#include "l_bitmap.h"

L_LTIMGCOR_API L_INT EXT_FUNCTION L_InvertedPageBitmap(pBitmap, bIsInverted, uFlags)

Detects whether the specified image (page) is inverted (white text and black background). Can invert it if it is not.



Pointer to the bitmap handle that references the bitmap.

L_BOOL * bIsInverted

Address of a variable to be updated with the detection result. Possible values are:

Value Meaning
TRUE The image is inverted.
FALSE The image is not inverted.

L_UINT uFlags

Flags that indicate whether to invert the image and how to do it. Possible values are:

Value Meaning
INVERTEDPAGE_PROCESS [0x00000000] Invert the image.
INVERTEDPAGE_NOPROCESS [0x00000001] Do not invert the image. Generally this flag is used to find whether the image is inverted.
INVERTEDPAGE_EXCLUDE_BORDER [0x00000002] Excludes White or Black borders from the calculations.
INVERTEDPAGE_USE_ZONES [0x00000004] An advanced version that is able to detect figure images before inverting them. This option is slower than the other options. This flag cannot be used with INVERTEDPAGE_EXCLUDE_BORDER.


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


This function does not support signed data images. It returns the error code ERROR_SIGNED_DATA_NOT_SUPPORTED if a signed data image is passed to this function.

If uFlags contains INVERTEDPAGE_NOPROCESS, the function will update bIsInverted with the result, without inverting the image.

To update a status bar or detect a user interrupt during execution of this function, refer to L_SetStatusCallback.

This function does not support 12 and 16-bit grayscale and 48 and 64-bit color images. If the image is 12 and 16-bit grayscale and 48 and 64-bit color, the function will not return an error.

This function does not support 32-bit grayscale images. It returns the error code ERROR_GRAY32_UNSUPPORTED if a 32-bit grayscale image is passed to this function.

Required DLLs and Libraries


Win32, x64, Linux.

See Also




L_INT InvertedPageBitmapExample(L_VOID) 
   L_INT nRet; 
   BITMAPHANDLE LeadBitmap;   /* Bitmap handle to hold the loaded image. */ 
   L_BOOL IsInverted; /* the boolean  that will hold the value of (Is the page inverted or not) */ 
   /* Load the bitmap, keeping the bits per pixel of the file */ 
   nRet = L_LoadBitmap (MAKE_IMAGE_PATH(TEXT("OCR1.TIF")), &LeadBitmap, sizeof(BITMAPHANDLE), 0, ORDER_BGR, NULL, NULL); 
   if(nRet !=SUCCESS) 
      return nRet; 
   nRet = L_InvertedPageBitmap(&LeadBitmap, &IsInverted, INVERTEDPAGE_PROCESS); 
   if(nRet !=SUCCESS) 
      return nRet; 
   nRet = L_SaveBitmap(MAKE_IMAGE_PATH(TEXT("Result.BMP")), &LeadBitmap, FILE_BMP, 24, 0, NULL); 
   if(nRet !=SUCCESS) 
      return nRet; 
   //free bitmap  
   return SUCCESS; 
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