C# 使用GDI绘制雷达图

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 = ;
         static float mH = ;
         static Dictionary<string, float> mData = new Dictionary<string, float>
         {
                 //{ "速度",77},
                 { "力量", },
                 { "防守", },
                 { "射门", },
                 { "传球", },
                 { "耐力",  }
         };//维度数据
         static float mCount = mData.Count; //边数
         static float mCenter = mW * 0.5f; //中心点
         static float mRadius = mCenter - ; //半径(减去的值用于给绘制的文本留空间)
         static double mAngle = (Math.PI * ) / mCount; //角度
         static Graphics graphics = null;
         static int mPointRadius = ;  // 各个维度分值圆点的半径
         static int textFontSize = ;   //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(, , , );
         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 = ; i < mCount; i++)
             {
                 var points = new List<PointF>();
                 var currR = r * (i + ); //当前半径
                 //画6条边
                 for (var j = ; 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 = ; 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 = ;
             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 >  && mAngle * i <= Math.PI / )
                 {
                     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 /  && 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 *  / )
                 {
                     ctx.DrawString(item.Key, font, new SolidBrush(fontColor), x - ctx.MeasureString(item.Key, font).Width, y);
                 }
                 else if (mAngle * i > Math.PI *  / )
                 {
                     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 = ;
             List<PointF> points = new List<PointF>();
             foreach (var item in mData)
             {
                 var x = (float)(mCenter + mRadius * Math.Cos(mAngle * i) * item.Value / );
                 var y = (float)(mCenter + mRadius * Math.Sin(mAngle * i) * item.Value / );

                 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 = ;
             foreach (var item in mData)
             {
                 var x = (float)(mCenter + mRadius * Math.Cos(mAngle * i) * item.Value / );
                 var y = (float)(mCenter + mRadius * Math.Sin(mAngle * i) * item.Value / );
                 ctx.FillPie(new SolidBrush(fillColor), x - r, y - r, r * , r * , , );
                 //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