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MFC初学者,曲线一闪一闪的

2012-08-14 
MFC菜鸟,曲线一闪一闪的我已经用class CMemDC : public CDC {private:CBitmap m_bitmap// Offscreen bitm

MFC菜鸟,曲线一闪一闪的
我已经用
class CMemDC : public CDC {
private:
  CBitmap m_bitmap;// Offscreen bitmap
  CBitmap* m_oldBitmap;// bitmap originally found in CMemDC
  CDC* m_pDC;// Saves CDC passed in constructor
  CRect m_rect;// Rectangle of drawing area.
  BOOL m_bMemDC;// TRUE if CDC really is a Memory DC.
public:
  CMemDC(CDC* pDC) : CDC(), m_oldBitmap(NULL), m_pDC(pDC)
  {
  ASSERT(m_pDC != NULL);// If you asserted here, you passed in a NULL CDC.
   
  m_bMemDC = !pDC->IsPrinting();
   
  if (m_bMemDC){
  // Create a Memory DC
  CreateCompatibleDC(pDC);
  pDC->GetClipBox(&m_rect);
  m_bitmap.CreateCompatibleBitmap(pDC, m_rect.Width(), m_rect.Height());
  m_oldBitmap = SelectObject(&m_bitmap);
  SetWindowOrg(m_rect.left, m_rect.top);
  } else {
  // Make a copy of the relevent parts of the current DC for printing
  m_bPrinting = pDC->m_bPrinting;
  m_hDC = pDC->m_hDC;
  m_hAttribDC = pDC->m_hAttribDC;
  }
  }
   
  ~CMemDC()
  {
  if (m_bMemDC) {
  // Copy the offscreen bitmap onto the screen.
  m_pDC->BitBlt(m_rect.left, m_rect.top, m_rect.Width(), m_rect.Height(),
  this, m_rect.left, m_rect.top, SRCCOPY);
  //Swap back the original bitmap.
  SelectObject(m_oldBitmap);
  } else {
  // All we need to do is replace the DC with an illegal value,
  // this keeps us from accidently deleting the handles associated with
  // the CDC that was passed to the constructor.
  m_hDC = m_hAttribDC = NULL;
  }
  }
   
  // Allow usage as a pointer
  CMemDC* operator->() {return this;}
   
  // Allow usage as a pointer
  operator CMemDC*() {return this;}
};

这样一个类去实现双缓存画图了,为什么图像还是一闪一闪的啊?

[解决办法]
亲 发错地方了 该发到MFC板块去
[解决办法]

探讨

我在cplot中是这样调用的
void clPlot::OnPaint()
{
CPaintDC dc(this); // device context for painting
CMemDC pdc(&dc); // non flickering painting
Draw(&pdc);// Do not call……

[解决办法]
一闪一闪的问题,有可能是你刷新太快。。就是调用Onpait函数太频繁

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