LBitmapBase::CreateAlphaBitmap

Summary

Creates an alpha bitmap from the alpha channel of another class object's bitmap.

Syntax

#include "ltwrappr.h"

virtual L_INT LBitmapBase::CreateAlphaBitmap(LBitmapSrc)

Parameters

LBitmapBase& LBitmapSrc

The source class object from which to create the alpha bitmap.

Returns

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

Comments

Call this function to create an alpha bitmap from the alpha channel of another class object's bitmap.

Note: The LBitmapSrc parameter is passed by reference, and is a required parameter.

Required DLLs and Libraries

LTDIS
LTFIL
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.

Example

The following function checks if an image has a useful alpha channel bitmap.

L_INT LBitmapBase__CreateAlphaBitmapExample(L_TCHAR* pszImageFile) 
{ 
   L_INT nRet; 
   LBitmapBase Bitmap, AlphaBitmap; 
   LBitmapRgn Region; 
   L_SIZE_T  uArea; 
 
   nRet =Bitmap.Load(pszImageFile, 0, ORDER_BGR); 
   if(nRet !=SUCCESS) 
      return nRet; 
   nRet =AlphaBitmap.CreateAlphaBitmap(Bitmap); 
   if(nRet !=SUCCESS) 
      return nRet; 
 
   Region.SetBitmap(&AlphaBitmap); 
   Region.SetRgnCombineMode(L_RGN_SETNOT); 
   Region.SetRgnColor(RGB(0, 0, 0) /* Black */); 
 
   Region.GetRgnArea(&uArea); 
 
   if (uArea != 0) 
      MessageBox(NULL, TEXT("The image has a useful alpha bitmap."), TEXT("Test"), MB_OK); 
 
   return SUCCESS; 
}