How to draw an OCX to a CBitmap (MFC, c++)

Question

How can I draw an OCX (I do have the sources) to an CBitmap-Object or something alike?

Background: My client creates PDF-Documents and part of these documents is an Output from an OCX. The PDF-lib-Interface has a Method to put an Image from an CBitmap-Object to the PDF-Page. So what i want to do ist let the Program create an CBitmap-Object, pass that to the OCX to let it draw its content onto it and then pass the he CBitmap to the PDF-library to get it into the document. So the main question is: how to draw my ocx into a CBitmap-Object?

I'm using Visual C++, Windows, MFC/ATL. Thanks a lot

This essentially done just like rendering to a printer. Except, this time you will have to create the device context yourself, and select an appropriately sized CBitmap into it, prior to passing the device context on to the rendering code. Once rendering is done, the bitmap contains the visual representation. Make sure to select it out of the DC before moving on. — IInspectable

suriel suriel · Accepted Answer · 2019-06-03T07:35:02

actually I didn't manage to render the OXC to a CBitmap (just got a black box drawn) but rendering into an ATL::CImage and making a CBitmap out of it worked:

    ATL::CImage* CPrnBasePrinter::DrawBeamerToImage(CSPCListView* pListViewWithBeamer, const CRect& rect4Beamer)
    {
        ASSERT(pListViewWithBeamer != nullptr);

        auto* pRetVal = new CImage();

        pRetVal->Create(rect4Beamer.Width(), rect4Beamer.Height(), 24);
        HDC hdcImage = pRetVal->GetDC();

        //Draw Control to CImage
        pListViewWithBeamer->DrawBeamerToDC(HandleToLong(hdcImage),
            rect4Beamer.left, rect4Beamer.top, rect4Beamer.right, rect4Beamer.bottom);

        pRetVal->ReleaseDC();
        return pRetVal;
    }

    void CPrnBasePrinter::DrawImageFromCImage(
        const ATL::CImage* pImage, const CRect& rect) const
    {
        CBitmap* pbmp2Print = CBitmap::FromHandle(*pImage);

        // Get the size of the bitmap
        BITMAP bmpInfo;
        pbmp2Print->GetBitmap(&bmpInfo);


        //virtual - Draws the CBitmap to an Printer-DC or a PDF-Document
        DrawImageFromLoadedBitmap(pbmp2Print, &bmpInfo, rect);
    }

    void CPrnBasePrinter::Draw()
    {
        //m_pListviewDataSource is an OCX capable of drawing itself into a given DC
        ATL::CImage* pBeamerImage = DrawBeamerToImage(m_pListviewDataSource, CRect(0, 0, 100, 50));

        if (pBeamerImage != nullptr){
            DrawImageFromCImage(pBeamerImage, CRect(0, 0, 100, 50));
            delete pBeamerImage;
        }
    }

How to draw an OCX to a CBitmap (MFC, c++)

1 Answers