LBitmapBase::CreateAlphaBitmap

#include "ltwrappr.h"

virtual L_INT LBitmapBase::CreateAlphaBitmap(LBitmapSrc)

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

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

Platforms

Win32, x64.

See Also

Functions

Topics

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; 
} 

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