Ios 当UIBezierPath超过阈值时,如何更改其笔划和路径颜色
刚接触核心图形,有一个问题我不知道如何解决 我需要绘制一个图形,在路径穿过阈值线时更改笔划和填充颜色,如本例所示: 我可以毫无问题地把这张图画成全绿色。我不知道该怎么做的是高于或低于阈值线的部分。路径可能在点之间穿过阈值 我曾想过画两次图形,先是橙色,然后是绿色,然后在绿色路径上添加一个遮罩,阈值线形成一个矩形,使橙色版本的图形可以显示出来Ios 当UIBezierPath超过阈值时,如何更改其笔划和路径颜色,ios,swift,uibezierpath,Ios,Swift,Uibezierpath,刚接触核心图形,有一个问题我不知道如何解决 我需要绘制一个图形,在路径穿过阈值线时更改笔划和填充颜色,如本例所示: 我可以毫无问题地把这张图画成全绿色。我不知道该怎么做的是高于或低于阈值线的部分。路径可能在点之间穿过阈值 我曾想过画两次图形,先是橙色,然后是绿色,然后在绿色路径上添加一个遮罩,阈值线形成一个矩形,使橙色版本的图形可以显示出来 我相信有更好的方法。任何指点都将不胜感激。我用的是Swift 4。你的思路是对的。对于每个色带: 保存图形状态 将上下文剪裁到当前色带覆盖的区域 用适当的
我相信有更好的方法。任何指点都将不胜感激。我用的是Swift 4。你的思路是对的。对于每个色带:
for band in bands {
let y0 = max(CGPoint(x: 0, y: band.min).applying(transform).y, 0)
let y1 = min(CGPoint(x: 0, y: band.max).applying(transform).y, mySize.height)
gc.saveGState(); do {
gc.clip(to: CGRect(x: 0, y: y0, width: mySize.width, height: y1 - y0))
band.fillColor.setFill()
gc.addPath(pathForFilling)
gc.fillPath()
band.strokeColor.setStroke()
gc.addPath(pathForStroking)
gc.strokePath()
}; gc.restoreGState()
}
结果:
以下是我的完整操场代码:
import UIKit
class BandedGraphView: UIView {
struct Band {
var min: CGFloat // In data geometry
var max: CGFloat // In data geometry
var strokeColor: UIColor
var fillColor: UIColor { return strokeColor.withAlphaComponent(0.2) }
}
var bands: [Band] = [] {
didSet { setNeedsDisplay() }
}
/// The minimum visible data geometry coordinate
var minVisiblePoint = CGPoint.zero {
didSet { setNeedsDisplay() }
}
/// The maximum visible data geometry coordinate
var maxVisiblePoint = CGPoint(x: 1, y: 1) {
didSet { setNeedsDisplay() }
}
/// Data points, in data geometry.
var data: [CGPoint] = [] {
didSet { setNeedsDisplay() }
}
var lineWidth: CGFloat = 2 {
didSet { setNeedsDisplay() }
}
override func draw(_ rect: CGRect) {
guard
minVisiblePoint.x != maxVisiblePoint.x,
minVisiblePoint.y != maxVisiblePoint.y,
!bands.isEmpty,
!data.isEmpty,
let gc = UIGraphicsGetCurrentContext()
else { return }
let mySize = bounds.size
var transform = CGAffineTransform.identity
transform = transform.scaledBy(x: mySize.width / (maxVisiblePoint.x - minVisiblePoint.x), y: mySize.height / (maxVisiblePoint.y - minVisiblePoint.y))
transform = transform.translatedBy(x: -minVisiblePoint.x, y: -minVisiblePoint.y)
let pathForStroking = CGMutablePath()
pathForStroking.addLines(between: data, transform: transform)
let pathForFilling = pathForStroking.mutableCopy(using: nil)!
let firstPoint = data.first!.applying(transform)
let lastPoint = data.last!.applying(transform)
print(pathForFilling)
pathForFilling.addLine(to: CGPoint(x: lastPoint.x, y: -CGFloat.greatestFiniteMagnitude))
pathForFilling.addLine(to: CGPoint(x: firstPoint.x, y: -CGFloat.greatestFiniteMagnitude))
pathForFilling.closeSubpath()
print(pathForFilling)
// Transform the context so the origin is at the lower left.
gc.translateBy(x: 0, y: mySize.height)
gc.scaleBy(x: 1, y: -1)
for band in bands {
let y0 = max(CGPoint(x: 0, y: band.min).applying(transform).y, 0)
let y1 = min(CGPoint(x: 0, y: band.max).applying(transform).y, mySize.height)
gc.saveGState(); do {
gc.clip(to: CGRect(x: 0, y: y0, width: mySize.width, height: y1 - y0))
band.fillColor.setFill()
gc.addPath(pathForFilling)
gc.fillPath()
band.strokeColor.setStroke()
gc.addPath(pathForStroking)
gc.strokePath()
}; gc.restoreGState()
}
}
}
import PlaygroundSupport
let view = BandedGraphView(frame: CGRect(x: 0, y: 0, width: 400, height: 300))
view.backgroundColor = .white
view.bands = [
.init(min: -CGFloat.infinity, max: -0.8, strokeColor: .blue),
.init(min: -0.8, max: 0.2, strokeColor: .red),
.init(min: 0.2, max: CGFloat.infinity, strokeColor: .orange),
]
view.minVisiblePoint = CGPoint(x: 0, y: -2)
view.maxVisiblePoint = CGPoint(x: 10, y: 2)
view.lineWidth = 2
view.data = stride(from: CGFloat(0), through: CGFloat(10), by: CGFloat(0.01)).map { CGPoint(x: $0, y: cos($0)) }
PlaygroundPage.current.liveView = view
你在正确的轨道上。对于每个色带:
for band in bands {
let y0 = max(CGPoint(x: 0, y: band.min).applying(transform).y, 0)
let y1 = min(CGPoint(x: 0, y: band.max).applying(transform).y, mySize.height)
gc.saveGState(); do {
gc.clip(to: CGRect(x: 0, y: y0, width: mySize.width, height: y1 - y0))
band.fillColor.setFill()
gc.addPath(pathForFilling)
gc.fillPath()
band.strokeColor.setStroke()
gc.addPath(pathForStroking)
gc.strokePath()
}; gc.restoreGState()
}
结果:
以下是我的完整操场代码:
import UIKit
class BandedGraphView: UIView {
struct Band {
var min: CGFloat // In data geometry
var max: CGFloat // In data geometry
var strokeColor: UIColor
var fillColor: UIColor { return strokeColor.withAlphaComponent(0.2) }
}
var bands: [Band] = [] {
didSet { setNeedsDisplay() }
}
/// The minimum visible data geometry coordinate
var minVisiblePoint = CGPoint.zero {
didSet { setNeedsDisplay() }
}
/// The maximum visible data geometry coordinate
var maxVisiblePoint = CGPoint(x: 1, y: 1) {
didSet { setNeedsDisplay() }
}
/// Data points, in data geometry.
var data: [CGPoint] = [] {
didSet { setNeedsDisplay() }
}
var lineWidth: CGFloat = 2 {
didSet { setNeedsDisplay() }
}
override func draw(_ rect: CGRect) {
guard
minVisiblePoint.x != maxVisiblePoint.x,
minVisiblePoint.y != maxVisiblePoint.y,
!bands.isEmpty,
!data.isEmpty,
let gc = UIGraphicsGetCurrentContext()
else { return }
let mySize = bounds.size
var transform = CGAffineTransform.identity
transform = transform.scaledBy(x: mySize.width / (maxVisiblePoint.x - minVisiblePoint.x), y: mySize.height / (maxVisiblePoint.y - minVisiblePoint.y))
transform = transform.translatedBy(x: -minVisiblePoint.x, y: -minVisiblePoint.y)
let pathForStroking = CGMutablePath()
pathForStroking.addLines(between: data, transform: transform)
let pathForFilling = pathForStroking.mutableCopy(using: nil)!
let firstPoint = data.first!.applying(transform)
let lastPoint = data.last!.applying(transform)
print(pathForFilling)
pathForFilling.addLine(to: CGPoint(x: lastPoint.x, y: -CGFloat.greatestFiniteMagnitude))
pathForFilling.addLine(to: CGPoint(x: firstPoint.x, y: -CGFloat.greatestFiniteMagnitude))
pathForFilling.closeSubpath()
print(pathForFilling)
// Transform the context so the origin is at the lower left.
gc.translateBy(x: 0, y: mySize.height)
gc.scaleBy(x: 1, y: -1)
for band in bands {
let y0 = max(CGPoint(x: 0, y: band.min).applying(transform).y, 0)
let y1 = min(CGPoint(x: 0, y: band.max).applying(transform).y, mySize.height)
gc.saveGState(); do {
gc.clip(to: CGRect(x: 0, y: y0, width: mySize.width, height: y1 - y0))
band.fillColor.setFill()
gc.addPath(pathForFilling)
gc.fillPath()
band.strokeColor.setStroke()
gc.addPath(pathForStroking)
gc.strokePath()
}; gc.restoreGState()
}
}
}
import PlaygroundSupport
let view = BandedGraphView(frame: CGRect(x: 0, y: 0, width: 400, height: 300))
view.backgroundColor = .white
view.bands = [
.init(min: -CGFloat.infinity, max: -0.8, strokeColor: .blue),
.init(min: -0.8, max: 0.2, strokeColor: .red),
.init(min: 0.2, max: CGFloat.infinity, strokeColor: .orange),
]
view.minVisiblePoint = CGPoint(x: 0, y: -2)
view.maxVisiblePoint = CGPoint(x: 10, y: 2)
view.lineWidth = 2
view.data = stride(from: CGFloat(0), through: CGFloat(10), by: CGFloat(0.01)).map { CGPoint(x: $0, y: cos($0)) }
PlaygroundPage.current.liveView = view
您可以检查颜色混合模式:。带有屏幕混合的红色层将在绿色上产生类似的结果。您可以检查颜色混合模式:。带有混合屏幕的红色图层将在你的green.Rob上产生类似的效果。这是一个很大的帮助。谢谢我必须分别画出三个带,而不是画成一个圈,才能让它填充到正确的方向,否则我会竖起大拇指。这是一个很大的帮助。谢谢我必须分别画出三个带,而不是画成一个圈,才能让它填充到正确的方向,否则我会竖起大拇指。