L_SaveFileOffset

#include "l_bitmap.h"

L_LTFIL_API L_INT L_SaveFileOffset(fd, nOffsetBegin, nSizeWritten, pBitmap, nFormat, nBitsPerPixel, nQFactor, uFlags, pfnCallback, pUserData, pSaveOptions)

Saves a bitmap to a file in any supported format, using a callback function, and letting you specify an offset within the file to begin saving. This enables you to embed an image file in another file.

Returns

Comments

This function overwrites existing data at the specified location in the file.

You can use this function to update an image that you loaded with the L_LoadFileOffset function.

The offset is specified in bytes. You must open the file and get a Windows file handle before calling this function. You must also declare a variable to receive the resulting size of the embedded image file (in the nSizeWritten parameter).

If you use a callback and save the bitmap as a MacPaint (MAC) file, the image to be saved must have a width of 576 and a height of 720 (the required dimensions of that format).

Support for writing AVI files is only available in the Multimedia toolkits.

This function supports signed data images, but only DICOM and TIFF formats support signed data. This function will return an error if you attempt to save a signed image to a format other than DICOM or TIFF.

For information on saving bitmaps that have been window leveled, refer to Saving Window-Leveled Bitmaps.

If the bitmap has a region, the region stored in the bitmap will be saved, if the image is saved as one of the TIFF file formats.

Required DLLs and Libraries

Platforms

Windows 2000 / XP/Vista, Windows CE.

See Also

For a list of functions that utilize the LOADFILEOPTION or SAVEFILEOPTION structures, refer to Functions Utilizing the LOADFILEOPTION or SAVEFILEOPTION structures.

Example

For complete sample code, refer to the OFFSET example. This example saves an image file with a 30-byte offset. It then loads the file that it just saved. Note that the zSizeWritten variable from the save is reused when loading. A real application would have to get this information another way when loading.

 
 L_INT SaveFileOffsetExample(pBITMAPHANDLE LeadBitmap)
{
   L_INT nRet;              /* Return value                     */
   L_TCHAR szMessage[80];   /* Buffer for the MessageBox string */
   HANDLE  OffsetFile=NULL; /* File handle                      */
   L_SSIZE_T zSizeWritten;  /* Variable to be updated with the size written */
   DWORD     dwSizeWrite;

   /* Create a file */
   OffsetFile = CreateFile(TEXT("C:\\Program Files\\LEAD Technologies\\LEADTOOLS 15\\Images\\TOFFSET.TST"), GENERIC_WRITE, 0, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, 0);

   /* Write some text in the file -- 29 characters and a terminator */
   WriteFile(OffsetFile, TEXT("This is a 29-character string"), 30, &dwSizeWrite, NULL);

   /* Save the image file with an offset inside the TOFFSET.TST file */
   nRet = L_SaveFileOffset((L_HFILE)OffsetFile, 30, &zSizeWritten, LeadBitmap, FILE_BMP, 8, 0, SAVEFILE_FIXEDPALETTE, NULL, NULL, NULL);
   if(nRet != SUCCESS)
      return nRet;

   /* Close the file */
   CloseHandle(OffsetFile);

   /* Notify the user with a message box */
   if (nRet == SUCCESS)
   {
      MessageBox (NULL, TEXT("File was saved"), TEXT("Notice"), MB_OK);
   }
   else
   {
      wsprintf (szMessage, TEXT("Error %d saving the file"), nRet);
      MessageBox (NULL, szMessage, TEXT("Error"), MB_OK);
      return nRet;
   }

   /* Free the bitmap */
   L_FreeBitmap (LeadBitmap);

   /* Now load the file we just saved */
   /* Open the file and get the file handle */
   OffsetFile = CreateFile (TEXT("C:\\Program Files\\LEAD Technologies\\LEADTOOLS 15\\Images\\TOFFSET.TST"), GENERIC_READ | GENERIC_WRITE, 0, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0);

   /* Load the file with a 30-byte offset */
   nRet = L_LoadFileOffset((L_HFILE) OffsetFile, 30, zSizeWritten,
                           LeadBitmap, sizeof(BITMAPHANDLE), 0, ORDER_BGR,
                           LOADFILE_ALLOCATE | LOADFILE_STORE,
                           NULL, NULL, NULL, NULL);
   /* Close the file */
   CloseHandle(OffsetFile);

   /* Notify the user with a message box. The BPS in the message confirms that it is a new image. */
   if (nRet == SUCCESS)
   {
      wsprintf (szMessage, TEXT("New file loaded at %d BPS"), LeadBitmap->BitsPerPixel);
      MessageBox (NULL, szMessage, TEXT("Notice"), MB_OK);
   }
   else
   {
      wsprintf (szMessage, TEXT("Error %d loading the file"), nRet);
      MessageBox (NULL, szMessage, TEXT("Error"), MB_OK);
      return nRet;
   }
   return SUCCESS;
}