[Bug 44409] New: png with indexed colors and alpha miss the alpha channel on loading

https://bugs.winehq.org/show_bug.cgi?id=44409

Bug ID: 44409
           Summary: png with indexed colors and alpha miss the alpha
                    channel on loading
           Product: Wine
           Version: 3.0
          Hardware: x86
                OS: Linux
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: gdiplus
          Assignee: [e-mail]
          Reporter: [e-mail]
      Distribution: ---

Created attachment 60332
  --> https://bugs.winehq.org/attachment.cgi?id=60332
1 bit png with alpha

The 1bit png with alpha is attached.
Wine loads it as PixelFormat1bppIndexed, which means no alpha preserved
Windows loads it as PixelFormat32bppARGB which means windows does conversion
because pixelformat is not match to PixelFormat1bppIndexed(because otherwise it
lost alpha).
The same happens for 8 bit png with alpha.
Could you please add supporting loading alpha channel for 1 and 8 bit pngs in
the same way as windows does, ie convert to PixelFormat32bppARGB.
Thanks.

The func to load png:

HBITMAP loadBitmap(const wchar_t* path)
{
   HBITMAP tBmp = NULL;
   ULONG_PTR token = 0;
   Gdiplus::GdiplusStartupInput input = NULL;
   Gdiplus::GdiplusStartup(&token, &input, NULL);
   if (token != 0)
   {
      Gdiplus::Bitmap* bmp = new Gdiplus::Bitmap(path);
      bmp->GetHBITMAP(Gdiplus::Color::Transparent, &tBmp);
      delete bmp;
      Gdiplus::GdiplusShutdown(token);
   }
   return tBmp;
}