sketchview.cpp

这是MFC Windows程序设计（第2版）书上的代码。第11章

// SketchView.cpp : implementation of the CSketchView class
//

#include "stdafx.h"
#include "Line.h"
#include "Sketch.h"
#include "SketchDoc.h"
#include "SketchView.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif

/////////////////////////////////////////////////////////////////////////////
// CSketchView

IMPLEMENT_DYNCREATE(CSketchView, CScrollView)

BEGIN_MESSAGE_MAP(CSketchView, CScrollView)
	//{{AFX_MSG_MAP(CSketchView)
	ON_WM_SETCURSOR()
	ON_WM_LBUTTONDOWN()
	ON_WM_MOUSEMOVE()
	ON_WM_LBUTTONUP()
	//}}AFX_MSG_MAP
END_MESSAGE_MAP()

/////////////////////////////////////////////////////////////////////////////
// CSketchView construction/destruction

CSketchView::CSketchView()
{
	m_hCursor = AfxGetApp ()->LoadStandardCursor (IDC_CROSS);
}

CSketchView::~CSketchView()
{
}

BOOL CSketchView::PreCreateWindow(CREATESTRUCT& cs)
{
	return CScrollView::PreCreateWindow(cs);
}

/////////////////////////////////////////////////////////////////////////////
// CSketchView drawing

void CSketchView::OnDraw(CDC* pDC)
{
	CSketchDoc* pDoc = GetDocument();
	ASSERT_VALID(pDoc);

    //
    // Draw the snap grid.
    //
    if (pDoc->IsGridVisible ()) {
        for (int x=25; x<1600; x+=25)
            for (int y=-25; y>-1200; y-=25)
                pDC->SetPixel (x, y, RGB (128, 128, 128));
    }

    //
    // Draw the lines.
    //
    int nCount = pDoc->GetLineCount ();
    if (nCount) {
        for (int i=0; i<nCount; i++)
            pDoc->GetLine (i)->Draw (pDC);
    }
}

void CSketchView::OnInitialUpdate()
{
	CScrollView::OnInitialUpdate();
	SetScrollSizes(MM_LOENGLISH, CSize (1600, 1200));
}

/////////////////////////////////////////////////////////////////////////////
// CSketchView diagnostics

#ifdef _DEBUG
void CSketchView::AssertValid() const
{
	CScrollView::AssertValid();
}

void CSketchView::Dump(CDumpContext& dc) const
{
	CScrollView::Dump(dc);
}

CSketchDoc* CSketchView::GetDocument() // non-debug version is inline
{
	ASSERT(m_pDocument->IsKindOf(RUNTIME_CLASS(CSketchDoc)));
	return (CSketchDoc*)m_pDocument;
}
#endif //_DEBUG

/////////////////////////////////////////////////////////////////////////////
// CSketchView message handlers

BOOL CSketchView::OnSetCursor(CWnd* pWnd, UINT nHitTest, UINT message) 
{
    ::SetCursor (m_hCursor);
    return TRUE;	
}

void CSketchView::OnLButtonDown(UINT nFlags, CPoint point) 
{
	CScrollView::OnLButtonDown(nFlags, point);

	CPoint pos = point;
    CClientDC dc (this);
    OnPrepareDC (&dc);
    dc.DPtoLP (&pos);

    if (GetDocument ()->IsGridVisible ()) {
        pos.x = ((pos.x + 12) / 25) * 25;
        pos.y = ((pos.y - 12) / 25) * 25;
    }

    m_ptFrom = pos;
    m_ptTo = pos;
    SetCapture ();
}

void CSketchView::OnMouseMove(UINT nFlags, CPoint point) 
{
	CScrollView::OnMouseMove(nFlags, point);

    if (GetCapture () == this) {
		CPoint pos = point;
		CClientDC dc (this);
		OnPrepareDC (&dc);
		dc.DPtoLP (&pos);

        if (GetDocument ()->IsGridVisible ()) {
            pos.x = ((pos.x + 12) / 25) * 25;
            pos.y = ((pos.y - 12) / 25) * 25;
        }

        if (m_ptTo != pos) {
            InvertLine (&dc, m_ptFrom, m_ptTo);
            InvertLine (&dc, m_ptFrom, pos);
            m_ptTo = pos;
        }
    }
}

void CSketchView::OnLButtonUp(UINT nFlags, CPoint point) 
{
	CScrollView::OnLButtonUp(nFlags, point);

    if (GetCapture () == this) {
        ::ReleaseCapture ();

		CPoint pos = point;
		CClientDC dc (this);
		OnPrepareDC (&dc);
		dc.DPtoLP (&pos);

        if (GetDocument ()->IsGridVisible ()) {
            pos.x = ((pos.x + 12) / 25) * 25;
            pos.y = ((pos.y - 12) / 25) * 25;
        }

        InvertLine (&dc, m_ptFrom, m_ptTo);

        CSketchDoc* pDoc = GetDocument ();
        CLine* pLine = pDoc->AddLine (m_ptFrom, m_ptTo);
    }	
}

void CSketchView::InvertLine(CDC *pDC, POINT from, POINT to)
{
    int nOldMode = pDC->SetROP2 (R2_NOT);
    pDC->MoveTo (from);
    pDC->LineTo (to);
    pDC->SetROP2 (nOldMode);
}

void CSketchView::OnUpdate(CView* pSender, LPARAM lHint, CObject* pHint) 
{
    if (lHint == 0x7C) {
		CLine* pLine = (CLine*) pHint;
		ASSERT (pLine->IsKindOf (RUNTIME_CLASS (CLine)));
		CClientDC dc (this);
		OnPrepareDC (&dc);
		pLine->Draw (&dc);
		return;
	}	
	CScrollView::OnUpdate (pSender, lHint, pHint);
}