void CEx10bView::OnPaint()
{
CPaintDC dc(this); // device context for painting
OnPrepareDC(&dc);
CRect rectUpdate;
dc.GetClipBox(&rectUpdate);
CBitmap* pOldBitmap = m_pdcMemory->SelectObject(m_pBitmap);
m_pdcMemory->SelectClipRgn(NULL);
m_pdcMemory->IntersectClipRect(&rectUpdate);
CBrush backgroundBrush((COLORREF) ::GetSysColor(COLOR_WINDOW));
CBrush* pOldBrush = m_pdcMemory->SelectObject(&backgroundBrush);
m_pdcMemory->PatBlt(rectUpdate.left, rectUpdate.top,
rectUpdate.Width(), rectUpdate.Height(),
PATCOPY);
OnDraw(m_pdcMemory);
dc.BitBlt(rectUpdate.left, rectUpdate.top,
rectUpdate.Width(), rectUpdate.Height(),
m_pdcMemory, rectUpdate.left, rectUpdate.top,
SRCCOPY);
m_pdcMemory->SelectObject(pOldBitmap);
m_pdcMemory->SelectObject(pOldBrush);
}m_pdcMemory->SelectClipRgn(NULL); 和 m_pdcMemory->IntersectClipRect(&rectUpdate);
这两句每句什么意思?加起来是什么意思?有什么效果?作者写这两句的思路是什么(就是先怎么做再怎么做)?
m_pdcMemory->IntersectClipRect(&rectUpdate);
{
CPaintDC dc(this); // device context for painting
OnPrepareDC(&dc);
CRect rectUpdate;
dc.GetClipBox(&rectUpdate);
CBitmap* pOldBitmap = m_pdcMemory->SelectObject(m_pBitmap);
m_pdcMemory->SelectClipRgn(NULL);
m_pdcMemory->IntersectClipRect(&rectUpdate);
CBrush backgroundBrush((COLORREF) ::GetSysColor(COLOR_WINDOW));
CBrush* pOldBrush = m_pdcMemory->SelectObject(&backgroundBrush);
m_pdcMemory->PatBlt(rectUpdate.left, rectUpdate.top,
rectUpdate.Width(), rectUpdate.Height(),
PATCOPY);
OnDraw(m_pdcMemory);
dc.BitBlt(rectUpdate.left, rectUpdate.top,
rectUpdate.Width(), rectUpdate.Height(),
m_pdcMemory, rectUpdate.left, rectUpdate.top,
SRCCOPY);
m_pdcMemory->SelectObject(pOldBitmap);
m_pdcMemory->SelectObject(pOldBrush);
}m_pdcMemory->SelectClipRgn(NULL); 和 m_pdcMemory->IntersectClipRect(&rectUpdate);
这两句每句什么意思?加起来是什么意思?有什么效果?作者写这两句的思路是什么(就是先怎么做再怎么做)?
m_pdcMemory->IntersectClipRect(&rectUpdate);
解决方案 »
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