How to Transparent PNG file From Raster API

C++ Class Leadtools PRO V14

/* Image Got Alpha Channel */
{
HDC hMemDC;
HBITMAP hMemBitmap;
HBITMAP hOldBitmap;

double dResizeRatio = 1;

LBitmap MaskBitmap;
LBitmap ResizedBitmap;
LBitmap FeatherBitmap;

/* Create Background DDB to CPhotoBitmap */
hMemDC = CreateCompatibleDC(hDC);
hMemBitmap = CreateCompatibleBitmap(hDC,prcDest->right-prcDest->left,prcDest->bottom-prcDest->top);
hOldBitmap = (HBITMAP)SelectObject(hMemDC,hMemBitmap);

::SetStretchBltMode(hDC, COLORONCOLOR);

n_Ret = BitBlt(hMemDC,
0,
0,
prcDest->right-prcDest->left,
prcDest->bottom-prcDest->top,
hDC,
prcDest->left,
prcDest->top,
SRCCOPY);

if(n_Ret == 0)
{
#ifdef _DEBUG
DWORD dLastError = GetLastError();
TRACE("BitBlt FAIL (%u)",dLastError);
#endif
return FALSE;
}

n_Ret = FeatherBitmap.ConvertFromDDB(hMemDC,hMemBitmap,NULL);

if(n_Ret != SUCCESS)
{
#ifdef _DEBUG
LBase::DisplayErrorList(NULL,n_Ret);
#endif
return FALSE;
}

/* Resize For Feather AlphaBlend */
ResizedBitmap.Copy((LBitmapBase&)(m_Bitmap));

if(!(ResizedBitmap.GetWidth() == prcDest->right-prcDest->left &&
ResizedBitmap.GetHeight() == prcDest->bottom-prcDest->top))
{
ResizedBitmap.Trim(prcSrc);
ResizedBitmap.Size(prcDest->right-prcDest->left,prcDest->bottom-prcDest->top,SIZE_NORMAL);
}

/* Create Src's Mask Bitmap */
MaskBitmap.CreateAlphaBitmap((LBitmapBase&)ResizedBitmap);

/* Blend to FeatherBitmap(Background) */
n_Ret = FeatherBitmap.FeatherAlphaBlend(
0,
0,
prcDest->right-prcDest->left,
prcDest->bottom-prcDest->top,
&ResizedBitmap,
0,
0,
&MaskBitmap
);
if(n_Ret != SUCCESS)
{
#ifdef _DEBUG
LBase::DisplayErrorList(NULL,n_Ret);
#endif
return FALSE;
}

/* Set Old and Destroy */
SelectObject(hMemDC,hOldBitmap);
DeleteObject(hMemDC);
DeleteObject(hMemBitmap);

FeatherBitmap.SetDisplayMode(DISPLAYMODE_FASTPAINT|DISPLAYMODE_RESAMPLE|DISPLAYMODE_BICUBIC,uFlag);
FeatherBitmap.Paint()->SetDC(hDC);
FeatherBitmap.SetDstRect(prcDest);

n_Ret = FeatherBitmap.Paint()->PaintDC();

if(n_Ret != SUCCESS)
{
#ifdef _DEBUG
LBase::DisplayErrorList(NULL,n_Ret);
#endif
return FALSE;
}

n_Ret = TRUE;
}

return n_Ret;


how to convert Raster API Code...?

Are you trying to convert the above C++ code into DLL API
code? If yes, you can refer to our LEADTOOLS API Help file. Our LEADTOOLS Class
Library programming interface and our API mostly use similar functions names
and declarations. Actually our LEADTOOLS Class Library wraps around the API functions.

For example, the CreateAlphaBitmap function calls the L_GetBitmapAlpha internally, and so on.

If you search for the API equivalent for a C++ Class Library function and you can't find it, tell us which one it is and we will help you.