Advanced MFC Programming

Chapter 8. DC, Pen, Brush and Palette
CGDIView::CGDIView()
{
m_bNeedErase=FALSE;
m_bCapture=FALSE;
}
Message handlers for WM_LBUTTONDOWN, WM_MOUSEMOVE and WM_LBUTTONUP are added to class CGDIView
through using Class Wizard. They are implemented as follows:
void CGDIView::OnLButtonDown(UINT nFlags, CPoint point)
{
m_rectDraw.left=point.x;
m_rectDraw.top=point.y;
SetCapture();
m_bCapture=TRUE;
CView::OnLButtonDown(nFlags, point);
}
void CGDIView::OnLButtonUp(UINT nFlags, CPoint point)
{
CClientDC dc(this);
CPen pen;
CPen *ptrPenOld;
CBrush brush;
CBrush *ptrBrushOld;
int nMode;
CGDIDoc *ptrDoc;
ptrDoc=(CGDIDoc *)GetDocument();
pen.CreatePen(PS_DASH, 1, RGB(0, 0, 0));
ptrPenOld=dc.SelectObject(&pen);
brush.Attach(::GetStockObject(HOLLOW_BRUSH));
ptrBrushOld=dc.SelectObject(&brush);
nMode=dc.SetROP2(R2_XORPEN);
dc.Rectangle(m_rectDraw);
dc.SetROP2(nMode);
dc.SelectObject(ptrBrushOld);
dc.SelectObject(ptrPenOld);
pen.DeleteObject();
brush.Detach();
}
m_bNeedErase=FALSE;
m_rectDraw.right=point.x;
m_rectDraw.bottom=point.y;
ptrDoc->AddRect(m_rectDraw);
if(m_bCapture == TRUE)
{
::ReleaseCapture();
m_bCapture=FALSE;
}
Invalidate();
CView::OnLButtonUp(nFlags, point);
void CGDIView::OnMouseMove(UINT nFlags, CPoint point)
{
CClientDC dc(this);
CPen pen;
CPen *ptrPenOld;
CBrush brush;
CBrush *ptrBrushOld;
int nMode;
if(nFlags & MK_LBUTTON)
{
pen.CreatePen(PS_DASH, 1, RGB(0, 0, 0));
ptrPenOld=dc.SelectObject(&pen);
brush.Attach(::GetStockObject(HOLLOW_BRUSH));
ptrBrushOld=dc.SelectObject(&brush);
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