1using System;
  2using System.Drawing;
  3
  4namespace WindowCapture.Models
  5{
  6    public class ArrowAnnotation
  7    {
  8        public Point Start;
  9        public Point End;
 10        public PointF Control1;
 11        public PointF Control2;
 12        public bool HasCurve;
 13        public Color Color;
 14        public float Width;
 15
 16        public ArrowAnnotation(Point start, Point end)
 17        {
 18            Color = Settings.ArrowColor;
 19            Width = Settings.ArrowWidth;
 20            Start = start;
 21            End = end;
 22            // Initialize control points for a straight line initially
 23            Control1 = new PointF(
 24                start.X + (end.X - start.X) * 0.3f,
 25                start.Y + (end.Y - start.Y) * 0.3f);
 26            Control2 = new PointF(
 27                start.X + (end.X - start.X) * 0.7f,
 28                start.Y + (end.Y - start.Y) * 0.7f);
 29            HasCurve = false;
 30        }
 31
 32        public void UpdateControlPoints()
 33        {
 34            UpdateControlPointsForNewEndpoints();
 35        }
 36
 37        public void UpdateControlPointsForNewEndpoints()
 38        {
 39            Control1 = new PointF(
 40                Start.X + (End.X - Start.X) * 0.3f,
 41                Start.Y + (End.Y - Start.Y) * 0.3f);
 42            Control2 = new PointF(
 43                Start.X + (End.X - Start.X) * 0.7f,
 44                Start.Y + (End.Y - Start.Y) * 0.7f);
 45        }
 46
 47        public PointF GetBezierPoint(float t)
 48        {
 49            float u = 1 - t;
 50            float tt = t * t;
 51            float uu = u * u;
 52            float uuu = uu * u;
 53            float ttt = tt * t;
 54
 55            float x = uuu * Start.X + 3 * uu * t * Control1.X + 3 * u * tt * Control2.X + ttt * End.X;
 56            float y = uuu * Start.Y + 3 * uu * t * Control1.Y + 3 * u * tt * Control2.Y + ttt * End.Y;
 57
 58            return new PointF(x, y);
 59        }
 60
 61        public PointF GetBezierTangent(float t)
 62        {
 63            // Derivative of Bezier curve
 64            float u = 1 - t;
 65
 66            float dx = 3 * u * u * (Control1.X - Start.X) +
 67                       6 * u * t * (Control2.X - Control1.X) +
 68                       3 * t * t * (End.X - Control2.X);
 69            float dy = 3 * u * u * (Control1.Y - Start.Y) +
 70                       6 * u * t * (Control2.Y - Control1.Y) +
 71                       3 * t * t * (End.Y - Control2.Y);
 72
 73            // Normalize
 74            float len = (float)Math.Sqrt(dx * dx + dy * dy);
 75            if (len > 0.001f)
 76            {
 77                dx /= len;
 78                dy /= len;
 79            }
 80
 81            return new PointF(dx, dy);
 82        }
 83
 84        public Rectangle GetStartRect(int size)
 85        {
 86            return new Rectangle(Start.X - size / 2, Start.Y - size / 2, size, size);
 87        }
 88
 89        public Rectangle GetEndRect(int size)
 90        {
 91            return new Rectangle(End.X - size / 2, End.Y - size / 2, size, size);
 92        }
 93
 94        public Rectangle GetControl1Rect(int size)
 95        {
 96            return new Rectangle((int)Control1.X - size / 2, (int)Control1.Y - size / 2, size, size);
 97        }
 98
 99        public Rectangle GetControl2Rect(int size)
100        {
101            return new Rectangle((int)Control2.X - size / 2, (int)Control2.Y - size / 2, size, size);
102        }
103    }
104}