再问闪烁的问题???
请给位高手帮我看看下面的代码,我读入一幅图片在OnDraw()中显示,并自定义了一个消息,每五秒更新一次数据,可是每当更新是总会有明显的闪烁,我重载了OnEraseBkgnd()
函数,直接返回,在滚动条没有滚动时,没出现闪烁,感觉不错,可是当滚动条滚动到图片的另一部分时,就会有明显的闪烁,我实在是想不到怎样才能修正这个不足,希望大家能帮个忙,谢谢!!!!
void CcltView::OnInitialUpdate()
{
CScrollView::OnInitialUpdate();
CSize sizeTotal;
// TODO: calculate the total size of this view
sizeTotal.cx = m_nImageWidth;
sizeTotal.cy = m_nImageHeight;
SetScrollSizes(MM_TEXT, sizeTotal);
}
void CcltView::OnDraw(CDC* pDC)
{
CWorkDoc* pDoc =(CWorkDoc*) GetDocument();
CBitmap* pOldBitmap;
CDC MemDC;
MemDC.CreateCompatibleDC(pDC);
pOldBitmap=MemDC.SelectObject(&m_Bitmap); //将位图选入内存场境
pDC->BitBlt(0,0,m_nImageWidth,m_nImageHeight,&MemDC,0,0,SRCCOPY); ///显示它
MemDC.SelectObject(pOldBitmap);
if(pDoc->m_pdRealTimeData==NULL and and pDoc->m_pnAlarmState==NULL)
return;
ShowParamer(pDC,148,34,pDoc->m_pdRealTimeData[23],
pDoc->m_pnAlarmState[23],24);
}
/////////////////////////////////////////////////////////////////////////////
// CcltView diagnostics
#ifdef _DEBUG
void CcltView::AssertValid() const
{
CScrollView::AssertValid();
}
void CcltView::Dump(CDumpContext& dc) const
{
CScrollView::Dump(dc);
}
#endif //_DEBUG
/////////////////////////////////////////////////////////////////////////////
// CcltView message handlers
int CcltView::OnCreate(LPCREATESTRUCT lpCreateStruct)
{
if (CScrollView::OnCreate(lpCreateStruct) == -1)
return -1;
// TODO: Add your specialized creation code here
TCHAR sPath[_MAX_PATH];
TCHAR sDrive[_MAX_DRIVE];
TCHAR sDir[_MAX_DIR];
GetModuleFileName(NULL, sPath, _MAX_PATH);
_tsplitpath(sPath, sDrive, sDir, NULL, NULL);
_tmakepath(sPath, sDrive, sDir, _T("VIEW"), _T("BMP"));
HANDLE hBitmap = LoadImage(NULL, sPath, IMAGE_BITMAP, 0, 0, LR_LOADFROMFILE and LR_CREATEDIBSECTION and LR_DEFAULTSIZE);
ASSERT(hBitmap != NULL);
m_Bitmap.Attach(hBitmap);
BITMAP bm;
m_Bitmap.GetObject(sizeof(bm), &bm);
m_nImageWidth = bm.bmWidth;
m_nImageHeight = bm.bmHeight;
m_wndTip.Create(this);
return 0;
}
long CcltView::OnRealTimeDataUpdated(WPARAM wParam, LPARAM lParam)
{
CWorkDoc* pDoc = (CWorkDoc*)GetDocument();
pDoc -> GetRealTimeData();
OnDraw(GetDC());
return 0;
}
BOOL CcltView::ShowParamer(CDC *pDC,int x, int y, double RealTimeData, int AlermState,int Count)
{ .
.
.
.
.
return TRUE;
}
BOOL CcltView::OnEraseBkgnd(CDC* pDC)
{
return TRUE;
// return CScrollView::OnEraseBkgnd(pDC);
}