LBitmapBase::CreateAlphaBitmap

#include "ltwrappr.h"

virtual L_INT LBitmapBase::CreateAlphaBitmap(LBitmapSrc)

/* the source class object */

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

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

Returns

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.

See Also

Elements:	LFile::LoadCMYKArray, LFile::SaveCMYKArray, LPaint::PaintDCCMYKArray, LBitmapBase::Free, LBitmapBase::Create, Class Members
Topics:	Defining and Using a Bitmap Region
	Saving a Region

Example

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

void CheckAlphaBitmap(L_TCHAR* pszImageFile)
{
   LBitmapBase Bitmap, AlphaBitmap;
   LBitmapRgn Region;
   L_UINT32 uArea;

   Bitmap.Load(pszImageFile, 0, ORDER_BGR);

   AlphaBitmap.CreateAlphaBitmap(Bitmap);

   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);
}