C# 使用GDI绘制雷达图的实例

最近项目要用C#实现画一个雷达图，搜了搜网上竟然找不到C#画雷达图的解决方案，那么自己实现一个吧

实现效果如下图：

代码如下：

public static class RadarDemo
  {
    static float mW = 1200;
    static float mH = 1200;
    static Dictionary<string, float> mData = new Dictionary<string, float>
    {
        //{ "速度",77},
        { "力量", 72},
        { "防守", 110},
        { "射门", 50},
        { "传球", 80},
        { "耐力", 60 }
    };//维度数据
    static float mCount = mData.Count; //边数
    static float mCenter = mW * 0.5f; //中心点
    static float mRadius = mCenter - 100; //半径(减去的值用于给绘制的文本留空间)
    static double mAngle = (Math.PI * 2) / mCount; //角度
    static Graphics graphics = null;
    static int mPointRadius = 5; // 各个维度分值圆点的半径  
    static int textFontSize = 18;  //顶点文字大小 px
    const string textFontFamily = "Microsoft Yahei"; //顶点字体
    static Color lineColor = Color.Green;
    static Color fillColor = Color.FromArgb(128, 255, 0, 0);
    static Color fontColor = Color.Black;
    public static void Show()
    {
      Bitmap img = new Bitmap((int)mW, (int)mH); 
      graphics = Graphics.FromImage(img); 
      graphics.Clear(Color.White);
      img.Save($"{AppDomain.CurrentDomain.BaseDirectory}radar/0.png", ImageFormat.Png);
      DrawPolygon(graphics);
      img.Save($"{AppDomain.CurrentDomain.BaseDirectory}radar/1.png", ImageFormat.Png);
      DrawLines(graphics);
      img.Save($"{AppDomain.CurrentDomain.BaseDirectory}radar/2.png", ImageFormat.Png);
      DrawText(graphics);
      img.Save($"{AppDomain.CurrentDomain.BaseDirectory}radar/3.png", ImageFormat.Png);
      DrawRegion(graphics);
      img.Save($"{AppDomain.CurrentDomain.BaseDirectory}radar/4.png", ImageFormat.Png);
      DrawCircle(graphics);
      img.Save($"{AppDomain.CurrentDomain.BaseDirectory}radar/5.png", ImageFormat.Png);
      img.Dispose();
      graphics.Dispose();
    }
    // 绘制多边形边
    private static void DrawPolygon(Graphics ctx)
    {
      var r = mRadius / mCount; //单位半径
      Pen pen = new Pen(lineColor);
      //画6个圈
      for (var i = 0; i < mCount; i++)
      {
        var points = new List<PointF>();
        var currR = r * (i + 1); //当前半径
        //画6条边
        for (var j = 0; j < mCount; j++)
        {
          var x = (float)(mCenter + currR * Math.Cos(mAngle * j));
          var y = (float)(mCenter + currR * Math.Sin(mAngle * j));
          points.Add(new PointF { X = x, Y = y });
        }
        ctx.DrawPolygon(pen, points.ToArray());
        //break;
      }
      ctx.Save();
    }
    //顶点连线
    private static void DrawLines(Graphics ctx)
    {
      for (var i = 0; i < mCount; i++)
      {
        var x = (float)(mCenter + mRadius * Math.Cos(mAngle * i));
        var y = (float)(mCenter + mRadius * Math.Sin(mAngle * i));
        ctx.DrawLine(new Pen(lineColor), new PointF { X = mCenter, Y = mCenter }, new PointF { X = x, Y = y });
        //break;
      }
      ctx.Save();
    }
    //绘制文本
    private static void DrawText(Graphics ctx)
    {
      var fontSize = textFontSize;//mCenter / 12;
      Font font = new Font(textFontFamily, fontSize, FontStyle.Regular);
      int i = 0;
      foreach (var item in mData)
      {
        var x = (float)(mCenter + mRadius * Math.Cos(mAngle * i));
        var y = (float)(mCenter + mRadius * Math.Sin(mAngle * i) - fontSize);
        if (mAngle * i > 0 && mAngle * i <= Math.PI / 2)
        {
          ctx.DrawString(item.Key, font, new SolidBrush(fontColor), x - ctx.MeasureString(item.Key, font).Width * 0.5f, y + fontSize/* y + fontSize*/);
        }
        else if (mAngle * i > Math.PI / 2 && mAngle * i <= Math.PI)
        {
          ctx.DrawString(item.Key, font, new SolidBrush(fontColor), x - ctx.MeasureString(item.Key, font).Width, y /*y + fontSize*/);
        }
        else if (mAngle * i > Math.PI && mAngle * i <= Math.PI * 3 / 2)
        {
          ctx.DrawString(item.Key, font, new SolidBrush(fontColor), x - ctx.MeasureString(item.Key, font).Width, y);
        }
        else if (mAngle * i > Math.PI * 3 / 2)
        {
          ctx.DrawString(item.Key, font, new SolidBrush(fontColor), x - ctx.MeasureString(item.Key, font).Width * 0.5f, y - fontSize * 0.5f);
        }
        else
        {
          ctx.DrawString(item.Key, font, new SolidBrush(fontColor), x, y /* y + fontSize*/);
        }
        i++;
      }
      ctx.Save();
    }
    //绘制数据区域
    private static void DrawRegion(Graphics ctx)
    {
      int i = 0;
      List<PointF> points = new List<PointF>();
      foreach (var item in mData)
      {
        var x = (float)(mCenter + mRadius * Math.Cos(mAngle * i) * item.Value / 100);
        var y = (float)(mCenter + mRadius * Math.Sin(mAngle * i) * item.Value / 100);
        points.Add(new PointF { X = x, Y = y });
        //ctx.DrawArc(new Pen(lineColor), x, y, r, r, 0, (float)Math.PI * 2); 
        i++;
      }
      //GraphicsPath path = new GraphicsPath();
      //path.AddLines(points.ToArray());
      ctx.FillPolygon(new SolidBrush(fillColor), points.ToArray());
      ctx.Save();
    }
    //画点
    private static void DrawCircle(Graphics ctx)
    {
      //var r = mCenter / 18;
      var r = mPointRadius;
      int i = 0;
      foreach (var item in mData)
      {
        var x = (float)(mCenter + mRadius * Math.Cos(mAngle * i) * item.Value / 100);
        var y = (float)(mCenter + mRadius * Math.Sin(mAngle * i) * item.Value / 100);
        ctx.FillPie(new SolidBrush(fillColor), x - r, y - r, r * 2, r * 2, 0, 360);
        //ctx.DrawArc(new Pen(lineColor), x, y, r, r, 0, (float)Math.PI * 2); 
        i++;
      }
      ctx.Save();
    }
  }

把这个类粘贴到你的项目中，执行RadarDemo.Show();就会在你的根目录里生成雷达图了，为了方便理解怎么画出来的，我把画每一个步骤时的图片都保存下来了。可以自行运行查看

总结

以上所述是小编给大家介绍的C# 使用GDI绘制雷达图的实例，希望对大家有所帮助，如果大家有任何疑问请给我留言，小编会及时回复大家的。在此也非常感谢大家对猪先飞网站的支持！
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