I am currently creating a game in SpriteKit. In this game, I am trying to draw an outline of a circle with a small gap(s) in the outline of this circle (possibly about 1/8 the entire circumference of the circle). Here is a drawn picture of what I am visualizing.
How would I do this using SpriteKit? Would I use SKShapeNode? Any help would be appreciated. Thank you.
You can get something similar using the SKShapeNode in combination with SKEffectNode, like this:
override func didMoveToView(view: SKView) {
let effectNode = SKEffectNode()
let gap = CGFloat(M_PI_4 / 4.0)
for i in 0...3 {
let shape = SKShapeNode(circleOfRadius: 50)
shape.fillColor = .clearColor()
shape.lineWidth = 6.8
shape.strokeColor = .darkGrayColor()
let startAngle:CGFloat = CGFloat(i) * CGFloat(M_PI_2) + gap
let endAngle:CGFloat = startAngle + CGFloat(M_PI_2) - gap * 2
print("Iteration \(i) : start angle (\(startAngle * 180 / CGFloat(M_PI)), end angle (\(endAngle * 180 / CGFloat(M_PI)))")
shape.path = UIBezierPath(arcCenter: CGPointZero, radius: -50, startAngle: startAngle, endAngle: endAngle, clockwise: true).CGPath
effectNode.addChild(shape)
}
effectNode.position = CGPoint(x: frame.midX, y: frame.midY)
effectNode.shouldRasterize = true
addChild(effectNode)
}
The result:
Or you could make a mask programatically and apply it to a SKCropNode. The SKCropNode of course will be a parent of a ring (SKShapeNode with fillColor set to .clearColor() and strokeColor set to appropriate value).
Related
What I am trying to do that draw a circle node using its radius and origin points.
Is there any way to draw a circle node in SceneKit?
How can I draw that?
First approach
Use SceneKit SCNCylinder's procedural mesh to create a circle.
func circle(origin: SCNVector3, radius: CGFloat) -> SCNNode {
let cylinderNode = SCNNode()
cylinderNode.geometry = SCNCylinder(radius: radius, height: 0.001)
cylinderNode.geometry?.firstMaterial?.diffuse.contents = UIColor.red
cylinderNode.geometry?.firstMaterial?.isDoubleSided = true
cylinderNode.position = origin
cylinderNode.eulerAngles.x = .pi/2
return cylinderNode
}
sceneView.scene?.rootNode.addChildNode(circle(
origin: SCNVector3(), radius: 0.5)
)
Second approach
This approach is impractical for your particular case, because you must specify the radius in UIKit units, not in meters like in SceneKit. However, I decided to publish it as option B.
// Path
let circlePath = UIBezierPath(arcCenter: CGPoint(x: 0, y: 0),
radius: 20,
startAngle: 0.0,
endAngle: .pi * 2,
clockwise: true)
circlePath.flatness = 0.1
// Shape
let material = SCNMaterial()
material.diffuse.contents = UIColor.systemRed
material.isDoubleSided = true
let circleShape = SCNShape(path: circlePath, extrusionDepth: 0.001)
circleShape.materials = [material]
// Node
let circleNode = SCNNode()
circleNode.geometry = circleShape
sceneView.scene?.rootNode.addChildNode(circleNode)
You could probably do something like this:
let circle = SCNPlane(width: 1.0, height: 1.0)
circle.cornerRadius = circle.width/2
hope, this is, what you are looking for.
another approch might be the SCNCylinder with a very small height or even SCNTorus with a very small pipe radius.
EDIT: Sorry, I wasn't clear originally. I want to get the "outline" path of a line or shape. I'm specifically trying to understand how to use:
context.replacePathWithStrokedPath()
and / or:
CGPathRef CGPathCreateCopyByStrokingPath(CGPathRef path, const CGAffineTransform *transform, CGFloat lineWidth, CGLineCap lineCap, CGLineJoin lineJoin, CGFloat miterLimit);
https://developer.apple.com/documentation/coregraphics/1411128-cgpathcreatecopybystrokingpath?language=objc
I'm not looking for workarounds, thanks.
=====
I'm really trying to wrap my head around drawing a line with an outline around it. i'm using UIBezier, but running into brick walls. So far, I've got this:
import UIKit
import PlaygroundSupport
let screenWidth = 375.0 // points
let screenHeight = 467.0 // points
let centerX = screenWidth / 2.0
let centerY = screenHeight / 2.0
let screenCenterCoordinate = CGPoint(x: centerX, y: centerY)
class LineDrawingView: UIView {
override func draw(_ rect: CGRect) {
let path = UIBezierPath()
path.lineWidth = 5
path.lineCapStyle = .round
//Move to Drawing Point
path.move(to: CGPoint(x:20, y:120))
path.addLine(to: CGPoint(x:200, y:120))
path.stroke()
let dot = UIBezierPath()
dot.lineWidth = 1
dot.lineCapStyle = .round
dot.move(to: CGPoint(x:200, y:120))
dot.addArc(withCenter: CGPoint(x:200, y:120), radius: 5, startAngle: CGFloat(0.0), endAngle: CGFloat(8.0), clockwise: true)
UIColor.orange.setStroke()
UIColor.orange.setFill()
path.stroke()
dot.fill()
let myStrokedPath = UIBezierPath.copy(path)
myStrokedPath().stroke()
}
}
let tView = LineDrawingView(frame: CGRect(x: 0,y: 0, width: screenWidth, height: screenHeight))
tView.backgroundColor = UIColor.white
PlaygroundPage.current.liveView = tView
So, where am I going wrong in this? I cannot seem to figure out where to use CGPathCreateCopyByStrokingPath...or how...
EDIT 2:
Ok, now I've got this. Closer, but how do I fill the path again?
let c = UIGraphicsGetCurrentContext()!
c.setLineWidth(15.0)
let clipPath = UIBezierPath(arcCenter: CGPoint(x:centerX,y:centerY), radius: 90.0, startAngle: -0.5 * .pi, endAngle: 1.0 * .pi, clockwise: true).cgPath
c.addPath(clipPath)
c.saveGState()
c.replacePathWithStrokedPath()
c.setLineWidth(0.2)
c.setStrokeColor(UIColor.black.cgColor)
c.strokePath()
The class was modified slightly to produce this graphic:
The path was not copied in the modified code. Instead the existing path was used to draw, then modified and reused. The dot did not have a stroke so that was added. Since only closed paths can be filled, I drew a thinner path on top of a thicker path by changing the line width.
This is the modified code:
class LineDrawingView: UIView {
override func draw(_ rect: CGRect) {
let path = UIBezierPath()
path.lineWidth = 7
path.lineCapStyle = .round
//Move to Drawing Point
path.move(to: CGPoint(x:20, y:120))
path.addLine(to: CGPoint(x:200, y:120))
path.stroke()
let dot = UIBezierPath()
dot.lineWidth = 1
dot.lineCapStyle = .round
dot.move(to: CGPoint(x:200, y:120))
dot.addArc(withCenter: CGPoint(x:200, y:120), radius: 5, startAngle: CGFloat(0.0), endAngle: CGFloat(8.0), clockwise: true)
dot.stroke()
UIColor.orange.setStroke()
UIColor.orange.setFill()
path.lineWidth = 5
path.stroke()
dot.fill()
}
}
So, I've found the (an) answer. I used CAShapeLayer:
let c = UIGraphicsGetCurrentContext()!
c.setLineCap(.round)
c.setLineWidth(15.0)
c.addArc(center: CGPoint(x:centerX,y:centerY), radius: 90.0, startAngle: -0.5 * .pi, endAngle: (-0.5 * .pi) + (3 / 2 * .pi ), clockwise: false)
c.replacePathWithStrokedPath()
let shape = CAShapeLayer()
shape.path = c.path
shape.fillColor = UIColor.yellow.cgColor
shape.strokeColor = UIColor.darkGray.cgColor
shape.lineWidth = 1
myView.layer.addSublayer(shape)
It works well enough, but not on overlapping layers. I need to learn how to connect contours or something.
i want to display an arbitray part of a circle.
I know how to get a round View using layer.cornerRadius now i want to see only a part of that circle(for any given radiant value). It would be ok, if the rest of it would be simply hidden beneath something white.
Any ideas, how to achieve that?
edit:
i have written a class for my View:
class Circle:UIView {
var rad = 0
let t = CGFloat(3.0)
override func draw(_ rect: CGRect) {
super.draw(rect)
let r = self.frame.width / CGFloat(2)
let center = CGPoint(x: r, y: r)
let path = UIBezierPath()
path.move(to: CGPoint(x: t, y: r))
path.addLine(to: CGPoint(x: 0.0, y: r))
path.addArc(withCenter: center, radius: CGFloat(r), startAngle: CGFloat(Double.pi), endAngle: CGFloat(Double.pi+rad), clockwise: true)
let pos = path.currentPoint
let dx = r - pos.x
let dy = r - pos.y
let d = sqrt(dx*dx+dy*dy)
let p = t / d
path.addLine(to: CGPoint(x: pos.x + p * dx, y: pos.y + p * dy))
path.addArc(withCenter: center, radius: r-t, startAngle: CGFloat(Double.pi+rad), endAngle: CGFloat(Double.pi), clockwise: false)
UIColor(named: "red")?.setFill()
path.fill()
}
}
public func setRad(perc:Double) {
rad = Double.pi * 2 * perc
}
in my view controller i call
circleView.layer.cornerRadius = circleView.frame.size.width / 2
circleView.clipsToBounds = true
circleView.layer.borderWidth = 1
circleView.layer.borderColor = UIColor.darkGray.cgColor
circleView.layer.shadowColor = UIColor.black.cgColor
circleView.layer.shadowOpacity = 1
circleView.layer.shadowOffset = CGSize.zero
circleView.layer.shadowRadius = 3
circleView.layer.masksToBounds = false
circleView.addGestureRecognizer(UITapGestureRecognizer(target: self, action: #selector(self.onTap)))
now i get the full square View with a black circle from the corner and the red arc that i draw. If necessary i will post a picture tomorrow
One way to do it is to draw a UIBezierPath.
If you just want an arc, you can call the init(arcCenter:radius:startAngle:endAngle:clockwise:) initializer. Remember to specify the start and end angles in radians!
After that, you can set the stroke color and call stroke
If you want a sector of a circle, you can create a UIBezierPath with the parameterless initializer, then move(to:) the center of the circle, and then addLine(to:) the start of the arc. You can probably calculate where this point is with a bit of trigonometry. After that, call addArc like I described above, then addLine(to:) the point where you started. After that, you can fill the path.
Could you please advice why CATransform3DRotate doesnt work for layer in my case, its blue layer on the image.
I have custom view, where I draw nature view, I want to animate changing the moon phase that will be done inside the white circle layer as its mask. I suppose that it is good idea to apply here 3DRotation, but for some reason it doesn't work even without animation, could be please advice what I am doing wrong?
func drawMoonPhase(inRect rect:CGRect, inContext context: CGContext) {
let moonShape = UIBezierPath(ovalIn: rect)
moonShape.lineWidth = 4.0
UIColor.white.setStroke()
moonShape.stroke()
moonShape.close()
let moonLayer = CAShapeLayer()
moonLayer.path = moonShape.cgPath
moonLayer.opacity = 0
self.layer.addSublayer(moonLayer)
let circlePath = UIBezierPath(ovalIn: rect)
UIColor.blue.setFill()
circlePath.fill()
circlePath.close()
let circleShape = CAShapeLayer()
circleShape.path = circlePath.cgPath
circleShape.opacity = 0
var transform = CATransform3DIdentity
transform.m34 = -1 / 500.0
transform = CATransform3DRotate(transform, (CGFloat(Double.pi * 0.3)), 0, 1, 0)
circleShape.transform = transform
moonLayer.mask = circleShape
}
Thanks in advance
EDIT:
Maybe I want clear , the effect i want is the below:
The transform occurs around the layer's anchor point that by default is in the center. Therefore what it is happening there is that the shape rotates around itself causing no visible result. :)
what you should do in this layout of layer is to use cos and sin math functions in order to determine the x and y position of your moon.
Let me know if you need more insights I will be happy to help.
also, please note that you don't need 2 shapeLayers in order to have the blue moon with the white stroke. CAShapeLayer has properties for both fill and stroke so you can simplify your code.
Based on the new info here is my new answer:
I was not able to get a nice effect by using the transform, so I decided to write the mask manually. this is the result:
/**
Draw a mask based on the moon phase progress.
- parameter rect: The rect where the mon will be drawn
- parameter progress: The progress of the moon phase. This value must be between 0 and 1
*/
func moonMask(in rect: CGRect, forProgress progress: CGFloat)->CALayer {
let path = CGMutablePath()
let center = CGPoint(x: rect.midX, y: rect.midY)
path.move(to: CGPoint(x: rect.midX, y: 0))
let relativeProgress = (max(min(progress, 1), 0) - 0.5) * 2
let radius = rect.width/2
let tgX = rect.midX+(relativeProgress * (radius*4/3))
path.addCurve(to: CGPoint(x: rect.midX, y: rect.maxY), control1: CGPoint(x: tgX, y: 0), control2: CGPoint(x: tgX, y: rect.maxY))
path.addArc(center: center, radius: rect.width/2, startAngle: .pi/2, endAngle: .pi*3/2, clockwise: false)
//path.closeSubpath()
let mask = CAShapeLayer()
mask.path = path
mask.fillColor = UIColor.black.cgColor
return mask
}
The function above draws a shapelier that can be used as mask for your moonLayer. This layer will be drawnin relation to a progress parameter that you will pass in the function where 1 is full moon and 0 is new moon.
You can put everything together to have the desired effect, and you can extract the path creation code to make a nice animation if you want.
This should answer your question I hope.
To quick test I wrote this playground:
import UIKit
let rect = CGRect(origin: .zero, size: CGSize(width: 200, height: 200))
let view = UIView(frame: rect)
view.backgroundColor = .black
let layer = view.layer
/**
Draw a mask based on the moon phase progress.
- parameter rect: The rect where the mon will be drawn
- parameter progress: The progress of the moon phase. This value must be between 0 and 1
*/
func moonMask(in rect: CGRect, forProgress progress: CGFloat)->CALayer {
let path = CGMutablePath()
let center = CGPoint(x: rect.midX, y: rect.midY)
path.move(to: CGPoint(x: rect.midX, y: 0))
let relativeProgress = (max(min(progress, 1), 0) - 0.5) * 2
let radius = rect.width/2
let tgX = rect.midX+(relativeProgress * (radius*4/3))
path.addCurve(to: CGPoint(x: rect.midX, y: rect.maxY), control1: CGPoint(x: tgX, y: 0), control2: CGPoint(x: tgX, y: rect.maxY))
path.addArc(center: center, radius: rect.width/2, startAngle: .pi/2, endAngle: .pi*3/2, clockwise: false)
//path.closeSubpath()
let mask = CAShapeLayer()
mask.path = path
mask.fillColor = UIColor.white.cgColor
return mask
}
let moonLayer = CAShapeLayer()
moonLayer.path = UIBezierPath(ovalIn: rect).cgPath
moonLayer.fillColor = UIColor.clear.cgColor
moonLayer.strokeColor = UIColor.white.cgColor
moonLayer.lineWidth = 2
moonLayer.shadowColor = UIColor.white.cgColor
moonLayer.shadowOpacity = 1
moonLayer.shadowRadius = 10
moonLayer.shadowPath = moonLayer.path
moonLayer.shadowOffset = .zero
layer.addSublayer(moonLayer)
let moonPhase = moonMask(in: rect, forProgress: 0.3)
moonPhase.shadowColor = UIColor.white.cgColor
moonPhase.shadowOpacity = 1
moonPhase.shadowRadius = 10
moonPhase.shadowPath = moonLayer.path
moonPhase.shadowOffset = .zero
layer.addSublayer(moonPhase)
view
I'm writing a program that will take a number between 0 and 1, and then spits out a circle (or arc I guess) that is completed by that much.
So for example, if 0.5 was inputted, the program would output a semicircle
if 0.1, the program would output a tiny little arc that would ultimately be 10% of the whole circle.
I can get this to work by making the angle starting point 0, and the angle ending point 2*M_PI*decimalInput
However, I need to have the starting point at the top of the circle, so the starting point is 3*M_PI_2 and the ending point would be 7*M_PI_2
I'm just having trouble drawing a circle partially complete with these new starting/ending points. And I'll admit, my math is not the best so any advice/input is appreciated
Here is what I have so far
var decimalInput = 0.75 //this number can be any number between 0 and 1
let start = CGFloat(3*M_PI_2)
let end = CGFloat(7*M_PI_2*decimalInput)
let circlePath = UIBezierPath(arcCenter: circleCenter, radius: circleRadius, startAngle: start, endAngle: end, clockwise: true)
circlePath.stroke()
I just cannot seem to get it right despite what I try. I reckon the end angle is culprit, unless I'm going about this the wrong way
The arc length is 2 * M_PI * decimalInput. You need to add the arc length to the starting angle, like this:
let circleCenter = CGPointMake(100, 100)
let circleRadius = CGFloat(80)
var decimalInput = 0.75
let start = CGFloat(3 * M_PI_2)
let end = start + CGFloat(2 * M_PI * decimalInput)
let circlePath = UIBezierPath(arcCenter: circleCenter, radius: circleRadius, startAngle: start, endAngle: end, clockwise: true)
XCPCaptureValue("path", circlePath)
Result:
Note that the path will be flipped vertically when used to draw in a UIView.
You can use this extension to draw a partial circle
extension UIBezierPath {
func addCircle(center: CGPoint, radius: CGFloat, startAngle: Double, circlePercentage: Double) {
let start = deg2rad(startAngle)
let end = start + CGFloat(2 * Double.pi * circlePercentage)
addArc(withCenter: center,
radius: radius,
startAngle: start,
endAngle: end,
clockwise: true)
}
private func deg2rad(_ number: Double) -> CGFloat {
return CGFloat(number * Double.pi / 180)
}
}
Example usage (you can copy paste it in a playground to see the result)
let view = UIView(frame: CGRect(x: 0, y: 0, width: 100, height: 100))
view.backgroundColor = UIColor.green
let layer = CAShapeLayer()
layer.strokeColor = UIColor.red.cgColor
layer.fillColor = UIColor.clear.cgColor
layer.lineWidth = 8
let path = UIBezierPath()
path.addCircle(center: CGPoint(x: 50, y: 50), radius: 50, startAngle: 270, circlePercentage: 0.87)
layer.path = path.cgPath
view.layer.addSublayer(layer)
view.setNeedsLayout()