Saving view

I have an application that compound more CBitmaps into single one, and all of them I spread it into CScrollView. How can I save entire view (helped by CImage), but not just visible part in window client ? I saw on internet a lot of examples of how to save CDC, but just visible part ... in my case this is not suitable ... could you help me ?

You save that absolutely same way: create memory dc, create compatible bitmap, draw there as you wish, detach bitmap from dc, save bitmap to file.

Once you have the (composed) bitmap, there's no sweat to attach it to a CImage object, then save it in a file.

Example

Code:

---

HRESULT CFoo::SaveCBitmapToFile(CBitmap* pBitmap, LPCTSTR szFilePath)
{
    ASSERT_VALID(pBitmap);

    CImage image;
    image.Attach((HBITMAP)pBitmap->GetSafeHandle());
    HRESULT hr = image.Save(szFilePath);
    image.Detach(); // Do not forget this!
   
    return hr;
}

---

// like a walk in the park. :)

See

• MSDN: CImage::Attach
• MSDN: CImage::Save
• MSDN: CImage:: Detach

[ additional note ]

CImage is a wonderful ATL/MFC class which can help you to save lines, time and improve the code readability and maintainability, by making not obviously necessary to write yourself code for creating memory DCs, compatible bitmaps, bit-blitting, and so on, and so on.

Example

Code:

---

    // ...
    CImage imageToSave;
    imageToSave.Create(nDestWidth, nDestHeight, nBPP);
    HDC hDestDC = imageToSave.GetDC();

    // fill the destination background
    CDC::FromHandle(hDestDC)->FillSolidRect(0, 0, nDestWidth, nDestHeight, crBack);

    // draw a bitmap into the destination at coordinates x, y
    CImage image1;
    image1.Attach((HBITMAP)pBitmap1->GetSafeHandle());
    image1.Draw(hDestDC, x, y);

    // draw anything else your muscles want
    // ...

    // save the destination image to a file
    HRESULT hr = imageToSave.Save(pszFilePath);


    image1.Detach();        // Do not forget Detach if a bitmap was previously attached!
    imageToSave.ReleaseDC(); // Do not forget ReleaseDC if GetDC was previously called!
    // ...

---

See also

• CImage::Create
• CImage:: Draw
• CImage::GetDC
• CImage::ReleaseDC
• and why not... the whole CImage Class in MSDN documentation.

Sorry for later response ... I have wrote the same code, except one line:

Code:

---

Image.Attach((HBITMAP)pBitmap->m_hObject);

---

instead of

Code:

---

image.Attach((HBITMAP)pBitmap->GetSafeHandle());

---

I noticed that with my code, I couldn't save extra large images, with yours, I do. Thank you.

Quote:

---

Originally Posted by mesajflaviu

Sorry for later response ... I have wrote the same code, except one line:

Code:

---

Image.Attach((HBITMAP)pBitmap->m_hObject);

---

instead of

Code:

---

image.Attach((HBITMAP)pBitmap->GetSafeHandle());

---

---

Generally, if using pointers, calling CGdiObject::GetSafeHandle is safer than directly accessing the m_hObject member.
In our case, if pBitmap is NULL, pBitmap->GetSafeHandle() will return NULL while pBitmap->m_hObject will lead in an access violation and the application will crash.