#include "l_bitmap.h"

L_LTIMGEFX_API L_INT L_EdgeDetectEffectBitmap(pBitmap, uLevel, nThreshold, uFlags)

Performs edge detection on the image.



Pointer to the bitmap handle that references the bitmap on which to apply the effect.

L_UINT uLevel

Level value used to determine the brightness of the edges. Standard value is 50. Range between 1 and 100. Big values will produce bright edges.

L_INT nThreshold

Threshold value used to determine which pixels are going to be filtered. If the difference determined for a pixel is less than this value, the pixel is set to 0. If the difference is greater, the filter will be applied to the pixel. The valid range is from 0 - 65535 for 64-bit, 48-bit and 16-bit grayscale images and from 0 - 4095 for 12-bit grayscale images. Otherwise, it is from 0 to 255.

L_UINT uFlags

Flag that indicates the type of edge to generate. Possible values are:

Value Meaning
EDGE_SOFT [0] Generate softer (smoother) edges.
EDGE_SOLID [1] Generate rougher edges.


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.

This function detects the edges in a bitmap and then replaces the values of edges by new values calculated according to the uFlags.

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.

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

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 EdgeDetectEffectBitmapExample(L_VOID) 
   L_INT nRet; 
   BITMAPHANDLE LeadBitmap;   /* Bitmap handle for the image */ 
   /* Load a bitmap at its own bits per pixel  */ 
   nRet = L_LoadBitmap (MAKE_IMAGE_PATH(TEXT("sample5.cmp")), &LeadBitmap, sizeof(BITMAPHANDLE), 0, ORDER_BGR, NULL, NULL);  
   if(nRet !=SUCCESS) 
      return nRet; 
   /* Apply find edges effect on the image*/ 
   nRet = L_EdgeDetectEffectBitmap(&LeadBitmap, 50, 0, EDGE_SOFT); 
   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; 
Help Version 21.0.2021.3.5
Products | Support | Contact Us | Intellectual Property Notices
© 1991-2021 LEAD Technologies, Inc. All Rights Reserved.

LEADTOOLS Raster Imaging C API Help