Swiftgram/submodules/GraphCore/Sources/Charts/Renderes/VerticalLinesRenderer.swift

//
//  VerticalLinesRenderer.swift
//  GraphTest
//
//  Created by Andrei Salavei on 4/8/19.
//  Copyright © 2019 Andrei Salavei. All rights reserved.
//

import Foundation
#if os(macOS)
import Cocoa
#else
import UIKit
#endif

class VerticalLinesRenderer: BaseChartRenderer {
    var values: [CGFloat] = [] {
        didSet {
            alphaAnimators = values.map { _ in AnimationController<CGFloat>(current: 1.0, refreshClosure: refreshClosure) }
            setNeedsDisplay()
        }
    }
    var offset: CGFloat = 0.0
    private var alphaAnimators: [AnimationController<CGFloat>] = []
    
    var linesColor: GColor = .black
    var linesWidth: CGFloat = GView.oneDevicePixel
    
    func setLineVisible(_ isVisible: Bool, at index: Int, animated: Bool) {
        if alphaAnimators.count > index {
            alphaAnimators[index].animate(to: isVisible ? 1 : 0, duration: animated ? .defaultDuration : 0)
        }
    }
    
    override func render(context: CGContext, bounds: CGRect, chartFrame: CGRect) {
        guard isEnabled && verticalRange.current.distance > 0 && verticalRange.current.distance > 0 else { return }
        
        context.setLineWidth(linesWidth)

        for (index, value) in values.enumerated() {
            let alpha = alphaAnimators[index].current
            if alpha == 0 { continue }

            context.setStrokeColor(linesColor.withAlphaComponent(linesColor.alphaValue * alpha).cgColor)
            let pointX = transform(toChartCoordinateHorizontal: value, chartFrame: chartFrame) + offset
            context.strokeLineSegments(between: [CGPoint(x: pointX, y: chartFrame.minY),
                                                 CGPoint(x: pointX, y: chartFrame.maxY)])
        }
    }
}