MLineStyle

Author: DomCR

src/ACadSharp/IO/DWG/DwgStreamReaders/DwgObjectReader.cs

@@ -5596,7 +5596,7 @@ 1024			512
 				}
 
 				template.ElementTemplates.Add(elementTemplate);
-				mlineStyle.Elements.Add(element);
+				mlineStyle.AddElement(element);
 			}
 
 			return template;

src/ACadSharp/IO/DWG/DwgStreamWriters/DwgObjectWriter.Objects.cs

@@ -534,7 +534,7 @@ private void writeMLineStyle(MLineStyle mlineStyle)
 			this._writer.WriteBitDouble(mlineStyle.EndAngle);
 
 			//linesinstyle RC Number of lines in this style
-			this._writer.WriteByte((byte)mlineStyle.Elements.Count);
+			this._writer.WriteByte((byte)mlineStyle.Elements.Count());
 			foreach (MLineStyle.Element element in mlineStyle.Elements)
 			{
 				//Offset BD Offset of this segment

src/ACadSharp/IO/DXF/DxfStreamWriter/DxfObjectsSectionWriter.cs

@@ -467,7 +467,7 @@ protected void writeMLineStyle(MLineStyle style)
 
 			this._writer.Write(51, style.StartAngle, map);
 			this._writer.Write(52, style.EndAngle, map);
-			this._writer.Write(71, (short)style.Elements.Count, map);
+			this._writer.Write(71, (short)style.Elements.Count(), map);
 			foreach (MLineStyle.Element element in style.Elements)
 			{
 				this._writer.Write(49, element.Offset, map);

src/ACadSharp/IO/DXF/DxfStreamWriter/DxfSectionWriterBase.Entities.cs

@@ -775,7 +775,7 @@ private void writeMLine(MLine mLine)
 
 			if (mLine.Style != null)
 			{
-				this._writer.Write(73, (short)mLine.Style.Elements.Count);
+				this._writer.Write(73, (short)mLine.Style.Elements.Count());
 			}
 
 			this._writer.Write(10, mLine.StartPoint, map);

src/ACadSharp/Objects/MLineStyle.Element.cs

@@ -1,4 +1,5 @@
 using ACadSharp.Attributes;
+using ACadSharp.Extensions;
 using ACadSharp.Tables;
 
 namespace ACadSharp.Objects
@@ -8,22 +9,58 @@ public partial class MLineStyle
 		public class Element
 		{
 			/// <summary>
-			/// Element offset
+			/// Element color.
+			/// </summary>
+			[DxfCodeValue(62)]
+			public Color Color { get; set; } = Color.ByLayer;
+
+			/// <summary>
+			/// Element linetype.
+			/// </summary>
+			[DxfCodeValue(6)]
+			public LineType LineType
+			{
+				get => _lineType;
+				set
+				{
+					this._lineType = CadObject.updateCollection(value, this.Owner?.Document?.LineTypes);
+				}
+			}
+
+			/// <summary>
+			/// Element offset.
 			/// </summary>
 			[DxfCodeValue(49)]
 			public double Offset { get; set; }
 
 			/// <summary>
-			/// Element color
+			/// Line type where this segment belongs.
 			/// </summary>
-			[DxfCodeValue(62)]
-			public Color Color { get; set; } = Color.ByBlock;
+			public MLineStyle Owner { get; internal set; }
+
+			private LineType _lineType = LineType.ByLayer;
 
 			/// <summary>
-			/// Element linetype
+			/// Clone the current segment.
 			/// </summary>
-			[DxfCodeValue(6)]
-			public LineType LineType { get; set; } = LineType.ByLayer;
+			/// <returns></returns>
+			public MLineStyle.Element Clone()
+			{
+				Element clone = MemberwiseClone() as Element;
+				clone.Owner = null;
+				clone._lineType = (LineType)(this.LineType?.Clone());
+				return clone;
+			}
+
+			internal void AssignDocument(CadDocument doc)
+			{
+				this._lineType = CadObject.updateCollection(this._lineType, doc.LineTypes);
+			}
+
+			internal void UnassignDocument()
+			{
+				this._lineType = this._lineType.CloneTyped();
+			}
 		}
 	}
-}
+}

src/ACadSharp/Objects/MLineStyle.cs

@@ -1,5 +1,9 @@
 using ACadSharp.Attributes;
+using ACadSharp.Tables;
+using CSMath;
+using System;
 using System.Collections.Generic;
+using System.Linq;
 
 namespace ACadSharp.Objects
 {
@@ -15,23 +19,64 @@ namespace ACadSharp.Objects
 	public partial class MLineStyle : NonGraphicalObject
 	{
 		/// <summary>
-		/// Default multiline style name
+		/// Gets the default multiline style with predefined settings.
 		/// </summary>
-		public const string DefaultName = "Standard";
+		/// <remarks>This property provides a preconfigured instance of <see cref="MLineStyle"/> that can be used as a
+		/// baseline for creating multiline styles. The default configuration includes two elements with offsets of 0.5 and
+		/// -0.5, respectively.</remarks>
+		public static MLineStyle Default
+		{
+			get
+			{
+				var def = new MLineStyle(DefaultName);
+				def.StartAngle = MathHelper.HalfPI;
+				def.EndAngle = MathHelper.HalfPI;
+				def.AddElement(new Element
+				{
+					LineType = LineType.ByLayer,
+					Offset = 0.5
+				});
+				def.AddElement(new Element
+				{
+					LineType = LineType.ByLayer,
+					Offset = -0.5
+				});
+				return def;
+			}
+		}
 
 		/// <summary>
-		/// Gets the default MLine style
+		/// Style description
 		/// </summary>
-		public static MLineStyle Default { get { return new MLineStyle(DefaultName); } }
+		/// <value>
+		/// 255 characters maximum
+		/// </value>
+		[DxfCodeValue(3)]
+		public string Description { get; set; }
 
-		/// <inheritdoc/>
-		public override ObjectType ObjectType => ObjectType.MLINESTYLE;
+		/// <summary>
+		/// Elements in the style
+		/// </summary>
+		[DxfCodeValue(DxfReferenceType.Count, 71)]
+		public IEnumerable<Element> Elements => this._elements;
 
-		/// <inheritdoc/>
-		public override string ObjectName => DxfFileToken.ObjectMLineStyle;
+		/// <summary>
+		/// End angle
+		/// </summary>
+		[DxfCodeValue(DxfReferenceType.IsAngle, 52)]
+		public double EndAngle { get; set; } = System.Math.PI / 2;
 
-		/// <inheritdoc/>
-		public override string SubclassMarker => DxfSubclassMarker.MLineStyle;
+		/// <summary>
+		/// Fill color
+		/// </summary>
+		[DxfCodeValue(62)]
+		public Color FillColor { get; set; } = Color.ByLayer;
+
+		/// <summary>
+		/// Multi line style flags
+		/// </summary>
+		[DxfCodeValue(70)]
+		public MLineStyleFlags Flags { get; set; }
 
 		/// <summary>
 		/// Mline style name
@@ -49,50 +94,104 @@ public override string Name
 			}
 		}
 
-		/// <summary>
-		/// Multi line style flags
-		/// </summary>
-		[DxfCodeValue(70)]
-		public MLineStyleFlags Flags { get; set; }
-
-		/// <summary>
-		/// Style description
-		/// </summary>
-		/// <value>
-		/// 255 characters maximum
-		/// </value>
-		[DxfCodeValue(3)]
-		public string Description { get; set; }
+		/// <inheritdoc/>
+		public override string ObjectName => DxfFileToken.ObjectMLineStyle;
 
-		/// <summary>
-		/// Fill color
-		/// </summary>
-		[DxfCodeValue(62)]
-		public Color FillColor { get; set; } = Color.ByLayer;
+		/// <inheritdoc/>
+		public override ObjectType ObjectType => ObjectType.MLINESTYLE;
 
 		/// <summary>
 		/// Start angle
 		/// </summary>
 		[DxfCodeValue(DxfReferenceType.IsAngle, 51)]
 		public double StartAngle { get; set; } = System.Math.PI / 2;
 
-		/// <summary>
-		/// End angle
-		/// </summary>
-		[DxfCodeValue(DxfReferenceType.IsAngle, 52)]
-		public double EndAngle { get; set; } = System.Math.PI / 2;
+		/// <inheritdoc/>
+		public override string SubclassMarker => DxfSubclassMarker.MLineStyle;
 
 		/// <summary>
-		/// Elements in the style
+		/// Default multiline style name
 		/// </summary>
-		[DxfCodeValue(DxfReferenceType.Count, 71)]
-		public List<MLineStyle.Element> Elements { get; } = new List<Element>();
+		public const string DefaultName = "Standard";
 
-		internal MLineStyle() { }
+		private List<Element> _elements = new List<Element>();
 
 		public MLineStyle(string name)
 		{
 			this.Name = name;
 		}
+
+		internal MLineStyle()
+		{
+		}
+
+		/// <summary>
+		/// Adds a segment to the current line style.
+		/// </summary>
+		/// <remarks>The method associates the specified element with the current line style and updates its line type
+		/// using the document's line type collection, if available.</remarks>
+		/// <param name="element">The element to add as a segment. The element must not already belong to another line style.</param>
+		/// <exception cref="ArgumentException">Thrown if the <paramref name="element"/> is already assigned to another line style.</exception>
+		public void AddElement(Element element)
+		{
+			if (element.Owner != null)
+				throw new ArgumentException($"Element already assigned to a MLineStyle: {element.Owner.Name}");
+
+			element.LineType = CadObject.updateCollection(element.LineType, this.Document?.LineTypes);
+			element.Owner = this;
+			this._elements.Add(element);
+		}
+
+		/// <inheritdoc/>
+		public override CadObject Clone()
+		{
+			MLineStyle clone = (MLineStyle)base.Clone();
+
+			clone._elements = new List<Element>();
+			foreach (var element in this._elements)
+			{
+				clone.AddElement(element.Clone());
+			}
+
+			return clone;
+		}
+
+		internal override void AssignDocument(CadDocument doc)
+		{
+			base.AssignDocument(doc);
+
+			foreach (var item in this._elements.Where(s => s.LineType != null))
+			{
+				item.AssignDocument(doc);
+			}
+
+			doc.TextStyles.OnRemove += this.tableOnRemove;
+		}
+
+		internal override void UnassignDocument()
+		{
+			this.Document.TextStyles.OnRemove -= this.tableOnRemove;
+
+			foreach (var item in this._elements.Where(s => s.LineType != null))
+			{
+				item.UnassignDocument();
+			}
+
+			base.UnassignDocument();
+		}
+
+		protected void tableOnRemove(object sender, CollectionChangedEventArgs e)
+		{
+			if (e.Item is LineType style)
+			{
+				foreach (var item in this._elements.Where(s => s.LineType != null))
+				{
+					if (item.LineType == style)
+					{
+						item.LineType = null;
+					}
+				}
+			}
+		}
 	}
-}
+}