private double CalSegDurationSecond(XAxisPlotElementInfo axisX, Graphics graphics, double durationTimeMillisecond)
        {
            string labelText         = this.GetLabelText(DateTime.Now, double.NaN);
            SizeF  labelTextSize     = graphics.MeasureString(labelText, axisX.Font);
            float  labelTextMinWidth = labelTextSize.Width * 2;
            int    maxLabelCount     = (int)(axisX.Area.Width / labelTextMinWidth);
            double separatorSecond;
            double segDurationMillisecond = durationTimeMillisecond / maxLabelCount;

            if (segDurationMillisecond < 500)
            {
                separatorSecond = 0.5d;
            }
            else if (segDurationMillisecond < 1000)
            {
                separatorSecond = 1d;
            }
            else
            {
                separatorSecond = (int)Math.Ceiling(segDurationMillisecond / 1000);
            }

            return(separatorSecond);
        }
        private void DrawTimeAxis(Graphics graphics, WavePlotPara plotPara)
        {
            XAxisPlotElementInfo axisX = this._xAxis;

            if (axisX == null)
            {
                return;
            }

            //时间图背景
            RectangleF rectangleTimeArea = axisX.Area;

            graphics.FillRectangle(axisX.BackgroudColor, rectangleTimeArea);

            if (plotPara == null)
            {
                return;
            }

            //边框
            //graphics.DrawLine(this._borderPen, rectangleTimeArea.X, rectangleTimeArea.Y, rectangleTimeArea.X, rectangleTimeArea.Y + rectangleTimeArea.Height);
            //float borderX = rectangleTimeArea.X + rectangleTimeArea.Width - this._borderPen.Width;
            //graphics.DrawLine(this._borderPen, borderX, rectangleTimeArea.Y, borderX, rectangleTimeArea.Y + rectangleTimeArea.Height);
            //graphics.DrawLine(this._borderPen, rectangleTimeArea.X, rectangleTimeArea.Y, rectangleTimeArea.X + rectangleTimeArea.Width, rectangleTimeArea.Y);

            //绘制起始时间-毫秒
            double beginTimeMillisecond = plotPara.SBTOMillisecond;

            //绘制结束时间-毫秒
            double endTimeMillisecond = plotPara.GetSETOMillisecond();

            //绘制总时长
            double durationTimeMillisecond = endTimeMillisecond - beginTimeMillisecond;

            if (durationTimeMillisecond <= 0d)
            {
                return;
            }

            //绘制时间间隔
            double separatorSecond = this.CalSegDurationSecond(axisX, graphics, durationTimeMillisecond);

            //绘制起始时间-秒
            double beginTimeSecond = beginTimeMillisecond / 1000;

            //绘制时间-秒
            double timeSecond = PlotConstant.ZEROR_D;

            if (beginTimeMillisecond > PlotConstant.ZEROR_D)
            {
                int    mult = (int)(beginTimeSecond / separatorSecond);
                double mod  = beginTimeSecond % separatorSecond;
                if (mod - separatorSecond < PlotConstant.ZEROR_D)
                {
                    mult = mult + 1;
                }
                timeSecond = separatorSecond * mult;
            }

            //绘制时间
            DateTime time    = plotPara.BaseTime.AddSeconds(timeSecond);
            DateTime endTime = plotPara.BaseTime.AddMilliseconds(endTimeMillisecond);


            float  labelHeight = rectangleTimeArea.Height / 3;
            float  y1 = rectangleTimeArea.Y + rectangleTimeArea.Height;
            float  y2 = y1 - labelHeight;
            float  y3 = y1 - labelHeight / 2;
            float  labelX, labelSmallX;
            double separatorSecondHalf = separatorSecond / 2;

            float  secondLength = (float)(axisX.Area.Width / (durationTimeMillisecond / 1000));
            string labelText;
            SizeF  labelTextSize;
            float  labelTextX, lastLabelTextRightX = 0f;
            float  labelTextY = rectangleTimeArea.Y + labelHeight / 2;

            AxisLabelLocation labelTextLocation = AxisLabelLocation.First;
            var contentWidth = axisX.Area.Width;
            Pen pen          = axisX.Pen;

            while (true)
            {
                //刻度-x
                labelX      = (float)(secondLength * (timeSecond - beginTimeSecond));
                labelSmallX = (float)(secondLength * (timeSecond - beginTimeSecond - separatorSecondHalf));

                //绘制刻度文本
                labelText     = this.GetLabelText(time, separatorSecond);
                labelTextSize = graphics.MeasureString(labelText, axisX.Font);
                labelTextX    = labelX - labelTextSize.Width / 2;

                switch (labelTextLocation)
                {
                case AxisLabelLocation.First:
                    if (labelTextX < PlotConstant.ZEROR_D && beginTimeMillisecond <= PlotConstant.ZEROR_D)
                    {
                        labelTextX = (float)PlotConstant.ZEROR_D;
                    }
                    labelTextLocation = AxisLabelLocation.Middle;
                    break;

                case AxisLabelLocation.Middle:
                    if (labelTextX + labelTextSize.Width - contentWidth > PlotConstant.ZEROR_D)
                    {
                        labelTextX = contentWidth - labelTextSize.Width;
                    }
                    break;

                case AxisLabelLocation.Last:
                    if (labelTextX + labelTextSize.Width - contentWidth > PlotConstant.ZEROR_D)
                    {
                        labelTextX = contentWidth - labelTextSize.Width;
                        if (labelTextX - lastLabelTextRightX < PlotConstant.ZEROR_D)
                        {
                            if (labelSmallX - contentWidth < PlotConstant.ZEROR_D)
                            {
                                graphics.DrawLine(pen, labelSmallX, y1, labelSmallX, y3);
                            }

                            return;
                        }
                    }
                    break;

                default:
                    throw new NotImplementedException();
                }

                graphics.DrawString(labelText, axisX.Font, axisX.ForeColor, labelTextX, labelTextY);
                lastLabelTextRightX = labelTextX + labelTextSize.Width;

                //绘制刻度
                if (labelSmallX > PlotConstant.ZEROR_D)
                {
                    graphics.DrawLine(pen, labelSmallX, y1, labelSmallX, y3);
                }

                if (labelX - contentWidth < PlotConstant.ZEROR_D)
                {
                    graphics.DrawLine(pen, labelX, y1, labelX, y2);
                }

                if (labelTextLocation == AxisLabelLocation.Last)
                {
                    break;
                }

                timeSecond += separatorSecond;
                time        = plotPara.BaseTime.AddSeconds(timeSecond);
                if (time >= endTime)
                {
                    time = endTime;
                    labelTextLocation = AxisLabelLocation.Last;
                }
            }
        }