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L_OcrPage_GetBitmap

Summary

Gets the original or processing bitmap data of this page as a bitmap handle.

Syntax

#include "ltocr.h"

L_LTOCR_API L_INT EXT_FUNCTION L_OcrPage_GetBitmap(page, bitmapType, bitmapHandle, bitmapHandleSize)

Parameters

L_OcrPage page

Handle to the OCR page.

L_OcrPageBitmapType bitmapType

The page type to get.

BITMAPHANDLE* bitmapHandle

Address to BITMAPHANDLE variable to be updated with the page bitmap.

L_UINT bitmapHandleSize

Size of the BITMAPHANDLE structure, use sizeof(BITMAPHANDLE).

Returns

Value	Meaning
SUCCESS	The function was successful.
< 1	An error occurred. Refer to Return Codes.

Comments

Each L_OcrPage contains two versions of the image used to create it: an original and an optional processing version. The processing version usually black/white and has uniform resolution (if the original image is FAX for example) and it gets passed to the internal OCR engine during the zoning and recognition process. The L_OcrPage_AutoPreprocess method also uses the B/W image to determine if the page is inverted, skewed, or has an orientation. However, it applies the correction to both the current and processing images.

You can use L_OcrPage_GetBitmap to get a copy of the processing image, but as for the original image this function returns a reference to the original bitmap handle (not a copy) so you should not call L_FreeBitmap on this bitmap type.

You cannot set the processing image of a page; it is created automatically by the engine.

If the original image is black and white and has uniform vertical and horizontal resolution, then the engine will not create a processing image, in other words, L_OcrPage_GetBitmap will return identical BITMAPHANDLE for both original and processing bitmap types.

If the original image has different horizontal and vertical resolution, such as a FAX image, the processing page will be have be resized to have uniform resolution.

Required DLLs and Libraries

LTOCR
For a listing of the exact DLLs and Libraries needed, based on the toolkit version, refer to Files To Be Included With Your Application.

Example

L_INT L_OcrPage_GetBitmapExample() 
{ 
   int bitsPerPixel = 0; 
   int qualityFactor = 2; 
   L_OcrEngine ocrEngine = NULL; 
   L_OcrPage ocrPage = NULL; 
   BITMAPHANDLE bitmap = {0}, exportPage = {0}; 
   pLOADFILEOPTION loadOpts = NULL; 
   pSAVEFILEOPTION saveOpts = NULL; 
   pFILEINFO fileInfo = NULL; 
   L_OcrProgressCallback callback = NULL; 
   L_VOID* userData = NULL; 
 
   // Create an instance of the engine 
   L_INT retCode = L_OcrEngineManager_CreateEngine(L_OcrEngineType_LEAD, &ocrEngine); 
   if(retCode != SUCCESS) 
      return retCode; 
 
   // Start the engine using default parameters 
   retCode = L_OcrEngine_Startup(ocrEngine, NULL, OCR_LEAD_RUNTIME_DIR); 
   if(retCode != SUCCESS) 
      goto CLEANUP; 
 
   // Load an image file 
   retCode = L_LoadBitmap(MAKE_IMAGE_PATH(L_TEXT("Ocr1.tif")), &bitmap, sizeof(BITMAPHANDLE), bitsPerPixel, ORDER_RGB, loadOpts, fileInfo); 
   if(retCode != SUCCESS) 
      goto CLEANUP; 
 
   // Add the raster image into the OCR page 
   retCode = L_OcrPage_FromBitmap(ocrEngine, &ocrPage, &bitmap, L_OcrBitmapSharingMode_AutoFree, callback, userData); 
   if(retCode != SUCCESS) 
   { 
      L_FreeBitmap(&bitmap); 
      goto CLEANUP; 
   } 
 
   // At this point, we have a valid page and bitmap ownership has transfered, so, we do not need to free the bitmap anymore 
   bitmap.Flags.Allocated = 0; 
 
   retCode = L_OcrPage_GetBitmap(ocrPage, L_OcrPageBitmapType_Original, &exportPage, sizeof(BITMAPHANDLE)); 
   if(retCode != SUCCESS) 
      goto CLEANUP; 
 
   // Save this image to disk 
   bitsPerPixel = 24; 
   L_SaveBitmap(MAKE_IMAGE_PATH(L_TEXT("OcrExported.jpg")), &exportPage, FILE_JPEG, bitsPerPixel, qualityFactor, saveOpts); 
 
CLEANUP: 
   if(ocrPage != NULL) 
      L_OcrPage_Destroy(ocrPage); 
 
   if(L_OcrEngine_IsStarted(ocrEngine)) 
      L_OcrEngine_Shutdown(ocrEngine); 
 
   L_OcrEngine_Destroy(ocrEngine); 
 
   return retCode; 
}