mdibackground.cpp

这是MFC经典问答书的光盘内容

// MdiBackground.cpp : implementation file
//

#include "stdafx.h"
#include "MdiBackground.h"

#include "resource.h"	// For access to our bitmap image
#include "MainFrm.h"	// For access to the m_MdiBackStyle member

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

/////////////////////////////////////////////////////////////////////////////
// CMdiBackground

CMdiBackground::CMdiBackground()
{
	VERIFY( m_bitmap.LoadBitmap( IDB_CLOUDS ) );
}

CMdiBackground::~CMdiBackground()
{
}


BEGIN_MESSAGE_MAP(CMdiBackground, CWnd)
	//{{AFX_MSG_MAP(CMdiBackground)
	ON_WM_ERASEBKGND()
	ON_WM_SIZE()
	//}}AFX_MSG_MAP
END_MESSAGE_MAP()


/////////////////////////////////////////////////////////////////////////////
// CMdiBackground message handlers

BOOL CMdiBackground::OnEraseBkgnd(CDC* pDC) 
{
	// Get a pointer to our main frame window
 	// (to access the m_MdiBackStyle member variable)
	CMainFrame* pMainFrame = static_cast< CMainFrame* >( GetParentFrame() );
	ASSERT_KINDOF( CMainFrame, pMainFrame );

	switch( pMainFrame->m_MdiBackStyle )
	{
		default:
			ASSERT( FALSE );	// Should never get here
			return TRUE;

		case CMainFrame::NORMAL:
			// Draw the standard MDI background
			CWnd::OnEraseBkgnd( pDC );
			break;

		case CMainFrame::CUSTOM:
		{
			// 1 - Draw the standard MDI background
			CWnd::OnEraseBkgnd( pDC );

			// 2 - Now draw a yellow rectangle (centered)
			CRect rect;
			GetClientRect( &rect );

			CBrush brYellow( RGB( 255, 255, 0 ) );
			CBrush* pOldBrush = pDC->SelectObject( &brYellow );

			pDC->PatBlt(	rect.left + rect.Width() / 4,
							rect.top + rect.Height() / 4,
							rect.Width() / 2,
							rect.Height() / 2,
							PATCOPY );

			pDC->SelectObject( pOldBrush );

			// 3 - Finally draw the coordinates of the window's corners
			pDC->SetTextColor( RGB( 255, 255, 255 ) );
			pDC->SetBkMode( TRANSPARENT );

			CString s;

			// 3a - Upper-left
			pDC->SetTextAlign( TA_TOP | TA_LEFT );
			s.Format( "( %ld, %ld )", rect.left, rect.top );
			pDC->TextOut( rect.left, rect.top, s );

			// 3b - Bottom-left
			pDC->SetTextAlign( TA_BOTTOM | TA_LEFT );
			s.Format( "( %ld, %ld )", rect.left, rect.bottom );
			pDC->TextOut( rect.left, rect.bottom, s );
			
			// 3c - Upper-right
			pDC->SetTextAlign( TA_TOP | TA_RIGHT );
			s.Format( "( %ld, %ld )", rect.right, rect.top );
			pDC->TextOut( rect.right, rect.top, s );

			// 3d - Bottom-right
			pDC->SetTextAlign( TA_BOTTOM | TA_RIGHT );
			s.Format( "( %ld, %ld )", rect.right, rect.bottom );
			pDC->TextOut( rect.right, rect.bottom, s );

			break;
		}

		case CMainFrame::BITMAP:
		{
			// 1 - Create a memory DC and select our bitmap into it
			CDC dcMem;
			dcMem.CreateCompatibleDC( pDC );
			CBitmap* pOldBitmap = dcMem.SelectObject( &m_bitmap );

			// 2 - Retrieve the size of our bitmap...
			BITMAP bmp;
			m_bitmap.GetObject( sizeof( bmp ), &bmp );

			// 3 - ... and the size of our window's client area
			CRect rect;
			GetClientRect( &rect );

			// 4 - Fill the window's client area with our bitmap
			pDC->StretchBlt(	rect.left, rect.top,
								rect.Width(), rect.Height(),
								&dcMem,
								0, 0, bmp.bmWidth, bmp.bmHeight,
								SRCCOPY );

			dcMem.SelectObject( pOldBitmap );

			break;
		}
	}

	return TRUE;	// Background was erased
}

void CMdiBackground::OnSize(UINT nType, int cx, int cy) 
{
	CWnd::OnSize(nType, cx, cy);
	Invalidate( TRUE );
}