C / C++ / MFC

<br />
<br />
class CSomething<br />
{<br />
<br />
public:<br />
<br />
  struct MyInterface<br />
  {<br />
    public:<br />
    int Increment( void );<br />
  };<br />
<br />
  MyInterface* QueryInterface()<br />
  {<br />
    return dynamic_cast<myinterface*>(&aHiddenInstance);<br />
  }<br />
<br />
private:<br />
<br />
  struct stHidden : public CSomething::MyInterface<br />
  {<br />
    int Increment( void )<br />
    {<br />
      iHiddenStructMember++;<br />
    }<br />
<br />
    int iHiddenStructMember;<br />
  };<br />
<br />
  stHidden aHiddenInstance;<br />
};<br />
<br />

void CMyView::OnDraw(CDC* pDC)
{
    CTestDoc* pDoc = GetDocument();
    ASSERT_VALID(pDoc);
    if (!pDoc)
        return;

    CRect rcClient;

    if (pDC->IsPrinting()) 
    {
        rcClient = m_rcPrintRect;
    }
    else
    {
        GetClientRect(&rcClient);
    }    

    HBITMAP bmp;
    BYTE* drawingSurfaceBits;
    BITMAPINFOHEADER            BMIH;
    BMIH.biSize = sizeof(BITMAPINFOHEADER);
    BMIH.biBitCount = 24;
    BMIH.biPlanes = 1;
    BMIH.biCompression = BI_RGB;
    BMIH.biWidth = rcClient.Width();
    BMIH.biHeight = rcClient.Height();
    BMIH.biSizeImage = ((((BMIH.biWidth * BMIH.biBitCount) + 31) & ~31) >> 3) * BMIH.biHeight;
    bmp = CreateDIBSection(pDC->GetSafeHdc(), (CONST BITMAPINFO*)&BMIH, DIB_RGB_COLORS, (void**)&drawingSurfaceBits, NULL, 0);
    if((bmp == NULL) || (drawingSurfaceBits == NULL))
    {
        AfxMessageBox(L"Bitmap not created", MB_OK | MB_ICONSTOP);
        return;
    }

    memDC.CreateCompatibleDC(pDC);
    memDC.SelectObject(bmp);

     memDC.DrawText(L"Hello", &rcClient, DT_CENTER | DT_VCENTER);
     pDC->BitBlt(0,0,rcClient.Width(), rcClient.Height(), &memDC, 0, 0, SRCCOPY);

    return;
}

theCPkid wrote:

(CONST BITMAPINFO*)&BMIH

BITMAPINFO bmi;
memset(&bmi, 0, sizeof(BITMAPINFO));
bmi.bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
bmi.bmiHeader.biWidth = rcClient.Width();
bmi.bmiHeader.biHeight = rcClient.Height();
bmi.bmiHeader.biPlanes = 1;
bmi.bmiHeader.biBitCount = 24;
bmi.bmiHeader.biCompression = BI_RGB;
bmi.bmiHeader.biSizeImage = ((((bmi.bmiHeader.biWidth * bmi.bmiHeader.biBitCount) + 31) & ~31) >> 3) * bmi.bmiHeader.biHeight;
//bmi.bmiHeader.biXPelsPerMeter = 0;
//bmi.bmiHeader.biYPelsPerMeter = 0;
//bmi.bmiHeader.biClrUsed = 0;
//bmi.bmiHeader.biClrImportant = 0;

bmp = ::CreateDIBSection(NULL, &bmi, DIB_RGB_COLORS, (void**)&drawingSurfaceBits, NULL, 0);

Mark Salsbery
Microsoft MVP - Visual C++

Roger Allen wrote:

but you have it reversed which makes me intrigued (and I have even come out of CP semi-retirment to answer )

Roger Allen wrote:

The first thing I would say is drop BitBlt altogether. its not guaranteed to be compatible with both display DCs and printer DCs. Your best option would be to switch to StretchDIBits, from memory this is compatible with all DC types.

Roger Allen wrote:

Try creating your comapatible DC directtly from the screen by passing NULL instead of pDC. If that fixes the issues then I would say its down to the preview DC supporting all the world transforms and your in effect drawing of the edge of the comaptible bitmap.

SNArruda wrote:

Some one knows what i need read or learn to create this kind of program ?

simon alec smith wrote:

I can not seem to find a reason why this shouldn't work

class CMyView : public CView
{
    ...
    int m_nHorzOffset;
    ...
};

void CMyView::OnDraw(CDC* pDC)
{
   CRect rc;
   GetClientRect (&rc);
   // Make a point in the middle
   CPoint ptCentre = rc.CenterPoint ();

   ptCentre.x = rc.Width () / 4; // make it 1/4 the way across if we like...

   // draw a vertical centre line
   pDC->MoveTo (ptCentre.x, rc.top);
   pDC->LineTo (ptCentre.x, rc.bottom);

   // draw a triangle, offset by m_nHorzOffset
   pDC->MoveTo (ptCentre.x + m_nHorzOffset - 100, ptCentre.y + 50);
   pDC->LineTo (ptCentre.x + m_nHorzOffset + 100, ptCentre.y + 50);
   pDC->LineTo (ptCentre.x + m_nHorzOffset, ptCentre.y - 100);
   pDC->LineTo (ptCentre.x + m_nHorzOffset - 100, ptCentre.y + 50);
}
...

void CMyView::OnLeftABit ()
{
   m_nHorzOffset -= 10;
   Invalidate ();
}

simon alec smith wrote:

widthRatio = Rect.Width() / 756;
then * the x posistion by the widthRatio

Mark Salsbery
Microsoft MVP - Visual C++