An ASP.NET thumbnail solution

// Copyright Philipos Sakellaropoulos 2002

namespace PhilipSoft.Thumbnails {
    using System;
    using System.Text;
    using System.IO;
    using System.Drawing;
    using System.Drawing.Imaging;
    using System.Drawing.Drawing2D;
    using THUMBEXTRACTLib; // our COM object wrapper

    /// <summary>
    /// Uses the shell interface IImageExtract2
    /// </summary>
public class ThumbGenerator {
   private String _path;
   private int _width,_height;
   private bool _bStretch,_bBevel,_bUseCOMobject;
   private IFileThumbExtract _oCOMThumb;  
        /// <summary>
        /// Creates a new instance of ThumbGenerator<br/>
        /// bUseCOMobject: If use COM object to create thumbnails
        /// </summary>

   public void SetParams(String path,int width,int height,
      bool bStretch,bool bBevel,bool bUseCOMobject) {
     // cache parameters
      _path = path; _width= width; _height=height;
      _bStretch=bStretch; _bBevel=bBevel; _bUseCOMobject=bUseCOMobject;
   }   
   
        /// <summary>
        /// Extracts thumbnail based on physical image path, width, height
        /// </summary>
        /// <param>path</param>
        /// <param>width</param>
        /// <param>height</param>
        /// <param>bStretch</param>
        /// <param>bBevel</param>
    public Bitmap ExtractThumbnail()
    {
     Bitmap bitmapNew; float fx,fy,f; 
     int widthTh,heightTh; float widthOrig,heightOrig;
     if(_bUseCOMobject) {
       if(_oCOMThumb==null) _oCOMThumb = new FileThumbExtract();
       _oCOMThumb.SetPath(_path);
       _oCOMThumb.SetThumbnailSize(_width,_height);
       IntPtr hBitmap = (IntPtr)_oCOMThumb.ExtractThumbnail();
       bitmapNew = Bitmap.FromHbitmap(hBitmap);
       _oCOMThumb.FreeThumbnail();
      }
      else {
      // create thumbnail using .net function GetThumbnailImage
       bitmapNew = new Bitmap(_path); // load original image
       if(!_bStretch) { // retain aspect ratio
         widthOrig = bitmapNew.Width;
         heightOrig = bitmapNew.Height;
         fx = widthOrig/_width;
         fy = heightOrig/_height; // subsample factors
         // must fit in thumbnail size
         f=Math.Max(fx,fy); if(f<1) f=1;
         widthTh = (int)(widthOrig/f); heightTh = (int)(heightOrig/f);
       }
       else {
        widthTh = _width; heightTh = _height;
       }
       bitmapNew = (Bitmap)bitmapNew.GetThumbnailImage(widthTh, heightTh,
         new Image.GetThumbnailImageAbort(ThumbnailCallback),IntPtr.Zero);
      }
      if(!_bBevel) return bitmapNew;
      // ---- apply bevel
      int widTh,heTh;
      widTh = bitmapNew.Width; heTh = bitmapNew.Height;
      int BevW = 10, LowA=0, HighA=180, Dark=80, Light=255;
      // hilight color, low and high
      Color clrHi1 = Color.FromArgb(LowA,Light,Light,Light);
      Color clrHi2 = Color.FromArgb(HighA,Light,Light,Light);
      Color clrDark1 = Color.FromArgb(LowA,Dark,Dark,Dark);
      Color clrDark2 = Color.FromArgb(HighA,Dark,Dark,Dark);
      LinearGradientBrush br; Rectangle rectSide;
      Graphics newG = Graphics.FromImage(bitmapNew);   
      Size szHorz = new Size(widTh,BevW);
      Size szVert = new Size(BevW,heTh);
      // ---- draw dark (shadow) sides first
      // draw bottom-side of bevel
      szHorz+=new Size(0,2); szVert+=new Size(2,0);
      rectSide = new Rectangle(new Point(0,heTh-BevW),szHorz);
      br = new LinearGradientBrush(
        rectSide,clrDark1,clrDark2,LinearGradientMode.Vertical);
      rectSide.Inflate(0,-1);
      newG.FillRectangle(br,rectSide);  
      // draw right-side of bevel
      rectSide = new Rectangle(new Point(widTh-BevW,0),szVert);
      br = new LinearGradientBrush(
        rectSide,clrDark1,clrDark2,LinearGradientMode.Horizontal);
      rectSide.Inflate(-1,0);
      newG.FillRectangle(br,rectSide);  
      // ---- draw bright (hilight) sides next
      szHorz-=new Size(0,2); szVert-=new Size(2,0);
      // draw top-side of bevel
      rectSide = new Rectangle(new Point(0,0),szHorz);
      br = new LinearGradientBrush(
        rectSide,clrHi2,clrHi1,LinearGradientMode.Vertical);
      newG.FillRectangle(br,rectSide);  
      // draw left-side of bevel
      rectSide = new Rectangle(new Point(0,0),szVert);
      br = new LinearGradientBrush(
        rectSide,clrHi2,clrHi1,LinearGradientMode.Horizontal);
      newG.FillRectangle(br,rectSide);  
      // dispose graphics objects and return bitmap
      br.Dispose(); newG.Dispose();
      return bitmapNew;
    }
    
    public String GetUniqueThumbName() {
      StringBuilder sUN = new StringBuilder();
      sUN.AppendFormat("Thumb_{0}_{1}x{2}",
        Path.GetFileName(_path),_width,_height);
      if(_bStretch) sUN.Append("_S");
      if(_bBevel) sUN.Append("_B");
      if(_bUseCOMobject) sUN.Append("_COM");
      sUN.Append(".jpg");
      return sUN.ToString();
     }
  
        /// <summary>
        /// Saves a thumbnail in JPEG format
        /// </summary>
    public void SaveThumbnail(Bitmap bmThumb,String path)
    { 
       bmThumb.Save(path,ImageFormat.Jpeg);
    }

    public bool ThumbnailCallback() { return false; }
    }
}