refactor(shapes): generalize OctagonShape to NgonShape

Parameterize side count so users can generate any regular n-gon (n>=3). Width remains the inscribed-circle diameter, preserving n=8 behavior; circumradius derives as Width / (2*cos(pi/n)). Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
2026-04-15 13:42:02 -04:00
parent 6fdf0ad3c5
commit 9b84508ff4
3 changed files with 63 additions and 41 deletions
@@ -0,0 +1,44 @@
+using OpenNest.Geometry;
+using System.Collections.Generic;
+
+namespace OpenNest.Shapes
+{
+    public class NgonShape : ShapeDefinition
+    {
+        public int Sides { get; set; }
+        public double Width { get; set; }
+
+        public override void SetPreviewDefaults()
+        {
+            Sides = 8;
+            Width = 8;
+        }
+
+        public override Drawing GetDrawing()
+        {
+            var n = Sides < 3 ? 3 : Sides;
+            var center = Width / 2.0;
+            var circumRadius = Width / (2.0 * System.Math.Cos(System.Math.PI / n));
+            var step = 2.0 * System.Math.PI / n;
+            var start = System.Math.PI / n;
+
+            var vertices = new Vector[n];
+            for (var i = 0; i < n; i++)
+            {
+                var angle = start + i * step;
+                vertices[i] = new Vector(
+                    center + circumRadius * System.Math.Cos(angle),
+                    center + circumRadius * System.Math.Sin(angle));
+            }
+
+            var entities = new List<Entity>();
+            for (var i = 0; i < n; i++)
+            {
+                var next = (i + 1) % n;
+                entities.Add(new Line(vertices[i], vertices[next]));
+            }
+
+            return CreateDrawing(entities);
+        }
+    }
+}