Advanced MFC Programming

Chapter 8. DC, Pen, Brush and Palette
……
……
protected:
};
BOOL m_bFloodFill;
Function CGDIDoc::GetFloodFill() allows m_bFloodFill to be accessed outside class CGDIDoc.
Variable m_bFloodFill is initialized in the constructor of class CGDIDoc as follows:
CGDIDoc::CGDIDoc()
{
m_bFloodFill=FALSE;
}
Functions CGDIDoc::OnFloodfill() and CGDIDoc::OnUpdateFloodfill(…) are implemented as
follows:
void CGDIDoc::OnFloodfill()
{
m_bFloodFill=m_bFloodFill ? FALSE:TRUE;
}
void CGDIDoc::OnUpdateFloodfill(CCmdUI* pCmdUI)
{
pCmdUI->SetCheck(m_bFloodFill);
}
We need to implement flood filling in response to left button up events when CGDIDoc::m_bFloodFill
is TRUE. So we need to modify function CGDIView::OnLButtonDown(…). In the sample, we first check flag
CGDIDoc::m_bFloodFill. If it is set, we create a gray brush, select it into the DC and implement the flood
filling. Otherwise we prepare for line drawing as we did before:
void CGDIView::OnLButtonDown(UINT nFlags, CPoint point)
{
CGDIDoc *ptrDoc;
CClientDC dc(this);
CBrush brush;
CBrush *ptrBrushOld;
}
ptrDoc=GetDocument();
if(ptrDoc->GetFloodFill() == TRUE)
{
brush.CreateSolidBrush(RGB(127, 127, 127));
ptrBrushOld=dc.SelectObject(&brush);
dc.FloodFill(point.x, point.y, RGB(255, 0, 0));
dc.SelectObject(ptrBrushOld);
}
else
{
m_ptStart=point;
SetCapture();
m_bCapture=TRUE;
}
CView::OnLButtonDown(nFlags, point);
In the other two mouse message handlers CGDIView::OnMouseMove(…) and CGDIView::
OnLButtonUp(…), we also need to check flag CGDIDoc::m_bFloodFill. If it is not set, we can proceed to
implement line drawing:
void CGDIView::OnMouseMove(UINT nFlags, CPoint point)
{
CClientDC dc(this);
CPen pen;
CPen *ptrPenOld;
int nMode;
218