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L_OcrPage_GetDeskewAngle

Summary

Gets the angle of the skew of this L_OcrPage in degrees.

Syntax

#include "ltocr.h"

L_LTOCR_API L_INT EXT_FUNCTION L_OcrPage_GetDeskewAngle(page, value)

Parameters

L_OcrPage page

Handle to the OCR page.

L_INT* value

Address to L_INT variable to be updated with the page deskew angle.

Returns

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

Comments

Gets the angle of the skew of this page expressed in tenth of degrees.

Use L_OcrPage_AutoPreprocess with L_OcrAutoPreprocessPageCommands_Deskew to automatically deskew the page bitmap prior to calling L_OcrPage_Recognize. This could enhance the quality of the image before starting its recognition.

If the bitmap is skewed, L_OcrPage_GetDeskewAngle will return the angle needed to deskew the page bitmap, if you call L_OcrPage_AutoPreprocess on the page, all subsequent calls to L_OcrPage_GetDeskewAngle will return 0 since the bitmap is not skewed. Hence, you must use L_OcrPage_GetDeskewAngle before calling L_OcrPage_AutoPreprocess.

Use L_OcrPage_GetAutoPreprocessValues to obtain the accumulative pre-processing values applied to this L_OcrPage.

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_GetDeskewAngleExample() 
{ 
   BITMAPHANDLE bitmap = { 0 }; 
   L_OcrEngine ocrEngine = NULL; 
   L_OcrPage ocrPage = NULL; 
   L_OcrDocumentManager ocrDocumentManager = NULL; 
   L_OcrDocument ocrDocument = NULL; 
 
   // Create an instance of the engine 
   L_INT retCode = L_OcrEngineManager_CreateEngine(L_OcrEngineType_LEAD, &ocrEngine); 
   if(retCode == SUCCESS) 
   { 
      // Start the engine using default parameters 
      retCode = L_OcrEngine_Startup(ocrEngine, NULL, OCR_LEAD_RUNTIME_DIR); 
      if(retCode != SUCCESS) 
         return retCode; 
 
      // Load a page to be recognized 
      retCode = L_LoadBitmap(MAKE_IMAGE_PATH(L_TEXT("Clean.tif")), &bitmap, sizeof(BITMAPHANDLE), 0, ORDER_RGB, NULL, NULL); 
      if(retCode != SUCCESS) 
         goto CLEANUP; 
 
      // Add an image to OCR page. don't transfer ownership of the bitmap to the page 
      retCode = L_OcrPage_FromBitmap(ocrEngine, &ocrPage, &bitmap, L_OcrBitmapSharingMode_None, NULL, NULL); 
      if(retCode != SUCCESS) 
         goto CLEANUP; 
 
      L_INT deskewAngle = 0; 
      L_OcrPage_GetDeskewAngle(ocrPage, &deskewAngle); 
      if(deskewAngle > 0) 
         L_DeskewBitmap(&bitmap, NULL,RGB(0, 0, 0), DSKW_PROCESS | DSKW_RESAMPLE); 
 
      L_INT rotateAngle = 0; 
      L_OcrPage_GetRotateAngle(ocrPage, &rotateAngle, NULL); 
      if(rotateAngle > 0) 
         L_RotateBitmap(&bitmap, rotateAngle, ROTATE_RESAMPLE, RGB(0, 0, 0)); 
 
      // set the bitmap back to the page after we corrected its deskew and rotate angle 
      retCode = L_OcrPage_SetBitmap(ocrPage, &bitmap, L_TRUE); 
      if(retCode != SUCCESS) 
         goto CLEANUP; 
 
      // Automatically find areas/zones on the page where text is located 
      retCode = L_OcrPage_AutoZone(ocrPage, NULL, NULL); 
      if(retCode != SUCCESS) 
         goto CLEANUP; 
 
      // Recognize the page 
      // Note: Recognize can be called without calling AutoZone or manually adding zones. 
      // The engine will check and automatically auto-zones the page. 
      retCode = L_OcrPage_Recognize(ocrPage, NULL, NULL); 
      if(retCode != SUCCESS) 
         goto CLEANUP; 
 
      //Get the document manager 
      retCode = L_OcrEngine_GetDocumentManager(ocrEngine, &ocrDocumentManager); 
      if(retCode != SUCCESS) 
         goto CLEANUP; 
 
      // Create file-based OCR document 
      retCode = L_OcrDocumentManager_CreateDocument(ocrDocumentManager, &ocrDocument, L_OcrCreateDocumentOptions_AutoDeleteFile, NULL); 
      if(retCode != SUCCESS) 
         goto CLEANUP; 
 
      // Add page to the document. 
      retCode = L_OcrDocument_AddPage(ocrDocument, ocrPage); 
      if(retCode != SUCCESS) 
         goto CLEANUP; 
 
      // Adding the page to a file based document will take a snap shot of the recognition data and store it in the document. At this 
      // point, the page is no longer needed. So destroy it to free up memory not used anymore 
      L_OcrPage_Destroy(ocrPage); 
      // Set the handle to NULL so we do not free it in our clean-up code 
      ocrPage = NULL; 
 
      // Save the document we have as PDF 
      retCode = L_OcrDocument_Save(ocrDocument, MAKE_IMAGE_PATH(L_TEXT("Ocr1.pdf")), DOCUMENTFORMAT_PDF, NULL, NULL); 
   } 
 
CLEANUP: 
   if(bitmap.Flags.Allocated) 
      L_FreeBitmap(&bitmap); 
 
   if(ocrPage != NULL) 
      L_OcrPage_Destroy(ocrPage); 
 
   if(ocrDocument != NULL) 
      L_OcrDocument_Destroy(ocrDocument); 
 
   if(ocrEngine != NULL) 
      L_OcrEngine_Destroy(ocrEngine); 
 
   return retCode; 
}