A few time ago, I begun writing a series of wrapper classes to make easier the using of Direct2D interfaces. Meanwhile, I discovered that MFC Library, beginning with Visual Studio 2010 SP1, offers an excelent built-in support. That’s pretty cool!
So, let’s use Direct2D (D2D) MFC classes for making a simple image viewer.

Image viewer using Direct2D MFC classes

1. In the view’s class definition, add data members for render target and Direct2D bitmap.
   

   #pragma once
   #include <memory>
   
   class CDemoView : public CScrollView
   {
       CHwndRenderTarget m_renderTarget;
       std::shared_ptr<CD2DBitmap> m_spBitmap;
       // ...
   };

2. Create the render target in the view’s WM_CREATE message handler.
   

   int CDemoView::OnCreate(LPCREATESTRUCT lpCreateStruct)
   {
       if (CScrollView::OnCreate(lpCreateStruct) == -1)
           return -1;
   
       HRESULT hr = m_renderTarget.Create(m_hWnd);
       return SUCCEEDED(hr) ? 0 : -1;    
   }

3. In the view’s WM_SIZE message handler resize the render target.
   

   void CDemoView::OnSize(UINT nType, int cx, int cy)
   {
       CScrollView::OnSize(nType, cx, cy);
   
       if(m_renderTarget.IsValid())
       {
           m_renderTarget.Resize(CD2DSizeU(cx, cy));
       }
   }

4. Override CView::OnUpdate and load the bitmap from the current document’s file.
   

   void CDemoView::OnUpdate(CView* pSender, LPARAM lHint, CObject* pHint)
   {
       CDemoDoc* pDoc = GetDocument();
       ASSERT_VALID(pDoc);
   
       if(nullptr != m_spBitmap)
       {
           m_spBitmap->Destroy();
       }
       CSize sizeImage(100, 100);
   
       const CString& strFile = pDoc->GetPathName();
       if(! strFile.IsEmpty())
       {
           m_spBitmap = std::make_shared<CD2DBitmap>(&m_renderTarget, strFile);
           HRESULT hr = m_spBitmap->Create(&m_renderTarget);
           if(m_spBitmap->IsValid())
           {
               CD2DSizeF size = m_spBitmap->GetSize();
               sizeImage.SetSize(static_cast<int>(size.width), static_cast<int>(size.height));
           }
       }
      SetScrollSizes(MM_TEXT, sizeImage);
      ScrollToPosition(CPoint(0, 0));
   }

5. Prevent painintg in WM_ERASEBKGND message handler.
   

   BOOL CDemoView::OnEraseBkgnd(CDC* pDC)
   {
       if(m_renderTarget.IsValid() && m_spBitmap->IsValid())
       {
           return TRUE; // all drawing is made in WM_PAINT handler
       }
       else
       {
           return CScrollView::OnEraseBkgnd(pDC);
       }
   }

6. Finally, override CView::OnDraw and draw the bitmap.
   

   void CDemoView::OnDraw(CDC* pDC)
   {
   	if(m_renderTarget.IsValid())
       {
           // initiate drawing on render target
           m_renderTarget.BeginDraw();
           // clear background using white color
           D2D1_COLOR_F color = {1.f, 1.f, 1.f, 1.f}; // r, g, b, a
           m_renderTarget.Clear(color);
           if((nullptr != m_spBitmap) && m_spBitmap->IsValid())
           {
               // apply translation transform according to view's scroll position
               CPoint point = GetScrollPosition();
               D2D1_MATRIX_3X2_F matrix = D2D1::Matrix3x2F::Translation((float)-point.x, (float)-point.y);
               m_renderTarget.SetTransform(matrix);
               // draw the bitmap
               CD2DSizeF size = m_spBitmap->GetSize();
               m_renderTarget.DrawBitmap(m_spBitmap.get(), CD2DRectF(0, 0, size.width, size.height));
           }
           // ends drawing operations 
           HRESULT hr = m_renderTarget.EndDraw();
           // if the render target has been lost, then recreate it
           if(D2DERR_RECREATE_TARGET == hr)
           {
               m_renderTarget.ReCreate(m_hWnd);
           }
       }
   }

Notes

• CD2DBitmap::Create uses WIC (Windows Imaging Component) interfaces, so beside common image formats like BMP, JPEG, GIF, PNG, and TIFF, can deal also with any other image format for which a WIC-compliant decoder is installed in system.
• Next article will show an even easier mode of using Direct2D MFC support.

Demo project

Download: Image Viewer - Using Direct2D MFC Classes.zip (246)

Using Direct2D MFC Classes – Demo Project

Resources and related articles

• MSDN: MFC Classes Added for Visual Studio 2010 SP1
• Codexpert blog: MFC Support for Direct2D – Part 2
• Codexpert blog: Using Direct2D for Rendering WIC Bitmap Sources