ArcEngine根据对称轴生成镜像实体

用过CAD的同志应该清楚，在CAD中可以指定对称轴，然后根据对称轴生成镜像，ArcEngine中也可以进行类似操作，如下图所示：

代码如下：

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using ESRI.ArcGIS.Carto;
using ESRI.ArcGIS.Controls;
using ESRI.ArcGIS.DataSourcesFile;
using ESRI.ArcGIS.DataSourcesGDB;
using ESRI.ArcGIS.Display;
using ESRI.ArcGIS.esriSystem;
using ESRI.ArcGIS.Geodatabase;
using ESRI.ArcGIS.Geometry;
using ESRI.ArcGIS.Output;
using ESRI.ArcGIS.SystemUI;

namespace WindowsFormsApplication1
{
    public partial class MainForm : Form
    {
        public MainForm()
        {
            InitializeComponent();
            axMapControl1.LoadMxFile(@"C:\Users\DSF\Desktop\data\无标题.mxd");
        }

        // 创建缓冲区
        private void btnCreateGeometry_Click(object sender, EventArgs e)
        {
            // 线要素
            IFeatureLayer pPolylineFeatureLayer = axMapControl1.get_Layer(0) as IFeatureLayer;
            IFeatureClass pPolylineFeatureClass = pPolylineFeatureLayer.FeatureClass;
            IPolyline pPolyline = pPolylineFeatureClass.GetFeature(0).Shape as IPolyline;

            // 对称轴
            ILine pLine = new Line();
            pLine.PutCoords(pPolyline.FromPoint, pPolyline.ToPoint);

            // 面要素
            IFeatureLayer pPolygonFeatureLayer = axMapControl1.get_Layer(1) as IFeatureLayer;
            IFeatureClass pPolygonFeatureClass = pPolygonFeatureLayer.FeatureClass;

            // 绘制镜像
            IFeatureCursor pPolygonFeatureCursor = pPolygonFeatureClass.Search(null, true);
            IFeature pPolygonFeature = pPolygonFeatureCursor.NextFeature();
            while (pPolygonFeature != null)
            {
                IGeometry pGeometry = CreateGeometry(pPolygonFeature.ShapeCopy, pLine);
                Draw(pGeometry);
                pPolygonFeature = pPolygonFeatureCursor.NextFeature();
            }
            System.Runtime.InteropServices.Marshal.ReleaseComObject(pPolygonFeatureCursor);
        }

        // 生成镜像实体
        private IGeometry CreateGeometry(IGeometry pGeometry, ILine pLine)
        {
            IAffineTransformation2D pAffineTransformation2D = new AffineTransformation2D() as IAffineTransformation2D;
            pAffineTransformation2D.DefineReflection(pLine);
            ITransform2D pTransform2D = pGeometry as ITransform2D;
            pTransform2D.Transform(esriTransformDirection.esriTransformForward, pAffineTransformation2D);
            return pTransform2D as IGeometry;
        }

        // 绘制
        private void Draw(IGeometry pGeometry)
        {
            IRgbColor pRgbColor = new RgbColor();
            pRgbColor.Red = 0;
            pRgbColor.Green = 255;
            pRgbColor.Blue = 0;

            // 创建符号
            ISimpleFillSymbol pSimpleFillSymbol = new SimpleFillSymbol();
            pSimpleFillSymbol.Color = pRgbColor;

            // 创建元素
            IFillShapeElement pFillShapeElement = new PolygonElement() as IFillShapeElement;
            pFillShapeElement.Symbol = pSimpleFillSymbol;
            IElement pElement = pFillShapeElement as IElement;
            pElement.Geometry = pGeometry;

            // 绘制元素
            IActiveView pActiveView = axMapControl1.ActiveView;
            IGraphicsContainer pGraphicsContainer = pActiveView.GraphicsContainer;
            pGraphicsContainer.AddElement(pElement, 0);
            pActiveView.PartialRefresh(esriViewDrawPhase.esriViewGraphics, null, null);
        }
    }
}