C++ (Cpp) CControlBase::UpdateControl Examples

Example #1

File: Panel.cpp Project: hezlog/DuiVision

// 画子控件(支持滚动显示)
BOOL CDuiPanel::DrawSubControls(CDC &dc, CRect rcUpdate)
{
	// 如果不需要滚动条,则直接使用父控件的画图方法
	if(!m_bEnableScroll || ((m_nVirtualHeight <= m_rc.Height()) && (m_nVirtualWidth <= m_rc.Width())))
	{
		return __super::DrawSubControls(dc, rcUpdate);
	}

	BOOL bShowScrollV = m_nVirtualHeight > m_rc.Height();
	BOOL bShowScrollH = m_nVirtualWidth > m_rc.Width();

	// 计算显示位置
	CDuiScrollVertical* pScrollV = (CDuiScrollVertical*)m_pControScrollV;
	int nCurPosV = pScrollV->GetScrollCurrentPos();	// 当前top位置
	int nMaxRangeV = pScrollV->GetScrollMaxRange();
	int nVirtualTop = (nMaxRangeV > 0) ? nCurPosV*(m_nVirtualHeight-m_rc.Height())/nMaxRangeV : 0;	// 当前显示的是虚拟图片中什么位置开始的图片

	CDuiScrollHorizontal* pScrollH = (CDuiScrollHorizontal*)m_pControScrollH;
	int nCurPosH = pScrollH->GetScrollCurrentPos();	// 当前top位置
	int nMaxRangeH = pScrollH->GetScrollMaxRange();
	int nVirtualLeft = (nMaxRangeH > 0) ? nCurPosH*(m_nVirtualWidth-m_rc.Width())/nMaxRangeH : 0;	// 当前显示的是虚拟图片中什么位置开始的图片

	// 根据滚动条位置画子控件
	// 初始化虚拟显示dc,并复制背景到虚拟显示dc
	CBitmap	virtualBitmap;
	CDC virtualDC;
	virtualDC.CreateCompatibleDC(&dc);
	virtualBitmap.CreateCompatibleBitmap(&dc,
				bShowScrollH ? (m_rc.left + m_nVirtualWidth) : (m_rc.right - (bShowScrollV ? m_nScrollWidth : 0)),
				bShowScrollV ? (m_rc.top + m_nVirtualHeight) : (m_rc.bottom - (bShowScrollH ? m_nScrollWidth : 0)) );
	CBitmap* pOldVirtualBitmap = virtualDC.SelectObject(&virtualBitmap);
	virtualDC.BitBlt(m_rc.left+nVirtualLeft, m_rc.top+nVirtualTop,
				m_rc.Width()-(bShowScrollV ? m_nScrollWidth : 0),
				m_rc.Height()-(bShowScrollH ? m_nScrollWidth : 0),
				&dc, m_rc.left, m_rc.top, SRCCOPY);	// 背景复制到虚拟显示dc

	// 更新区域按照显示区域调整
	rcUpdate.OffsetRect(nVirtualLeft, nVirtualTop);

	// 画子控件到虚拟dc
	for (size_t i = 0; i < m_vecControl.size(); i++)
	{
		CControlBase * pControlBase = m_vecControl.at(i);
		if (pControlBase && pControlBase->GetVisible()
			&& (pControlBase != m_pControScrollV) && (pControlBase != m_pControScrollH))
		{
			// 如果顶部位置发生了变化,需要重画所有子控件,但会造成速度很慢
			if(m_nVirtualTop != nVirtualTop)
			{
				pControlBase->UpdateControl(true);
			}
			pControlBase->Draw(virtualDC, rcUpdate);		
		}
	}

	// 画滚动条,滚动条整个区域都需要更新
	m_pControScrollV->Draw(dc, m_pControScrollV->GetRect());
	m_pControScrollH->Draw(dc, m_pControScrollH->GetRect());

	m_nVirtualTop = nVirtualTop;
	m_nVirtualLeft = nVirtualLeft;

	// 虚拟显示dc复制到dc(滚动条部分不用复制)
	dc.BitBlt(m_rc.left, m_rc.top, m_rc.Width()-(bShowScrollV ? m_nScrollWidth : 0),
			m_rc.Height()-(bShowScrollH ? m_nScrollWidth : 0),
			&virtualDC, m_rc.left + nVirtualLeft, m_rc.top + nVirtualTop, SRCCOPY);

	// 释放虚拟显示dc
	virtualDC.SelectObject(pOldVirtualBitmap);
	virtualDC.DeleteDC();
	virtualBitmap.DeleteObject();

	return TRUE;
}