LMemoryFile::SaveFileBuffer

#include "ltwrappr.h"

virtual L_INT LMemoryFile::SaveFileBuffer(pLBuffer, puFileSize, nFormat, nBitsPerPixel, nQFactor, uFlags, pSaveOptions)

Saves the class object's associated bitmap into an LBuffer object. The size of the LBuffer object's buffer must be specified by the user. The output can be in any of the supported, compressed or uncompressed file formats.

Returns

Comments

LMemoryFile::SaveFileBuffer saves the class object's associated bitmap to an LBuffer object. The output can be in any of the supported, compressed or uncompressed file formats. The user is responsible for allocating/reallocating buffers. If the buffer of the LBuffer object is not large enough, the LMemoryFile::SaveFileBufferCallBack is called so the user can re-allocate the buffer.

If the user wants to allocate a buffer that is large enough to hold the file in memory, an upper bound on the file size can be estimated by the following formula:

RequiredBytes = (Image Width) * (Image Height) * (BitsPerPixel) / 8

Note that this is an estimatethis does not include the size of the file header, and it does not take into account any compression. It is best to use a LMemoryFile::SaveFileBufferCallBack so that the user can be notified if the buffer is not large enough.

Support for 12 and 16-bit grayscale images is only available in the Document/Medical toolkits.

This function cannot be used in combination with the redirecting I/O functions.

This function does not support signed data images, unless they are DICOM images. It returns the error code ERROR_SIGNED_DATA_NOT_SUPPORTED if a signed data image that is not a DICOM image is passed to this function.

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

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.

In LEADTOOLS version 17 and up, when saving a colored image (such as a 24-bits per pixel image) to bitonal (1-bit per pixel), the toolkit will not use any dithering when converting the image data. This is done because dithering is not the recommended when converting colored images containing text for document processing such as OCR and Barcode. The result text will be fuzzy and hard for a recognition engine to process. To save a colored image as bitonal with Floyd-Stein dithering (the behavior of LEADTOOLS 16.5 and earlier) use the ESO_USEDITHERINGMETHOD along with LBitmapBase::SetDitheringMethod as illustrated below:

// 'leadBitmap' is a colored LBitmapBase
// 'leadFile' is LFile object

// Setup FloydStein dithering:
leadBitmap.SetDitheringMethod(FLOYD_STEIN_DITHERING);
SAVEFILEOPTION saveOptions = {0};
leadFile.GetDefaultSaveFileOption(&saveOptions, sizeof(SAVEFILEOPTION));
saveOptions.Flags |= ESO_USEDITHERINGMETHOD;
leadFile.Save(FILE_CCITT_GROUP4, 1, 0, 0, &saveOptions);
// or any other Save overloads or methods

Required DLLs and Libraries

Platforms

Win32, x64.

See Also

Example

L_INT LMemoryFile__SaveFileBufferExample(LBitmapBase & Bitmap)
{
   LMemoryFile MemoryFile;
   LBuffer Buffer(5000); // 5000 bytes; supposed to be enough
   L_SIZE_T dwFileSize;
   L_INT nRet;
   MemoryFile.SetBitmap(&Bitmap);
   nRet = MemoryFile.SaveFileBuffer(&Buffer,
                  &dwFileSize,
                  FILE_TIF,
                  0,
                  QS,
                  SAVEFILE_FIXEDPALETTE,
                  NULL);
   if (nRet == SUCCESS)
   {
      L_TCHAR szFileSize[100];
      wsprintf(szFileSize, TEXT("The file size in memory is: %d"), dwFileSize);
      MessageBox(NULL, szFileSize, TEXT("Testing"), MB_OK);
   }
   return nRet;
}