原文

　　图表控件一直是很难找的，特别是免费又强大的。NPlot是一款非常难得的.Net平台下的图表控件，能做各种曲线图，柱状图，饼图，散点图，股票图等，而且它免费又开源，使用起来也非常符合程序员的习惯。唯一的缺点就是文档特别难找，难读。通过对其文档的阅读和对示例程序源代码的分析，现在将NPlot的基本概念整理如下：

    NPlot的命名空间包括NPlot,NPlot.Bitmap,NPlot.Web,NPlot.Web.Design,NPlot.Windows等，其中最核心的，管理各种图表的类都属于NPlot命名空间，NPlot.Bitmap针对位图的管理，NPlot.Web,NPlot.Web.Design和NPlot.Windows则可视为NPlot图表在Web Form和Windows Form上的容器(PlotSurface2D)。这些容器可以拖到Form上，也可以位于其他容器之中。

    要在应用程序中应用NPlot控件，首先要把所下载的NPlot.dll添加到.Net工程中。并将其添加到工具箱托盘中。添加方式为：在工具箱上单击右键，选择“选择项”，会出现“选择工具箱项”对话框，在“.Net Frameworks组件”属性页，选择浏览，找到NPlot.dll添加到工具箱项。这时工具箱中会出现NPlot控件。在设计应用程序界面时，可以将其拖入应用程序界面，系统会在代码中自动创建一个PlotSurface2D对象。

    PlotSurface2D对象是NPlot图表的容器，所有的图表图形，坐标，标题（都继承IDrawable接口）等各种信息都可以被加入PlotSurface2D。PlotSurface2D拥有一个非常重要的方法：Add。各种图表图形，坐标，标题都可以通过Add加入PlotSurface2D对象。

我们可以通过下面简单的代码示例来了解NPlot的基本用法：

 

public void plotline(){// --- Plotting ---    plot.Clear();// --- Grid Code ---    Grid mygrid = new Grid();    mygrid.HorizontalGridType = Grid.GridType.None;    mygrid.VerticalGridType = Grid.GridType.Fine;    plot.Add(mygrid);    plot.Title = "Test";    StepPlot line = new StepPlot();    line.Pen = new Pen (Color.Red, 1);    line.OrdinateData = new int [] {
   0, 1, 0, 1, 1, 0};    line.HideVerticalSegments = false;    plot.Add(line);    plot.Refresh();    return;}

Grid对象和StepPlot对象都是NPlot命名空间中的对象，都继承于，都可以作为PlotSurface2D.Add函数调用，在NPlot中画图，就是把网格，坐标，图形等各种对象加入PlotSurface2D对象中，一切就那么简单！

 

下面给出更多代码例子

 

////对所绘的图进行打印与保存//private void print(){    myPlot.Print(true);}private void save(){    saveFileDialog1.Filter = "位图(*.bmp)|*.bmp|JPEG(*.jpg)|*.jpg;*.jpeg;*,jpe|Gif(*.gif)|*.gif|Tiff(*.tiff)|*.tiff|Png(*.png)|*.png|Exif(*.exif)|*.exif|所有文件(*.*)|*.*";    if (saveFileDialog1.ShowDialog() == DialogResult.OK)    {       try        {            int h = myPlot.Size.Height;            int w = myPlot.Size.Width;            Bitmap bm = new Bitmap(w, h);            Bitmap bm1 = new Bitmap(w, h);            Rectangle rt = new Rectangle(1, 1, w, h);            saveFileDialog1.RestoreDirectory = true;            saveFileDialog1.CreatePrompt = true;            myPlot.DrawToBitmap(bm, rt);            if (saveFileDialog1.FilterIndex == 1)            {                bm.Save(saveFileDialog1.FileName);            }            if (saveFileDialog1.FilterIndex == 2)            {                bm.Save(saveFileDialog1.FileName, ImageFormat.Jpeg);            }            if (saveFileDialog1.FilterIndex == 3)            {                bm.Save(saveFileDialog1.FileName, ImageFormat.Gif);            }            if (saveFileDialog1.FilterIndex == 4)            {                bm.Save(saveFileDialog1.FileName, ImageFormat.Tiff);            }            if (saveFileDialog1.FilterIndex == 5)            {                bm.Save(saveFileDialog1.FileName, ImageFormat.Png);            }            if (saveFileDialog1.FilterIndex == 6)            {                bm.Save(saveFileDialog1.FileName, ImageFormat.Exif);            }        }        catch (Exception MyEx)        {            MessageBox.Show(MyEx.ToString(), "错误提示", MessageBoxButtons.OK, MessageBoxIcon.Warning);        }    }}///放大缩小private void changeSize(){    this.myPlot.XAxis1.IncreaseRange(0.1);    this.myPlot.YAxis1.IncreaseRange(0.1); //缩小    this.myPlot.XAxis1.IncreaseRange(-0.1);    this.myPlot.YAxis1.IncreaseRange(-0.1); //放大    this.myPlot.Refresh();}/各种绘图//         private void plot(){    this.myPlot.Clear(    ////标签//    string[] strLabel = new string[leng];    for (int i = 0; i < leng; i++)        strLabel[i] = Convert.ToString(p[i]);    LabelPointPlot labp = new LabelPointPlot();    labp.AbscissaData = X;    labp.OrdinateData = p;    labp.TextData = strLabel;    labp.LabelTextPosition = LabelPointPlot.LabelPositions.Above;    labp.Marker = new Marker(Marker.MarkerType.Square, 8);    labp.Marker.Color = Color.Blue;    myPlot.Add(labp);    myPlot.Refresh();               ////网格//    Grid mygrid = new Grid();    mygrid.HorizontalGridType = Grid.GridType.Fine;    mygrid.VerticalGridType = Grid.GridType.Fine;    this.myPlot.Add(mygrid);    ////曲线，双坐标轴//    ///水平线//    HorizontalLine line = new HorizontalLine(1.2);    line.LengthScale = 0.89f;    this.myPlot.Add(line, -10);    ///垂直线///    VerticalLine line2 = new VerticalLine(1.2);    line2.LengthScale = 0.89f;    this.myPlot.Add(line2);    ///普通的线///    LinePlot lp3 = new LinePlot();    lp3.OrdinateData = yPW;    lp3.AbscissaData = x;    lp3.Pen = new Pen(Color.Orange);    lp3.Pen.Width = 2;    lp3.Label = " 价格";    this.myPlot.Add(lp3);    LinearAxis linx = (LinearAxis)myPlot.XAxis1;    this.myPlot.XAxis1 = linx;    LinearAxis liny = (LinearAxis)myPlot.YAxis1;    liny.Label = "价格";    liny.AxisColor = Color.Orange;    liny.LabelColor = Color.Orange;    liny.TickTextColor = Color.Orange;    this.myPlot.YAxis1 = liny;    LinePlot lp4 = new LinePlot();    lp4.OrdinateData = yUw;    lp4.AbscissaData = x;    lp4.Pen = new Pen(Color.Green);    lp4.Pen.Width = 2;    lp4.Label = "销售量";    this.myPlot.Add(lp4, PlotSurface2D.XAxisPosition.Top, PlotSurface2D.YAxisPosition.Right);    LinearAxis liny2 = (LinearAxis)myPlot.YAxis2;    liny2.WorldMax = 1.2;    liny2.WorldMin = 0;    liny2.Label = "销售量";    liny2.AxisColor = Color.Green;    liny2.LabelColor = Color.Green;    liny2.TickTextColor = Color.Green;    this.myPlot.YAxis2 = liny2;    ///图例//    this.myPlot.Legend = new Legend();    this.myPlot.Legend.AttachTo(PlotSurface2D.XAxisPosition.Top, PlotSurface2D.YAxisPosition.Right);    this.myPlot.Legend.NumberItemsHorizontally = 2;    this.myPlot.Legend.HorizontalEdgePlacement = Legend.Placement.Inside;    this.myPlot.Legend.VerticalEdgePlacement = Legend.Placement.Inside;    this.myPlot.Legend.YOffset = 5;    this.myPlot.Legend.XOffset = -5;    ///窗体移动//    this.myPlot.AddInteraction(new NPlot.Windows.PlotSurface2D.Interactions.HorizontalDrag());    this.myPlot.AddInteraction(new NPlot.Windows.PlotSurface2D.Interactions.VerticalDrag());    this.myPlot.AddInteraction(new NPlot.Windows.PlotSurface2D.Interactions.AxisDrag(true));    //累加的柱状图////    HistogramPlot hp3 = new HistogramPlot();    hp3.AbscissaData = x;    hp3.OrdinateData = yCC1;    hp3.BaseWidth = 0.6f;    hp3.RectangleBrush = RectangleBrushes.Vertical.FaintBlueFade;    hp3.Filled = true;    hp3.Label = "一月";    HistogramPlot hp4 = new HistogramPlot();    hp4.AbscissaData = x;    hp4.OrdinateData = yCC2;    hp4.Label = "二月";    hp4.RectangleBrush = RectangleBrushes.Horizontal.FaintGreenFade;    hp4.Filled = true;    hp4.StackedTo(hp3);    this.myPlot.Add(hp3);    this.myPlot.Add(hp4);    //阶状图////                      StepPlot sp1 = new StepPlot();    sp1.OrdinateData = yCH1;    sp1.AbscissaData = x;    sp1.Label = "高度";    sp1.Pen.Width = 2;    sp1.Pen.Color = Color.Blue;    this.myPlot.Add(sp1);    /////点状图////       Marker m = new Marker(Marker.MarkerType.Cross1, 6, new Pen(Color.Blue, 2.0F));    PointPlot pp = new PointPlot(m);    pp.OrdinateData = a;    pp.AbscissaData = new StartStep(-500.0, 10.0);    pp.Label = "Random";    this.myPlot.Add(pp);    /////Image图////    double[,] map = new double[19, 19];    for (int i = 0; i < 19; ++i)    {        for (int j = 0; j < 19; ++j)        {            map[i, j] = Convert.ToDouble(tokens[i * 19 + j], new                System.Globalization.CultureInfo("en-US"));        }    }    ImagePlot ip = new ImagePlot(map, -9.0f, 1.0f, -9.0f, 1.0f);    ip.Gradient = new LinearGradient(Color.Gold, Color.Black);    this.myPlot.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.None;    this.myPlot.AddInteraction(new NPlot.Windows.PlotSurface2D.Interactions.RubberBandSelection());    this.myPlot.Add(ip);    ///蜡烛图///    int[] opens =  { 1, 2, 1, 2, 1, 3 };    double[] closes = { 2, 2, 2, 1, 2, 1 };    float[] lows =   { 0, 1, 1, 1, 0, 0 };    System.Int64[] highs =  { 3, 2, 3, 3, 3, 4 };    int[] times =  { 0, 1, 2, 3, 4, 5 };    CandlePlot cp = new CandlePlot();    cp.CloseData = closes;    cp.OpenData = opens;    cp.LowData = lows;    cp.HighData = highs;    cp.AbscissaData = times;    this.myPlot.Add(cp);    /////对数坐标轴////         // x axis    LogAxis logax = new LogAxis(plotSurface.XAxis1);    logax.WorldMin = xmin;    logax.WorldMax = xmax;    logax.AxisColor = Color.Red;    logax.LabelColor = Color.Red;    logax.TickTextColor = Color.Red;    logax.LargeTickStep = 1.0f;    logax.Label = "x";    this.myPlot.XAxis1 = logax;    // y axis    LogAxis logay = new LogAxis(plotSurface.YAxis1);    logay.WorldMin = ymin;    logay.WorldMax = ymax;    logay.AxisColor = Color.Red;    logay.LabelColor = Color.Red;    logay.TickTextColor = Color.Red;    logay.LargeTickStep = 1.0f;    logay.Label = "x^2";    this.myPlot.YAxis1 = logay;    /////字符坐标轴////    LabelAxis la1 = new LabelAxis(this.myPlot.XAxis1);    string[] sX = new string [15];    for (int i = 0; i < 15; i++)    {        la1.AddLabel(sX[i].ToString(), i);    }    la1.Label = "时间";    la1.TickTextFont = new Font("Courier New", 10);    la1.TicksBetweenText = true;    this.myPlot.XAxis1 = la1;    /////区域着色////              FilledRegion fr = new FilledRegion(new VerticalLine(1.2),new VerticalLine(2.4));    //两条线之间的区域： FilledRegion fr = new FilledRegion(lp1, lp2);    fr.Brush = Brushes.BlanchedAlmond;    this.myPlot.Add(fr);   //画箭头//    ArrowItem a = new ArrowItem(new PointD(2, 4),360-(30-90), "Arrow");    a.HeadOffset = 5;    a.ArrowColor = Color.Red;    a.TextColor = Color.Purple;    this.myPlot.Add(a);    this.myPlot.Refresh();}