support for tooltips longer than 80 characters

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/WX_2_4_BRANCH@17640 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/msw/tooltip.cpp

@@ -274,12 +274,14 @@ void wxToolTip::Add(WXHWND hWnd)
 
     wxToolInfo ti(hwnd);
 
-    // as we store our text anyhow, it seems useless to waste system memory
-    // by asking the tooltip ctrl to remember it too - instead it will send
-    // us TTN_NEEDTEXT (via WM_NOTIFY) when it is about to be shown
+    // another possibility would be to specify LPSTR_TEXTCALLBACK here as we
+    // store the tooltip text ourselves anyhow, and provide it in response to
+    // TTN_NEEDTEXT (sent via WM_NOTIFY), but then we would be limited to 79
+    // character tooltips as this is the size of the szText buffer in
+    // NMTTDISPINFO struct -- and setting the tooltip here we can have tooltips
+    // of any length
     ti.hwnd = hwnd;
-    ti.lpszText = LPSTR_TEXTCALLBACK;
-    // instead of: ti.lpszText = (char *)m_text.c_str();
+    ti.lpszText = (wxChar *)m_text.c_str(); // const_cast
 
     if ( !SendTooltipMessage(GetToolTipCtrl(), TTM_ADDTOOL, 0, &ti) )
     {