C# 使用NPlot绘图技巧

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NPlot.IDrawable，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();

}