using System;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Drawing.Imaging;
using System.Windows.Forms;

namespace WindowsApplication1
{
    class PictureBoxDeluxe : System.Windows.Forms.PictureBox
    {
        public PictureBoxDeluxe()
        {
          
        }

       
        #region props

        private float _ZoomStep;

        public float ZoomStep
        {
            get { return _ZoomStep; }
            set { _ZoomStep = value; }
        }
	
        private bool _AllowZoom;

        public bool AllowZoom
        {
            get { return _AllowZoom; }
            set { _AllowZoom = value; }
        }


        private bool _AllowDrag = true;

        public bool AllowDrag
        {
            get { return _AllowDrag; }
            set { _AllowDrag = value; }
        }
	

        private float _ZoomLevel = 1;

        public float ZoomLevel
        {
            get {return _ZoomLevel; }
            set
            {
                _ZoomLevel = value;
                this.Invalidate();
            }
        }

        private Point _PictureLocation = new Point(0, 0);

        public Point PictureLocation
        {
            get { return _PictureLocation; }
            set
            {
                _PictureLocation = value;
                this.Invalidate();
            }
        }

        #endregion

        protected override void OnPaint(System.Windows.Forms.PaintEventArgs pe)
        {
            
            if (this.Image != null)
            {
                pe.Graphics.DrawImage(
                    this.Image,
                    new Rectangle(
                        _PictureLocation.X,
                        _PictureLocation.Y,
                        (int)(_ZoomLevel * this.Image.Width),
                        (int)(_ZoomLevel * this.Image.Height)),
                    0,
                    0,
                    this.Image.Width,
                    this.Image.Height,
                    GraphicsUnit.Pixel,
                    new ImageAttributes());
            }
        }


        private bool IsDragging = false;
        private Point DragOffset = Point.Empty;
        protected override void OnMouseDown(System.Windows.Forms.MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Left)
            {
                IsDragging = true;
                DragOffset.X = e.X - _PictureLocation.X;
                DragOffset.Y = e.Y - _PictureLocation.Y;
            }
            
            base.OnMouseDown(e);
        }

        protected override void OnMouseMove(MouseEventArgs e)
        {
            if (IsDragging)
            {
                this.PictureLocation = new Point(e.X - DragOffset.X, e.Y - DragOffset.Y);
            }

          
            base.OnMouseMove(e);
        }

        protected override void OnMouseUp(MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Left) IsDragging = false;

            base.OnMouseUp(e);
        }

        /// <summary>
        /// doesn't work
        /// </summary>
        /// <param name="e"></param>
        protected override void OnMouseWheel(MouseEventArgs e)
        {
            if (e.Delta < 0)
            {
                //scroll down, zoom out
                this.ZoomLevel += _ZoomStep;
            }
            else if (e.Delta > 0)
            {
                this.ZoomLevel -= _ZoomStep;
            }
            
            base.OnMouseWheel(e);
        }
      
    }
}