Visual C++ and MFC Programming 2nd Edition

Chapter 9 Strings Visual C++ and MFC Fundamentals

By the way, as you probably know already, you can change the dimensions of the

window with a code similar to the following:

BOOL CMainFrame::PreCreateWindow(CREATESTRUCT& cs)

{

if( !CFrameWnd::PreCreateWindow(cs) )

return FALSE;

// The new width of the window's frame

cs.cx = 450;

// The new height of the window's frame

cs.cy = 370;

// Remove the Untitled thing

cs.style &= ~FWS_ADDTOTITLE;

return TRUE;

}

Now that we know how to control the origin, we will position it at a fixed point, 320 units

to the right and 220 units down. We can also easily draw the (Cartesian) axes now:

void CExoView::OnDraw(CDC* pDC)

{

CExoDoc* pDoc = GetDocument();

ASSERT_VALID(pDoc);

pDC->SetViewportOrg(220, 150);

// Use a red pen

CPen PenRed(PS_SOLID, 1, RGB(255, 0, 0));

CPen *pOld = pDC->SelectObject(&PenRed);

// A circle whose center is at the origin (0, 0)

pDC->Ellipse(-100, -100, 100, 100);

// Use a blue pen

CPen PenBlue(PS_SOLID, 1, RGB(0, 0, 255));

pOld = pDC->SelectObject(&PenBlue);

// Horizontal axis

pDC->MoveTo(-320, 0);

pDC->LineTo( 320, 0);

// Vertical axis

pDC->MoveTo( 0, -220);

pDC->LineTo( 0, 220);

pDC->SelectObject(pOld);

}