c#画图之折线图

public JsonResult DrawLineChart()
        {
            // 预置颜色
            List<Color> colors = new List<Color>()
            {
                Color.FromArgb(,,),
                Color.FromArgb(,,),
                Color.FromArgb(,,),
                Color.FromArgb(,,),
                Color.FromArgb(,,),
                Color.FromArgb(,,),
                Color.FromArgb(,,),
                Color.FromArgb(,,),
                Color.FromArgb(,,)
            };

            #region 允许配置项

            //定义宽高
            int height = , width = ;

            //边缘位置留白
            int margin_top = ;
            int margin_right = ;
            int margin_bottom = ;
            int margin_left = ;

            //辅助线距离顶部的距离
            int xsubline = ;

            //文字大小，单位：px
            int fontsize = ;

            // 折线名称预留的位置  颜色框20，与文字间隙5，文字80，距离折线图10，需要包含边缘留白
            int lineNameWidth =  - margin_right;

            #endregion

            #region 数据

            //最大数量/总数量--生成y轴时，显示数字需要
            int maxCount = ;

            //x轴底部显示的名称
            string[] bottomData = new string[] { "第一个", "第二个", "第三个", "第四个", "第五个" };

            //折线名称
            string[] lineName = new string[] { "折线1", "折线2" };

            //折线数据
            List<List<int>> lineData = new List<List<int>> {
                new List<int>(){ ,,,, },
                new List<int>(){ ,,,, }
            };

            //maxCount = xCount.Max();
            for (int i = ; i < lineData.Count; i++)
            {
                int tempMaxCount = lineData[i].Max();

                if (tempMaxCount > maxCount)
                {
                    maxCount = tempMaxCount;
                }
            }

            maxCount = maxCount ==  ?  : maxCount;

            #endregion

            //单位转换对象
            Spire.Pdf.Graphics.PdfUnitConvertor unitCvtr = new Spire.Pdf.Graphics.PdfUnitConvertor();

            //生成图像对象
            Bitmap image = new Bitmap(width + margin_left + margin_right + lineNameWidth, height + margin_top + margin_bottom);

            //创建画布
            Graphics g = Graphics.FromImage(image);
            //消除锯齿
            g.SmoothingMode = SmoothingMode.AntiAlias;
            //质量
            g.InterpolationMode = InterpolationMode.HighQualityBicubic;
            g.CompositingQuality = CompositingQuality.HighQuality;

            //黑色画笔--主轴颜色
            Brush blackBrush = new SolidBrush(Color.FromArgb(, , , ));
            Pen blackPen = new Pen(blackBrush, );

            //灰色画笔--辅助线条颜色
            Brush grayBrush = new SolidBrush(Color.FromArgb(, , , ));
            Pen grayPen = new Pen(grayBrush, );

            //填充区域内容
            g.FillRectangle(Brushes.WhiteSmoke, , , width + margin_left + margin_right + lineNameWidth, height + margin_top + margin_bottom);

            //y轴
            g.DrawLine(blackPen, margin_left, margin_top, margin_left, (height + margin_top));

            //x轴
            g.DrawLine(blackPen, margin_left, (height + margin_top), (width + margin_left), (height + margin_top));

            Font font = new Font("宋体", unitCvtr.ConvertUnits(fontsize, Spire.Pdf.Graphics.PdfGraphicsUnit.Pixel, Spire.Pdf.Graphics.PdfGraphicsUnit.Point));

            //x轴--辅助线

            //画5条辅助线，不管数字大小
            int avgCount = Convert.ToInt32(Math.Ceiling(maxCount / 5.0));

            // 为了适应后面的计算
            maxCount = avgCount * ;

            int lineHeight = (height - xsubline) / ;

            //画辅助线与文字
            for (int i = ; i <= ; i++)
            {
                //辅助线
                if (i > )
                {
                    g.DrawLine(grayPen, margin_left, (height + margin_top - lineHeight * i), (width + margin_left), (height + margin_top - lineHeight * i));
                }

                //指向文字的线
                g.DrawLine(blackPen, (margin_left - ), (height + margin_top - lineHeight * i), margin_left, (height + margin_top - lineHeight * i));
                //文字
                int text = avgCount * i;

                RectangleF rec = new RectangleF(, (height + margin_top - lineHeight * i - fontsize / ), margin_left - , );
                StringFormat format = new StringFormat(StringFormatFlags.DirectionRightToLeft);
                g.DrawString(text.ToString(), font, blackBrush, rec, format);
            }

            //底部文字
            int singleWidth = width / (bottomData.Length - );

            for (int i = ; i < bottomData.Length; i++)
            {
                StringFormat format = new StringFormat();
                format.Alignment = StringAlignment.Center; //居中

                //x轴下的文字
                //指向线
                g.DrawLine(blackPen, margin_left + i * singleWidth, (height + margin_top), margin_left + i * singleWidth, (height + margin_top + ));
                //文字
                RectangleF rec = new RectangleF(margin_left + (i * singleWidth) - singleWidth / , (height + margin_top + ), singleWidth, (margin_bottom - ));
                g.DrawString(bottomData[i].ToString(), font, blackBrush, rec, format);
            }

            //预定颜色
            for (int i = ; i < lineName.Length; i++)
            {
                //随机颜色
                Color tempColor = colors[i];//GetRandomColor();

                //文字内容
                StringFormat format = new StringFormat(StringFormatFlags.DirectionVertical);
                //format.Alignment = StringAlignment.Center; //居中

                //画笔
                SolidBrush brush = new SolidBrush(tempColor);
                Pen pen = new Pen(brush, );

                // 折线名称处理
                // 颜色块
                Rectangle rectangle = new Rectangle(margin_left + width + , margin_top + i * , , );
                g.FillRectangle(brush, rectangle);

                // 文字
                RectangleF rec = new RectangleF(margin_left + width +  + , margin_top + i * , , );
                g.DrawString(bottomData[i].ToString(), font, blackBrush, rec, format);

                //这里要开始画折线了
                Point[] points = new Point[lineData[i].Count];

                for (int j = ; j < lineData[i].Count; j++)
                {
                    int x = j * singleWidth + margin_left;
                    int y = height + margin_top - Convert.ToInt32(lineData[i][j] / Convert.ToDouble(maxCount) * (height - xsubline));

                    Point point = new Point(x,y);

                    points[j] = point;
                }

                g.DrawLines(pen, points);
            }

            string relativePath = @"\draw-image\" + DateTime.Now.ToString("yyyyMMddHHmmssfff") + ".jpg";
            string path = Server.MapPath(relativePath);
            image.Save(path, System.Drawing.Imaging.ImageFormat.Jpeg);

            //return relativePath;
            return Json(relativePath, JsonRequestBehavior.AllowGet);
        }

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