ScrollablePictureBoxUserControl. cs

using System;
using System.ComponentModel;
using System.Drawing;
using System.Windows.Forms;
 
namespace be.gaudry.view.controls
{
    public partial class ScrollablePictureBoxUserControl : UserControl
    {
        #region declarations and constructors
        private float zoom;
        private Bitmap bitmap;
        public ScrollablePictureBoxUserControl()
        {
            zoom = 0.05F;
            InitializeComponent();
            /*
            this.SetStyle(ControlStyles.UserPaint, true);
            this.SetStyle(ControlStyles.AllPaintingInWmPaint, true);
            this.SetStyle(ControlStyles.DoubleBuffer, true);
            this.SetStyle(ControlStyles.ResizeRedraw, true);
            */
        } 
        #endregion
 
        #region properties
        /// <summary>
        /// Image to display in the scrollable thumb panel
        /// </summary>
        [
        Category("Image options"),
        Description("Bitmap to display in the scrollable picturebox")
        ]
        public Bitmap Bitmap
        {
            get
            {
                return bitmap;
            }
            set
            {
                if (value != null && value.Width > 1 && value.Height > 1)
                {
                    bitmap = value;
                    thumbPB.Image = bitmap;
 
                    //setThumbPanel();
                    //thumbPanel.AutoScrollMinSize = thumbPanel.Size;
                    //zoom = (float)bitmap.Width / thumbPanel.Width;
                    zoom = (float)thumbPanel.Width / bitmap.Width;
                    zoomThumbTrkB.Minimum = 5;
                    zoomThumbTrkB.Maximum = 210;
                    setZoomTrkValue();
                    zoomThumbTrkB.Visible = true;
                    thumbSizeLbl.Visible = true;
                    thumbPB.Invalidate(thumbPB.ClientRectangle);
                }
            }
        }
        /// <summary>
        /// Image to display in the scrollable thumb panel
        /// </summary>
        [
        Category("Image options"),
        Description("Zoom to apply on the displayed image")
        ]
        public float Zoom
        {
            get
            {
                return zoom;
            }
            /*set
            {
                if (value != null)
                {
                    zoom = value;
                    if (bitmap != null)
                    {
                        setZoomTrkValue();
                        zoomThumbTrkB.Visible = true;
                        thumbSizeLbl.Visible = true;
                    }
                }
            }*/
        }
        public void setBitmap(Bitmap newBitmap)
        {
            thumbPB.Image = newBitmap;
        }
        public void zoomIn()
        {
            zoom += ((float)zoomThumbTrkB.LargeChange / 100);
            int i = zoomThumbTrkB.Value+zoomThumbTrkB.LargeChange;
            if (i > zoomThumbTrkB.Maximum)
            {
                zoomThumbTrkB.Maximum = i;
                zoomThumbTrkB.Invalidate();
            }
            setThumbPanel();
            setZoomTrkValue();
        }
        public void zoomOut()
        {
            zoom -= ((float)zoomThumbTrkB.LargeChange / 100);
            setThumbPanel();
            setZoomTrkValue();
        }
        public void zoomToFit()
        {
            thumbPanel.AutoScrollMinSize = thumbPanel.Size;
            zoom = (float)bitmap.Width / thumbPanel.Width;
            thumbPanel.Invalidate(thumbPanel.ClientRectangle);
            zoomThumbTrkB.Value = zoomThumbTrkB.Minimum;
        }
        public void zoomToRealSize()
        {
            zoom = 1F;
            setThumbPanel();
            setZoomTrkValue();
        }
 
        private void setZoomTrkValue()
        {
            int trkVal = (int)(zoom * 100);
            if (trkVal < zoomThumbTrkB.Minimum)
                trkVal = zoomThumbTrkB.Minimum;
            if (trkVal > zoomThumbTrkB.Maximum)
                trkVal = zoomThumbTrkB.Maximum;
            zoom = (float)trkVal / 100;
            zoomThumbTrkB.Value = trkVal;
        }
        #endregion
 
        private void zoomThumbTrkB_Scroll(object sender, EventArgs e)
        {
            zoom = (float)zoomThumbTrkB.Value / 100;
            setThumbPanel();
        }
 
        private void setThumbPanel()
        {
            thumbPanel.AutoScrollMinSize = new Size((int)(bitmap.Width * zoom), (int)(bitmap.Height * zoom));
            thumbPanel.Invalidate(thumbPanel.ClientRectangle); 
 
        }
        private void thumbPanel_Paint(object sender, PaintEventArgs e)
        {
            /*if (bitmap != null)
            {
                Graphics g = e.Graphics;
                g.DrawImage(bitmap, new Rectangle(
                    thumbPanel.AutoScrollPosition.X + ((thumbPanel.Width - newWidth) / 2),
                    thumbPanel.AutoScrollPosition.Y + ((thumbPanel.Height - newHeight) / 2),
                    newWidth,
                    newHeight)
                    );
            }*/
        }
 
        private void thumbPB_Paint(object sender, PaintEventArgs e)
        {
            if (bitmap != null)
            {
                zoom = (float)thumbPB.Width / bitmap.Width;
                zoomThumbTrkB.Minimum = (int)(((float)thumbPanel.Width / bitmap.Width)*100);
                thumbSizeLbl.Text = String.Format("Affichage : {0}% ({1} * {2} pixels)", (int)(zoom*100), thumbPB.Width, thumbPB.Height);
            }
        } 
    }
}