L_BorderRemoveBitmap

#include "l_bitmap.h"

L_INT EXT_FUNCTION L_BorderRemoveBitmap(pBitmap, pBorderRemove, pfnCallback, pUserData)

pBITMAPHANDLE pBitmap;	/* pointer to the bitmap */
LPBORDERREMOVE pBorderRemove;	/* pointer to a structure */
BORDERREMOVECALLBACK pfnCallback;	/* optional callback function */
L_VOID L_FAR * pUserData	/* pointer to more parameters for the callback */

Removes the black borders in a 1-bit black and white image.

This function is available in the Document/Medical Toolkits.

Parameter	Description
pBitmap	Pointer to the bitmap handle referencing the bitmap from which to remove borders.
pBorderRemove	Pointer to the BORDERREMOVE structure that LEADTOOLS uses to remove borders.
pfnCallback	Optional callback function for additional processing.
	$image\sqrblit.gif$ If you do not provide a callback function, use NULL as the value of this parameter.
	$image\sqrblit.gif$ If you do provide a callback function, use the function pointer as the value of this parameter.
	The callback function must adhere to the function prototype described in BORDERREMOVECALLBACK Function.
pUserData	Void pointer that you can use to pass one or more additional parameters that the callback function needs.
	To use this feature, assign a value to a variable or create a structure that contains as many fields as you need. Then, in this parameter, pass the address of the variable or structure, casting it to L_VOID L_FAR *. The callback function, which receives the address in its own pUserData parameter, can cast it to a pointer of the appropriate data type to access your variable or structure.
	If the additional parameters are not needed, you can pass NULL in this parameter.

Returns

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

Comments

(Document) This function removes borders that commonly appear in scanned text documents. Any or all of the four borders can be detected and removed. The behavior of this function can be modified by using its callback.

This function works only on 1-bit black and white images.

If a region is selected, only the selected region will be changed by this function. If no region is selected, the whole image will be processed.

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.

Required DLLs and Libraries

LTIMG

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

Platforms

Windows 95 / 98 / Me, Windows 2000 / XP.

See Also

Functions:	BORDERREMOVECALLBACK, L_SmoothBitmap,
	L_LineRemoveBitmap, L_InvertedTextBitmap,
	L_DotRemoveBitmap, L_HolePunchRemoveBitmap, L_HolesRemovalBitmapRgn
Topics:	Cleaning Up 1-Bit Images

Example

//Border Remove
//This example returns a region corresponding to the borders of a bitmap
//For the example, windows regions are returned in the callback and combined.
//Inn practice it would easier and faster to just return a LEAD region representing the changes
//The border is removed from the image

L_INT L_EXPORT EXT_CALLBACK ExampleBorderRemoveCB(
    HRGN          hRgn,
    L_UINT32      uBorderToRemove,
    LPRECT        pBoundingRect,
    L_VOID L_FAR *pUserData
    )
{
   L_TCHAR  szMsg[200];
   L_TCHAR *pszBorder;
   HRGN   hRgnAll;

   hRgnAll = (HRGN)(pUserData);
   CombineRgn( hRgnAll, hRgnAll, hRgn,  RGN_OR);
   DeleteObject(hRgn);

   switch (uBorderToRemove)
   {
   case BORDER_TOP:
      pszBorder = TEXT("Top");
      break;

   case BORDER_LEFT:
      pszBorder = TEXT("Left");
      break;

   case BORDER_RIGHT:
      pszBorder = TEXT("Right");
      break;

   case BORDER_BOTTOM:
      pszBorder = TEXT("Bottom");
      break;
   }
   wsprintf(
      szMsg,
      TEXT("Border[%s]\tBounds[%d,%d][%d,%d]\n"),
      pszBorder,
      pBoundingRect->left,
      pBoundingRect->top,
      pBoundingRect->right,
      pBoundingRect->bottom
      );
   OutputDebugString(szMsg);

   return SUCCESS_REMOVE;
}

L_VOID ExampleBorderRemove(pBITMAPHANDLE pBitmap)
{
   L_INT32        nRet;
   BORDERREMOVE   br;
   HRGN           hRgnAll;

   //Create a NULL region
   hRgnAll = CreateRectRgn(0, 0, 0, 0);
   br.uStructSize = sizeof(BORDERREMOVE);
   br.iBorderPercent    = 20;
   br.iVariance         = 2;
   br.iWhiteNoiseLength = 5;
   br.uBorderToRemove   = BORDER_TOP | BORDER_BOTTOM | BORDER_LEFT | BORDER_RIGHT;
   br.uFlags            = BORDER_CALLBACK_REGION | BORDER_USE_VARIANCE;

   nRet = L_BorderRemoveBitmap(
      pBitmap,
      &br,
      (BORDERREMOVECALLBACK)(ExampleBorderRemoveCB),
      (L_VOID L_FAR *)hRgnAll
      );

   if (nRet == SUCCESS)
   {
      RECT rectRgn;

      GetRgnBox(hRgnAll, &rectRgn);
      if (!IsRectEmpty(&rectRgn))
      {
          L_SetBitmapRgnHandle(pBitmap, NULL, hRgnAll, L_RGN_SET);
          DeleteObject(hRgnAll);
      }
   }

}