Victor Image Processing Library How-to Tips

Tiff Page View

The Victor Library gives the web .ASPX developer and the desktop .Net developer the advantages of speed, small size, and ease of use when creating an application to modify or analyze images.

For a developer using the Victor Library it is easy to load any page from a tiff file and display it in the user's browser.

To load and display a tiff page a typical sequence is:

Load the tiff file into a byte array from the desktop or from a url
Use loadtiffdata() to put an individual page into an image buffer
Use setup_to_displayimage() to convert the image into jpeg or gif format in another byte array
Store the byte array in a Session variable
Set the imageurl of the image control to an aspx page that will binary write the image from the Session variable

In this example we load a tiff file into a byte array and when a new page or size is requested it is loaded into the image buffer and the image is displayed.

For an introduction to creating online applications using the Victor Library see the application note Creating an ASP.NET Online Image Processing Application

C Sharp ASP.NET Source Code | Viewimage Source Code | Entire App Source Code with eval copy of Victor Library

Tiff Page View - the ASPX C# Source Code

Requires Victor Image Processing Library 6 or higher, commercial release or eval copy.

		


<%@ import namespace="viclib" %>

// The tiff file is in a byte array in memory and we will load each page as requested		
int loadtiffdata(ref byte bd, ref vicwin.imgdes timage, int pindex, int magnification){
int rcode;
vicwin.TiffData tinfo;
int tpages=0;
int noull=0;
int lpage;
vicwin.imgdes tempimage;
int bpp=0;


   tinfo = new vicwin.TiffData();
   tempimage = new vicwin.imgdes();
   // Determine total pages in the file, put value in tpages		
   rcode = vicwin.tiffgetpageinfofrombuffer(ref bd, ref tpages, ref noull, (int)0); 
   if(rcode == vicwin.NO_ERROR){
      numpages.Text = tpages.ToString( "0" );
      lpage = tpages - 1;
      lastpage.Text = lpage.ToString( "0" );

      // Get the image dimensions for the page of interest, put values into tinfo data structure
	   rcode = vicwin.tiffinfopagebyindexfrombuffer(ref bd, ref tinfo, pindex);  
	   if(rcode == vicwin.NO_ERROR) {
	      // Allocate space for the image in memory, timage is the image descriptor
		   rcode = vicwin.allocimage(ref timage, tinfo.width, tinfo.length, tinfo.vbitcount);
		   if(rcode == vicwin.NO_ERROR) {
		      // Load the image from the tiff file into the image buffer described by timage
			   rcode = vicwin.loadtifpagebyindexfrombuffer(ref bd, ref timage, pindex);
		      if(rcode == vicwin.NO_ERROR || rcode == vicwin.BAD_DATA) {
		            dimensions.Text = tinfo.width.ToString( "0" ) + " x " + tinfo.length.ToString( "0" ) + "  " + tinfo.vbitcount.ToString( "0" ) + "-bit";

		         if(tinfo.vbitcount == 16){ // Replace 16-bit grayscale image with 8-bit grayscale
		            rcode = vicwin.allocimage(ref tempimage, tinfo.width, tinfo.length, 8);
		            rcode = vicwin.convertgray16to8(ref timage, ref tempimage);
		            if(rcode == vicwin.NO_ERROR) {
		               vicwin.freeimage(ref timage);
		               vicwin.copyimgdes(ref tempimage, ref timage);
		               }
		            }
		         if(magnification != 100){      // Resize if necessary
		            bpp = getbpp(ref timage);
		            rcode = vicwin.allocimage(ref tempimage, tinfo.width * magnification / 100, tinfo.length  * magnification / 100, bpp);
		            if(rcode == vicwin.NO_ERROR) { // The Victor Library resize will be faster and better quality than a browser resize
		               rcode = vicwin.resizeex(ref timage, ref tempimage, 1);
		               if(rcode == vicwin.NO_ERROR) {
		                  vicwin.freeimage(ref timage);
		                  vicwin.copyimgdes(ref tempimage, ref timage);
                        }		               
   		            }
		            }
               }
            }
      }
   }
   else  // Error loading tiff file
   {
      numpages.Text = "0";
      lastpage.Text = "0";
   }
   return(rcode);
   } 

   
   
// This function receives an image descriptor and sets up the gif or jpeg to be displayed   
int setup_to_displayimage(ref vicwin.imgdes lsrcimg)
{
int outbuff=0;
int mode=0;
int transcolor=0;
int rcode;
int quality=75;
string ftype = "image/gif";
int buffsize = 0;
byte [] imgbytearray= {0,0,0};
int bpp;



   bpp = getbpp(ref lsrcimg);

   // Ready to display image. Use jpg for 24-bit images, gif for all others   
   if(bpp == 24)
  	   {
         rcode = vicwin.savejpgtobuffer (ref outbuff, ref lsrcimg, quality);
         ftype = "image/jpeg";
    	   }
	else {
         rcode = vicwin.savegiftobufferex (ref outbuff, ref lsrcimg, mode, transcolor);
	   }
	   
	// Copy the jpeg or gif data into a byte array for sending to the browser      
	if(rcode == vicwin.NO_ERROR) {   
     	   imgbytearray = transferbuffertobytearray(outbuff); 
         vicwin.freebuffer(outbuff);
         }
   
      // Store the image and file type in session variables   
      Session["outfilebinarydata"] = imgbytearray;
      Session["outfilecontent"] = ftype;

   // viewimage_cs.aspx will simply binary write the image to the browser   
   image1.ImageUrl = "viewimage_cs.aspx";
   return(rcode);
   }

Tiff Page View - Viewimage Source Code

//  viewimage_cs.aspx  
void  Page_Load (object sender, EventArgs e){
string contentype;
byte [] imgbytearray;

   imgbytearray = (byte [])Session["outfilebinarydata"]; 
   contentype = (string)Session["outfilecontent"];

   Response.ContentType = contentype;
   Response.Expires = 0;
   Response.Buffer = true;
   Response.Clear();
   Response.BinaryWrite(imgbytearray);  // Send the image to the browser 
   Response.End();
}

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