before candybox editor update

Plugins/CandyboxPlugin/Geometry/DefaultRectangle2Algorithm.cs

@@ -0,0 +1,120 @@
+namespace CandyboxPlugin.Geometry
+{
+    public class DefaultRectangle2Algorithm
+    {
+        public List<IntPoint> FindRectangle2(List<IntPoint> hullPoints)
+        {
+			//check if no bounding box available
+            if (hullPoints.Count <= 1)
+                return hullPoints;
+
+            Rectangle2d minBox = null;
+            var minAngle = 0d;
+
+            //foreach edge of the convex hull
+            for (var i = 0; i < hullPoints.Count; i++)
+            {
+                var nextIndex = i + 1;
+
+                var current = hullPoints[i];
+                var next = hullPoints[nextIndex % hullPoints.Count];
+
+                
+
+                //min / max points
+                var top = double.MinValue;
+                var bottom = double.MaxValue;
+                var left = double.MaxValue;
+                var right = double.MinValue;
+
+                //get angle of segment to x axis
+                var angle = AngleToXAxis(current,next);
+
+                //rotate every point and get min and max values for each direction
+                foreach (var p in hullPoints)
+                {
+                    var rotatedPoint = RotateToXAxis(p, angle);
+
+                    top = Math.Max(top, rotatedPoint.Y);
+                    bottom = Math.Min(bottom, rotatedPoint.Y);
+
+                    left = Math.Min(left, rotatedPoint.X);
+                    right = Math.Max(right, rotatedPoint.X);
+                }
+
+                //create axis aligned bounding box
+                var box = new Rectangle2d(new IntPoint((int)left, (int)bottom), new IntPoint((int)right, (int)top));
+
+                if (minBox == null || minBox.Area() > box.Area())
+                {
+                    minBox = box;
+                    minAngle = angle;
+                }
+            }
+
+            //rotate axis algined box back
+            var minimalBoundingBox = minBox.Points.Select(p => RotateToXAxis(p, -minAngle)).ToList();
+            return minimalBoundingBox;
+		}
+        /// <summary>
+        /// Calculates the angle to the X axis.
+        /// </summary>
+        /// <returns>The angle to the X axis.</returns>
+        /// <param name="s">The segment to get the angle from.</param>
+        static double AngleToXAxis(IntPoint a, IntPoint b)
+        {
+            var delta = a-b;
+            return -Math.Atan((float)delta.Y / (float)delta.X);
+        }
+
+        /// <summary>
+        /// Rotates vector by an angle to the x-Axis
+        /// </summary>
+        /// <returns>Rotated vector.</returns>
+        /// <param name="v">Vector to rotate.</param>
+        /// <param name="angle">Angle to trun by.</param>
+        static IntPoint RotateToXAxis(IntPoint v, double angle)
+        {
+            var newX = v.X * Math.Cos(angle) - v.Y * Math.Sin(angle);
+            var newY = v.X * Math.Sin(angle) + v.Y * Math.Cos(angle);
+
+            return new IntPoint((int)newX, (int)newY);
+        }
+    }
+    public class Rectangle2d
+    {
+        public IntPoint Location { get; set; }
+
+        public IntPoint Size { get; set; }
+
+        public Rectangle2d()
+        {
+        }
+
+        public Rectangle2d(IntPoint a, IntPoint c) : this()
+        {
+            Location = a;
+            Size = c - a;
+        }
+
+        public double Area()
+        {
+            return Size.X * Size.Y;
+        }
+
+        public IntPoint[] Points
+        {
+            get
+            {
+                return new[] {
+                    new IntPoint (Location.X, Location.Y),
+                    new IntPoint (Location.X + Size.X, Location.Y),
+                    new IntPoint (Location.X + Size.X, Location.Y + Size.Y),
+                    new IntPoint (Location.X, Location.Y + Size.Y)
+                };
+            }
+        }
+
+     
+    }
+}