C# DxfDocument.AddEntity方法代码示例

        public static void ModifyingXData()
        {
            Line line = new Line(Vector2.Zero, Vector2.UnitX);

            ApplicationRegistry appReg = new ApplicationRegistry("netDxf");
            XData xdata = new XData(appReg);
            xdata.XDataRecord.Add(new XDataRecord(XDataCode.String, "Length"));
            line.XData.Add(xdata);

            DxfDocument doc = new DxfDocument();
            doc.AddEntity(line);

            // modifying existing extended data
            line.XData[appReg.Name].XDataRecord.Add(new XDataRecord(XDataCode.Real, Vector3.Distance(line.StartPoint, line.EndPoint)));

            // adding new extended data entry to an existing entity
            ApplicationRegistry appReg2 = new ApplicationRegistry("newXData");
            XData xdata2 = new XData(appReg2);
            xdata2.XDataRecord.Add(new XDataRecord(XDataCode.String, "XData entries"));
            line.XData.Add(xdata2);

            Debug.Assert(ReferenceEquals(line.XData[appReg2.Name].ApplicationRegistry, doc.ApplicationRegistries[appReg2.Name]));

            // deleting existing extended data
            line.XData.Remove(appReg.Name);

            // we can also change the name of the application registry name
            doc.ApplicationRegistries["newXData"].Name = "netDxfRenamed";

            doc.Save("xData.dxf");

            doc = DxfDocument.Load("xData.dxf");
        }

        public static void Draw(DxfDocument dxf, Location location)
        {
            Vector3f v1 = new Vector3f(location.X - 2.0f, location.Y + 4.0f, location.Z);
            Vector3f v2 = new Vector3f(location.X + 2.0f, location.Y + 4.0f, location.Z);
            Vector3f v0=new Vector3f(location.X,location.Y,location.Z);
            Layer layer = new Layer("line");

            Line line10 = new Line(v0, v1);
            line10.Layer = layer;
            dxf.AddEntity(line10);

            Line line20 = new Line(v0, v2);
            line20.Layer = layer;
            dxf.AddEntity(line20);
        }

        /// <summary>
        /// 绘制风扇
        /// </summary>
        /// <param name="dxf"></param>
        /// <param name="startPoint">风扇起点，如果为横置，由左向右；如果为竖置，由下到上</param>
        /// <param name="endPoint">风扇终点，如果为横置，由左向右；如果为竖置，由下到上</param>
        /// <param name="pointerLocation">箭头位置，默认=0为无，=1代表箭头在中间，=2代表箭头在底部</param>
        public static void Draw(DxfDocument dxf, Vector3f startPoint, Vector3f endPoint,int pointerLocation=0)
        {
            Layer layer = new Layer("line");
            Line line = new Line(startPoint, endPoint);
            line.Layer = layer;
            dxf.AddEntity(line);

            //如果为横置
            if (startPoint.Y == endPoint.Y)
            {
                float segment = (endPoint.X - startPoint.X) / 4;
                Slash.Draw(dxf, new Location(startPoint.X + segment, startPoint.Y, startPoint.Z));
                Slash.Draw(dxf, new Location(startPoint.X + 2 * segment, startPoint.Y, startPoint.Z));
                Slash.Draw(dxf, new Location(startPoint.X + 3 * segment, startPoint.Y, startPoint.Z));
            }
            //如果为竖置
            else if (startPoint.X == endPoint.X)
            {
                float segment = (endPoint.Y - startPoint.Y) / 5;
                Slash.Draw(dxf, new Location(startPoint.X, startPoint.Y + segment, startPoint.Z));
                Slash.Draw(dxf, new Location(startPoint.X, startPoint.Y + 2 * segment, startPoint.Z));
                Slash.Draw(dxf, new Location(startPoint.X, startPoint.Y + 3 * segment, startPoint.Z));
                Slash.Draw(dxf, new Location(startPoint.X, startPoint.Y + 4 * segment, startPoint.Z));
                if (pointerLocation == 1)
                {
                    LinePointer.Draw(dxf,new Location(startPoint.X,(startPoint.Y+endPoint.Y)/2,startPoint.Z));
                }
                else if(pointerLocation==2)
                {
                    LinePointer.Draw(dxf, new Location(startPoint.X, startPoint.Y, startPoint.Z));
                }
            }
        }

        public static void Draw(DxfDocument dxf, Location location,List<string> configurations)
        {
            Vector3f confStrVector3f = new Vector3f(location.X + 5.0f, location.Y - 5.0f, location.Z);
            TextStyle style = new TextStyle("True type font", "Arial.ttf");
            Text text1 = new Text("CONFIGURATION:                   NOTE:  Assembly drawing for overall dimesions,  actual door size and handle position may vary",
                confStrVector3f, 2.0f, style);
            Layer layer = new Layer("text");
            text1.Layer = layer;
            //text1.Layer.Color.Index = 8;
            text1.Alignment = TextAlignment.TopLeft;
            dxf.AddEntity(text1);

            for (int i = 0; i < configurations.Count(); i++)
            {
                Vector3f confVector3f = new Vector3f(location.X+10.0f, location.Y - 5.0f * (i + 2), location.Z);
                Text text = new Text(configurations[i], confVector3f, 2.0f, style);
                text.Layer = layer;
                //text.Layer.Color.Index = 8;
                text.Alignment = TextAlignment.TopLeft;
                dxf.AddEntity(text);
            }
        }

        /// <summary>
        /// 风向绘制
        /// </summary>
        /// <param name="dxf"></param>
        /// <param name="location"></param>
        /// <param name="isRight"></param>
        public static void Draw(DxfDocument dxf, Location location, bool isRight)
        {
            float factor = 0.5f;
            Vector3f v1 = new Vector3f();
            Vector3f v2 = new Vector3f();
            Vector3f v3 = new Vector3f();
            Vector3f v4 = new Vector3f();
            Vector3f v5 = new Vector3f();
            Vector3f v6 = new Vector3f();
            Vector3f v7 = new Vector3f();
            if (isRight)
            {
                v1 = new Vector3f(10*factor + location.X, location.Y, location.Z);
                v2 = new Vector3f(location.X, location.Y + 10 * factor, location.Z);
                v3 = new Vector3f(location.X + 10 * factor, location.Y + 10 * factor, location.Z);
                v4 = new Vector3f(location.X + 20 * factor, location.Y + 15 * factor, location.Z);
                v5 = new Vector3f(location.X, location.Y + 20 * factor, location.Z);
                v6 = new Vector3f(location.X + 10 * factor, location.Y + 20 * factor, location.Z);
                v7 = new Vector3f(location.X + 10 * factor, location.Y + 30 * factor, location.Z);
            }
            else
            {
                v1 = new Vector3f(10 * factor + location.X, location.Y, location.Z);
                v2 = new Vector3f(location.X + 20 * factor, location.Y + 10 * factor, location.Z);
                v3 = new Vector3f(location.X + 10 * factor, location.Y + 10 * factor, location.Z);
                v4 = new Vector3f(location.X, location.Y + 15 * factor, location.Z);
                v5 = new Vector3f(location.X + 20 * factor, location.Y + 20 * factor, location.Z);
                v6 = new Vector3f(location.X + 10 * factor, location.Y + 20 * factor, location.Z);
                v7 = new Vector3f(location.X + 10 * factor, location.Y + 30 * factor, location.Z);
            }
            Layer layer = new Layer("line");
            Line line23 = new Line(v2, v3);
            line23.Layer = layer;
            dxf.AddEntity(line23);

            Line line56 = new Line(v5, v6);
            line56.Layer = layer;
            dxf.AddEntity(line56);

            Line line14 = new Line(v1, v4);
            line14.Layer = layer;
            dxf.AddEntity(line14);

            Line line74 = new Line(v7, v4);
            line74.Layer = layer;
            dxf.AddEntity(line74);

            Line line25 = new Line(v2, v5);
            line25.Layer = layer;
            dxf.AddEntity(line25);

            Line line71 = new Line(v7, v1);
            line71.Layer = layer;
            dxf.AddEntity(line71);
        }

        private static void SolidEntity()
        {
            // The solid vertexes are expressed in OCS (object coordinate system)
            // Now they are stored as Vector2 to force all vertexes to lay on a plane, this is similar as how the LwPolyline works.
            // The Z coordinate is controlled by the elevation property of the Solid.
            Vector2 a = new Vector2(-1, -1);
            Vector2 b = new Vector2(1, -1);
            Vector2 c = new Vector2(-1, 1);
            Vector2 d = new Vector2(1, 1);

            Solid solid = new Solid(a, b, c, d);
            solid.Normal = new Vector3(1, 1, 0);

            solid.Elevation = 2;

            DxfDocument doc = new DxfDocument();
            doc.AddEntity(solid);
            doc.Save("SolidEntity.dxf");
        }

        static void doDXF(List<Polyline3dVertex> vertexes, double[] x)
        {
            // create a dxf for those who want to "see" the calibration
            DxfDocument dxf = new DxfDocument();

            Polyline3d polyline = new Polyline3d(vertexes, true);
            polyline.Layer = new Layer("polyline3d");
            polyline.Layer.Color.Index = 24;
            dxf.AddEntity(polyline);

            var pnt = new Point(new Vector3f(-(float) x[0], -(float) x[1], -(float) x[2]));
            pnt.Layer = new Layer("new offset");
            pnt.Layer.Color.Index = 21;
            dxf.AddEntity(pnt);

            dxf.Save("magoffset.dxf", DxfVersion.AutoCad2000);

            log.Info("dxf Done " + DateTime.Now);
        }

        /// <summary>
        /// 绘制左下角区域的Section块
        /// </summary>
        /// <param name="dxf"></param>
        /// <param name="location"></param>
        /// <param name="configurations"></param>
        public static void Draw(DxfDocument dxf, Location location,SectionEntity sectionEntity)
        {
            float factor=0.6f;
            Vector3f v1 = new Vector3f(location.X, location.Y + 40.0f*factor, location.Z);
            Vector3f v2 = new Vector3f(location.X + 50.0f * factor, location.Y + 40.0f * factor, location.Z);
            Vector3f v3 = new Vector3f(location.X + 90.0f * factor, location.Y + 40.0f * factor, location.Z);
            Vector3f v4 = new Vector3f(location.X + 140.0f * factor, location.Y + 40.0f * factor, location.Z);

            Vector3f v5 = new Vector3f(location.X, location.Y + 50.0f * factor, location.Z);
            Vector3f v6 = new Vector3f(location.X + 140.0f * factor, location.Y + 50.0f * factor, location.Z);

            Vector3f v7 = new Vector3f(location.X, location.Y + 60.0f * factor, location.Z);
            Vector3f v8 = new Vector3f(location.X + 140.0f * factor, location.Y + 60.0f * factor, location.Z);

            Vector3f v9 = new Vector3f(location.X, location.Y + 70.0f * factor, location.Z);
            Vector3f v10 = new Vector3f(location.X + 50.0f * factor, location.Y + 70.0f * factor, location.Z);
            Vector3f v11 = new Vector3f(location.X + 90.0f * factor, location.Y + 70.0f * factor, location.Z);
            Vector3f v12 = new Vector3f(location.X + 140.0f * factor, location.Y + 70.0f * factor, location.Z);

            Layer layer = new Layer("line");

            //横向四道
            Line line14 = new Line(v1, v4);
            line14.Layer = layer;
            dxf.AddEntity(line14);

            Line line56 = new Line(v5, v6);
            line56.Layer = layer;
            dxf.AddEntity(line56);

            Line line78 = new Line(v7, v8);
            line78.Layer = layer;
            dxf.AddEntity(line78);

            Line line912 = new Line(v9, v12);
            line912.Layer = layer;
            dxf.AddEntity(line912);

            //纵向四道
            Line line91 = new Line(v9, v1);
            line91.Layer = layer;
            dxf.AddEntity(line91);

            Line line210 = new Line(v2, v10);
            line210.Layer = layer;
            dxf.AddEntity(line210);

            Line line311 = new Line(v3, v11);
            line311.Layer = layer;
            dxf.AddEntity(line311);

            Line line412 = new Line(v4, v12);
            line412.Layer = layer;
            dxf.AddEntity(line412);

            TextStyle style = new TextStyle("True type font", "Arial.ttf");
            Vector3f vt1 = new Vector3f(v1.X+1.0f, v1.Y+2.5f, v1.Z);
            Text t1 = new Text("COIL", vt1, 2.0f, style);
            t1.Layer = layer;
            t1.Alignment = TextAlignment.TopLeft;
            dxf.AddEntity(t1);

            Vector3f vt2 = new Vector3f(v2.X + 1.0f, v2.Y + 2.5f, v2.Z);
            Text t2 = new Text("CLF", vt2, 2.0f, style);
            t2.Layer = layer;
            t2.Alignment = TextAlignment.TopLeft;
            dxf.AddEntity(t2);

            Vector3f vt3 = new Vector3f(v3.X + 1.0f, v3.Y + 2.5f, v3.Z);
            Text t3 = new Text(sectionEntity.CoolValue, vt3, 2.0f, style);
            t3.Layer = layer;
            t3.Alignment = TextAlignment.TopLeft;
            dxf.AddEntity(t3);

            Vector3f vt4 = new Vector3f(v5.X + 1.0f, v5.Y + 2.5f, v5.Z);
            Text t4 = new Text("FILTER", vt4, 2.0f, style);
            t4.Layer = layer;
            t4.Alignment = TextAlignment.TopLeft;
            dxf.AddEntity(t4);

            Vector3f vt5 = new Vector3f(v2.X + 1.0f, v5.Y + 2.5f, v5.Z);
            Text t5 = new Text("FTA", vt5, 2.0f, style);
            t5.Layer = layer;
            t5.Alignment = TextAlignment.TopLeft;
            dxf.AddEntity(t5);

            Vector3f vt6 = new Vector3f(v3.X + 1.0f, v5.Y + 2.5f, v5.Z);
            Text t6 = new Text(sectionEntity.FilterValue, vt6, 2.0f, style);
            t6.Layer = layer;
            t6.Alignment = TextAlignment.TopLeft;
            dxf.AddEntity(t6);

            Vector3f vt7 = new Vector3f(v7.X + 1.0f, v7.Y + 2.5f, v7.Z);
            Text t7 = new Text("SECTION", vt7, 2.0f, style);
//.........这里部分代码省略.........

        private void DrawRectangleInternal(DxfDocument doc, Layer layer, bool isFilled, bool isStroked, Test2d.BaseStyle style, ref Test2d.Rect2 rect)
        {
            double x = rect.X;
            double y = rect.Y;
            double w = rect.Width;
            double h = rect.Height;

            var dxfLine1 = CreateLine(x, y, x + w, y);
            var dxfLine2 = CreateLine(x + w, y, x + w, y + h);
            var dxfLine3 = CreateLine(x + w, y + h, x, y + h);
            var dxfLine4 = CreateLine(x, y + h, x, y);

            if (isFilled)
            {
                var fill = GetColor(style.Fill);
                var fillTransparency = GetTransparency(style.Fill);

                var bounds =
                    new List<HatchBoundaryPath>
                    {
                        new HatchBoundaryPath(
                            new List<EntityObject>
                            {
                                (Line)dxfLine1.Clone(),
                                (Line)dxfLine2.Clone(),
                                (Line)dxfLine3.Clone(),
                                (Line)dxfLine4.Clone()
                            })
                    };

                var hatch = new Hatch(HatchPattern.Solid, bounds, false);
                hatch.Layer = layer;
                hatch.Color = fill;
                hatch.Transparency.Value = fillTransparency;

                doc.AddEntity(hatch);
            }

            if (isStroked)
            {
                var stroke = GetColor(style.Stroke);
                var strokeTansparency = GetTransparency(style.Stroke);
                var lineweight = ThicknessToLineweight(style.Thickness);

                dxfLine1.Layer = layer;
                dxfLine1.Color = stroke;
                dxfLine1.Transparency.Value = strokeTansparency;
                dxfLine1.Lineweight.Value = lineweight;

                dxfLine2.Layer = layer;
                dxfLine2.Color = stroke;
                dxfLine2.Transparency.Value = strokeTansparency;
                dxfLine2.Lineweight.Value = lineweight;

                dxfLine3.Layer = layer;
                dxfLine3.Color = stroke;
                dxfLine3.Transparency.Value = strokeTansparency;
                dxfLine3.Lineweight.Value = lineweight;

                dxfLine4.Layer = layer;
                dxfLine4.Color = stroke;
                dxfLine4.Transparency.Value = strokeTansparency;
                dxfLine4.Lineweight.Value = lineweight;

                doc.AddEntity(dxfLine1);
                doc.AddEntity(dxfLine2);
                doc.AddEntity(dxfLine3);
                doc.AddEntity(dxfLine4);
            }
        }

        public static void ModifyingGroups()
        {
            Line line1 = new Line(new Vector2(0, 0), new Vector2(100, 100));
            line1.Color = AciColor.Red;
            Line line2 = new Line(new Vector2(100, 0), new Vector2(200, 100));
            line2.Color = AciColor.Yellow;
            Line line3 = new Line(new Vector2(200, 0), new Vector2(300, 100));
            line3.Color = AciColor.Magenta;

            DxfDocument doc = new DxfDocument();

            Block blk = new Block("MyBlock");
            blk.Entities.Add(line1);
            Insert ins = new Insert(blk);
            doc.AddEntity(ins);

            doc.AddEntity(line2);

            Layout layout = new Layout("Layout1");
            doc.Layouts.Add(layout);
            doc.ActiveLayout = layout.Name;
            doc.AddEntity(line3);
            
            // group
            Group group = new Group("MyGroup");
            doc.Groups.Add(group);

            // the Add method will also add the entities contained in a group to the document (in the active layout).
            doc.Groups.Add(group);

            // when the group belongs to a document, all entities must belong to the same document.
            // even if it does not sound very useful, a group can contain entities that belongs to different layouts and even blocks.
            group.Entities.Add(line1);
            group.Entities.Add(line2);
            group.Entities.Add(line3);

            Line line4 = new Line(new Vector2(300, 0), new Vector2(400, 100));
            line4.Color = AciColor.Blue;
            // if a new entity, that does not belong to any document, is added to the group, it will be added to the group document active layout.
            doc.ActiveLayout = Layout.ModelSpaceName;
            group.Entities.Add(line4);

            Line line5 = new Line(new Vector2(400, 0), new Vector2(500, 100));
            line5.Color = AciColor.Green;
            DxfDocument doc2 = new DxfDocument();
            doc2.AddEntity(line5);

            // this is illegal, line5 belongs to another document.
            //group.Entities.Add(line5);
            // you need to clone the entity before adding it to the group. This is also the common practice to copy entities between documents.
            group.Entities.Add((EntityObject) line5.Clone());

            // remember removing a group only deletes it from the collection not the entities
            //doc.Groups.Remove(group);
            doc.Save("group.dxf");

            doc = DxfDocument.Load("group.dxf");
        }

        public static void ModifyingDimensionGeometryAndStyle()
        {
            DimensionStyle style = new DimensionStyle("MyStyle");
            Vector3 p1 = new Vector3(-2.5, 0, 0);
            Vector3 p2 = new Vector3(2.5, 0, 0);

            LinearDimension dim = new LinearDimension(p1, p2, 4, 0, style);

            // This is illegal. Trying to rebuild the dimension block before it has been added to a document will throw an exception
            //dim.RebuildBlock();

            DxfDocument doc = new DxfDocument();
            doc.AddEntity(dim);

            // modifying the dimension style
            dim.Style.DIMBLK = DimensionArrowhead.ArchitecturalTick;
            // if we make any change to the dimension style, we need to manually call the RebuildBlock method to reflect the new changes
            // since we will also modify the geometry of the dimension we will rebuild the block latter
            //dim.RebuildBlock();

            // the same kind of procedure needs to be done when modifying the geometry of a dimension
            dim.FirstReferencePoint = new Vector3(-5.0, 0, 0);
            dim.SecondReferencePoint = new Vector3(5.0, 0, 0);
            // now that all necessary changes has been made, we will rebuild the block.
            // this is an expensive operation, use it only when need it.

            dim.Style.DIMBLK = DimensionArrowhead.Box;
            dim.Style.DIMBLK = DimensionArrowhead.ArchitecturalTick;
            Debug.Assert(ReferenceEquals(dim.Style.DIMBLK, doc.Blocks[dim.Style.DIMBLK.Name]), "References are not equal.");
            Debug.Assert(ReferenceEquals(style.DIMBLK, doc.Blocks[style.DIMBLK.Name]), "References are not equal.");
            //dim.Style.DIMBLK = null;

            // VERY IMPORTANT: If any change is made to the dimension geometry and/or its style, we need to rebuild the drawing representation
            // so the dimension block will reflect the new changes. This is only necessary for dimension that already belongs to a document.
            // This process is automatically called when a new dimension is added to a document.
            dim.Update();
            Debug.Assert(ReferenceEquals(dim.Block, doc.Blocks[dim.Block.Name]));

            doc.Save("dimension.dxf");
            Test("dimension.dxf");

        }

        public static void ModifyingMLineStyles()
        {
            DxfDocument doc = new DxfDocument(DxfVersion.AutoCad2010);
            doc.DrawingVariables.LtScale = 10;

            List<Vector2> vertexes = new List<Vector2>
                                            {
                                                new Vector2(0, 0),
                                                new Vector2(0, 150),
                                                new Vector2(150, 150),
                                                new Vector2(150, 0)
                                            };

            MLine mline = new MLine(vertexes);
            mline.Scale = 20;
            mline.Justification = MLineJustification.Zero;

            MLineStyle style = new MLineStyle("MyStyle", "Personalized style.");
            style.Elements.Add(new MLineStyleElement(0.25));
            style.Elements.Add(new MLineStyleElement(-0.25));
         
            // if we add new elements directly to the list we need to sort the list,
            style.Elements.Sort();           
            style.Flags = MLineStyleFlags.EndInnerArcsCap | MLineStyleFlags.EndRoundCap | MLineStyleFlags.StartInnerArcsCap | MLineStyleFlags.StartRoundCap;

            // AutoCad2000 dxf version does not support true colors for MLineStyle elements
            style.Elements[0].Color = new AciColor(180, 230, 147);
           
            doc.AddEntity(mline);

            // change the multi line style after it has been added to the document
            mline.Style = style;
            Debug.Assert(ReferenceEquals(mline.Style, doc.MlineStyles[mline.Style.Name]), "Reference not equals.");

            // VERY IMPORTANT: We have modified the MLine after setting its vertexes so we need to manually call this method.
            // It is also necessary when manually editing the vertex distances.
            mline.Update();
            
            // the line type will be automatically added to the document
            foreach (MLineStyleElement e in style.Elements)
            {
                // making changes after the MLineStyle has been added to the document
                e.LineType = LineType.Dashed;
                Debug.Assert(ReferenceEquals(e.LineType, doc.LineTypes[e.LineType.Name]), "Reference not equals.");
            }

            MLine copy = (MLine) mline.Clone();
            copy.Scale = 100;
            doc.AddEntity(copy);
            // once the entity has been added to the document, changing its style requires that the new style is also present in the document.
            copy.Style = doc.MlineStyles["standard"];
            // VERY IMPORTANT: We have modified the MLine after setting its vertexes so we need to manually call this method.
            // It is also necessary when manually editing the vertex distances.
            copy.Update();

            doc.Save("ModifyingMLineStyle.dxf");
            Test("ModifyingMLineStyle.dxf");
        }

        public static void ModifyingBlockProperties()
        {
            DxfDocument doc = new DxfDocument();
            doc.DrawingVariables.InsUnits = DrawingUnits.Centimeters;
            Line existingLine = new Line(new Vector2(-10, 10), new Vector2(10, -10));
            doc.AddEntity(existingLine);

            AttributeDefinition attDef4 = new AttributeDefinition("MyAttribute4");
            attDef4.Value = "MyValue4";
            attDef4.Alignment = TextAlignment.TopCenter;
            Block block = new Block("MyBlock", null, new List<AttributeDefinition>{attDef4});
            block.Record.Units = DrawingUnits.Millimeters;

            // this is incorrect we cannot add an entity that belongs to a document when the block does not belong to anyone.
            //block.Entities.Add(existingLine);
            doc.Blocks.Add(block);
            // when the block and the entity that is being added belong to the same document, the entity will be removed from its current layout and added to the block
            // you cannot add an entity that belongs to a different document or block. Clone it instead.
            block.Entities.Add(existingLine);

            // now we can modify the block properties even if it has been already added to the document
            Line line = new Line(new Vector2(-10, -10), new Vector2(10, 10));

            // when new entities that do not belong to anyone are added to an existing block, they will also be added to the document
            block.Entities.Add(line);

            DxfDocument doc2 = new DxfDocument();
            Circle circle = new Circle(Vector2.Zero, 5);
            doc2.AddEntity(circle);

            // this is incorrect the circle already belongs to another document
            //block.Entities.Add(circle);
            // we need to clone it first
            Circle circle2 = (Circle) circle.Clone();
            circle2.Radius = 2.5;
            block.Entities.Add(circle2);

            //you could also remove circle2 from doc2 and add it to the block
            doc2.RemoveEntity(circle);
            block.Entities.Add(circle);

            AttributeDefinition attDef = new AttributeDefinition("MyAttribute1");
            attDef.Value = "MyValue1";
            block.AttributeDefinitions.Add(attDef);

            // the same that is applicable to entities is also true to attribute definitions
            AttributeDefinition attDef2 = new AttributeDefinition("MyAttribute2");
            attDef2.Value = "MyValue2";
            attDef2.Alignment = TextAlignment.BaselineRight;
            block.AttributeDefinitions.Add(attDef2);

            Insert ins = new Insert(block);
            doc.AddEntity(ins);

            // if the insert has been added to a document, any new attribute definitions added to the block will not be reflected in the insert
            // this mimics the behavior in AutoCad
            AttributeDefinition attDef3 = new AttributeDefinition("MyAttribute3");
            attDef3.Value = "MyValue3";
            attDef3.Alignment = TextAlignment.TopCenter;
            block.AttributeDefinitions.Add(attDef3);
            ins.Rotation = 30;

            // to update the insert attributes call the method Sync, this method will also call the method TransformAttributes
            ins.Sync();

            // the ins2 will have all three attributes
            Insert ins2 = new Insert(block, new Vector2(20,0));
            doc.AddEntity(ins2);

            doc.Save("Test.dxf");

            block.Name = "MyBlockRenamed";

            doc.Save("BlockRename.dxf");

            doc = Test("BlockRename.dxf");
        }

        public static void ModifyingDocumentEntities()
        {
            Layer layer1 = new Layer("layer1");
            Layer layer2 = new Layer("layer2");
            Layer layer3 = new Layer("layer3");

            LineType lineType1 = LineType.Dot;
            LineType lineType2 = LineType.Dashed;

            Line line = new Line(Vector2.Zero, Vector2.UnitX);
            line.Layer = layer1;
            line.LineType = lineType1;

            DxfDocument doc = new DxfDocument();
            doc.AddEntity(line);

            // if the layer does not exist in the document it will be added automatically
            line.Layer = layer2;
            Debug.Assert(ReferenceEquals(line.Layer, doc.Layers[line.Layer.Name]), "References are not equal.");

            // you can always add it first
            doc.Layers.Add(layer3);
            // layer3 is defined in the document
            line.Layer = layer3;
            Debug.Assert(ReferenceEquals(line.Layer, doc.Layers[line.Layer.Name]), "References are not equal.");

            // same thing is applicable to line types
            line.LineType = lineType2;
            Debug.Assert(ReferenceEquals(line.LineType, doc.LineTypes[line.LineType.Name]), "References are not equal.");

            doc.Save("entity.dxf");

            // it is also possible to rename table objects
            layer1.Name = "New layer1 name";
            lineType1.Name = "DotDot";

            // this operation is illegal, you cannot rename reserved table objects.
            //doc.Layers[Layer.DefaultName].Name = "NewName";

            doc.Save("test.dxf");
        }

        private static void NestedBlock()
        {
            Block blockMM = new Block("BlockMM");
            blockMM.Record.Units = DrawingUnits.Millimeters;
            AttributeDefinition attDefMM = new AttributeDefinition("MyAttributeMM");
            attDefMM.Height = 1.0;
            attDefMM.Value = "This is block mm";
            blockMM.AttributeDefinitions.Add(attDefMM);
            Line line1MM = new Line(Vector2.Zero, Vector2.UnitX);
            blockMM.Entities.Add(line1MM);
            Insert insMM = new Insert(blockMM);
            insMM.TransformAttributes();

            Block blockCM = new Block("BlockCM");
            blockCM.Record.Units = DrawingUnits.Centimeters;
            AttributeDefinition attDefCM = new AttributeDefinition("MyAttributeCM");
            attDefCM.Height = 1.0;
            attDefCM.Value = "This is block cm";
            blockCM.AttributeDefinitions.Add(attDefCM);
            Line line1CM = new Line(Vector2.Zero, Vector2.UnitY);
            blockCM.Entities.Add(line1CM);
            blockCM.Entities.Add(insMM);
            Insert insCM = new Insert(blockCM);

            DxfDocument doc = new DxfDocument();
            doc.DrawingVariables.InsUnits = DrawingUnits.Meters;
            //doc.AddEntity(insMM);
            doc.AddEntity(insCM);

            doc.Save("test.dxf");
        }