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[操作系统][深入浅出Windows 10]实现饼图控件


13.2 实现饼图控件

    上一小节讲解了动态生成折线图和区域图,对于简单的图形这样通过C#代码来生成的方式是很方便的,但是当我们的图表要实现更加复杂的逻辑的时候,这种动态生成的方式就显得力不从心了,那就需要利用控件封装的方式来实现更加强大的图表控件功能。这一小节将来讲解怎样去用封装控件的方式去实现图表,用一个饼图控件作为例子进行分析讲解。

13.2.1 自定义饼图片形形状

    饼图其实就是把一个圆形分成若干块,每一块代表着一个类别的数据,可以把这每一块的图形看作是饼图片形形状。要实现一个饼图控件,首先需要做的就是要实现饼图片形形状,在第4章里面讲解了实现如何实现自定义的形状,饼图片形形状也可以通过这种方式来实现。饼图片形形状有一些重要的属性,如饼图半径Radius,内圆半径InnerRadius,旋转角度RotationAngle,片形角度WedgeAngle,点innerArcStartPoint,点innerArcEndPoint,点outerArcStartPoint和点outerArcEndPoint等,这些属性的含义如图13.5所示。要绘制出这个饼图片形形状需要计算出4个点的坐标(点innerArcStartPoint,点innerArcEndPoint,点outerArcStartPoint和点outerArcEndPoint),这4的点的坐标需要通过半径和角度相关的属性计算出来。计算出这4个点的坐标的坐标之后,然后通过这4个点创建一个Path图形,这个Path图形由两条直线和两条弧线组成,形成了一个饼图片形形状。通过这种方式不仅仅把这个饼图片形形状创建好了,连这个图形在整个饼图的位置也设置好了。代码如下所示。

代码清单5-2饼图图表(源代码:第5章\Examples_5_2)

PiePiece.cs文件代码:自定义的饼图片形形状------------------------------------------------------------------------------------------------------------------  using System;  using Windows.Foundation;  using Windows.UI.Xaml;  using Windows.UI.Xaml.Media;  using Windows.UI.Xaml.Shapes;  namespace PieChartDemo  {    /// <summary>    /// 自定义的饼图片形形状    /// </summary>    class PiePiece : Path    {      #region 依赖属性      // 注册半径属性      public static readonly DependencyProperty RadiusProperty =        DependencyProperty.Register("RadiusProperty", typeof(double), typeof(PiePiece),        new PropertyMetadata(0.0));      // 饼图半径      public double Radius      {        get { return (double)GetValue(RadiusProperty); }        set { SetValue(RadiusProperty, value); }      }      // 注册饼图片形点击后推出的距离      public static readonly DependencyProperty PushOutProperty =        DependencyProperty.Register("PushOutProperty", typeof(double), typeof(PiePiece),        new PropertyMetadata(0.0));      // 距离饼图中心的距离      public double PushOut      {        get { return (double)GetValue(PushOutProperty); }        set { SetValue(PushOutProperty, value); }      }      // 注册饼图内圆半径属性      public static readonly DependencyProperty InnerRadiusProperty =        DependencyProperty.Register("InnerRadiusProperty", typeof(double), typeof(PiePiece),        new PropertyMetadata(0.0));      // 饼图内圆半径      public double InnerRadius      {        get { return (double)GetValue(InnerRadiusProperty); }        set { SetValue(InnerRadiusProperty, value); }      }      // 注册饼图片形的角度属性      public static readonly DependencyProperty WedgeAngleProperty =        DependencyProperty.Register("WedgeAngleProperty", typeof(double), typeof(PiePiece),        new PropertyMetadata(0.0));      // 饼图片形的角度      public double WedgeAngle      {        get { return (double)GetValue(WedgeAngleProperty); }        set        {          SetValue(WedgeAngleProperty, value);          this.Percentage = (value / 360.0);        }      }      // 注册饼图片形旋转角度的属性      public static readonly DependencyProperty RotationAngleProperty =        DependencyProperty.Register("RotationAngleProperty", typeof(double), typeof(PiePiece),        new PropertyMetadata(0.0));      // 旋转的角度      public double RotationAngle      {        get { return (double)GetValue(RotationAngleProperty); }        set { SetValue(RotationAngleProperty, value); }      }      // 注册中心点的X坐标属性      public static readonly DependencyProperty CentreXProperty =        DependencyProperty.Register("CentreXProperty", typeof(double), typeof(PiePiece),        new PropertyMetadata(0.0));      // 中心点的X坐标      public double CentreX      {        get { return (double)GetValue(CentreXProperty); }        set { SetValue(CentreXProperty, value); }      }      // 注册中心点的Y坐标属性      public static readonly DependencyProperty CentreYProperty =        DependencyProperty.Register("CentreYProperty", typeof(double), typeof(PiePiece),        new PropertyMetadata(0.0));      // 中心点的Y坐标      public double CentreY      {        get { return (double)GetValue(CentreYProperty); }        set { SetValue(CentreYProperty, value); }      }      // 注册该饼图片形所占饼图的百分比属性      public static readonly DependencyProperty PercentageProperty =        DependencyProperty.Register("PercentageProperty", typeof(double), typeof(PiePiece),        new PropertyMetadata(0.0));      // 饼图片形所占饼图的百分比      public double Percentage      {        get { return (double)GetValue(PercentageProperty); }        private set { SetValue(PercentageProperty, value); }      }      // 注册该饼图片形所代表的数值属性      public static readonly DependencyProperty PieceValueProperty =        DependencyProperty.Register("PieceValueProperty", typeof(double), typeof(PiePiece),        new PropertyMetadata(0.0));      // 该饼图片形所代表的数值      public double PieceValue      {        get { return (double)GetValue(PieceValueProperty); }        set { SetValue(PieceValueProperty, value); }      }      #endregion      public PiePiece()      {        CreatePathData(0, 0);      }      private double lastWidth = 0;      private double lastHeight = 0;      private PathFigure figure;      // 在图形中添加一个点      private void AddPoint(double x, double y)      {        LineSegment segment = new LineSegment();        segment.Point = new Point(x + 0.5 * StrokeThickness,          y + 0.5 * StrokeThickness);        figure.Segments.Add(segment);      }      // 在图形中添加一条线段      private void AddLine(Point point)      {        LineSegment segment = new LineSegment();        segment.Point = point;        figure.Segments.Add(segment);      }      // 在图形中添加一个圆弧      private void AddArc(Point point, Size size, bool largeArc, SweepDirection sweepDirection)      {        ArcSegment segment = new ArcSegment();        segment.Point = point;        segment.Size = size;        segment.IsLargeArc = largeArc;        segment.SweepDirection = sweepDirection;        figure.Segments.Add(segment);      }      private void CreatePathData(double width, double height)      {        // 用于退出布局的循环逻辑        if (lastWidth == width && lastHeight == height) return;        lastWidth = width;        lastHeight = height;        Point startPoint = new Point(CentreX, CentreY);        // 计算饼图片形内圆弧的开始点        Point innerArcStartPoint = ComputeCartesianCoordinate(RotationAngle, InnerRadius);        // 根据中心点来校正坐标的位置        innerArcStartPoint = Offset(innerArcStartPoint,CentreX, CentreY);        // 计算饼图片形内圆弧的结束点        Point innerArcEndPoint = ComputeCartesianCoordinate(RotationAngle + WedgeAngle, InnerRadius);        innerArcEndPoint = Offset(innerArcEndPoint, CentreX, CentreY);        // 计算饼图片形外圆弧的开始点        Point outerArcStartPoint = ComputeCartesianCoordinate(RotationAngle, Radius);        outerArcStartPoint = Offset(outerArcStartPoint, CentreX, CentreY);        // 计算饼图片形外圆弧的结束点        Point outerArcEndPoint = ComputeCartesianCoordinate(RotationAngle + WedgeAngle, Radius);        outerArcEndPoint = Offset(outerArcEndPoint, CentreX, CentreY);        // 判断饼图片形的角度是否大于180度        bool largeArc = WedgeAngle > 180.0;        // 把扇面饼图往偏离中心点推出一部分        if (PushOut > 0)        {          Point offset = ComputeCartesianCoordinate(RotationAngle + WedgeAngle / 2, PushOut);          // 根据偏移量来重新设置圆弧的坐标          innerArcStartPoint = Offset(innerArcStartPoint,offset.X, offset.Y);          innerArcEndPoint = Offset(innerArcEndPoint,offset.X, offset.Y);          outerArcStartPoint = Offset(outerArcStartPoint,offset.X, offset.Y);          outerArcEndPoint = Offset(outerArcEndPoint,offset.X, offset.Y);        }        // 外圆的大小        Size outerArcSize = new Size(Radius, Radius);        // 内圆的大小        Size innerArcSize = new Size(InnerRadius, InnerRadius);        var geometry = new PathGeometry();        figure = new PathFigure();        // 从内圆开始坐标开始画一个闭合的扇形图形        figure.StartPoint = innerArcStartPoint;        AddLine(outerArcStartPoint);        AddArc(outerArcEndPoint, outerArcSize, largeArc, SweepDirection.Clockwise);        AddLine(innerArcEndPoint);        AddArc(innerArcStartPoint, innerArcSize, largeArc, SweepDirection.Counterclockwise);        figure.IsClosed = true;        geometry.Figures.Add(figure);        this.Data = geometry;      }      protected override Size MeasureOverride(Size availableSize)      {        return availableSize;      }      protected override Size ArrangeOverride(Size finalSize)      {        CreatePathData(finalSize.Width, finalSize.Height);        return finalSize;      }      //把点进行偏移转换      private Point Offset(Point point, double offsetX, double offsetY)      {        point.X += offsetX;        point.Y += offsetY;        return point;      }      /// <summary>      /// 根据角度和半径来计算出圆弧上的点的坐标      /// </summary>      /// <param name="angle">角度</param>      /// <param name="radius">半径</param>      /// <returns>圆弧上的点坐标</returns>      private Point ComputeCartesianCoordinate(double angle, double radius)      {        // 转换成弧度单位        double angleRad = (Math.PI / 180.0) * (angle - 90);        double x = radius * Math.Cos(angleRad);        double y = radius * Math.Sin(angleRad);        return new Point(x, y);      }    }  }

13.2.2 封装饼图控件

    创建好了PiePiece形状之后,下面就要开始创建利用PiePiece形状来创建饼图控件了。创建饼图控件是通过UserControl控件来实现,UserControl控件的XAML代码里面只有一个Grid面板,是用来加载PiePiece形状来组成饼图。XAML代码如下所示:

PiePlotter.xaml文件代码------------------------------------------------------------------------------------------------------------------  <UserControl x:Class="PieChartDemo.PiePlotter"    ="http://schemas.microsoft.com/winfx/2006/xaml/presentation"    ="http://schemas.microsoft.com/winfx/2006/xaml"    ="http://schemas.microsoft.com/expression/blend/2008"    ="http://schemas.open    mc:Ignorable="d"    FontFamily="{StaticResource PhoneFontFamilyNormal}"    FontSize="{StaticResource PhoneFontSizeNormal}"    Foreground="{StaticResource PhoneForegroundBrush}"    d:DesignHeight="480" d:DesignWidth="480" >    <Grid x:Name="LayoutRoot"></Grid>  </UserControl>

    在实现饼图之前,需要知道饼图里面的数据集合的,还需要用一个实体类PieDataItem来表示饼图的数据项,有两个属性一个是表示图形的数值Value属性,另外一个是表示饼图片形块的颜色Brush属性。PieDataItem代码如下:

PieDataItem.cs文件代码------------------------------------------------------------------------------------------------------------------  using Windows.UI.Xaml.Media;  namespace PieChartDemo  {    /// <summary>    /// 饼图数据实体    /// </summary>    public class PieDataItem    {      public double Value { get; set; }      public SolidColorBrush Brush { get; set; }    }  }

    下面来实现饼图控件加载的逻辑,在饼图控件里面还需要自定义一些相关的属性,用来传递相关的参数。属性HoleSize表示饼图内圆的大小,按照比例来计算;属性PieWidth表示饼图的宽度。饼图的数据集合是通过控件的数据上下文属性DataContext属性来传递,在初始化饼图的时候需要把DataContext的数据读取出来然后再创建PiePiece图形。每个PiePiece图形都添加了Tap事件,用来实现当用户点击饼图的时候,相应的某一块回往外推出去。代码如下所示:

PiePlotter.xaml.cs文件代码------------------------------------------------------------------------------------------------------------------  using System.Collections.Generic;  using Windows.UI.Xaml;  using Windows.UI.Xaml.Controls;  using Windows.UI.Xaml.Input;  namespace PieChartDemo  {    /// <summary>    /// 饼图控件    /// </summary>    public partial class PiePlotter : UserControl    {      #region dependency properties      // 注册内圆大小属性      public static readonly DependencyProperty HoleSizeProperty =              DependencyProperty.Register("HoleSize", typeof(double), typeof(PiePlotter), new PropertyMetadata(0.0));      // 内圆的大小,按照比例来计算      public double HoleSize      {        get { return (double)GetValue(HoleSizeProperty); }        set        {          SetValue(HoleSizeProperty, value);        }      }      // 注册饼图宽度属性      public static readonly DependencyProperty PieWidthProperty =          DependencyProperty.Register("PieWidth", typeof(double), typeof(PiePlotter), new PropertyMetadata(0.0));      // 饼图宽度      public double PieWidth      {        get { return (double)GetValue(PieWidthProperty); }        set { SetValue(PieWidthProperty, value); }      }      #endregion      // 饼图的片形PiePiece的集合      private List<PiePiece> piePieces = new List<PiePiece>();      // 选中的当前饼图的数据项      private PieDataItem CurrentItem;      public PiePlotter()      {        InitializeComponent();      }      // 初始化展示饼图的方法      public void ShowPie()      {        // 获取控件的数据上下文,转化成数据集合        List<PieDataItem> myCollectionView = (List<PieDataItem>)this.DataContext;        if (myCollectionView == null)          return;        // 半径的大小        double halfWidth = PieWidth / 2;         // 内圆半径大小        double innerRadius = halfWidth * HoleSize;        // 计算图表数据的总和        double total = 0;        foreach (PieDataItem item in myCollectionView)        {          total += item.Value;        }        // 通过PiePiece构建饼图        LayoutRoot.Children.Clear();        piePieces.Clear();        double accumulativeAngle = 0;        foreach (PieDataItem item in myCollectionView)        {          bool selectedItem = item == CurrentItem;          double wedgeAngle = item.Value * 360 / total;          // 根据数据来创建饼图的每一块图形          PiePiece piece = new PiePiece()          {            Radius = halfWidth,            InnerRadius = innerRadius,            CentreX = halfWidth,            CentreY = halfWidth,            PushOut = (selectedItem ? 10.0 : 0),            WedgeAngle = wedgeAngle,            PieceValue = item.Value,            RotationAngle = accumulativeAngle,            Fill = item.Brush,            Tag = item          };          // 添加饼图片形的点击事件          piece.Tapped += piece_Tapped;          piePieces.Add(piece);          LayoutRoot.Children.Add(piece);          accumulativeAngle += wedgeAngle;        }      }          void piece_Tapped(object sender, TappedRoutedEventArgs e)      {        PiePiece piePiece = sender as PiePiece;        CurrentItem = piePiece.Tag as PieDataItem;        ShowPie();      }    }  }

    在调用饼图控件时需要引用控件所属的空间,然后在XAML上调用饼图控件。

MainPage.xaml文件主要代码------------------------------------------------------------------------------------------------------------------  ……省略若干代码<local:PiePlotter x:Name="piePlotter" Width="400" Height="400" PieWidth="400" HoleSize="0.2"></local:PiePlotter>

    在C#代码里面,对饼图的DataContext属性进行赋值饼图的数据集合,然后调用ShowPie方法初始化饼图。代码如下:

MainPage.xaml.cs文件主要代码------------------------------------------------------------------------------------------------------------------  public MainPage()  {    InitializeComponent();    List<PieDataItem> datas=new List<PieDataItem>();    datas.Add(new PieDataItem{ Value=30, Brush = new SolidColorBrush(Colors.Red)});    datas.Add(new PieDataItem { Value = 40, Brush = new SolidColorBrush(Colors.Orange) });    datas.Add(new PieDataItem { Value = 50, Brush = new SolidColorBrush(Colors.Blue) });    datas.Add(new PieDataItem { Value = 30, Brush = new SolidColorBrush(Colors.LightGray) });    datas.Add(new PieDataItem { Value = 20, Brush = new SolidColorBrush(Colors.Purple) });    datas.Add(new PieDataItem { Value = 40, Brush = new SolidColorBrush(Colors.Green) });    piePlotter.DataContext = datas;    piePlotter.ShowPie();  }

本文来源于《深入浅出Windows 10通用应用开发》

源代码下载:http://vdisk.weibo.com/u/2186322691

目录:http://www.cnblogs.com/linzheng/p/5021428.html

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