Add polygon drawing

1 files changed, 116 insertions, 0 deletions

diff --git a/UVtools.Core/Extensions/DrawingExtensions.cs b/UVtools.Core/Extensions/DrawingExtensions.cs
index b1d8050..db5ec69 100644
--- a/UVtools.Core/Extensions/DrawingExtensions.cs
+++ b/UVtools.Core/Extensions/DrawingExtensions.cs
@@ -20,5 +20,121 @@ namespace UVtools.Core.Extensions
                 Math.Min(Math.Max(min, color.B * factor), max));
             return Color.FromArgb(r, g, b);
         }
+
+        public static double CalculateSideLength(int sides, int radius)
+        {
+            return 2 * radius * Math.Sin(Math.PI / sides);
+        }
+
+        /*public static Point[] GetPolygonVertices(int sides, int radius, Point center, double startingAngle = 0)
+        {
+            if (sides < 3)
+                throw new ArgumentException("Polygons can't have less than 3 sides...", nameof(sides));
+
+
+            // Fix rotation
+            switch (sides)
+            {
+                case 3:
+                    startingAngle += 90;
+                    break;
+                case 4:
+                    startingAngle += 45;
+                    break;
+                case 5:
+                    startingAngle += 22.5;
+                    break;
+            }
+
+            var points = new Point[sides];
+            var step = 360.0 / sides;
+            int i = 0;
+            for (var angle = startingAngle; angle < startingAngle + 360.0; angle += step) //go in a circle
+            {
+                if (i == sides) break; // Fix floating problem
+                double radians = angle * Math.PI / 180.0;
+                points[i++] = new(
+                    (int) Math.Round(Math.Cos(radians) * radius + center.X),
+                    (int) Math.Round(Math.Sin(-radians) * radius + center.Y)
+                );
+            }
+
+            return points;
+        }*/
+
+        /*public static Point[] GetPolygonVertices(int sides, int radius, Point center, double startingAngle = 0)
+        {
+            startingAngle = -45;
+            if (sides < 3)
+                throw new ArgumentException("Polygons can't have less than 3 sides...", nameof(sides));
+
+            var vertex = new Point[sides];
+            //var deg = (180.0 * (sides - 2)) / sides + startingAngle;
+            var deg = ((180.0 * (sides - 2) / sides) - 180) / 2 + startingAngle;
+            var step = 360.0 / sides;
+            var rad = deg * (Math.PI / 180);
+
+            double nSinDeg = Math.Sin(rad);
+            double nCosDeg = Math.Cos(rad);
+
+            vertex[0] = center;
+            //vertex[0].X += radius; 
+            vertex[0].Y -= radius; 
+            //vertex[0].X += (int)Math.Cos(deg) / 2 *radius; 
+            //vertex[0].Y -= (int)Math.Sin(deg) / 2 *radius; 
+            int length = (int)Math.Round(CalculateSideLength(sides, radius));
+
+            for (int i = 1; i < vertex.Length; i++)
+            {
+                vertex[i] = new(
+                    (int)Math.Round(vertex[i - 1].X - nCosDeg * length),
+                    (int)Math.Round(vertex[i - 1].Y - nSinDeg * length));
+
+
+                //recalculate the degree for the next vertex
+                deg -= step;
+                rad = deg * (Math.PI / 180);
+
+                nSinDeg = Math.Sin(rad);
+                nCosDeg = Math.Cos(rad);
+
+            }
+            return vertex;
+        }*/
+
+        public static Point[] GetPolygonVertices(int sides, int radius, Point center, double startingAngle = 0)
+        {
+            if (sides < 3)
+                throw new ArgumentException("Polygons can't have less than 3 sides...", nameof(sides));
+
+            var vertices = new Point[sides];
+
+            double deg = 360.0 / sides;//calculate the rotation angle
+            //double a = radius * Math.Cos(Math.PI / sides);//calculate vertical length
+            //double s = CalculateSideLength(sides, radius);//calculate the side length
+            var rad = Math.PI / 180.0;
+
+            vertices[0] = new(
+                (int) Math.Round(center.X + radius * Math.Cos(-(((180 - deg) / 2) + startingAngle) * rad)),
+                (int) Math.Round(center.Y - radius * Math.Sin(-(((180 - deg) / 2) + startingAngle) * rad)));
+
+            vertices[1] = new(
+                (int) Math.Round(center.X + radius * Math.Cos(-(((180 - deg) / 2) + deg + startingAngle) * rad)),
+                (int) Math.Round(center.Y - radius * Math.Sin(-(((180 - deg) / 2) + deg + startingAngle) * rad)
+                ));
+
+            for (int i = 0; i < sides - 2; i++)
+            {
+                double dsinrot = Math.Sin((deg * (i + 1)) * rad);
+                double dcosrot = Math.Cos((deg * (i + 1)) * rad);
+
+                vertices[i + 2] = new(
+                        (int)Math.Round(center.X + dcosrot * (vertices[1].X - center.X) - dsinrot * (vertices[1].Y - center.Y)),
+                        (int)Math.Round(center.Y + dsinrot * (vertices[1].X - center.X) + dcosrot * (vertices[1].Y - center.Y))
+                );
+            }
+
+            return vertices;
+        }
     }
 }