scale transform), or change the layer's anchorPoint before performing the transform.
Another serious problem with your code is that your layer has no assigned size. This causes the results of your transform to be very misleading.
I ran this version of your code and got exactly the results you are asking for. I have put a star next to the key lines that I added. (Note that this is Swift 3; you really need to step up to the plate and update here.)
let view = UIView(frame:CGRect(x: 0, y: 0, width: 200, height: 150))
let layer = CAShapeLayer()
layer.frame = view.layer.bounds // *
let triangle = UIBezierPath()
triangle.move(to: CGPoint(x: 50, y: 150))
triangle.addLine(to: CGPoint(x: 100, y: 50))
triangle.addLine(to: CGPoint(x: 150, y: 150))
triangle.close()
layer.path = triangle.cgPath
layer.strokeColor = UIColor.blue.cgColor
layer.lineWidth = 3
view.layer.addSublayer(layer)
view
layer.anchorPoint = CGPoint(x: 0.5, y: 0) // *
layer.setAffineTransform(CGAffineTransform(scaleX: 1, y: 0.5))
view
Before:
After: