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using System;
using System.Collections.Generic;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using Sicon.Snipper.Enums;
using Sicon.Snipper.Tools;

namespace Sicon.Snipper.Annotations
{
    /// <summary>
    /// Highlight Annotation
    /// </summary>
    public class HighlightAnnotation : BaseAnnotation
    {
        #region Members

        protected Rectangle _selection = Rectangle.Empty;
        protected const int _transparancyAlpha = 110;
        private ShapeEnum _shape = ShapeEnum.Rectangle;
        List<Point> points = new List<Point>();
        private const int PS_SOLID = 0;
        private const int R2_MASKPEN = 9;
        private const int R2_COPYPEN = 13;

        #endregion Members

        #region Properties

        /// <summary>
        /// Gets or Sets the Shape
        /// </summary>
        public ShapeEnum Shape
        {
            get { return _shape; }
            set { _shape = value; }
        }

        /// <summary>
        /// Gets the Selection
        /// </summary>
        public Rectangle Selection
        {
            get { return _selection; }
            protected set { _selection = value; }
        }

        #endregion Properties

        #region Constructors

        /// <summary>
        /// Constructor
        /// </summary>
        /// <param name="imageRef">Reference to the image</param>
        public HighlightAnnotation(Image imageRef, Control host, ShapeEnum shape)
            : base(imageRef, new Pen(Color.Yellow, 16), host)
        {
            _shape = shape;
        }

        #endregion Constructors

        #region Methods

        /// <summary>
        /// Handles on Mouse down
        /// </summary>
        /// <param name="e">args</param>
        public override void OnMouseDown(MouseEventArgs e)
        {
            if (base.Enabled)
            {
                // Start the snip on mouse down
                if (e.Button != MouseButtons.Left) return;

                _startPoint = e.Location;
                _selection = new Rectangle(e.Location, new Size(0, 0));
            }
        }

        /// <summary>
        /// Handles Mouse Move
        /// </summary>
        /// <param name="e">args</param>
        public override void OnMouseMove(MouseEventArgs e)
        {
            if (base.Enabled)
            {
                // Modify the selection on mouse move
                if (e.Button != MouseButtons.Left) return;

                //Add freehand points
                points.Add(new Point(e.X, e.Y));

                //Update selection rectangele
                int x1 = Math.Min(e.X, _startPoint.X);
                int y1 = Math.Min(e.Y, _startPoint.Y);
                int x2 = Math.Max(e.X, _startPoint.X);
                int y2 = Math.Max(e.Y, _startPoint.Y);
                _selection = new Rectangle(x1, y1, x2 - x1, y2 - y1);
            }
        }

        /// <summary>
        /// Handles on mouse up
        /// </summary>
        /// <param name="e">args</param>
        public override void OnMouseUp(MouseEventArgs e)
        {
            if (base.Enabled)
            {
                if (_selection.Width <= 0 || _selection.Height <= 0) return;

                using (Graphics g = Graphics.FromImage(this.ImageRef))
                {
                    switch (this.Shape)
                    {
                        case ShapeEnum.Freehand:

                            DrawHighlight(g, points.ToArray());

                            break;

                        case ShapeEnum.Rectangle:

                            Rectangle dest = new Rectangle(
                                TranslateCenterImageMousePosition(_startPoint),
                                _selection.Size);

                            DrawRectange(g);

                            break;

                        default: return;
                    }
                }

                this.Enabled = false;
            }
        }

        /// <summary>
        /// Hanles on paint
        /// </summary>
        /// <param name="g">graphics</param>
        public override void OnPaint(System.Drawing.Graphics g)
        {
            if (base.Enabled)
            {
                switch (this.Shape)
                {
                    case ShapeEnum.Freehand:

                        DrawHighlight(g, points.ToArray());

                        break;

                    case ShapeEnum.Rectangle:

                        DrawRectange(g);

                        break;

                    default: return;
                }
            }
        }

        /// <summary>
        /// Draws a highlight
        /// </summary>
        /// <param name="g">graphics</param>
        /// <param name="usePoints">points to draw</param>
        private void DrawHighlight(Graphics g, Point[] usePoints)
        {
            int useColor = System.Drawing.ColorTranslator.ToWin32(base.Pen.Color);
            IntPtr pen = GDI32.CreatePen(PS_SOLID, (int)base.Pen.Width, (uint)useColor);
            IntPtr hDC = g.GetHdc();
            IntPtr xDC = GDI32.SelectObject(hDC, pen);
            GDI32.SetROP2(hDC, R2_MASKPEN);
            for (int i = 1; i <= usePoints.Length - 1; i++)
            {
                Point p1 = usePoints[i - 1];
                Point p2 = usePoints[i];
                GDI32.MoveToEx(hDC, p1.X, p1.Y, IntPtr.Zero);
                GDI32.LineTo(hDC, p2.X, p2.Y);
            }
            GDI32.SetROP2(hDC, R2_COPYPEN);
            GDI32.SelectObject(hDC, xDC);
            GDI32.DeleteObject(pen);
            g.ReleaseHdc(hDC);
        }

        /// <summary>
        /// Draws a rectangle
        /// </summary>
        /// <param name="g">Graphics</param>
        private void DrawRectange(Graphics g)
        {
            Rectangle dest = new Rectangle(
                                TranslateCenterImageMousePosition(_startPoint),
                                _selection.Size);

            int useColor = System.Drawing.ColorTranslator.ToWin32(base.Pen.Color);
            IntPtr pen = GDI32.CreatePen(PS_SOLID, (int)base.Pen.Width, (uint)useColor);
            IntPtr hDC = g.GetHdc();
            IntPtr xDC = GDI32.SelectObject(hDC, pen);
            GDI32.SetROP2(hDC, R2_MASKPEN);
            GDI32.Rectangle(hDC, dest.Left, dest.Top, dest.Right, dest.Bottom);
            GDI32.SetROP2(hDC, R2_COPYPEN);
            GDI32.SelectObject(hDC, xDC);
            GDI32.DeleteObject(pen);
            g.ReleaseHdc(hDC);
        }

        #endregion Methods
    }
}