#include "l_bitmap.h"

L_LTIMGCOR_API L_INT L_GetAutoTrimRect(pBitmap, uThreshold, pRect, uFlags)

Gets the rectangle that would be used to trim the bitmap if L_AutoTrimBitmap were used.



Pointer to the bitmap handle that references the bitmap to be trimmed.

L_UINT uThreshold

Delta value for detecting blank space. Starting at each edge of the bitmap and evaluating toward the center, any change in intensity that is less than or equal to uThreshold is considered blank space. Valid values are 0 to 255.

RECT *pRect

Address of the RECT variable to be updated.

L_UINT32 uFlags

Reserved for future use. Must be 0.


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.

Use this function in conjunction with L_TrimBitmap instead of L_AutoTrimBitmap when you want to modify the trim rectangle. For example, you could let the user preview the rectangle, or you could add a margin.

This function uses bitmap coordinates to specify the area to be trimmed. Therefore, you must account for the view perspective of the bitmap. For information about bitmap coordinates, refer to Accounting for View Perspective.

This function supports 12 and 16-bit grayscale and 48 and 64-bit color images. Support for 12 and 16-bit grayscale and 48 and 64-bit color images is available in the Document and Medical Imaging toolkits.

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




This example loads an image, gets the AutoTrim RECT, modifies it,
and then trims the bitmap

L_INT GetAutoTrimRectExample(L_VOID) 
   L_INT nRet; 
   BITMAPHANDLE LeadBitmap;   /* Bitmap handle to hold the loaded image. */ 
   RECT rc; 
   /* Load the bitmap, keeping the bits per pixel of the file */ 
   nRet = L_LoadBitmap (MAKE_IMAGE_PATH(TEXT("IMAGE1.CMP")), &LeadBitmap, sizeof(BITMAPHANDLE), 0, ORDER_BGR, NULL, NULL); 
   if(nRet !=SUCCESS) 
      return nRet; 
   /* Get the RECT for AutoTrim with 0 tolerance */ 
   nRet = L_GetAutoTrimRect ( &LeadBitmap, 0, &rc , 0); 
   if(nRet !=SUCCESS) 
      return nRet; 
   /* Trim the bitmap with modified RECT */ 
   nRet = L_TrimBitmap ( &LeadBitmap, rc.left - 10, rc.top - 10, rc.right - rc.left + 20, rc.bottom - rc.top + 20 ); 
   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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