CDC MemDC; //首先定義一個顯示裝置對象
CBitmap MemBitmap;//定義一個位圖對象
//随後建立與螢幕顯示相容的記憶體顯示裝置
MemDC.CreateCompatibleDC(NULL);
//這時還不能繪圖,因為沒有地方畫 ^_^
//下面建立一個與螢幕顯示相容的位圖,至于位圖的大小嘛,可以用視窗的大小
MemBitmap.CreateCompatibleBitmap(pDC,nWidth,nHeight);
//将位圖選入到記憶體顯示裝置中
//隻有選入了位圖的記憶體顯示裝置才有地方繪圖,畫到指定的位圖上
CBitmap *pOldBit=MemDC.SelectObject(&MemBitmap);
//先用背景色将位圖清除幹淨,這裡我用的是白色作為背景
//你也可以用自己應該用的顔色
MemDC.FillSolidRect(0,0,nWidth,nHeight,RGB(255,255,255));
//繪圖
MemDC.MoveTo(……);
MemDC.LineTo(……);
//将記憶體中的圖拷貝到螢幕上進行顯示
pDC->BitBlt(0,0,nWidth,nHeight,&MemDC,0,0,SRCCOPY);
//繪圖完成後的清理
MemBitmap.DeleteObject();
MemDC.DeleteDC();
之後又重載了:WM_ERASEBKGND消息
例如
void CSlidView::OnPaint()
{
CPaintDC dc(this);
CRect clientRect;
GetClientRect( &clientRect );
CDC MemDC;
CBitmap Membitmap;
Membitmap.CreateCompatibleBitmap( &dc, clientRect.Width(), clientRect.Height() );
MemDC.CreateCompatibleDC( &dc );
CBitmap *pOldBitmap = MemDC.SelectObject( &Membitmap );
MemDC.FillSolidRect( 0, 0, clientRect.Width(), clientRect.Height(), RGB( 255, 255, 255 ) );
MemDC.Ellipse( &clientRect ); //記住 畫圖時候用 CDC MemDC; 即先在CDC上畫 之後拷貝上去
dc.BitBlt( 0, 0, clientRect.Width(), clientRect.Height(), &MemDC, 0, 0, SRCCOPY );
MemDC.DeleteDC();
Membitmap.DeleteObject();
}
BOOL CSlidView::OnEraseBkgnd(CDC* pDC)
{
return CView::OnEraseBkgnd(pDC);
}
下面是我的程式中的例子:
void CViewDlg::OnPaint()
{
CPaintDC dc(this); // device context for painting
if (!m_bDrawLine)
{
return;
}
CRect rcClient;
CRect rcCurve;
int nWidth;
int nHeight;
GetClientRect(rcClient);
CRect rtTree;
CWnd *pWnd = (CWnd *)GetDlgItem(IDC_TREE_ACC);
if (pWnd)
{
pWnd->GetClientRect(rtTree);
rcCurve.left = rtTree.right + 4 +SPLITTER_WIDTH +10;
rcCurve.top = rcClient.top +10;
rcCurve.right = rcClient.right -10 ;
rcCurve.bottom = rcClient.bottom -10 ;
m_FrameRect.left = rcCurve.left + 40;
m_FrameRect.top = rcCurve.top + 30;
m_FrameRect.right = rcCurve.right - 20;
m_FrameRect.bottom = rcCurve.bottom - 20;
}
m_RectInvalidate = rcCurve;
nHeight = rcClient.Height();
nWidth = rcClient.Width();
CDC MemDC; //首先定義一個顯示裝置對象
CBitmap MemBitmap;//定義一個位圖對象
//随後建立與螢幕顯示相容的記憶體顯示裝置
MemDC.CreateCompatibleDC(NULL);
//這時還不能繪圖,因為沒有地方畫
//下面建立一個與螢幕顯示相容的位圖,至于位圖的大小嘛,可以用視窗的大小
MemBitmap.CreateCompatibleBitmap(&dc,nWidth,nHeight);
//将位圖選入到記憶體顯示裝置中
//隻有選入了位圖的記憶體顯示裝置才有地方繪圖,畫到指定的位圖上
CBitmap *pOldBit=MemDC.SelectObject(&MemBitmap);
MemDC.FillSolidRect(0,0,nWidth,nHeight,RGB(255,255,255));
MemDC.MoveTo(rcCurve.left, rcCurve.top);
MemDC.LineTo(rcCurve.left, rcCurve.bottom);
MemDC.LineTo(rcCurve.right, rcCurve.bottom);
MemDC.LineTo(rcCurve.right, rcCurve.top);
MemDC.LineTo(rcCurve.left, rcCurve.top);
//
// //繪制背景色
if (m_pObj->m_bDrawBk)
{
CBrush brush;
COLORREF color = m_pObj->m_pHMIWizardAPI->ColorGet(m_pObj->m_shBkColor);
brush.CreateSolidBrush(color);
CBrush* pOldbrush = MemDC.SelectObject(&brush);
FillRect(MemDC, m_FrameRect, brush);
MemDC.SelectObject(pOldbrush);
brush.DeleteObject();
}
DrawStatic(&MemDC, m_FrameRect);
DrawCurve(&MemDC, m_FrameRect);
dc.BitBlt(0,0,nWidth,nHeight,&MemDC,0,0,SRCCOPY);
//繪圖完成後的清理
MemBitmap.DeleteObject();
MemDC.SelectObject(pOldBit);
MemDC.DeleteDC();
}
BOOL CViewDlg::OnEraseBkgnd(CDC* pDC)
{
// TODO: Add your message handler code here and/or call default
return TRUE; //很重要
}