C# 把halcon中的任意图形HXLD在WPF中绘制出来

首先要知道在halcon中，可以通过get_contour_xld算子获取一个xld对象的所有坐标点：

然后问题就变成了把这些坐标点在WPF中绘制出来。

针对这些点集，WPF中可以使用Geometry对象表示；

Geometry抽象类有一个派生类：StreamGeometry：

如何：使用 StreamGeometry 创建形状 - WPF | Microsoft Learn

根据官网Demo，发现可以通过 StreamGeometryContext.PolyLineTo(IList<Point>, Boolean, Boolean) 方法描述整个点集。

按照这个逻辑，可以封装以下方法：

cs 复制代码

 internal static Geometry GetXldGeometry(HXLD xld)
 {
     if (xld == null || xld.Key == IntPtr.Zero)
     {
         return Geometry.Empty;
     }
     //将 HALCON 的 HXLDCont 轮廓（XLD 轮廓）转换为 WPF 的 StreamGeometry 对象
     if (xld is HXLDCont cont)
     {
         cont.GetContourXld(out HTuple row, out HTuple col);
         var points = GetXldPoints(row.DArr, col.DArr);
         StreamGeometry geometry = new StreamGeometry();
         var c = geometry.Open();
         c.BeginFigure(points[0], false, false);
         c.PolyLineTo(points, true, false);
         c.Close();
         return geometry;
     }
     else if (xld is HXLDPoly poly)
     {
         poly.GetPolygonXld(out HTuple row, out HTuple col, out _, out _);
         var points = GetXldPoints(row.DArr, col.DArr);
         StreamGeometry geometry = new StreamGeometry();
         var c = geometry.Open();
         c.BeginFigure(points[0], false, false);
         c.PolyLineTo(points, true, false);
         c.Close();
         return geometry;
     }
     else
     {
         var objClass = xld.GetObjClass();
         if (objClass == "xld_cont")
         {
             var cont1 = new HXLDCont(xld);
             cont1.GetContourXld(out HTuple row, out HTuple col);//row和col都有上千个点
             var points = GetXldPoints(row.DArr, col.DArr);
             StreamGeometry geometry = new StreamGeometry();
             var c = geometry.Open();
             c.BeginFigure(points[0], false, false);
             c.PolyLineTo(points, true, false);
             cont1.Dispose();
             c.Close();
             return geometry;
         }
         else if (objClass == "xld_poly")
         {
             var poly1 = new HXLDPoly(xld);
             poly1.GetPolygonXld(out HTuple row, out HTuple col, out _, out _);
             var points = GetXldPoints(row.DArr, col.DArr);
             StreamGeometry geometry = new StreamGeometry();
             var c = geometry.Open();
             c.BeginFigure(points[0], false, false);
             c.PolyLineTo(points, true, false);
             poly1.Dispose();
             c.Close();
             return geometry;
         }
         else
         {
             return Geometry.Empty;
         }
     }
 }

 internal static IList<Point> GetXldPoints(double[] row, double[] column)
 {
     if (row == null || column == null || row.Length != column.Length)
     {
         return null;
     }
     //var rowSpan = new Span<double>(row);
     //var colSpan = new Span<double>(column);
     List<Point> points = new List<Point>(row.Length);
     for (int i = 0; i < row.Length; i++)
     {
         // Halcon: (row, column) 像素中心
         // .NET System.Drawing: (x, y) 像素左上角
         points.Add(new Point(column[i] + 0.5, row[i] + 0.5));
     }
     return points;
 }

得到Geometry对象之后，可以通过GeometryDrawing 对象再包装一层：

cs 复制代码

 GeometryDrawing drawing = new GeometryDrawing
 {
     Geometry = geometry
 };

然后通过DrawingContext类中提供的DrawDrawing方法绘制GeometryDrawing对象：

(GeometryDrawing继承自Drawing)