feat: switch from netDxf to ACadSharp for DXF operations

Replace vendored netDxf git submodule with ACadSharp NuGet package
(v3.1.32). This aligns the DXF dependency with the parent project.

API migration: DxfDocument→CadDocument, Vector3→XYZ, Vector2→XY,
MText.Position→MText.InsertPoint, Line.Linetype→Line.LineType,
DxfDocument.Load()→DxfReader, doc.Save()→DxfWriter.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.gitmodules

@@ -1,3 +0,0 @@
-[submodule "netDxf"]
-	path = netDxf
-	url = https://github.com/haplokuon/netDxf.git

EtchBendLines/Bend.cs

@@ -1,6 +1,4 @@
-using netDxf;
+using ACadSharp.Entities;
-using netDxf.Entities;
-using netDxf.Tables;
 using System;
 using System.Collections.Generic;
 

EtchBendLines/BendLineExtractor.cs

@@ -1,5 +1,7 @@
-using netDxf;
+using ACadSharp;
-using netDxf.Entities;
+using ACadSharp.Entities;
+using ACadSharp.IO;
+using CSMath;
 using System.Collections.Generic;
 using System.Globalization;
 using System.Linq;
@@ -11,12 +13,13 @@ namespace EtchBendLines
     {
         public BendLineExtractor(string dxfFile)
         {
-            DxfDocument = DxfDocument.Load(dxfFile);
+            using var reader = new DxfReader(dxfFile);
+            Document = reader.Read();
         }
 
-        public BendLineExtractor(DxfDocument dxfDocument)
+        public BendLineExtractor(CadDocument document)
         {
-            DxfDocument = dxfDocument;
+            Document = document;
         }
 
         /// <summary>
@@ -37,7 +40,7 @@ namespace EtchBendLines
             RegexOptions.Compiled | RegexOptions.IgnoreCase
         );
 
-        public DxfDocument DxfDocument { get; private set; }
+        public CadDocument Document { get; private set; }
 
         public List<Bend> GetBendLines()
         {
@@ -47,7 +50,7 @@ namespace EtchBendLines
             if (ReplaceSharpRadius)
                 FixSharpBends();
 
-            foreach (var line in DxfDocument.Lines)
+            foreach (var line in Document.Entities.OfType<Line>())
             {
                 if (!IsBendLine(line))
                     continue;
@@ -68,7 +71,7 @@ namespace EtchBendLines
 
         private bool IsBendLine(Line line)
         {
-            if (line.Linetype.Name != "CENTERX2")
+            if (line.LineType.Name != "CENTERX2")
                 return false;
 
             switch (line.Layer.Name.ToUpperInvariant())
@@ -84,7 +87,7 @@ namespace EtchBendLines
 
         private List<MText> GetBendNotes()
         {
-            return DxfDocument.MTexts
+            return Document.Entities.OfType<MText>()
                 .Where(t => GetBendDirection(t) != BendDirection.Unknown)
                 .ToList();
         }
@@ -159,7 +162,7 @@ namespace EtchBendLines
             for (int i = bendNotesList.Count - 1; i >= 0; i--)
             {
                 var note = bendNotesList[i];
-                var notePos = note.Position.ToVector2();
+                var notePos = note.InsertPoint.ToXY();
                 var perpendicularPoint = bendLine.PointPerpendicularTo(notePos);
                 var dist = notePos.DistanceTo(perpendicularPoint);
                 var maxAcceptableDist = note.Height * 2.0;
@@ -172,14 +175,14 @@ namespace EtchBendLines
                 return null;
 
             var closestNote = bendNotesList.First();
-            var p1 = closestNote.Position.ToVector2();
+            var p1 = closestNote.InsertPoint.ToXY();
             var p2 = bendLine.ClosestPointOnLineTo(p1);
             var dist2 = p1.DistanceTo(p2);
 
             for (int i = 1; i < bendNotesList.Count; i++)
             {
                 var note = bendNotesList[i];
-                var p3 = note.Position.ToVector2();
+                var p3 = note.InsertPoint.ToXY();
                 var p4 = bendLine.ClosestPointOnLineTo(p3);
                 var dist = p3.DistanceTo(p4);
 

EtchBendLines/EtchBendLines.csproj

@@ -11,11 +11,8 @@
   </PropertyGroup>
 
   <ItemGroup>
+    <PackageReference Include="ACadSharp" Version="3.1.32" />
     <PackageReference Include="System.Configuration.ConfigurationManager" Version="8.0.0" />
   </ItemGroup>
 
-  <ItemGroup>
-    <ProjectReference Include="..\netDxf\netDxf\netDxf.csproj" />
-  </ItemGroup>
-
 </Project>

EtchBendLines/Etcher.cs

@@ -1,6 +1,8 @@
-using netDxf;
+using ACadSharp;
-using netDxf.Entities;
+using ACadSharp.Entities;
-using netDxf.Tables;
+using ACadSharp.Tables;
+using ACadSharp.IO;
+using CSMath;
 using System;
 using System.Collections.Generic;
 using System.IO;
@@ -12,12 +14,12 @@ namespace EtchBendLines
     {
         public readonly Layer BendLayer = new Layer("BEND")
         {
-            Color = AciColor.Yellow
+            Color = Color.Yellow
         };
 
         static readonly Layer EtchLayer = new Layer("ETCH")
         {
-            Color = AciColor.Green,
+            Color = Color.Green,
         };
 
         private const double DefaultEtchLength = 1.0;
@@ -27,33 +29,34 @@ namespace EtchBendLines
         /// </summary>
         public double MaxBendRadius { get; set; } = 4.0;
 
-        private DxfDocument LoadDocument(string path)
+        private CadDocument LoadDocument(string path)
         {
             try
             {
-                return DxfDocument.Load(path)
+                using var reader = new DxfReader(path);
+                return reader.Read()
                     ?? throw new InvalidOperationException("DXF load returned null");
             }
-            catch (Exception ex)
+            catch (Exception ex) when (ex is not InvalidOperationException)
             {
                 throw new ApplicationException($"Failed to load DXF '{path}'", ex);
             }
         }
 
-        private List<Bend> ExtractBends(DxfDocument doc)
+        private List<Bend> ExtractBends(CadDocument doc)
         {
             var extractor = new BendLineExtractor(doc);
             return extractor.GetBendLines();
         }
 
-        private HashSet<string> BuildExistingKeySet(DxfDocument doc)
+        private HashSet<string> BuildExistingKeySet(CadDocument doc)
             => new HashSet<string>(
-                doc.Lines
+                doc.Entities.OfType<Line>()
                    .Where(l => IsEtchLayer(l.Layer))
                    .Select(l => KeyFor(l.StartPoint, l.EndPoint))
             );
 
-        private void InsertEtchLines(DxfDocument doc, IEnumerable<Bend> bends, HashSet<string> existingKeys, double etchLength)
+        private void InsertEtchLines(CadDocument doc, IEnumerable<Bend> bends, HashSet<string> existingKeys, double etchLength)
         {
             foreach (var bend in bends)
             {
@@ -63,28 +66,31 @@ namespace EtchBendLines
                     if (existingKeys.Contains(key))
                     {
                         // ensure correct layer
-                        var existing = doc.Lines.First(l => KeyFor(l) == key);
+                        var existing = doc.Entities.OfType<Line>().First(l => KeyFor(l) == key);
                         existing.Layer = EtchLayer;
                     }
                     else
                     {
                         etch.Layer = EtchLayer;
-                        doc.AddEntity(etch);
+                        doc.Entities.Add(etch);
                         existingKeys.Add(key);
                     }
                 }
             }
         }
 
-        private void SaveDocument(DxfDocument doc, string path)
+        private void SaveDocument(CadDocument doc, string path)
         {
-            doc.Save(path);
+            using (var writer = new DxfWriter(path, doc, false))
+            {
+                writer.Write();
+            }
             Console.WriteLine($"→ Saved with etch lines: {path}");
         }
 
         private static string KeyFor(Line l) => KeyFor(l.StartPoint, l.EndPoint);
 
-        private static string KeyFor(Vector3 a, Vector3 b) => $"{a.X:F3},{a.Y:F3}|{b.X:F3},{b.Y:F3}";
+        private static string KeyFor(XYZ a, XYZ b) => $"{a.X:F3},{a.Y:F3}|{b.X:F3},{b.Y:F3}";
 
         public void AddEtchLines(string filePath, double etchLength = DefaultEtchLength)
         {
@@ -129,8 +135,8 @@ namespace EtchBendLines
         {
             var lines = new List<Line>();
 
-            var startPoint = new Vector2(bendLine.StartPoint.X, bendLine.StartPoint.Y);
+            var startPoint = new XY(bendLine.StartPoint.X, bendLine.StartPoint.Y);
-            var endPoint = new Vector2(bendLine.EndPoint.X, bendLine.EndPoint.Y);
+            var endPoint = new XY(bendLine.EndPoint.X, bendLine.EndPoint.Y);
             var bendLength = startPoint.DistanceTo(endPoint);
 
             if (bendLength < (etchLength * 3.0))
@@ -151,26 +157,26 @@ namespace EtchBendLines
                     var topY1 = Math.Max(startPoint.Y, endPoint.Y);
                     var topY2 = topY1 - etchLength;
 
-                    var p1 = new Vector2(x, bottomY1);
+                    var p1 = new XYZ(x, bottomY1, 0);
-                    var p2 = new Vector2(x, bottomY2);
+                    var p2 = new XYZ(x, bottomY2, 0);
-                    var p3 = new Vector2(x, topY1);
+                    var p3 = new XYZ(x, topY1, 0);
-                    var p4 = new Vector2(x, topY2);
+                    var p4 = new XYZ(x, topY2, 0);
 
                     lines.Add(new Line(p1, p2));
                     lines.Add(new Line(p3, p4));
                 }
                 else
                 {
-                    var start = bendLine.StartPoint.ToVector2();
+                    var start = bendLine.StartPoint.ToXY();
-                    var end = bendLine.EndPoint.ToVector2();
+                    var end = bendLine.EndPoint.ToXY();
 
                     var dx = Math.Cos(angle) * etchLength;
                     var dy = Math.Sin(angle) * etchLength;
 
-                    var p1 = new Vector2(start.X, start.Y);
+                    var p1 = new XYZ(start.X, start.Y, 0);
-                    var p2 = new Vector2(start.X + dx, start.Y + dy);
+                    var p2 = new XYZ(start.X + dx, start.Y + dy, 0);
-                    var p3 = new Vector2(end.X, end.Y);
+                    var p3 = new XYZ(end.X, end.Y, 0);
-                    var p4 = new Vector2(end.X - dx, end.Y - dy);
+                    var p4 = new XYZ(end.X - dx, end.Y - dy, 0);
 
                     lines.Add(new Line(p1, p2));
                     lines.Add(new Line(p3, p4));

EtchBendLines/Extensions.cs

@@ -1,5 +1,5 @@
-using netDxf;
+using ACadSharp.Entities;
-using netDxf.Entities;
+using CSMath;
 using System;
 
 namespace EtchBendLines
@@ -8,12 +8,12 @@ namespace EtchBendLines
     {
         const double TwoPI = Math.PI * 2.0;
 
-        public static Vector2 ToVector2(this Vector3 pt)
+        public static XY ToXY(this XYZ pt)
         {
-            return new Vector2(pt.X, pt.Y);
+            return new XY(pt.X, pt.Y);
         }
 
-        public static bool IsEqualTo(this Vector3 pt, Vector3 pt1)
+        public static bool IsEqualTo(this XYZ pt, XYZ pt1)
         {
             return pt.X.IsEqualTo(pt1.X) && pt.Y.IsEqualTo(pt1.Y) && pt.Z.IsEqualTo(pt1.Z);
         }
@@ -50,10 +50,10 @@ namespace EtchBendLines
             return Math.Round(p1.Y - slope * p1.X, 4);
         }
 
-        public static Vector2 PointPerpendicularTo(this Line line, Vector2 pt)
+        public static XY PointPerpendicularTo(this Line line, XY pt)
         {
-            var startPoint = line.StartPoint.ToVector2();
+            var startPoint = line.StartPoint.ToXY();
-            var endPoint = line.EndPoint.ToVector2();
+            var endPoint = line.EndPoint.ToXY();
 
             var d1 = pt - startPoint;
             var d2 = endPoint - startPoint;
@@ -61,20 +61,20 @@ namespace EtchBendLines
             var lengthSquared = d2.X * d2.X + d2.Y * d2.Y;
             var param = dotProduct / lengthSquared;
 
-            return new Vector2(
+            return new XY(
                 startPoint.X + param * d2.X,
                 startPoint.Y + param * d2.Y);
         }
 
-        public static Vector2 MidPoint(this Line line)
+        public static XY MidPoint(this Line line)
         {
             var x = (line.StartPoint.X + line.EndPoint.X) * 0.5;
             var y = (line.StartPoint.Y + line.EndPoint.Y) * 0.5;
 
-            return new Vector2(x, y);
+            return new XY(x, y);
         }
 
-        public static double DistanceTo(this Vector2 startPoint, Vector2 endPoint)
+        public static double DistanceTo(this XY startPoint, XY endPoint)
         {
             var x = endPoint.X - startPoint.X;
             var y = endPoint.Y - startPoint.Y;
@@ -82,7 +82,7 @@ namespace EtchBendLines
             return Math.Sqrt(x * x + y * y);
         }
 
-        public static double AngleTo(this Vector2 startPoint, Vector2 endPoint)
+        public static double AngleTo(this XY startPoint, XY endPoint)
         {
             var x = endPoint.X - startPoint.X;
             var y = endPoint.Y - startPoint.Y;
@@ -133,10 +133,10 @@ namespace EtchBendLines
             return Math.Abs(b - a) <= tolerance;
         }
 
-        public static Vector2 ClosestPointOnLineTo(this Line line, Vector2 pt)
+        public static XY ClosestPointOnLineTo(this Line line, XY pt)
         {
-            var startPoint = line.StartPoint.ToVector2();
+            var startPoint = line.StartPoint.ToXY();
-            var endPoint = line.EndPoint.ToVector2();
+            var endPoint = line.EndPoint.ToXY();
 
             var diff1 = pt - startPoint;
             var diff2 = endPoint - startPoint;
@@ -150,7 +150,7 @@ namespace EtchBendLines
                 return endPoint;
             else
             {
-                return new Vector2(
+                return new XY(
                     startPoint.X + param * diff2.X,
                     startPoint.Y + param * diff2.Y);
             }