forked from zelo72/mastodon-ios
112 lines
3.3 KiB
Swift
112 lines
3.3 KiB
Swift
//
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// LineChartView.swift
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// Mastodon
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//
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// Created by Cirno MainasuK on 2021-10-18.
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//
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import UIKit
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import Accelerate
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import MastodonAsset
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public final class LineChartView: UIView {
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public var data: [CGFloat] = [] {
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didSet {
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setNeedsLayout()
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}
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}
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let lineShapeLayer = CAShapeLayer()
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let gradientLayer = CAGradientLayer()
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public override init(frame: CGRect) {
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super.init(frame: frame)
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_init()
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}
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public required init?(coder: NSCoder) {
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super.init(coder: coder)
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_init()
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}
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}
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extension LineChartView {
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private func _init() {
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lineShapeLayer.frame = bounds
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gradientLayer.frame = bounds
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layer.addSublayer(lineShapeLayer)
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layer.addSublayer(gradientLayer)
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gradientLayer.colors = [
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Asset.Colors.brandBlue.color.withAlphaComponent(0.5).cgColor, // set the same alpha to fill
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Asset.Colors.brandBlue.color.withAlphaComponent(0.5).cgColor,
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]
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gradientLayer.startPoint = CGPoint(x: 0.5, y: 0)
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gradientLayer.endPoint = CGPoint(x: 0.5, y: 1)
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}
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public override func layoutSubviews() {
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super.layoutSubviews()
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lineShapeLayer.frame = bounds
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gradientLayer.frame = bounds
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guard data.count > 1 else {
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lineShapeLayer.path = nil
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gradientLayer.isHidden = true
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return
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}
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gradientLayer.isHidden = false
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// Draw smooth chart
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guard let maxDataPoint = data.max() else {
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return
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}
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func calculateY(for point: CGFloat, in frame: CGRect) -> CGFloat {
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guard maxDataPoint > 0 else { return .zero }
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return (1 - point / maxDataPoint) * frame.height
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}
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let segmentCount = data.count - 1
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let segmentWidth = bounds.width / CGFloat(segmentCount)
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let points: [CGPoint] = {
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var points: [CGPoint] = []
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var x: CGFloat = 0
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for value in data {
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let point = CGPoint(x: x, y: calculateY(for: value, in: bounds))
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points.append(point)
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x += segmentWidth
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}
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return points
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}()
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guard let linePath = CurveAlgorithm.shared.createCurvedPath(points) else { return }
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let dotPath = UIBezierPath()
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if let last = points.last {
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dotPath.addArc(withCenter: last, radius: 3, startAngle: 0, endAngle: 2 * .pi, clockwise: true)
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}
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lineShapeLayer.lineWidth = 1
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lineShapeLayer.strokeColor = Asset.Colors.brandBlue.color.cgColor
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lineShapeLayer.fillColor = UIColor.clear.cgColor
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lineShapeLayer.lineJoin = .round
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lineShapeLayer.lineCap = .round
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lineShapeLayer.path = linePath.cgPath
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let maskPath = UIBezierPath(cgPath: linePath.cgPath)
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maskPath.addLine(to: CGPoint(x: bounds.maxX, y: bounds.maxY))
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maskPath.addLine(to: CGPoint(x: bounds.minX, y: bounds.maxY))
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maskPath.close()
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let maskLayer = CAShapeLayer()
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maskLayer.path = maskPath.cgPath
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maskLayer.fillColor = Asset.Colors.brandBlue.color.cgColor
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maskLayer.strokeColor = UIColor.clear.cgColor
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maskLayer.lineWidth = 0.0
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gradientLayer.mask = maskLayer
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}
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}
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