+void wxScrollHelperBase::HandleOnChildFocus(wxChildFocusEvent& event)
+{
+ // this event should be processed by all windows in parenthood chain,
+ // e.g. so that nested wxScrolledWindows work correctly
+ event.Skip();
+
+ // find the immediate child under which the window receiving focus is:
+ wxWindow *win = event.GetWindow();
+
+ if ( win == m_targetWindow )
+ return; // nothing to do
+
+#if defined( __WXOSX__ ) && wxUSE_SCROLLBAR
+ if (wxDynamicCast(win, wxScrollBar))
+ return;
+#endif
+
+ // Fixing ticket: http://trac.wxwidgets.org/ticket/9563
+ // When a child inside a wxControlContainer receives a focus, the
+ // wxControlContainer generates an artificial wxChildFocusEvent for
+ // itself, telling its parent that 'it' received the focus. The effect is
+ // that this->HandleOnChildFocus is called twice, first with the
+ // artificial wxChildFocusEvent and then with the original event. We need
+ // to ignore the artificial event here or otherwise HandleOnChildFocus
+ // would first scroll the target window to make the entire
+ // wxControlContainer visible and immediately afterwards scroll the target
+ // window again to make the child widget visible. This leads to ugly
+ // flickering when using nested wxPanels/wxScrolledWindows.
+ //
+ // Ignore this event if 'win' is derived from wxControlContainer AND its
+ // parent is the m_targetWindow AND 'win' is not actually reciving the
+ // focus (win != FindFocus). TODO: This affects all wxControlContainer
+ // objects, but wxControlContainer is not part of the wxWidgets RTTI and
+ // so wxDynamicCast(win, wxControlContainer) does not compile. Find a way
+ // to determine if 'win' derives from wxControlContainer. Until then,
+ // testing if 'win' derives from wxPanel will probably get >90% of all
+ // cases.
+
+ wxWindow *actual_focus=wxWindow::FindFocus();
+ if (win != actual_focus &&
+ wxDynamicCast(win, wxPanel) != 0 &&
+ win->GetParent() == m_targetWindow)
+ // if win is a wxPanel and receives the focus, it should not be
+ // scrolled into view
+ return;
+
+ const wxRect viewRect(m_targetWindow->GetClientRect());
+
+ // For composite controls such as wxComboCtrl we should try to fit the
+ // entire control inside the visible area of the target window, not just
+ // the focused child of the control. Otherwise we'd make only the textctrl
+ // part of a wxComboCtrl visible and the button would still be outside the
+ // scrolled area. But do so only if the parent fits *entirely* inside the
+ // scrolled window. In other situations, such as nested wxPanel or
+ // wxScrolledWindows, the parent might be way too big to fit inside the
+ // scrolled window. If that is the case, then make only the focused window
+ // visible
+ if ( win->GetParent() != m_targetWindow)
+ {
+ wxWindow *parent=win->GetParent();
+ wxSize parent_size=parent->GetSize();
+ if (parent_size.GetWidth() <= viewRect.GetWidth() &&
+ parent_size.GetHeight() <= viewRect.GetHeight())
+ // make the immediate parent visible instead of the focused control
+ win=parent;
+ }
+
+ // make win position relative to the m_targetWindow viewing area instead of
+ // its parent
+ const wxRect
+ winRect(m_targetWindow->ScreenToClient(win->GetScreenPosition()),
+ win->GetSize());
+
+ // check if it's fully visible
+ if ( viewRect.Contains(winRect) )
+ {
+ // it is, nothing to do
+ return;
+ }
+
+ // check if we can make it fully visible: this is only possible if it's not
+ // larger than our view area
+ if ( winRect.GetWidth() > viewRect.GetWidth() ||
+ winRect.GetHeight() > viewRect.GetHeight() )
+ {
+ // we can't make it fit so avoid scrolling it at all, this is only
+ // going to be confusing and not helpful
+ return;
+ }
+
+
+ // do make the window fit inside the view area by scrolling to it
+ int stepx, stepy;
+ GetScrollPixelsPerUnit(&stepx, &stepy);
+
+ int startx, starty;
+ GetViewStart(&startx, &starty);
+
+ // first in vertical direction:
+ if ( stepy > 0 )
+ {
+ int diff = 0;
+
+ if ( winRect.GetTop() < 0 )
+ {
+ diff = winRect.GetTop();
+ }
+ else if ( winRect.GetBottom() > viewRect.GetHeight() )
+ {
+ diff = winRect.GetBottom() - viewRect.GetHeight() + 1;
+ // round up to next scroll step if we can't get exact position,
+ // so that the window is fully visible:
+ diff += stepy - 1;
+ }
+
+ starty = (starty * stepy + diff) / stepy;
+ }