fix: apply SubProgramCall offset additively and restore curpos after expansion

ConvertMode.ToIncremental skips SubProgramCalls when computing deltas,
so all code paths that expand SubProgramCalls must: (1) set curpos to
savedPos + Offset before expanding, and (2) restore curpos afterward
so subsequent incremental codes get correct deltas.

Fixed in ConvertProgram, GraphicsHelper (AddProgram, AddProgramSplit),
PlateRenderer (DrawRapids, DrawProgramPiercePoints, GetFirstPiercePoint),
and CutDirectionArrows.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

OpenNest.Core/Converters/ConvertProgram.cs

@@ -43,13 +43,20 @@ namespace OpenNest.Converters
                     case CodeType.SubProgramCall:
                         var subpgm = (SubProgramCall)code;
                         var savedMode = mode;
+                        var savedPos = curpos;
 
-                        // Apply offset: sub-program executes at the call's offset position
+                        // Position the sub-program at savedPos + Offset.
-                        if (subpgm.Offset.X != 0 || subpgm.Offset.Y != 0)
+                        // savedPos is the base position ((0,0) here, Part.Location in rendering).
-                            curpos = subpgm.Offset;
+                        // Offset is the hole center in drawing-local coordinates.
+                        curpos = new Vector(savedPos.X + subpgm.Offset.X, savedPos.Y + subpgm.Offset.Y);
 
                         AddProgram(subpgm.Program, ref mode, ref curpos, ref geometry);
                         mode = savedMode;
+
+                        // Restore curpos: ConvertMode.ToIncremental skips SubProgramCalls
+                        // when computing deltas, so subsequent incremental codes expect
+                        // curpos to be where it was before the call.
+                        curpos = savedPos;
                         break;
                 }
             }

OpenNest.Tests/CuttingStrategy/HoleSubProgramTests.cs

@@ -1,5 +1,6 @@
 using OpenNest.CNC;
 using OpenNest.CNC.CuttingStrategy;
+using OpenNest.Converters;
 using OpenNest.Geometry;
 using System.Linq;
 
@@ -159,6 +160,127 @@ public class HoleSubProgramTests
         Assert.NotEqual(calls[0].Offset.X, calls[1].Offset.X);
     }
 
+    [Fact]
+    public void Apply_HoleCenters_PreservedInGeometry()
+    {
+        // Square perimeter 10x10 with two circle holes at known positions
+        var holeCenter1 = new Vector(3, 3);
+        var holeCenter2 = new Vector(7, 5);
+        var holeRadius = 0.5;
+
+        var pgm = new Program(Mode.Absolute);
+        // Perimeter
+        pgm.Codes.Add(new RapidMove(0, 0));
+        pgm.Codes.Add(new LinearMove(10, 0));
+        pgm.Codes.Add(new LinearMove(10, 10));
+        pgm.Codes.Add(new LinearMove(0, 10));
+        pgm.Codes.Add(new LinearMove(0, 0));
+        // Hole 1 at (3, 3)
+        pgm.Codes.Add(new RapidMove(holeCenter1.X + holeRadius, holeCenter1.Y));
+        pgm.Codes.Add(new ArcMove(
+            new Vector(holeCenter1.X + holeRadius, holeCenter1.Y),
+            holeCenter1, RotationType.CW));
+        // Hole 2 at (7, 5)
+        pgm.Codes.Add(new RapidMove(holeCenter2.X + holeRadius, holeCenter2.Y));
+        pgm.Codes.Add(new ArcMove(
+            new Vector(holeCenter2.X + holeRadius, holeCenter2.Y),
+            holeCenter2, RotationType.CW));
+
+        var strategy = new ContourCuttingStrategy
+        {
+            Parameters = new CuttingParameters
+            {
+                ArcCircleLeadIn = new LineLeadIn { Length = 0.125, ApproachAngle = 90 },
+                ArcCircleLeadOut = new NoLeadOut()
+            }
+        };
+
+        var result = strategy.Apply(pgm, new Vector(10, 10));
+
+        // Convert to geometry — this is what PlateView renders
+        var geometry = ConvertProgram.ToGeometry(result.Program);
+        var circles = geometry.OfType<Circle>().ToList();
+
+        Assert.Equal(2, circles.Count);
+
+        // Circle centers must match the original hole positions
+        var center1 = circles[0].Center;
+        var center2 = circles[1].Center;
+
+        Assert.Equal(holeCenter1.X, center1.X, 2);
+        Assert.Equal(holeCenter1.Y, center1.Y, 2);
+        Assert.Equal(holeCenter2.X, center2.X, 2);
+        Assert.Equal(holeCenter2.Y, center2.Y, 2);
+    }
+
+    [Fact]
+    public void Part_ApplyLeadIns_HolesAndPerimeter_CorrectPositions()
+    {
+        // Build a drawing with a square and two holes
+        var holeCenter1 = new Vector(3, 3);
+        var holeCenter2 = new Vector(7, 5);
+        var holeRadius = 0.5;
+
+        var pgm = new Program(Mode.Absolute);
+        pgm.Codes.Add(new RapidMove(0, 0));
+        pgm.Codes.Add(new LinearMove(10, 0));
+        pgm.Codes.Add(new LinearMove(10, 10));
+        pgm.Codes.Add(new LinearMove(0, 10));
+        pgm.Codes.Add(new LinearMove(0, 0));
+        pgm.Codes.Add(new RapidMove(holeCenter1.X + holeRadius, holeCenter1.Y));
+        pgm.Codes.Add(new ArcMove(
+            new Vector(holeCenter1.X + holeRadius, holeCenter1.Y),
+            holeCenter1, RotationType.CW));
+        pgm.Codes.Add(new RapidMove(holeCenter2.X + holeRadius, holeCenter2.Y));
+        pgm.Codes.Add(new ArcMove(
+            new Vector(holeCenter2.X + holeRadius, holeCenter2.Y),
+            holeCenter2, RotationType.CW));
+
+        var drawing = new Drawing("TestPart") { Program = pgm };
+        var part = new Part(drawing);
+
+        var parameters = new CuttingParameters
+        {
+            RoundLeadInAngles = true,
+            LeadInAngleIncrement = 5.0,
+            ArcCircleLeadIn = new LineLeadIn { Length = 0.125, ApproachAngle = 90 },
+            ArcCircleLeadOut = new NoLeadOut(),
+            ExternalLeadIn = new LineLeadIn { Length = 0.25, ApproachAngle = 90 },
+            ExternalLeadOut = new NoLeadOut()
+        };
+
+        part.ApplyLeadIns(parameters, new Vector(10, 10));
+
+        // Convert to geometry — this is what PlateView renders
+        var geometry = ConvertProgram.ToGeometry(part.Program);
+        var circles = geometry.OfType<Circle>().ToList();
+        var lines = geometry.OfType<Line>().Where(l => l.Layer != SpecialLayers.Rapid).ToList();
+
+        // Hole circles must be at correct positions
+        Assert.Equal(2, circles.Count);
+        Assert.Equal(holeCenter1.X, circles[0].Center.X, 2);
+        Assert.Equal(holeCenter1.Y, circles[0].Center.Y, 2);
+        Assert.Equal(holeCenter2.X, circles[1].Center.X, 2);
+        Assert.Equal(holeCenter2.Y, circles[1].Center.Y, 2);
+        Assert.Equal(holeRadius, circles[0].Radius, 2);
+        Assert.Equal(holeRadius, circles[1].Radius, 2);
+
+        // Perimeter lines must stay within the original 10x10 bounding box.
+        // This catches the mode conversion bug where perimeter gets shifted
+        // by the last hole's position.
+        foreach (var line in lines)
+        {
+            Assert.True(line.StartPoint.X >= -1 && line.StartPoint.X <= 11,
+                $"Perimeter line start X={line.StartPoint.X} is outside the 10x10 part bounds");
+            Assert.True(line.StartPoint.Y >= -1 && line.StartPoint.Y <= 11,
+                $"Perimeter line start Y={line.StartPoint.Y} is outside the 10x10 part bounds");
+            Assert.True(line.EndPoint.X >= -1 && line.EndPoint.X <= 11,
+                $"Perimeter line end X={line.EndPoint.X} is outside the 10x10 part bounds");
+            Assert.True(line.EndPoint.Y >= -1 && line.EndPoint.Y <= 11,
+                $"Perimeter line end Y={line.EndPoint.Y} is outside the 10x10 part bounds");
+        }
+    }
+
     [Fact]
     public void Program_BoundingBox_IncludesSubProgramOffset()
     {

OpenNest/Controls/CutDirectionArrows.cs

@@ -18,7 +18,12 @@ namespace OpenNest.Controls
                 {
                     var subpgm = (SubProgramCall)code;
                     if (subpgm.Program != null)
+                    {
+                        var savedPos = pos;
+                        pos = new Vector(savedPos.X + subpgm.Offset.X, savedPos.Y + subpgm.Offset.Y);
                         DrawProgram(g, view, subpgm.Program, ref pos, pen, spacing, arrowSize);
+                        pos = savedPos;
+                    }
                     continue;
                 }
 

OpenNest/Controls/PlateRenderer.cs

@@ -404,6 +404,9 @@ namespace OpenNest.Controls
         {
             for (var i = 0; i < pgm.Length; i++)
             {
+                if (pgm[i] is SubProgramCall call && call.Program != null)
+                    return GetFirstPiercePoint(call.Program, partLocation + call.Offset);
+
                 if (pgm[i] is Motion motion)
                 {
                     if (pgm.Mode == Mode.Incremental)
@@ -428,7 +431,12 @@ namespace OpenNest.Controls
                     var program = subpgm.Program;
 
                     if (program != null)
+                    {
+                        var savedPos = pos;
+                        pos = new Vector(savedPos.X + subpgm.Offset.X, savedPos.Y + subpgm.Offset.Y);
                         DrawRapids(g, program, ref pos);
+                        pos = savedPos;
+                    }
                 }
                 else
                 {
@@ -489,7 +497,12 @@ namespace OpenNest.Controls
                 {
                     var subpgm = (SubProgramCall)code;
                     if (subpgm.Program != null)
+                    {
+                        var savedPos = pos;
+                        pos = new Vector(savedPos.X + subpgm.Offset.X, savedPos.Y + subpgm.Offset.Y);
                         DrawProgramPiercePoints(g, subpgm.Program, ref pos, brush, pen);
+                        pos = savedPos;
+                    }
                 }
                 else
                 {

OpenNest/GraphicsHelper.cs

@@ -147,7 +147,10 @@ namespace OpenNest
                         {
                             cutPath.StartFigure();
                             leadPath.StartFigure();
+                            var savedPos = curpos;
+                            curpos = new Vector(savedPos.X + subpgm.Offset.X, savedPos.Y + subpgm.Offset.Y);
                             AddProgramSplit(cutPath, leadPath, subpgm.Program, mode, ref curpos);
+                            curpos = savedPos;
                         }
                         mode = tmpmode;
                         break;
@@ -305,7 +308,10 @@ namespace OpenNest
 
                             if (subpgm.Program != null)
                             {
+                                var savedPos = curpos;
+                                curpos = new Vector(savedPos.X + subpgm.Offset.X, savedPos.Y + subpgm.Offset.Y);
                                 AddProgram(path, subpgm.Program, mode, ref curpos);
+                                curpos = savedPos;
                             }
 
                             mode = tmpmode;