fix: simplify Shape.OffsetOutward winding normalization and sync designer

OffsetOutward now normalizes to CW winding before offsetting instead of
trial-and-error with bounding box comparison. CadConverterForm designer
regenerated with new entityView1 properties.

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

OpenNest.Core/Geometry/Shape.cs

@@ -579,43 +579,38 @@ namespace OpenNest.Geometry
         }
 
         /// <summary>
-        /// Offsets the shape outward by the given distance, detecting winding direction
+        /// Offsets the shape outward by the given distance.
-        /// to choose the correct offset side. Falls back to the opposite side if the
+        /// Normalizes to CW winding before offsetting Left (which is outward for CW),
-        /// bounding box shrinks (indicating the offset went inward).
+        /// making the method independent of the original contour winding direction.
         /// </summary>
         public Shape OffsetOutward(double distance)
         {
             var poly = ToPolygon();
-            var side = poly.Vertices.Count >= 3 && poly.RotationDirection() == RotationType.CW
-                ? OffsetSide.Left
-                : OffsetSide.Right;
 
-            var result = OffsetEntity(distance, side) as Shape;
+            if (poly == null || poly.Vertices.Count < 3
+                || poly.RotationDirection() == RotationType.CW)
+                return OffsetEntity(distance, OffsetSide.Left) as Shape;
 
-            if (result == null)
+            // Shape is CCW — reverse to CW so Left offset goes outward.
-                return null;
+            var copy = new Shape();
 
-            UpdateBounds();
+            for (var i = Entities.Count - 1; i >= 0; i--)
-            var originalBB = BoundingBox;
-            result.UpdateBounds();
-            var offsetBB = result.BoundingBox;
-
-            if (offsetBB.Width < originalBB.Width || offsetBB.Length < originalBB.Length)
             {
-                Trace.TraceWarning(
+                switch (Entities[i])
-                    "Shape.OffsetOutward: offset shrank bounding box " +
+                {
-                    $"(original={originalBB.Width:F3}x{originalBB.Length:F3}, " +
+                    case Line l:
-                    $"offset={offsetBB.Width:F3}x{offsetBB.Length:F3}). " +
+                        copy.Entities.Add(new Line(l.EndPoint, l.StartPoint) { Layer = l.Layer });
-                    "Retrying with opposite side.");
+                        break;
-
+                    case Arc a:
-                var opposite = side == OffsetSide.Left ? OffsetSide.Right : OffsetSide.Left;
+                        copy.Entities.Add(new Arc(a.Center, a.Radius, a.EndAngle, a.StartAngle, !a.IsReversed) { Layer = a.Layer });
-                var retry = OffsetEntity(distance, opposite) as Shape;
+                        break;
-
+                    case Circle c:
-                if (retry != null)
+                        copy.Entities.Add(new Circle(c.Center, c.Radius) { Layer = c.Layer });
-                    result = retry;
+                        break;
+                }
             }
 
-            return result;
+            return copy.OffsetEntity(distance, OffsetSide.Left) as Shape;
         }
 
         /// <summary>

OpenNest/Forms/CadConverterForm.Designer.cs

@@ -116,8 +116,15 @@ namespace OpenNest.Forms
             entityView1.BackColor = System.Drawing.Color.FromArgb(33, 40, 48);
             entityView1.Cursor = System.Windows.Forms.Cursors.Cross;
             entityView1.Dock = System.Windows.Forms.DockStyle.Fill;
+            entityView1.IsPickingBendLine = false;
             entityView1.Location = new System.Drawing.Point(0, 0);
             entityView1.Name = "entityView1";
+            entityView1.OriginalEntities = null;
+            entityView1.ShowEntityLabels = false;
+            entityView1.SimplifierHighlight = null;
+            entityView1.SimplifierPreview = null;
+            entityView1.SimplifierToleranceLeft = null;
+            entityView1.SimplifierToleranceRight = null;
             entityView1.Size = new System.Drawing.Size(759, 634);
             entityView1.TabIndex = 0;
             // 
@@ -215,52 +222,68 @@ namespace OpenNest.Forms
             // 
             btnSplit.FlatStyle = System.Windows.Forms.FlatStyle.Flat;
             btnSplit.Font = new System.Drawing.Font("Segoe UI", 9F);
-            btnSplit.Location = new System.Drawing.Point(291, 6);
+            btnSplit.Location = new System.Drawing.Point(289, 6);
-            btnSplit.Margin = new System.Windows.Forms.Padding(2, 0, 8, 0);
+            btnSplit.Margin = new System.Windows.Forms.Padding(0, 0, 10, 0);
             btnSplit.Name = "btnSplit";
-            btnSplit.Size = new System.Drawing.Size(60, 24);
+            btnSplit.Size = new System.Drawing.Size(60, 27);
             btnSplit.TabIndex = 6;
             btnSplit.Text = "Split...";
             // 
             // btnSimplify
             // 
+            btnSimplify.AutoSize = true;
             btnSimplify.FlatStyle = System.Windows.Forms.FlatStyle.Flat;
             btnSimplify.Font = new System.Drawing.Font("Segoe UI", 9F);
+            btnSimplify.Location = new System.Drawing.Point(359, 6);
+            btnSimplify.Margin = new System.Windows.Forms.Padding(0, 0, 10, 0);
+            btnSimplify.Name = "btnSimplify";
+            btnSimplify.Size = new System.Drawing.Size(75, 27);
+            btnSimplify.TabIndex = 7;
             btnSimplify.Text = "Simplify...";
-            btnSimplify.AutoSize = true;
+            btnSimplify.Click += OnSimplifyClick;
-            btnSimplify.Margin = new System.Windows.Forms.Padding(4, 0, 0, 0);
-            btnSimplify.Click += new System.EventHandler(this.OnSimplifyClick);
             // 
             // btnExportDxf
             // 
+            btnExportDxf.AutoSize = true;
             btnExportDxf.FlatStyle = System.Windows.Forms.FlatStyle.Flat;
             btnExportDxf.Font = new System.Drawing.Font("Segoe UI", 9F);
+            btnExportDxf.Location = new System.Drawing.Point(444, 6);
+            btnExportDxf.Margin = new System.Windows.Forms.Padding(0, 0, 10, 0);
+            btnExportDxf.Name = "btnExportDxf";
+            btnExportDxf.Size = new System.Drawing.Size(76, 27);
+            btnExportDxf.TabIndex = 8;
             btnExportDxf.Text = "Export DXF";
-            btnExportDxf.AutoSize = true;
+            btnExportDxf.Click += OnExportDxfClick;
-            btnExportDxf.Margin = new System.Windows.Forms.Padding(4, 0, 0, 0);
-            btnExportDxf.Click += new System.EventHandler(this.OnExportDxfClick);
             // 
             // chkShowOriginal
             // 
             chkShowOriginal.AutoSize = true;
             chkShowOriginal.Font = new System.Drawing.Font("Segoe UI", 9F);
-            chkShowOriginal.Text = "Original";
+            chkShowOriginal.Location = new System.Drawing.Point(536, 9);
             chkShowOriginal.Margin = new System.Windows.Forms.Padding(6, 3, 0, 0);
-            chkShowOriginal.CheckedChanged += new System.EventHandler(this.OnShowOriginalChanged);
+            chkShowOriginal.Name = "chkShowOriginal";
+            chkShowOriginal.Size = new System.Drawing.Size(68, 19);
+            chkShowOriginal.TabIndex = 9;
+            chkShowOriginal.Text = "Original";
+            chkShowOriginal.CheckedChanged += OnShowOriginalChanged;
             // 
             // chkLabels
             // 
             chkLabels.AutoSize = true;
             chkLabels.Font = new System.Drawing.Font("Segoe UI", 9F);
-            chkLabels.Text = "Labels";
+            chkLabels.Location = new System.Drawing.Point(610, 9);
             chkLabels.Margin = new System.Windows.Forms.Padding(6, 3, 0, 0);
-            chkLabels.CheckedChanged += new System.EventHandler(this.OnLabelsChanged);
+            chkLabels.Name = "chkLabels";
+            chkLabels.Size = new System.Drawing.Size(59, 19);
+            chkLabels.TabIndex = 10;
+            chkLabels.Text = "Labels";
+            chkLabels.CheckedChanged += OnLabelsChanged;
             // 
             // lblDetect
             // 
             lblDetect.AutoSize = true;
             lblDetect.Font = new System.Drawing.Font("Segoe UI", 9F);
-            lblDetect.Location = new System.Drawing.Point(361, 9);
+            lblDetect.Location = new System.Drawing.Point(671, 9);
             lblDetect.Margin = new System.Windows.Forms.Padding(2, 3, 0, 0);
             lblDetect.Name = "lblDetect";
             lblDetect.Size = new System.Drawing.Size(42, 15);
@@ -271,7 +294,7 @@ namespace OpenNest.Forms
             // 
             cboBendDetector.DropDownStyle = System.Windows.Forms.ComboBoxStyle.DropDownList;
             cboBendDetector.Font = new System.Drawing.Font("Segoe UI", 9F);
-            cboBendDetector.Location = new System.Drawing.Point(405, 6);
+            cboBendDetector.Location = new System.Drawing.Point(715, 6);
             cboBendDetector.Margin = new System.Windows.Forms.Padding(2, 0, 0, 0);
             cboBendDetector.Name = "cboBendDetector";
             cboBendDetector.Size = new System.Drawing.Size(90, 23);