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L_AverageFilterBitmap

Summary

Changes the color of each pixel in a bitmap to the average color of pixels in its neighborhood. This results in a blur effect.

Syntax

#include "l_bitmap.h"

L_LTIMGEFX_API L_INT L_AverageFilterBitmap(pBitmap, uDim, uFlags)

Parameters

pBITMAPHANDLE pBitmap

Pointer to the bitmap handle referencing the bitmap to average.

L_UINT uDim

Size of the averaging neighborhood. It is the length, in pixels, of one side of a square.

Returns

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

Comments

You control the amount of blur by specifying the size of the neighborhood that is used for averaging.

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

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 signed data images. It returns the error code ERROR_SIGNED_DATA_NOT_SUPPORTED if a signed data image is passed to this function.

Average Filter Function - Before

Average Filter Function - After

View additional platform support for this Average Filter function.

Required DLLs and Libraries

LTIMGEFX
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

Win32, x64, Linux.

Example

For complete sample code, refer to the CHILD.C module of the DEMO
This example loads a bitmap and applies an average filter.
example.

L_INT AverageFilterBitmapExample(L_VOID) 
{ 
   L_INT nRet; 
 
   BITMAPHANDLE LeadBitmap;   /* Bitmap handle to hold the loaded image. */ 
 
   /* Load the bitmap, keeping the bits per pixel of the file */ 
   nRet = L_LoadBitmap(MAKE_IMAGE_PATH(TEXT("sample2.cmp")), &LeadBitmap, sizeof(BITMAPHANDLE), 0, ORDER_BGR, NULL, NULL); 
   if (nRet != SUCCESS) 
      return nRet; 
 
   /* Average with a neighborhood of 3x3 pixels */ 
   nRet = L_AverageFilterBitmap(&LeadBitmap, 3, 0); 
   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 
   if (LeadBitmap.Flags.Allocated) 
      L_FreeBitmap(&LeadBitmap); 
 
   return SUCCESS; 
}