GDI+ 绘制砂岩含量图版

图版是在工作中经常会使用到的工具，它能够大大提高我们日常工作效率。地质图版在地质工作中具有举足轻重的作用，不仅可以轻松判断岩性，也可以依据经验图版直接得到结果，十分方便。

本程序目的绘制出一个地质常用三角图版：砂岩含量图版。图版的每个角代表每种含量,目标图版如下：

程序源代码下载地址见文章末尾。

---

首先建立一个TrianglePlate类。确定TrianglePlate类的属性两个：三角形中心（Center）和三角形边长（SideLength）。

/// <summary>
/// 三角形图版内心
/// </summary>
public PointF Center { set; get; }

/// <summary>
/// 三角形图版边长
/// </summary>
public float SideLength { get; set; }

定义一个PointF数组代表三角形图版三个点的具体坐标，采用PointF类型的原因是PointF比Point更加精确，能够保证图像的精度。为了对类进行封装，坐标数组采用private类型。

private PointF[] _points;

TrianglePlate类的构造函数如下：

public TrianglePlate(PointF center, float sidelength)
{
     this.Center = center;
     this.SideLength = sidelength;
     this.Scale = sacle;

     //计算三个点
     _points = new PointF[3];
     _points[0] = new PointF(this.Center.X - this.SideLength/2,
                           (float) (this.Center.Y - this.SideLength/(2*Math.Sqrt(3)))
           );
    _points[1] = new PointF(this.Center.X + this.SideLength/2,
                           (float) (this.Center.Y - this.SideLength/(2*Math.Sqrt(3)))
           );
    _points[2] = new PointF(this.Center.X,
                           (float) (this.Center.Y - 2*this.SideLength/(Math.Sqrt(3)))
           );
}

为了更好绘制图形，向TrianglePlate类加入DrawTrianglePlate方法，方便图形的绘制。

/// <summary>
/// 绘制三角形图版
/// </summary>
public void DrawTrianglePlate (Graphics g)
{
    DrawSildes (g);
}

/// <summary>
/// 绘制三角形图版三边
/// </summary>
private void DrawSildes (Graphics g)
{
    g.DrawLine (this.SidePen, _points[0], _points[1]);
    g.DrawLine (this.SidePen, _points[1], _points[2]);
    g.DrawLine (this.SidePen, _points[2], _points[0]);
}

在From进行TrianglePlate初始化后，就可以调用Form的Paint函数进行绘制了。

public FrmMain()
{
    InitializeComponent();
    tp.SidePen = new Pen (Color.Black, 3);
    tp.SidePen.StartCap = LineCap.Round;
    tp.SaclePen = new Pen (Color.Black, 3);

}

TrianglePlate tp = new TrianglePlate (new PointF (200, 500), 350);

private void tabPage1_Paint (object sender, PaintEventArgs e)
{
    Graphics g = e.Graphics;
    tp.DrawTrianglePlate (g, pcoursor);

    myBuffer.Render (e.Graphics);
    g.Dispose();
    myBuffer.Dispose(); //释放资源
}

一个简单的三角形就绘制完成了，如下：

---

接下来进行绘制三角形图版的倾斜刻度线，定义一个float数组Scale用来存储刻度值，方便使用。定义一个PointF数组_scalepoints用来存储刻度线与三角形边框相交的点。

public float[] Scale { get; set; }
private PointF[] _scalepoints;

对Scale和_scalepoints的初始化操作放在构造函数DrawTrianglePlate中。修改后的构造函数如下：

public TrianglePlate (PointF center, float sidelength, float[] sacle)
{
    this.Center = center;
    this.SideLength = sidelength;
    this.Scale = sacle;

    //计算三个点
    _points = new PointF[3];
    _points[0] = new PointF (this.Center.X - this.SideLength / 2,
                             (float) (this.Center.Y - this.SideLength / (2 * Math.Sqrt (3) ) )
                            );
    _points[1] = new PointF (this.Center.X + this.SideLength / 2,
                             (float) (this.Center.Y - this.SideLength / (2 * Math.Sqrt (3) ) )
                            );
    _points[2] = new PointF (this.Center.X,
                             (float) (this.Center.Y - 2 * this.SideLength / (Math.Sqrt (3) ) )
                            );

    //计算刻度点
    _scalepoints = new PointF[12];
    _scalepoints[0] = new PointF (_points[0].X + sidelength * this.Scale[0], _points[0].Y);
    _scalepoints[1] = new PointF (_points[0].X + sidelength * this.Scale[1], _points[0].Y);
    _scalepoints[2] = new PointF (_points[0].X + sidelength * (1 - this.Scale[1]), _points[0].Y);
    _scalepoints[3] = new PointF (_points[0].X + sidelength * (1 - this.Scale[0]), _points[0].Y);
    _scalepoints[4] = new PointF (_points[2].X - (float) (sidelength / 2) * this.Scale[0],
                                  _points[2].Y + (float) (sidelength * Math.Sqrt (3) / 2) * this.Scale[0]);
    _scalepoints[5] = new PointF (_points[2].X - (float) (sidelength / 2) * this.Scale[1],
                                  _points[2].Y + (float) (sidelength * Math.Sqrt (3) / 2) * this.Scale[1]);
    _scalepoints[6] = new PointF (_points[2].X + (float) (sidelength / 2) * this.Scale[0],
                                  _points[2].Y + (float) (sidelength * Math.Sqrt (3) / 2) * this.Scale[0]);
    _scalepoints[7] = new PointF (_points[2].X + (float) (sidelength / 2) * this.Scale[1],
                                  _points[2].Y + (float) (sidelength * Math.Sqrt (3) / 2) * this.Scale[1]);

    _scalepoints[8] = new PointF (_points[2].X,
                                  _points[1].Y - (0.5f - this.Scale[0]) * this.SideLength * (float) Math.Sqrt (3) );
    _scalepoints[11] = new PointF (_points[2].X,
                                   _points[1].Y - (0.5f - this.Scale[1]) * this.SideLength * (float) Math.Sqrt (3) );
    _scalepoints[9] =
        new PointF (_scalepoints[8].X - (_scalepoints[11].Y - _scalepoints[8].Y) / 2 / (float) Math.Sqrt (3),
                    (_scalepoints[8].Y + _scalepoints[11].Y) / 2);
    _scalepoints[10] =
        new PointF (_scalepoints[8].X + (_scalepoints[11].Y - _scalepoints[8].Y) / 2 / (float) Math.Sqrt (3),
                    (_scalepoints[8].Y + _scalepoints[11].Y) / 2);
}

加入DrawScale函数绘制刻度线，并在DrawTrianglePlate绘制函数进行调用。

private void DrawScale (Graphics g)
{
    g.DrawLine (this.SaclePen, _scalepoints[0], _scalepoints[6]);
    g.DrawLine (this.SaclePen, _scalepoints[1], _scalepoints[7]);
    g.DrawLine (this.SaclePen, _scalepoints[2], _scalepoints[5]);
    g.DrawLine (this.SaclePen, _scalepoints[3], _scalepoints[4]);
}

---

接下来对图版的刻度和文字进行绘制。

private void DrawTag (Graphics g)
{
    g.DrawString ("长石", new Font ("宋体", 11), Brushes.Black, new PointF (_points[0].X - 25f, _points[0].Y - 25f) );
    g.DrawString ("岩屑", new Font ("宋体", 11), Brushes.Black, new PointF (_points[1].X + 5f, _points[1].Y - 25f) );
    g.DrawString ("石英", new Font ("宋体", 11), Brushes.Black, new PointF (_points[2].X - 25f, _points[2].Y - 15f) );

    g.DrawString ( (100 - this.Scale[0] * 100).ToString(), new Font ("宋体", 11), Brushes.Black,
                   new PointF (_scalepoints[0].X, _scalepoints[0].Y + 3) );
    g.DrawString ( (100 - this.Scale[1] * 100).ToString(), new Font ("宋体", 11), Brushes.Black,
                   new PointF (_scalepoints[1].X, _scalepoints[1].Y + 3) );
    g.DrawString ( (this.Scale[1] * 100).ToString(), new Font ("宋体", 11), Brushes.Black,
                   new PointF (_scalepoints[2].X, _scalepoints[2].Y + 3) );
    g.DrawString ( (this.Scale[0] * 100).ToString(), new Font ("宋体", 11), Brushes.Black,
                   new PointF (_scalepoints[3].X, _scalepoints[3].Y + 3) );

    g.DrawString ( (this.Scale[0] * 100).ToString(), new Font ("宋体", 11), Brushes.Black,
                   new PointF (_scalepoints[4].X - 25f, _scalepoints[4].Y - 5) );
    g.DrawString ( (this.Scale[1] * 100).ToString(), new Font ("宋体", 11), Brushes.Black,
                   new PointF (_scalepoints[5].X - 25f, _scalepoints[5].Y - 5) );

    g.DrawString ( (this.Scale[0] * 100).ToString(), new Font ("宋体", 11), Brushes.Black,
                   new PointF (_scalepoints[6].X + 5f, _scalepoints[6].Y - 5) );
    g.DrawString ( (this.Scale[1] * 100).ToString(), new Font ("宋体", 11), Brushes.Black,
                   new PointF (_scalepoints[7].X + 5f, _scalepoints[7].Y - 5) );
}

DrawTag函数在DrawTrianglePlate绘制函数中进行调用，此时形成图形如下：

---

接下来是最后一步，绘制随鼠标移动的动态刻度线。目的实现结果如下：

为此，首先需要判断鼠标是否点在图版内，并获得鼠标的位置。向DrawTriangle类添加成员函数MouseIsIn。其中tpgp是一个GraphicsPath类型的变量，利用GraphicsPath提供的IsVisible函数判断鼠标是否在Path内。

public bool MouseIsIn (Graphics g, PointF pt)
{
    if (tpgp.IsVisible (pt) )
    {
        DrawDotDial (g, pt);
        return true;
    }

    else
        return false;
}

然后根据鼠标点与已知的刻度点计算得出动态刻度点坐标。

private void DrawDotDial (Graphics g, PointF pt)
{
    _dials = new PointF[6];
    float py = _points[0].Y - pt.Y;
    float px = pt.X - _points[0].X;

    _dials[0] = new PointF (pt.X - py / (float) Math.Sqrt (3), _points[0].Y);
    _dials[1] = new PointF (pt.X + py / (float) Math.Sqrt (3), _points[0].Y);
    _dials[2] = new PointF ( (_dials[1].X + _points[0].X) / 2,
                             _dials[0].Y - (_dials[1].X - _points[0].X) * (float) Math.Sqrt (3) / 2);
    _dials[4] = new PointF ( (_points[1].X + _dials[0].X) / 2,
                             _points[1].Y - (_points[1].X - _dials[0].X) * (float) Math.Sqrt (3) / 2);
    _dials[3] = new PointF (_points[0].X + py / (float) Math.Sqrt (3),
                            pt.Y);
    _dials[5] = new PointF (_points[1].X - (_dials[3].X - _points[0].X),
                            pt.Y);

    Pen tmpen = new Pen (Color.Black, 1);
    tmpen.DashStyle = DashStyle.Dash;

    g.DrawLine (tmpen, _dials[0], _dials[4]);
    g.DrawLine (tmpen, _dials[1], _dials[2]);
    g.DrawLine (tmpen, _dials[3], _dials[5]);
}

然后在DrawTrianglePlate函数内对DrawDotDial进行调用，就完成了。

---

完整代码如下：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Drawing;
using System.Drawing.Drawing2D;

namespace Ch_地质图版
{
    class TrianglePlate
    {
        public TrianglePlate(PointF center, float sidelength, float[] sacle)
        {
            this.Center = center;
            this.SideLength = sidelength;
            this.Scale = sacle;

            //计算三个点
            _points = new PointF[3];
            _points[0] = new PointF(this.Center.X - this.SideLength/2,
                                    (float) (this.Center.Y - this.SideLength/(2*Math.Sqrt(3)))
                );
            _points[1] = new PointF(this.Center.X + this.SideLength/2,
                                    (float) (this.Center.Y - this.SideLength/(2*Math.Sqrt(3)))
                );
            _points[2] = new PointF(this.Center.X,
                                    (float) (this.Center.Y - 2*this.SideLength/(Math.Sqrt(3)))
                );

            //计算刻度点
            _scalepoints = new PointF[12];
            _scalepoints[0] = new PointF(_points[0].X + sidelength * this.Scale[0], _points[0].Y);
            _scalepoints[1] = new PointF(_points[0].X + sidelength * this.Scale[1], _points[0].Y);
            _scalepoints[2] = new PointF(_points[0].X + sidelength * (1 - this.Scale[1]), _points[0].Y);
            _scalepoints[3] = new PointF(_points[0].X + sidelength * (1 - this.Scale[0]), _points[0].Y);
            _scalepoints[4] = new PointF(_points[2].X - (float)(sidelength / 2) * this.Scale[0],
                                         _points[2].Y + (float)(sidelength * Math.Sqrt(3) / 2) * this.Scale[0]);
            _scalepoints[5] = new PointF(_points[2].X - (float)(sidelength / 2) * this.Scale[1],
                                         _points[2].Y + (float)(sidelength * Math.Sqrt(3) / 2) * this.Scale[1]);
            _scalepoints[6] = new PointF(_points[2].X + (float)(sidelength / 2) * this.Scale[0],
                                         _points[2].Y + (float)(sidelength * Math.Sqrt(3) / 2) * this.Scale[0]);
            _scalepoints[7] = new PointF(_points[2].X + (float)(sidelength / 2) * this.Scale[1],
                                         _points[2].Y + (float)(sidelength * Math.Sqrt(3) / 2) * this.Scale[1]);

            _scalepoints[8] = new PointF(_points[2].X,
                                         _points[1].Y - (0.5f - this.Scale[0]) * this.SideLength * (float)Math.Sqrt(3));
            _scalepoints[11] = new PointF(_points[2].X,
                                          _points[1].Y - (0.5f - this.Scale[1]) * this.SideLength * (float)Math.Sqrt(3));
            _scalepoints[9] =
                new PointF(_scalepoints[8].X - (_scalepoints[11].Y - _scalepoints[8].Y) / 2 / (float)Math.Sqrt(3),
                           (_scalepoints[8].Y + _scalepoints[11].Y) / 2);
            _scalepoints[10] =
                new PointF(_scalepoints[8].X + (_scalepoints[11].Y - _scalepoints[8].Y) / 2 / (float)Math.Sqrt(3),
                           (_scalepoints[8].Y + _scalepoints[11].Y) / 2);

            tpgp = new GraphicsPath();
            tpgp.AddLines(_points);

            //DrawDotDial()
        }

        /// <summary>
        /// 三角形图版内心
        /// </summary>
        public PointF Center { set; get; }

        /// <summary>
        /// 三角形图版边长
        /// </summary>
        public float SideLength { get; set; }

        /// <summary>
        /// 三角形图版画边笔
        /// </summary>
        public Pen SidePen { get; set; }

        public Pen SaclePen { get; set; }

        public float[] Scale { get; set; }

        private PointF[] _points;

        private PointF[] _scalepoints;

        private GraphicsPath tpgp;

        private PointF[] _dials;

        public void DrawTrianglePlate(Graphics g,PointF tms)
        {
            DrawSildes(g);
            DrawScale(g);
            DrawTag(g);
            if(!tms.IsEmpty)
                    DrawDotDial(g, tms);
        }

        private void DrawSildes(Graphics g)
        {
            g.DrawLine(this.SidePen, _points[0], _points[1]);
            g.DrawLine(this.SidePen, _points[1], _points[2]);
            g.DrawLine(this.SidePen, _points[2], _points[0]);
        }

        private void DrawScale(Graphics g)
        {
            g.DrawLine(this.SaclePen, _scalepoints[0], _scalepoints[6]);
            g.DrawLine(this.SaclePen, _scalepoints[1], _scalepoints[7]);
            g.DrawLine(this.SaclePen, _scalepoints[2], _scalepoints[5]);
            g.DrawLine(this.SaclePen, _scalepoints[3], _scalepoints[4]);
        }

        private void DrawTag(Graphics g)
        {
            //g.DrawString("①", new Font("楷体", 12), Brushes.Purple, _scalepoints[4].X, _scalepoints[4].Y);
            //g.DrawString("②", new Font("楷体", 12), Brushes.Purple, _scalepoints[5].X, _scalepoints[5].Y);
            //g.DrawString("③", new Font("楷体", 12), Brushes.Purple, _scalepoints[6].X, _scalepoints[6].Y);
            //g.DrawLine(Pens.Black, _scalepoints[8], _scalepoints[11]);
            //g.DrawLine(Pens.Black, _scalepoints[9], _scalepoints[10]);

            //GraphicsPath gp = new GraphicsPath();
            //gp.AddLines(new PointF[] {_scalepoints[4], _scalepoints[8], _scalepoints[6], _points[2]});
            //g.FillPath(Brushes.Red, gp);


            //gp = new GraphicsPath();
            //gp.AddLines(new PointF[] { _scalepoints[4], _scalepoints[5], _scalepoints[9], _scalepoints[8] });
            //g.FillPath(Brushes.Purple, gp);

            //gp = new GraphicsPath();
            //gp.AddLines(new PointF[] { _scalepoints[6], _scalepoints[8], _scalepoints[10], _scalepoints[7] });
            //g.FillPath(Brushes.Pink, gp);

            //gp = new GraphicsPath();
            //gp.AddLines(new PointF[] { _scalepoints[8], _scalepoints[9], _scalepoints[11], _scalepoints[10] });
            //g.FillPath(Brushes.RoyalBlue, gp);

            //gp = new GraphicsPath();
            //gp.AddLines(new PointF[] { _scalepoints[5], _scalepoints[9], _scalepoints[0], _points[0] });
            //g.FillPath(Brushes.SkyBlue, gp);

            //gp = new GraphicsPath();
            //gp.AddLines(new PointF[] { _scalepoints[9], _scalepoints[11], _scalepoints[1], _scalepoints[0] });
            //g.FillPath(Brushes.Green, gp);

            //gp = new GraphicsPath();
            //gp.AddLines(new PointF[] { _scalepoints[11], _scalepoints[10], _scalepoints[3], _scalepoints[2] });
            //g.FillPath(Brushes.Yellow, gp);

            //gp = new GraphicsPath();
            //gp.AddLines(new PointF[] { _scalepoints[3], _scalepoints[10], _scalepoints[7], _points[1] });
            //g.FillPath(Brushes.Tomato, gp);

            g.DrawString("长石", new Font("宋体", 11), Brushes.Black, new PointF(_points[0].X - 25f, _points[0].Y - 25f));
            g.DrawString("岩屑", new Font("宋体", 11), Brushes.Black, new PointF(_points[1].X + 5f, _points[1].Y - 25f));
            g.DrawString("石英", new Font("宋体", 11), Brushes.Black, new PointF(_points[2].X - 25f, _points[2].Y - 15f));

            g.DrawString((100 - this.Scale[0]*100).ToString(), new Font("宋体", 11), Brushes.Black,
                         new PointF(_scalepoints[0].X, _scalepoints[0].Y+3));
            g.DrawString((100 - this.Scale[1] * 100).ToString(), new Font("宋体", 11), Brushes.Black,
                         new PointF(_scalepoints[1].X, _scalepoints[1].Y+3));
            g.DrawString((this.Scale[1] * 100).ToString(), new Font("宋体", 11), Brushes.Black,
                         new PointF(_scalepoints[2].X, _scalepoints[2].Y+3));
            g.DrawString((this.Scale[0] * 100).ToString(), new Font("宋体", 11), Brushes.Black,
                         new PointF(_scalepoints[3].X, _scalepoints[3].Y+3));

            g.DrawString((this.Scale[0] * 100).ToString(), new Font("宋体", 11), Brushes.Black,
                         new PointF(_scalepoints[4].X-25f, _scalepoints[4].Y-5));
            g.DrawString((this.Scale[1] * 100).ToString(), new Font("宋体", 11), Brushes.Black,
                         new PointF(_scalepoints[5].X - 25f, _scalepoints[5].Y - 5));

            g.DrawString((this.Scale[0] * 100).ToString(), new Font("宋体", 11), Brushes.Black,
                         new PointF(_scalepoints[6].X+5f, _scalepoints[6].Y - 5));
            g.DrawString((this.Scale[1] * 100).ToString(), new Font("宋体", 11), Brushes.Black,
                         new PointF(_scalepoints[7].X + 5f, _scalepoints[7].Y - 5));

        }

        public bool MouseIsIn(Graphics g, PointF pt)
        {
            if (tpgp.IsVisible(pt))
            {
                DrawDotDial(g, pt);
                return true;
            }
                
            else
                return false;
        }

        private void DrawDotDial(Graphics g,PointF pt)
        {
            _dials = new PointF[6];
            float py = _points[0].Y - pt.Y;
            float px = pt.X - _points[0].X;

            _dials[0] = new PointF(pt.X - py/(float) Math.Sqrt(3), _points[0].Y);
            _dials[1] = new PointF(pt.X + py/(float) Math.Sqrt(3), _points[0].Y);
            _dials[2] = new PointF((_dials[1].X + _points[0].X)/2,
                                  _dials[0].Y - (_dials[1].X - _points[0].X)*(float) Math.Sqrt(3)/2);
            _dials[4] = new PointF((_points[1].X + _dials[0].X)/2,
                                  _points[1].Y - (_points[1].X - _dials[0].X) * (float)Math.Sqrt(3) / 2);
            _dials[3] = new PointF(_points[0].X + py / (float)Math.Sqrt(3),
                                  pt.Y);
            _dials[5] = new PointF(_points[1].X-(_dials[3].X-_points[0].X),
                                  pt.Y);

            Pen tmpen = new Pen(Color.Black, 1);
            tmpen.DashStyle = DashStyle.Dash;

            g.DrawLine(tmpen, _dials[0], _dials[4]);
            g.DrawLine(tmpen, _dials[1], _dials[2]);
            g.DrawLine(tmpen, _dials[3], _dials[5]);

            //GetContentScale(pt);
            //g.DrawLine(tmpen,pt, new Point(0, 0));
        }

        private float[] GetContentScale(PointF pt)
        {
            float[] content = new float[3];
            content[0] = (_dials[1].X - _points[0].X)/this.SideLength;
            content[1] = (_points[1].X - _dials[0].X) / this.SideLength;
            //content[1] = content[1]/this.SideLength/this.SideLength;
            content[2] = Math.Abs(_points[2].X - _dials[0].X) * Math.Abs(_points[2].X - _dials[0].X) +
                         Math.Abs(_points[2].Y - _dials[0].Y) * Math.Abs(_points[2].Y - _dials[0].Y);
            content[2] = content[2] / this.SideLength / this.SideLength;
            //content[1] = Math.Sqrt((double)content[1]);
            //Math.Sqrt((double)(Math.Abs(_points[2].X - _dials[3].X)*Math.Abs(_points[2].X - _dials[3].X)) +
            //          (double)(Math.Abs(_points[2].Y - _dials[3].Y)*Math.Abs(_points[2].Y - _dials[3].Y)
            //          ))/this.SideLength;
            return content;
        }

        public string GetScaleDes(PointF pt)
        {
            GraphicsPath gptmp = new GraphicsPath();

            gptmp.AddLines(new PointF[] {_points[2], _scalepoints[4], _scalepoints[8], _scalepoints[6]});
            if (gptmp.IsVisible(pt))
                return "石英砂岩";

            gptmp.AddLines(new PointF[] { _scalepoints[4], _scalepoints[5], _scalepoints[9], _scalepoints[8] });
            if (gptmp.IsVisible(pt))
                return "长石石英砂岩";

            gptmp.AddLines(new PointF[] { _scalepoints[8], _scalepoints[9], _scalepoints[11], _scalepoints[10] });
            if (gptmp.IsVisible(pt))
                return "长石岩屑质石英砂岩";

            gptmp.AddLines(new PointF[] { _scalepoints[6], _scalepoints[7], _scalepoints[9], _scalepoints[10] });
            if (gptmp.IsVisible(pt))
                return "岩屑石英砂岩";

            gptmp.AddLines(new PointF[] { _scalepoints[5], _scalepoints[9], _scalepoints[0], _points[0] });
            if (gptmp.IsVisible(pt))
                return "长石砂岩";

            gptmp.AddLines(new PointF[] { _scalepoints[9], _scalepoints[0], _scalepoints[1], _scalepoints[11] });
            if (gptmp.IsVisible(pt))
                return "碎屑质长石砂岩";

            gptmp.AddLines(new PointF[] { _scalepoints[1], _scalepoints[2],  _scalepoints[11] });
            if (gptmp.IsVisible(pt))
                return "混合砂岩";

            gptmp.AddLines(new PointF[] { _scalepoints[10], _scalepoints[11], _scalepoints[2], _scalepoints[3] });
            if (gptmp.IsVisible(pt))
                return "长石质岩屑砂岩";

            gptmp.AddLines(new PointF[] { _scalepoints[7], _scalepoints[11], _scalepoints[3], _points[1] });
            if (gptmp.IsVisible(pt))
                return "岩屑砂岩";

            return "";
        }
    }
}

---

程序源代码地址：http://pan.baidu.com/s/1osgAU