我在 Playground 上创建了一个 uibezierpath,手动添加了值,它工作正常。结果是:
现在我的目标是平滑曲线并移除这些“尖角”。我正在考虑插值函数但不确定。在我的实际代码下面:
//: Playground - noun: a place where people can play
import Foundation
import UIKit
import CoreGraphics
import QuartzCore
class DemoView: UIView {
override func draw(_ rect: CGRect) {
let origin = CGPoint(x: frame.size.width / 2, y: frame.size.height / 2)
let radius = frame.size.width / 2
// self.createCircle(origin: origin, radius: radius)
self.addLinesInCircle(origin: origin, radius: radius)
}
func createCircle(origin: CGPoint, radius: CGFloat) {
let path = UIBezierPath()
path.addArc(withCenter: origin, radius: radius, startAngle: 0, endAngle: CGFloat(2 * Double.pi), clockwise: true)
path.close()
UIColor.clear.setFill()
path.fill()
}
func addLinesInCircle(origin: CGPoint, radius: CGFloat) {
let bezier = UIBezierPath()
let incrementAngle: CGFloat = CGFloat.pi / 24
let ratios: [CGFloat] = [3/6, 5/6, 3/6, 1/6, 5/6, 2/6, 4/6, 2/6, 4/6, 4/6, 4/6, 4/6,
3/6, 5/6, 3/6, 1/6, 5/6, 2/6, 4/6, 2/6, 4/6, 4/6, 4/6, 4/6,
3/6, 5/6, 3/6, 1/6, 5/6, 2/6, 4/6, 2/6, 4/6, 4/6, 4/6, 4/6,
3/6, 5/6, 3/6, 1/6, 5/6, 2/6, 4/6, 2/6, 4/6, 4/6, 4/6, 4/6]
for (index, ratio) in ratios.enumerated() {
let point = CGPoint(x: origin.x + cos(CGFloat(index) * incrementAngle) * radius * ratio,
y: origin.y + sin(CGFloat(index) * incrementAngle) * radius * ratio)
if index == 0 {
bezier.move(to: point)
} else {
bezier.addLine(to: point)
}
}
bezier.close()
let gradient = CGGradient(colorsSpace: nil, colors: [UIColor.red.cgColor,UIColor.blue.cgColor,UIColor.yellow.cgColor ,UIColor.black.cgColor] as CFArray, locations: nil)!
let ctx = UIGraphicsGetCurrentContext()!
ctx.saveGState()
// Clip to the path
bezier.addClip()
// Draw the gradient in the clipped region
ctx.drawLinearGradient(gradient, start: CGPoint(x: 0, y: 0), end: CGPoint(x: 0, y: frame.height), options: [])
ctx.restoreGState()
}
}
let demoView = DemoView(frame: CGRect(x: 0, y: 0, width: 1000, height: 1000))
如果有人有想法或只是关键词以便朝正确的方向看?在此先感谢您的帮助。我希望我的解释足够了......
最佳答案
使用二次曲线插值如下:
func
MidPoint( _ l: CGPoint, _ r: CGPoint ) -> CGPoint { return CGPoint( x: ( l.x + r.x ) / 2, y: ( l.y + r.y ) / 2 ) }
var start = CGPoint( x: 0, y: 0 )
var prev = CGPoint( x: 0, y: 0 )
for (index, ratio) in ratios.enumerated() {
let point = CGPoint(x: origin.x + cos(CGFloat(index) * incrementAngle) * radius * ratio,
y: origin.y + sin(CGFloat(index) * incrementAngle) * radius * ratio)
switch index {
case 0:
start = point
case 1:
bezier.move( to: MidPoint( start, point ) )
prev = point
default:
bezier.addQuadCurve( to: MidPoint( prev, point ), controlPoint: prev )
prev = point
}
}
bezier.addQuadCurve( to: MidPoint( prev, start ), controlPoint: prev )
关于swift - 平滑的 UIBezierPath,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/50812180/