Tracking tooltip in CScrollView? - c++

Question

In a standard C++/MFC MDI doc/view project, I want to implement a tracking tooltip in the view (the tabbed view windows which generally occupy most of the main frame window). So, in class MyAppView, I have a member CToolTipCtrl tooltip. Function MyAppView::OnInitialUpdate() contains the initialization
BOOL ok0 = tooltip.Create(this, TTS_ALWAYSTIP);
CRect clientRect; GetClientRect(&clientRect);
BOOL ok2 = tooltip.AddTool(this, LPSTR_TEXTCALLBACK, &clientRect, 1234/*tool ID*/);
tooltip.Activate(TRUE);
to make the entire client area of the view be the "tool". The message map contains an entry
ON_NOTIFY_EX(TTN_NEEDTEXT, 0, OnNeedToolTipText)
and the function OnNeedToolTipText is defined as
BOOL MyAppView::OnNeedToolTipText(UINT id, NMHDR *pNMHDR, LRESULT *pResult)
{
UNREFERENCED_PARAMETER(id);
NMTTDISPINFO *pTTT = (NMTTDISPINFO *)pNMHDR;
UINT_PTR nID = pNMHDR->idFrom;
BOOL bRet = FALSE;
if(nID == 1234)
{
// Come here when text is needed for tracking tooltip
}
if(pTTT->uFlags & TTF_IDISHWND)
{
// idFrom is actually the HWND of the tool
nID = ::GetDlgCtrlID((HWND)nID);
if(nID)
{
_stprintf_s(pTTT->szText, sizeof(pTTT->szText) / sizeof(TCHAR),
_T("Control ID = %d"), nID);
pTTT->hinst = AfxGetResourceHandle();
bRet = TRUE;
}
}
*pResult = 0;
return bRet;
}
What happens is that only placing the mouse on the menu items (File, Edit, View, Window, Help) causes the code to enter OnNeedToolTipText, with an ID of 0-5. Moving the mouse into the client area (the view) does nothing.
How can I get the tooltip to appear in the client area of the view only?
Visual Studio 2017; C++; 64-bit Windows 7

Answer 1

In order to solve the problem you need to do the following:
BOOL CMyAppView::PreTranslateMessage(MSG* pMsg)
{
switch (pMsg->message)
{
case WM_KEYDOWN:
case WM_SYSKEYDOWN:
case WM_LBUTTONDOWN:
case WM_RBUTTONDOWN:
case WM_MBUTTONDOWN:
case WM_LBUTTONUP:
case WM_RBUTTONUP:
case WM_MBUTTONUP:
case WM_MOUSEMOVE:
if (m_pToolTip->GetSafeHwnd () != NULL)
{
m_pToolTip->RelayEvent(pMsg);
}
break;
}
return CScrollView::PreTranslateMessage(pMsg);
}

Answer 2

If you want a tracking tooltip in a view, these are the steps to follow:
Create tooltip and add the tool.
void CToolTipDemoView::OnInitialUpdate()
{
// ...
m_toolTip.Create(this, TTS_ALWAYSTIP | TTS_NOANIMATE);
m_toolTip.AddTool(this, _T("Doesn't matter"));
}
Handle WM_MOUSEMOVE message. First, call _TrackMouseEvent in order to further receive WM_MOUSELEAVE and activate the tooltip. Second, update the tooltip text, and show it at mouse pointer coordinates.
void CToolTipDemoView::OnMouseMove(UINT nFlags, CPoint point)
{
if (!m_bTrackingMouseLeave)
{
TRACKMOUSEEVENT tme = { 0 };
tme.cbSize = sizeof(TRACKMOUSEEVENT);
tme.dwFlags = TME_LEAVE;
tme.hwndTrack = m_hWnd;
::_TrackMouseEvent(&tme);
m_toolTip.Activate(TRUE);
m_bTrackingMouseLeave = TRUE;
}
if (m_pointLastMousePos != point)
{
CString strText;
strText.Format(_T("x = %d y = %d"), point.x, point.y);
m_toolTip.UpdateTipText(strText, this);
m_toolTip.Popup();
m_pointLastMousePos = point;
}
CScrollView::OnMouseMove(nFlags, point);
}
Handle WM_MOUSELEAVE and deactivate the tooltip.
void CCToolTipDemoView::OnMouseLeave()
{
m_bTrackingMouseLeave = FALSE;
// mouse pointer leaves the window so deactivate the tooltip
m_toolTip.Activate(FALSE);
CScrollView::OnMouseLeave();
}
Notes:
there is no more necessary to handle TTN_NEEDTEXT.
also, there is no more necessary to override PreTranslateMessage

Answer 3

So I went back to see what I could be missing. I wrote this stuff over 10 years ago. I had also overridden a CWnd member
virtual INT_PTR OnToolHitTest( CPoint point, TOOLINFO* pTI ) const;
With:
INT_PTR HERichView::OnToolHitTest( CPoint point, TOOLINFO* pTI ) const
{
pTI->hwnd = m_hWnd;
pTI->uId = point.x + ( point.y << 16 );
CRect rect;
GetClientRect( rect );
pTI->rect= rect;
pTI->lpszText= LPSTR_TEXTCALLBACK;
return pTI->uId;
}
And I checked, it won't work without this. So your:
ON_NOTIFY_EX( TTN_NEEDTEXT, 0, OnToolTip )
Should get called if you add the above. And only EnableToolTips( ); Should be needed.

Answer 4

I have not succeeded in getting the tracking tooltip to work within MFC. The closest I have come is
In message map: ON_NOTIFY_EX(TTN_NEEDTEXT, 0, OnNeedToolTipText)
In OnInitialUpdate: BOOL ok1 = EnableTrackingToolTips(TRUE);
In override of virtual function OnToolHitTest:
pTI->hwnd = m_hWnd;
pTI->uId = (UINT_PTR)m_hWnd;
pTI->uFlags = TTF_IDISHWND | TTF_ALWAYSTIP | TTF_TRACK | TTF_NOTBUTTON | TTF_ABSOLUTE | TTF_SUBCLASS;
pTI->lpszText = LPSTR_TEXTCALLBACK;
return pTI->uId;
In OnNeedToolTipText:
NMTTDISPINFO *pTTT = (NMTTDISPINFO *)pNMHDR;
UINT_PTR nID = pNMHDR->idFrom;
BOOL bRet = FALSE;
if(pTTT->uFlags & TTF_IDISHWND)
{
// idFrom is actually the HWND of the tool
nID = ::GetDlgCtrlID((HWND)nID);
if(nID)
{
CURSORINFO ci; ci.cbSize = sizeof(CURSORINFO); // get something interesting to display
GetCursorInfo(&ci);
_stprintf_s(pTTT->szText, sizeof(pTTT->szText) / sizeof(TCHAR),
_T("Control ID = %lld at (%d, %d)"), nID, ci.ptScreenPos.x, ci.ptScreenPos.y);
pTTT->hinst = AfxGetResourceHandle();
bRet = TRUE;
}
}
*pResult = 0;
return bRet;
This produces the following peculiar behavior. When I start the app and move the mouse cursor into the client area of the CScrollView, a tooltip appears right next to the cursor.
If I move the mouse carefully (smoothly) the tooltip tracks properly. After a while, though, it disappears, and no further mouse motions, including leaving the CScrollView window and returning, make it re-appear.
I think what is happening is that when the mouse cursor moves over the tooltip window, the tooltip is turned off, permanently. This disappearance does not seem to be time-related (e g, due to auto-pop); if the mouse is left untouched, the tooltip remains indefinitely.