Title24

//
//  BarLineChartViewBase.swift
//  Charts
//
//  Created by Daniel Cohen Gindi on 4/3/15.
//
//  Copyright 2015 Daniel Cohen Gindi & Philipp Jahoda
//  A port of MPAndroidChart for iOS
//  Licensed under Apache License 2.0
//
//  https://github.com/danielgindi/Charts
//

import Foundation
import CoreGraphics

#if !os(OSX)
    import UIKit
#endif

/// Base-class of LineChart, BarChart, ScatterChart and CandleStickChart.
public class BarLineChartViewBase: ChartViewBase, BarLineScatterCandleBubbleChartDataProvider, NSUIGestureRecognizerDelegate
{

最大可顯示數值計算

    /// the maximum number of entries to which values will be drawn
    /// (entry numbers greater than this value will cause value-labels to disappear)

    ## 最大可顯示數值計算
    internal var _maxVisibleValueCount = 100

自動顯示比例

    /// flag that indicates if auto scaling on the y axis is enabled
    private var _autoScaleMinMaxEnabled = false
    private var _autoScaleLastLowestVisibleXIndex: Int!
    private var _autoScaleLastHighestVisibleXIndex: Int!

手勢改變

    //雙指放大縮小
    private var _pinchZoomEnabled = true
    //雙擊放大縮小
    private var _doubleTapToZoomEnabled = false
    //可否拖曳
    private var _dragEnabled = true

    //影響X比例
    private var _scaleXEnabled = true
    //影響Y軸比例
    private var _scaleYEnabled = true

網格背景顏色設定

    /// the color for the background of the chart-drawing area (everything behind the grid lines).
    public var gridBackgroundColor = NSUIColor(red: 255.0/255.0, green: 55.0/255.0, blue: 55.0/255.0, alpha: 1.0)

網格框線顏色與粗細

    public var borderColor = NSUIColor.blackColor()
    public var borderLineWidth: CGFloat = 1.0

網格背景顏色開啟與否

    /// flag indicating if the grid background should be drawn or not
    public var drawGridBackgroundEnabled = false

網格框線開啟與否

    /// Sets drawing the borders rectangle to true. If this is enabled, there is no point drawing the axis-lines of x- and y-axis.
    public var drawBordersEnabled = false

預留向內偏移量 minOffset 網內壓縮（留白）

    /// Sets the minimum offset (padding) around the chart, defaults to 10
    public var minOffset = CGFloat(10.0)

轉換螢幕方向是否維持比例（預設:False)

    /// Sets whether the chart should keep its position ( zoom / scroll) after a rotation (orientation change)
    /// **default**: false
    public var keepPositionOnRotation: Bool =  false

    /// the object representing the left y-axis
    //代表左軸的
    internal var _leftAxis: ChartYAxis!

    /// the object representing the right y-axis
    internal var _rightAxis: ChartYAxis!

    internal var _leftYAxisRenderer: ChartYAxisRenderer!
    internal var _rightYAxisRenderer: ChartYAxisRenderer!

    internal var _leftAxisTransformer: ChartTransformer!
    internal var _rightAxisTransformer: ChartTransformer!

    internal var _xAxisRenderer: ChartXAxisRenderer!

    internal var _tapGestureRecognizer: NSUITapGestureRecognizer!
    internal var _doubleTapGestureRecognizer: NSUITapGestureRecognizer!
    #if !os(tvOS)
    internal var _pinchGestureRecognizer: NSUIPinchGestureRecognizer!
    #endif
    internal var _panGestureRecognizer: NSUIPanGestureRecognizer!