//////////////////
// User pressed mouse: intialize and enter drag state
//
void CSizerBar::OnLButtonDown(UINT nFlags, CPoint pt)
{
m_bDragging=TRUE;
m_ptOriginal = m_ptPrevious = Rectify(pt);
GetWindowRect(&m_rcBar); // bar location in screen coords
DrawBar(); // draw it
SetCapture(); // all mouse messages are MINE
m_hwndPrevFocus = ::SetFocus(m_hWnd); // set focus to me to get Escape key
ASSERT(m_pWinMgr);
CWinMgr& wm = *m_pWinMgr;
// get WINRECTs on either side of me
WINRECT* pwrcSizeBar = wm.FindRect(GetDlgCtrlID());
ASSERT(pwrcSizeBar);
WINRECT* prev = pwrcSizeBar->Prev();
ASSERT(prev);
WINRECT* next = pwrcSizeBar->Next();
ASSERT(next);
// get rectangles on eithr side of me
CRect rcPrev = prev->GetRect();
CRect rcNext = next->GetRect();
// get parent window
CWnd * pParentWnd = GetParent();
ASSERT(pParentWnd);
// Get size info for next/prev rectangles, so I know what the min/max
// sizes are and don't violate them. Max size never tested.
SIZEINFO szi;
wm.OnGetSizeInfo(szi, prev, pParentWnd);
CRect rcPrevMin(rcPrev.TopLeft(),szi.szMin);
CRect rcPrevMax(rcPrev.TopLeft(),szi.szMax);
wm.OnGetSizeInfo(szi, next, pParentWnd);
CRect rcNextMin(rcNext.BottomRight()-szi.szMin, rcNext.BottomRight());
CRect rcNextMax(rcNext.BottomRight()-szi.szMax, rcNext.BottomRight());
// Initialize m_rcConstrain. This is the box the user is allowed to move
// the sizer bar in. Can't go outside of this--would violate min/max
// constraints of windows on either side.
m_rcConstrain.SetRect(
max(rcPrevMin.right, rcNextMax.left),
max(rcPrevMin.bottom,rcNextMax.top),
min(rcPrevMax.right, rcNextMin.left),
min(rcPrevMax.bottom,rcNextMin.top));
// convert to my client coords
pParentWnd->ClientToScreen(&m_rcConstrain);
ScreenToClient(&m_rcConstrain);
// Now adjust m_rcConstrain for the fact the bar is not a pure line, but
// has solid width -- so I have to make a little bigger/smaller according
// to the offset of mouse coords within the sizer bar rect iteself.
ClientToScreen(&pt);
m_rcConstrain.SetRect(m_rcConstrain.TopLeft() + (pt - m_rcBar.TopLeft()),
m_rcConstrain.BottomRight() - (m_rcBar.BottomRight()-pt));
}
