How to get a bitmap from a hdc?-CodePudding

I can load a hbitmap into a hdc like this:

        Gdiplus::Color Color{ 255, 255, 255 };
        hBitmap = NULL;
        Gdiplus::Bitmap* bitmap = Gdiplus::Bitmap::FromFile(L"home.png", false);
        if (bitmap)
        {
            bitmap->GetHBITMAP(Color, &hBitmap);
            delete bitmap;
        }

        BITMAP bm;
        GetObject(hBitmap, sizeof(bm), &bm);
        HDC hDCMem = CreateCompatibleDC(NULL);
        HBITMAP hBitmapOld = (HBITMAP)SelectObject(hDCMem, hBitmap);

How could I do the reverse, getting back a bitmap loaded into a specific hdc?

I would need first, retrieve the hbitmap and then the bitmap from it? How?

CodePudding user response：

You can use GetCurrentObject() to access the HBITMAP (and HPALETTE) currently selected into an HDC.

Alternatively, you can create a new HBITMAP of desired dimension and color depth, SelectObject() it into a new memory HDC, and then BitBlt()/StretchBlt() the source HDC into it.

Either way, once you have an HBITMAP, you can create a new GDI Bitmap from it using the Bitmap(HBITMAP, HPALETTE) constructor or Bitmap::FromHBITMAP() method.