Victor Image Processing Library How-to Tips

Remote TIFF to Local JPEG - the C/C++ Source Code

• establish an Internet connection
• acquire a handle to the remote file
• determine the file size
• allocate space in memory to hold the file
• download the file to memory

• determine the image dimensions and pixel depth: tiffinfofrombuffer
• allocate an image buffer to hold the image: allocimage
• load the image into the buffer: loadtiffrombuffer

• save the image in a local jpeg file: savejpg
• free the image buffer: freeimage

The default remote tiff file is www.catenary.com/howto/ibit.tif, a 1-bit tiff with group 4 compression.

Requires Victor Image Processing Library for 32-bit Windows static link library, vic32ss.lib.

These are the important functions extracted from the t2j.cpp file. For the complete ActiveX project source files download t2jsrc.zip

' ............................... Includes, Globals, and the Class methods .............................

#include "wininet.h"
#include <vicdefs.h>

int bringinthe_tif(imgdes *image);
int load_tif_local(void);

//................................. Globals 
char *Srcname;
char *Desname;

//................................. Methods 
STDMETHODIMP t2j::setremotetifname(BSTR remotetifname)
{
   char *localstring;
   int length;

   if(Srcname != 0)
      free(Srcname);

   localstring = (char *)(((BYTE *)remotetifname) + 0x00);
   length = (int)SysStringLen(remotetifname);

  if(length > 0) {
     Srcname = (char *)calloc(length+1, 1);
     WideCharToMultiByte(
        0, 
        0, 
        (LPCWSTR)localstring,
        length,              
        (LPSTR) Srcname,     
        length + 1,
        0,         
        0          
        );
     }

	return S_OK;
}

STDMETHODIMP t2j::setlocaljpgname(BSTR localjpgname)
{
   char *localstring;
   int length;

   if(Desname != 0)
      free(Desname);

   localstring = (char *)(((BYTE *)localjpgname) + 0x00);
   length = (int)SysStringLen(localjpgname);

  if(length > 0) {
     Desname = (char *)calloc(length+1, 1);
     WideCharToMultiByte(
        0, 
        0, 
        (LPCWSTR)localstring,
        length,              
        (LPSTR) Desname,     
        length + 1,
        0,         
        0          
        );
     }
	return S_OK;
}

STDMETHODIMP t2j::remotetif2localjpg()
{
int rcode;
imgdes timage;

   rcode = allocimage(&timage, 256, 256, 8);  // a default image
   if(rcode == NO_ERROR) {
      rcode = bringinthe_tif(&timage);
      freeimage(&timage);
      }

	return S_OK;
}

// ............................... Helper functions  .............................
int bringinthe_tif(imgdes *image)
{
   LPTSTR fname;
   HINTERNET hOpen; 
   HINTERNET hOpenUrl = 0;
   int rcode = -1;
   LPVOID filebuff = 0;
   DWORD filesize, bytesread; 
   TiffData tdat; 
   BOOL nRc, imageAllocd = FALSE;

   fname = Srcname;

   hOpen = InternetOpen("Victor Library Sample", INTERNET_OPEN_TYPE_PRECONFIG, 0, 0, 0);
   hOpenUrl = InternetOpenUrl(hOpen, fname, 0, 0, INTERNET_FLAG_RELOAD, 0);
   if(hOpenUrl) {
      // Get size of file with handle hOpenUrl
      filesize = getInetFileSize(hOpenUrl);
      if(filesize != 0) {
         // Allocate space to hold the tiff file
         filebuff = (LPVOID)calloc(filesize, sizeof(BYTE));
         if(filebuff) {
            // Read file into filebuff
            nRc = InternetReadFile(hOpenUrl, filebuff, filesize, &bytesread);
            if(nRc == TRUE) {
               rcode = tiffinfofrombuffer((UCHAR *)filebuff, &tdat);
               if(rcode == NO_ERROR) {
                  rcode = allocimage(image, tdat.width, tdat.length, tdat.vbitcount);
                  if(rcode == NO_ERROR) {
                     imageAllocd = TRUE; // Set flag that image was allocated
                     rcode = loadtiffrombuffer((UCHAR *)filebuff, image);
                     if(rcode == NO_ERROR)  {

                        if(tdat.vbitcount == 1) {  // If 1-bit image, create 8-bit version of it
                           imgdes timage;

                           rcode = allocimage(&timage, tdat.width, tdat.length, 8);  
                           if(rcode == NO_ERROR) {
                              rcode = convert1bitto8bit(image, &timage);  // could also use:convert1bitto8bitsmooth for scale-to-gray effect
                              if(rcode == NO_ERROR) {
                                 freeimage(image);   // free original image
                                 // Replace original image data with that describing the smoothed 8-bit image
                                 copyimgdes(&timage, image);  // copy data structure info 
                                 }
                              else
                                 freeimage(&timage);
                              }
                           }
                        rcode = savejpg(Desname, image, 75);
                        }
                     }
                  }
               }
            }
         }
      }
   // Free all!
   if(imageAllocd == TRUE)
      freeimage(image);
   if(filebuff)
      free(filebuff);
   if(hOpenUrl)
      InternetCloseHandle(hOpenUrl);
   if(hOpen)
      InternetCloseHandle(hOpen);
   return(rcode);
}


// Get size of file with handle hOpenUrl
static DWORD getInetFileSize(HINTERNET hOpenUrl)
{
#define FILEDATA_SIZE 32
   DWORD lenbufsiz = FILEDATA_SIZE;
   TCHAR filedata[FILEDATA_SIZE];
   BOOL nRc;
   DWORD filesize = 0;

   nRc = HttpQueryInfo(hOpenUrl, HTTP_QUERY_CONTENT_LENGTH, (LPVOID)filedata, &lenbufsiz, (LPDWORD)0);
   if(nRc == TRUE) // Get size of file
      filesize = atol(filedata);
   return(filesize);
}

Remote TIFF to Local JPEG - the JavaScript Source Code

<object 
   id = "t2j"
   codebase = "http://www.catenary.com/howto/tif2jpg.dll"
   classid = "CLSID:6875EE0C-CCB1-47DB-AEDF-A65F2B266F5E"
   >

   <span style="color:red"<ActiveX control tif2jpg.dll failed to load! 
   -- Please check browser security settings.</span>

</object>

<form name="testsendsrc">
   Remote TIFF file name url:              
   <input type = "text"   name = "srcfilename"     value = "http://www.catenary.com/howto/1bit.tif"  size = "50" maxlength = "100"     >

   <br>
   Local JPEG file name, complete path:     
   <input type = "text"   name = "desfilename"     value = "c:\test.jpg"                             size = "50" maxlength = "100"     >

   <br>
   <input type = "button" name = "rcd" value = "Load, convert, display"  onclick = "convert();check_for_ready()"    >
</form> 


<script language="javascript">

   var rc;
   var timerid;

   function convert(){
      t2j.setremotetifname(document.testsendsrc.srcfilename.value);
      t2j.setlocaljpgname(document.testsendsrc.desfilename.value);
      t2j.remotetif2localjpg();
      rc = 1;
      }

   function check_for_ready(){
      if (rc == 0)
         timerid = setTimeout("check_for_ready()", 100);
      
      if (rc == 1) {
         td.src = document.testsendsrc.desfilename.value;
         rc = 0;
         }
    }
</script>

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