refactor: extract PartGeometry from Helper

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
2026-03-15 17:44:17 -04:00
parent 84d3f90549
commit 2881815c7a
4 changed files with 132 additions and 122 deletions
--- a/OpenNest.Core/PartGeometry.cs
+++ b/OpenNest.Core/PartGeometry.cs
@@ -0,0 +1,126 @@
+using System.Collections.Generic;
+using System.Linq;
+using OpenNest.Converters;
+using OpenNest.Geometry;
+
+namespace OpenNest
+{
+    public static class PartGeometry
+    {
+        public static List<Line> GetPartLines(Part part, double chordTolerance = 0.001)
+        {
+            var entities = ConvertProgram.ToGeometry(part.Program);
+            var shapes = ShapeBuilder.GetShapes(entities.Where(e => e.Layer != SpecialLayers.Rapid));
+            var lines = new List<Line>();
+
+            foreach (var shape in shapes)
+            {
+                var polygon = shape.ToPolygonWithTolerance(chordTolerance);
+                polygon.Offset(part.Location);
+                lines.AddRange(polygon.ToLines());
+            }
+
+            return lines;
+        }
+
+        public static List<Line> GetPartLines(Part part, PushDirection facingDirection, double chordTolerance = 0.001)
+        {
+            var entities = ConvertProgram.ToGeometry(part.Program);
+            var shapes = ShapeBuilder.GetShapes(entities.Where(e => e.Layer != SpecialLayers.Rapid));
+            var lines = new List<Line>();
+
+            foreach (var shape in shapes)
+            {
+                var polygon = shape.ToPolygonWithTolerance(chordTolerance);
+                polygon.Offset(part.Location);
+                lines.AddRange(GetDirectionalLines(polygon, facingDirection));
+            }
+
+            return lines;
+        }
+
+        public static List<Line> GetOffsetPartLines(Part part, double spacing, double chordTolerance = 0.001)
+        {
+            var entities = ConvertProgram.ToGeometry(part.Program);
+            var shapes = ShapeBuilder.GetShapes(entities.Where(e => e.Layer != SpecialLayers.Rapid));
+            var lines = new List<Line>();
+
+            foreach (var shape in shapes)
+            {
+                // Add chord tolerance to compensate for inscribed polygon chords
+                // being inside the actual offset arcs.
+                var offsetEntity = shape.OffsetEntity(spacing + chordTolerance, OffsetSide.Left) as Shape;
+
+                if (offsetEntity == null)
+                    continue;
+
+                var polygon = offsetEntity.ToPolygonWithTolerance(chordTolerance);
+                polygon.RemoveSelfIntersections();
+                polygon.Offset(part.Location);
+                lines.AddRange(polygon.ToLines());
+            }
+
+            return lines;
+        }
+
+        public static List<Line> GetOffsetPartLines(Part part, double spacing, PushDirection facingDirection, double chordTolerance = 0.001)
+        {
+            var entities = ConvertProgram.ToGeometry(part.Program);
+            var shapes = ShapeBuilder.GetShapes(entities.Where(e => e.Layer != SpecialLayers.Rapid));
+            var lines = new List<Line>();
+
+            foreach (var shape in shapes)
+            {
+                var offsetEntity = shape.OffsetEntity(spacing + chordTolerance, OffsetSide.Left) as Shape;
+
+                if (offsetEntity == null)
+                    continue;
+
+                var polygon = offsetEntity.ToPolygonWithTolerance(chordTolerance);
+                polygon.RemoveSelfIntersections();
+                polygon.Offset(part.Location);
+                lines.AddRange(GetDirectionalLines(polygon, facingDirection));
+            }
+
+            return lines;
+        }
+
+        /// <summary>
+        /// Returns only polygon edges whose outward normal faces the specified direction.
+        /// </summary>
+        private static List<Line> GetDirectionalLines(Polygon polygon, PushDirection facingDirection)
+        {
+            if (polygon.Vertices.Count < 3)
+                return polygon.ToLines();
+
+            var sign = polygon.RotationDirection() == RotationType.CCW ? 1.0 : -1.0;
+            var lines = new List<Line>();
+            var last = polygon.Vertices[0];
+
+            for (int i = 1; i < polygon.Vertices.Count; i++)
+            {
+                var current = polygon.Vertices[i];
+                var dx = current.X - last.X;
+                var dy = current.Y - last.Y;
+
+                bool keep;
+
+                switch (facingDirection)
+                {
+                    case PushDirection.Left:  keep = -sign * dy > 0; break;
+                    case PushDirection.Right: keep =  sign * dy > 0; break;
+                    case PushDirection.Up:    keep = -sign * dx > 0; break;
+                    case PushDirection.Down:  keep =  sign * dx > 0; break;
+                    default: keep = true; break;
+                }
+
+                if (keep)
+                    lines.Add(new Line(last, current));
+
+                last = current;
+            }
+
+            return lines;
+        }
+    }
+}