C / C++ / MFC

WhiteSky wrote:

Can you be more specific

• CMyDialog *pMyDialog = (CMyDialog*) AfxGetMainWnd();
  This won't work because (I assume) your application's window is a mainframe window, not a dialog. Forcing the cast just tells the compiler to assume your main window is indeed a CMyDialog (which is why it compiles), but any attempt to treat the cast object as such will only cause you a lot of pain (because you've made an incorrect assumption about the structure of the dereferenced object).
  
  
• CDC *pDC = pMyDialog->m_StaticImage.GetDC();
pMyDialog is really a pointer to your application's mainframe window, so trying to reference its m_StaticImage member's DC is going to hurt. A lot.
  
  
• You're better off defining a method in your view class that exposes pertinent data required by any class who wishes to display the image. The displaying class (i.e. an instance of CMyDialog) can be passed a pointer to the view class - or can be so bold as to cast its GetParent() to your view class (assuming the dialog is and will always be only displayed by that view class) - in order to get at the image data, which it can then display in a suitable control.

CSize ts;<br />
	ts = pDC->GetTextExtent(pDoc->m_text);<br />
	pDoc->m_textRectangle.left = ts.cy;<br />
	pDoc->m_textRectangle.right = (pDoc->m_textRectangle.left + ts.cx);<br />
	pDoc->m_textRectangle.bottom = ts.cx;<br />
	pDoc->m_textRectangle.top = (pDoc->m_textRectangle.bottom - ts.cy);<br />
	pDoc->m_textRectangle.MoveToXY (pDoc->m_pos.x, pDoc->m_pos.y);

if((pDoc->m_mouse_captured))<br />
	{<br />
		pDoc->m_pos = point; // point contains the mouse coordinates<br />
		Invalidate();<br />
	}

Member variables:
   CPoint BasePoint;
   bool fInCapture;
   CRect TextRect;  // bounding rect of text (in client coordinates)
 
void CMyWnd::OnLButtonDown(UINT nFlags, CPoint point)
{
   if TextRect.PtInRect(point)
   {
      BasePoint = point;
      ::SetCapture(*this);
      fInCapture = true;
   }
}
 
void CMyWnd::OnMouseMove(UINT nFlags, CPoint point)
{
   if (fInCapture)
   {
      if (point != BasePoint)
      {
          TextRect.OffsetRect(point.x - BasePoint.x, point.y - BasePoint.y)
          Invalidate(TRUE);
          UpdateWindow();
          BasePoint = point;
      }
   }
}
 
void CMyWnd::OnLButtonUp(UINT nFlags, CPoint point)
{
   if (fInCapture)
   {
      fInCapture = false;
      ::ReleaseCapture();
   }
}