feat(engine): add PatternTiler for unit cell tiling across plates

OpenNest.Engine/PatternTiler.cs

@@ -0,0 +1,52 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using OpenNest.Geometry;
+
+namespace OpenNest.Engine
+{
+    public static class PatternTiler
+    {
+        public static List<Part> Tile(List<Part> cell, Size plateSize, double partSpacing)
+        {
+            if (cell == null || cell.Count == 0)
+                return new List<Part>();
+
+            var cellBox = cell.GetBoundingBox();
+            var halfSpacing = partSpacing / 2;
+
+            var cellWidth = cellBox.Width + partSpacing;
+            var cellHeight = cellBox.Length + partSpacing;
+
+            if (cellWidth <= 0 || cellHeight <= 0)
+                return new List<Part>();
+
+            // Size.Width = X-axis, Size.Length = Y-axis
+            var cols = (int)System.Math.Floor(plateSize.Width / cellWidth);
+            var rows = (int)System.Math.Floor(plateSize.Length / cellHeight);
+
+            if (cols <= 0 || rows <= 0)
+                return new List<Part>();
+
+            var cellOrigin = cellBox.Location;
+            var baseOffset = new Vector(halfSpacing - cellOrigin.X, halfSpacing - cellOrigin.Y);
+
+            var result = new List<Part>(cols * rows * cell.Count);
+
+            for (var row = 0; row < rows; row++)
+            {
+                for (var col = 0; col < cols; col++)
+                {
+                    var tileOffset = baseOffset + new Vector(col * cellWidth, row * cellHeight);
+
+                    foreach (var part in cell)
+                    {
+                        result.Add(part.CloneAtOffset(tileOffset));
+                    }
+                }
+            }
+
+            return result;
+        }
+    }
+}

OpenNest.Tests/PatternTilerTests.cs

@@ -0,0 +1,105 @@
+using OpenNest;
+using OpenNest.Engine;
+using OpenNest.Geometry;
+
+namespace OpenNest.Tests;
+
+public class PatternTilerTests
+{
+    private static Drawing MakeSquareDrawing(double size)
+    {
+        var pgm = new CNC.Program();
+        pgm.Codes.Add(new CNC.LinearMove(size, 0));
+        pgm.Codes.Add(new CNC.LinearMove(size, size));
+        pgm.Codes.Add(new CNC.LinearMove(0, size));
+        pgm.Codes.Add(new CNC.LinearMove(0, 0));
+        return new Drawing("square", pgm);
+    }
+
+    [Fact]
+    public void Tile_SinglePart_FillsGrid()
+    {
+        var drawing = MakeSquareDrawing(10);
+        var cell = new List<Part> { Part.CreateAtOrigin(drawing) };
+        var plateSize = new Size(30, 20);
+        var partSpacing = 0.0;
+
+        var result = PatternTiler.Tile(cell, plateSize, partSpacing);
+
+        Assert.Equal(6, result.Count);
+
+        foreach (var part in result)
+        {
+            Assert.True(part.BoundingBox.Right <= plateSize.Width + 0.001);
+            Assert.True(part.BoundingBox.Top <= plateSize.Length + 0.001);
+            Assert.True(part.BoundingBox.Left >= -0.001);
+            Assert.True(part.BoundingBox.Bottom >= -0.001);
+        }
+    }
+
+    [Fact]
+    public void Tile_TwoParts_TilesUnitCell()
+    {
+        var drawing = MakeSquareDrawing(10);
+        var partA = Part.CreateAtOrigin(drawing);
+        var partB = Part.CreateAtOrigin(drawing);
+        partB.Offset(10, 0);
+
+        var cell = new List<Part> { partA, partB };
+        var plateSize = new Size(40, 20);
+        var partSpacing = 0.0;
+
+        var result = PatternTiler.Tile(cell, plateSize, partSpacing);
+
+        Assert.Equal(8, result.Count);
+    }
+
+    [Fact]
+    public void Tile_WithSpacing_ReducesCount()
+    {
+        var drawing = MakeSquareDrawing(10);
+        var cell = new List<Part> { Part.CreateAtOrigin(drawing) };
+        var plateSize = new Size(30, 20);
+        var partSpacing = 2.0;
+
+        var result = PatternTiler.Tile(cell, plateSize, partSpacing);
+
+        Assert.Equal(2, result.Count);
+    }
+
+    [Fact]
+    public void Tile_EmptyCell_ReturnsEmpty()
+    {
+        var result = PatternTiler.Tile(new List<Part>(), new Size(100, 100), 0);
+        Assert.Empty(result);
+    }
+
+    [Fact]
+    public void Tile_NonSquarePlate_CorrectAxes()
+    {
+        var drawing = MakeSquareDrawing(10);
+        var cell = new List<Part> { Part.CreateAtOrigin(drawing) };
+        var plateSize = new Size(50, 10);
+
+        var result = PatternTiler.Tile(cell, plateSize, 0);
+
+        Assert.Equal(5, result.Count);
+
+        var maxRight = result.Max(p => p.BoundingBox.Right);
+        var maxTop = result.Max(p => p.BoundingBox.Top);
+        Assert.True(maxRight <= 50.001);
+        Assert.True(maxTop <= 10.001);
+    }
+
+    [Fact]
+    public void Tile_CellLargerThanPlate_ReturnsSingleCell()
+    {
+        var drawing = MakeSquareDrawing(50);
+        var cell = new List<Part> { Part.CreateAtOrigin(drawing) };
+        var plateSize = new Size(30, 30);
+
+        var result = PatternTiler.Tile(cell, plateSize, 0);
+
+        Assert.Empty(result);
+    }
+}