The problem I'm having with structs is trying to get and set values.
I try to store my ivars as such:
let origin.x = 10, origin.y = 10
However, I'm confused as to how to utilize the getter and setters. I have an origin, but what should I put into my newCenter parameter?
struct Point {
var x = 0.0, y = 0.0
}
struct Rect {
var origin = Point(x: 10, y: 10)
var size = Size()
var center: Point {
get {
let centerX = origin.x + (size.width / 2)
let centerY = origin.y + (size.height / 2)
return Point(x: centerX, y: centerY)
}
set(newCenter) {
origin.x = newCenter.x - (size.width / 2)
origin.y = newCenter.y - (size.height / 2)
}
}
}
This appears to be mostly correct - nothing need to be "put into" the newCenter parameter. However, you are incorrectly dividing by size.width instead of size.height when calculating the y position.
When you use foo.center = bar, bar will be the value of newCenter.
Related
I used this tutorial to create a hexagon shape:
https://www.hackingwithswift.com/quick-start/swiftui/how-to-draw-polygons-and-stars
My goal is to try to round the corners of my hexagon shape. I know I have to use the path.addCurve somehow, but I cannot figure out where I need to do that. I am only getting weird results. Has anyone got an idea?
struct Polygon: Shape {
let corners: Int
let smoothness: CGFloat
func path(in rect: CGRect) -> Path {
guard corners >= 2 else { return Path() }
let center = CGPoint(x: rect.width / 2, y: rect.height / 2)
var currentAngle = -CGFloat.pi / 2
let angleAdjustment = .pi * 2 / CGFloat(corners * 2)
let innerX = center.x * smoothness
let innerY = center.y * smoothness
var path = Path()
path.move(to: CGPoint(x: center.x * cos(currentAngle), y: center.y * sin(currentAngle)))
var bottomEdge: CGFloat = 0
for corner in 0 ..< corners * 2 {
let sinAngle = sin(currentAngle)
let cosAngle = cos(currentAngle)
let bottom: CGFloat
if corner.isMultiple(of: 2) {
bottom = center.y * sinAngle
path.addLine(to: CGPoint(x: center.x * cosAngle, y: bottom))
} else {
bottom = innerY * sinAngle
path.addLine(to: CGPoint(x: innerX * cosAngle, y: bottom))
}
if bottom > bottomEdge {
bottomEdge = bottom
}
currentAngle += angleAdjustment
}
let unusedSpace = (rect.height / 2 - bottomEdge) / 2
let transform = CGAffineTransform(translationX: center.x, y: center.y + unusedSpace)
return path.applying(transform)
}
}
struct Hexagon: View {
#Environment(\.colorScheme) var colorScheme
var body: some View {
Polygon(corners: 3, smoothness: 1)
.fill(.clear)
.frame(width: 76, height: 76)
}
}
Haven't found a fix but this library does what I want:
https://github.com/heestand-xyz/PolyKit
I'm trying to make Concentration game (with matching cards) and my task is to set frames for the array of 12 UIButtons with for-loop (I tried to realize it with switches, but it wan't right as my mentor said).
So maybe you can help me with this. The code added below works correctly, but l have to escape of switch and make it works with the help of for-loop and universal formulas.
func setFrames() {
for i in 0...11{
var x = CGFloat()
var y = CGFloat()
switch i {
case 0...2:
y = 50
case 3...5:
y = (7/36 * view.bounds.height + 50);
case 6...8:
y = (7/18 * view.bounds.height + 50);
default:
y = (7/12 * view.bounds.height + 50);
}
switch i {
case 0, 3, 6, 9:
x = 1/18 * view.bounds.width; //20
case 1, 4, 7, 10:
x = 3/8 * view.bounds.width; //3/8
default:
x = 3/4 * view.bounds.width - 20;
}
buttonsArray[i].frame = CGRect(x: x, y: y, width: (1/4 * view.bounds.width), height: (1/6 * view.bounds.height))
}
}
You can use something like so:
func placeBtnsIn(frame: CGRect, padding: CGFloat) {
let numCols = 3
let numRows = 4
let buttonWidth = (frame.width - CGFloat(numCols - 1) * padding) / CGFloat(numCols)
let buttonHeight = (frame.height - CGFloat(numRows - 1) * padding) / CGFloat(numRows)
var x: CGFloat
var y: CGFloat
for row in 0...(numRows - 1) {
y = frame.origin.y + (buttonHeight + padding) * CGFloat(row)
for col in 0...(numCols - 1) {
x = frame.origin.x + (buttonWidth + padding) * CGFloat(col)
let button = UIButton()
button.frame = CGRect(x: x, y: y, width: buttonWidth, height: buttonHeight)
self.addSubview(button)
}
}
}
Then in your code use it like so:
placeBtnsIn(frame: yourFrame, padding: 5)
Where yourFrame is a rectangle in which buttons should be drawn, and padding is the distance between button "cells"
I am trying to display an image as the content of a CALayer slightly zoomed in by changing its bounds to a bigger size. (This is so that I can pan over it later.)
For some reason however setting the bounds does not change them or trigger an animation to do so.
This is the code I use to change the bounds:
self.imageLayer.bounds = CGRect(x: 0, y: 0, width: 10, height: 10)
I have a function to compute the CGRect, but this dummy one leads to exactly the same result of the size not changing.
I have also determined, that while I can't see the size change, if I check the bounds of the layer right after setting it, it correctly has the value I set it to.
The following code is executed after setting the bounds. I couldn't find anything in it, that changes them back.
self.imageLayer.add(self.generatePanAnimation(), forKey: "pan")
func generatePanAnimation() -> CAAnimation {
var positionA = CGPoint(x: (self.bounds.width / 2), y: self.bounds.height / 2)
var positionB = CGPoint(x: (self.bounds.width / 2), y: self.bounds.height / 2)
positionA = self.generateZoomedPosition()
positionB = self.generateZoomedPosition()
let panAnimation = CABasicAnimation(keyPath: "position")
if self.direction == .AtoB {
panAnimation.fromValue = positionA
panAnimation.toValue = positionB
} else {
panAnimation.fromValue = positionB
panAnimation.toValue = positionA
}
panAnimation.duration = self.panAndZoomDuration
self.panAnimation = panAnimation
return panAnimation
}
func generateZoomedPosition() -> CGPoint {
let maxRight = self.zoomedImageLayerBounds.width / 2
let maxLeft = self.bounds.width - (self.zoomedImageLayerBounds.height / 2)
let maxUp = self.zoomedImageLayerBounds.height / 2
let maxDown = self.bounds.height - (self.zoomedImageLayerBounds.height / 2)
let horizontalFactor = CGFloat(arc4random()) / CGFloat(UINT32_MAX)
let verticalFactor = CGFloat(arc4random()) / CGFloat(UINT32_MAX)
let randomX = maxLeft + horizontalFactor * (maxRight - maxLeft)
let randomY = maxDown + verticalFactor * (maxUp - maxDown)
return CGPoint(x: randomX, y: randomY)
}
I even tried setting the bounds as shown below, but it didn't help.
CATransaction.begin()
CATransaction.setValue(true, forKey: kCATransactionDisableActions)
self.imageLayer.bounds = CGRect(x: 0, y: 0, width: 10, height: 10)
CATransaction.commit()
I really hope someone has an idea. Thanks a lot!
The way to change the apparent drawing size of a layer is not to change its bounds but to change its transform. To make the layer look larger, including its drawing, apply a scale transform.
I see some code on github.
private static var allMemes:[MemeModel]{
return getMemeStorage().memes
}
Is this a variable or a function or other?
Thanks
Computed Properties
In addition to stored properties, classes, structures, and
enumerations can define computed properties, which do not actually
store a value. Instead, they provide a getter and an optional setter
to retrieve and set other properties and values indirectly.
struct Point {
var x = 0.0, y = 0.0
}
struct Size {
var width = 0.0, height = 0.0
}
struct Rect {
var origin = Point()
var size = Size()
var center: Point {
get {
let centerX = origin.x + (size.width / 2)
let centerY = origin.y + (size.height / 2)
return Point(x: centerX, y: centerY)
}
set(newCenter) {
origin.x = newCenter.x - (size.width / 2)
origin.y = newCenter.y - (size.height / 2)
}
}
}
Ref :
https://developer.apple.com/library/content/documentation/Swift/Conceptual/Swift_Programming_Language/Properties.html
I'm looking for a way to programmatically create stars, sunburst, and other "spiky" effects using UIBezierPath.
UIBezierPath *sunbeamsPath = [UIBezierPath bezierPath];
[sunbeamsPath moveToPoint: CGPointMake(x, y)];
Are there any algorithms that can generate points for sunburst like shapes programmatically, without paths overlapping?
I'm also interested in an irregular shape sunburst like the one below:
I would imagine that such algorithm would take a certain number of rays, then roughly divide the circle in a number of segments and generate points for such segment in a clockwise direction. Does an algorithm like the one I'm describing already exists or will I have to write one by myself?
Thank you!
I know this old, but I was curious about the first part of this question myself, and going off jrturton's post, I created a custom UIView that generates a UIBezierPath from center of the view. Even animated it spinning for bonus points. Here is the result:
The code I used is here:
- (void)drawRect:(CGRect)rect {
CGFloat radius = rect.size.width/2.0f;
[self.fillColor setFill];
[self.strokeColor setStroke];
UIBezierPath *bezierPath = [UIBezierPath bezierPath];
CGPoint centerPoint = CGPointMake(rect.origin.x + radius, rect.origin.y + radius);
CGPoint thisPoint = CGPointMake(centerPoint.x + radius, centerPoint.y);
[bezierPath moveToPoint:centerPoint];
CGFloat thisAngle = 0.0f;
CGFloat sliceDegrees = 360.0f / self.beams / 2.0f;
for (int i = 0; i < self.beams; i++) {
CGFloat x = radius * cosf(DEGREES_TO_RADIANS(thisAngle + sliceDegrees)) + centerPoint.x;
CGFloat y = radius * sinf(DEGREES_TO_RADIANS(thisAngle + sliceDegrees)) + centerPoint.y;
thisPoint = CGPointMake(x, y);
[bezierPath addLineToPoint:thisPoint];
thisAngle += sliceDegrees;
CGFloat x2 = radius * cosf(DEGREES_TO_RADIANS(thisAngle + sliceDegrees)) + centerPoint.x;
CGFloat y2 = radius * sinf(DEGREES_TO_RADIANS(thisAngle + sliceDegrees)) + centerPoint.y;
thisPoint = CGPointMake(x2, y2);
[bezierPath addLineToPoint:thisPoint];
[bezierPath addLineToPoint:centerPoint];
thisAngle += sliceDegrees;
}
[bezierPath closePath];
bezierPath.lineWidth = 1;
[bezierPath fill];
[bezierPath stroke];
}
And you can download a sample project here:
https://github.com/meekapps/Sunburst
I'm not aware of an algorithm to create these but I do have some advice - create your bezier path such that (0,0) is the centre of the sunburst, then define however many points you need to draw one "beam" of your sunburst going upwards, returning to (0,0)
Then, for as many beams as you want, perform a loop: apply a rotation transform (2 pi / number of beams) to your sunbeam points (CGPointApplyTransform), and add them to the path.
Once you are finished, you can translate and scale the path for drawing.
I used a similar process to draw star polygons recently and it was very simple. Credit to Rob Napier's book for the idea.
Swift version for this
import UIKit
extension Int {
var degreesToRadians: Double { return Double(self) * .pi / 180 }
var radiansToDegrees: Double { return Double(self) * 180 / .pi }
}
extension FloatingPoint {
var degreesToRadians: Self { return self * .pi / 180 }
var radiansToDegrees: Self { return self * 180 / .pi }
}
class SunBurstView: UIView {
override func draw(_ rect: CGRect) {
let radius: CGFloat = rect.size.width / 2.0
UIColor.red.setFill()
UIColor.blue.setStroke()
let bezierPath = UIBezierPath()
let centerPoint = CGPoint(x: rect.origin.x + radius, y: rect.origin.y + radius)
var thisPoint = CGPoint(x: centerPoint.x + radius, y: centerPoint.y)
bezierPath.move(to: centerPoint)
var thisAngle: CGFloat = 0.0
let sliceDegrees: CGFloat = 360.0 / self.beams / 2.0
for _ in 0..<self.beams {
let x = radius * CGFloat(cosf(Float((thisAngle + sliceDegrees).degreesToRadians))) + centerPoint.x
let y = radius * CGFloat(sinf(Float((thisAngle + sliceDegrees).degreesToRadians))) + centerPoint.y
thisPoint = CGPoint(x: x, y: y)
bezierPath.addLine(to: thisPoint)
thisAngle += sliceDegrees
let x2 = radius * CGFloat(cosf(Float((thisAngle + sliceDegrees).degreesToRadians))) + centerPoint.x
let y2 = radius * CGFloat(sinf(Float((thisAngle + sliceDegrees).degreesToRadians))) + centerPoint.y
thisPoint = CGPoint(x: x2, y: y2)
bezierPath.addLine(to: thisPoint)
bezierPath.addLine(to: centerPoint)
thisAngle += sliceDegrees
}
bezierPath.close()
bezierPath.lineWidth = 1
bezierPath.fill()
bezierPath.stroke()
}
}
I noticed that the Swift version didn't compile for me or take up enough of the screen, so here's Reinier's answer in Swift 4 adjusted for a rectangular view.
extension Int {
var degreesToRadians: Double { return Double(self) * .pi / 180 }
var radiansToDegrees: Double { return Double(self) * 180 / .pi }
}
extension FloatingPoint {
var degreesToRadians: Self { return self * .pi / 180 }
var radiansToDegrees: Self { return self * 180 / .pi }
}
class SunBurstView: UIView {
var beams: CGFloat = 20
override func draw(_ rect: CGRect) {
self.clipsToBounds = false
self.layer.masksToBounds = false
let radius: CGFloat = rect.size.width * 1.5
UIColor.orange.withAlphaComponent(0.3).setFill()
UIColor.clear.setStroke()
let bezierPath = UIBezierPath()
let centerPoint = CGPoint(x: rect.origin.x + (radius / 3), y: rect.origin.y + (radius / 1.5))
var thisPoint = CGPoint(x: centerPoint.x + radius, y: centerPoint.y)
bezierPath.move(to: centerPoint)
var thisAngle: CGFloat = 0.0
let sliceDegrees: CGFloat = 360.0 / self.beams / 2.0
for _ in 0...Int(beams) {
let x = radius * CGFloat(cosf(Float((thisAngle + sliceDegrees).degreesToRadians))) + centerPoint.x
let y = radius * CGFloat(sinf(Float((thisAngle + sliceDegrees).degreesToRadians))) + centerPoint.y
thisPoint = CGPoint(x: x, y: y)
bezierPath.addLine(to: thisPoint)
thisAngle += sliceDegrees
let x2 = radius * CGFloat(cosf(Float((thisAngle + sliceDegrees).degreesToRadians))) + centerPoint.x
let y2 = radius * CGFloat(sinf(Float((thisAngle + sliceDegrees).degreesToRadians))) + centerPoint.y
thisPoint = CGPoint(x: x2, y: y2)
bezierPath.addLine(to: thisPoint)
bezierPath.addLine(to: centerPoint)
thisAngle += sliceDegrees
}
bezierPath.close()
bezierPath.lineWidth = 1
bezierPath.fill()
bezierPath.stroke()
}
}