scrolbar.cpp

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{
    int thumbOld = m_thumbPos;

    bool notify = false; // send an event about the change?

    wxEventType scrollType;

    // test for thumb move first as these events happen in quick succession
    if ( action == wxACTION_SCROLL_THUMB_MOVE )
    {
        DoSetThumb(numArg);

        // VS: we have to force redraw here, otherwise the thumb will lack
        //     behind mouse cursor
        UpdateThumb();

        scrollType = wxEVT_SCROLLWIN_THUMBTRACK;
    }
    else if ( action == wxACTION_SCROLL_LINE_UP )
    {
        scrollType = wxEVT_SCROLLWIN_LINEUP;
        ScrollLines(-1);
    }
    else if ( action == wxACTION_SCROLL_LINE_DOWN )
    {
        scrollType = wxEVT_SCROLLWIN_LINEDOWN;
        ScrollLines(1);
    }
    else if ( action == wxACTION_SCROLL_PAGE_UP )
    {
        scrollType = wxEVT_SCROLLWIN_PAGEUP;
        ScrollPages(-1);
    }
    else if ( action == wxACTION_SCROLL_PAGE_DOWN )
    {
        scrollType = wxEVT_SCROLLWIN_PAGEDOWN;
        ScrollPages(1);
    }
    else if ( action == wxACTION_SCROLL_START )
    {
        scrollType = wxEVT_SCROLLWIN_THUMBRELEASE; // anything better?
        ScrollToStart();
    }
    else if ( action == wxACTION_SCROLL_END )
    {
        scrollType = wxEVT_SCROLLWIN_THUMBRELEASE; // anything better?
        ScrollToEnd();
    }
    else if ( action == wxACTION_SCROLL_THUMB_DRAG )
    {
        // we won't use it but this line suppresses the compiler
        // warning about "variable may be used without having been
        // initialized"
        scrollType = wxEVT_NULL;
    }
    else if ( action == wxACTION_SCROLL_THUMB_RELEASE )
    {
        // always notify about this
        notify = true;
        scrollType = wxEVT_SCROLLWIN_THUMBRELEASE;
    }
    else
        return wxControl::PerformAction(action, numArg, strArg);

    // has scrollbar position changed?
    bool changed = m_thumbPos != thumbOld;
    if ( notify || changed )
    {
        if ( IsStandalone() )
        {
            // we should generate EVT_SCROLL events for the standalone
            // scrollbars and not the EVT_SCROLLWIN ones
            //
            // NB: we assume that scrollbar events are sequentially numbered
            //     but this should be ok as other code relies on this as well
            scrollType += wxEVT_SCROLL_TOP - wxEVT_SCROLLWIN_TOP;
            wxScrollEvent event(scrollType, this->GetId(), m_thumbPos,
                                IsVertical() ? wxVERTICAL : wxHORIZONTAL);
            event.SetEventObject(this);
            GetParent()->GetEventHandler()->ProcessEvent(event);
        }
        else // part of the window
        {
            wxScrollWinEvent event(scrollType, m_thumbPos,
                                   IsVertical() ? wxVERTICAL : wxHORIZONTAL);
            event.SetEventObject(this);
            GetParent()->GetEventHandler()->ProcessEvent(event);
        }
    }

    return true;
}

void wxScrollBar::ScrollToStart()
{
    DoSetThumb(0);
}

void wxScrollBar::ScrollToEnd()
{
    DoSetThumb(m_range - m_thumbSize);
}

bool wxScrollBar::ScrollLines(int nLines)
{
    DoSetThumb(m_thumbPos + nLines);
    return true;
}

bool wxScrollBar::ScrollPages(int nPages)
{
    DoSetThumb(m_thumbPos + nPages*m_pageSize);
    return true;
}

// ============================================================================
// scroll bar input handler
// ============================================================================

// ----------------------------------------------------------------------------
// wxScrollBarTimer
// ----------------------------------------------------------------------------

wxScrollBarTimer::wxScrollBarTimer(wxStdScrollBarInputHandler *handler,
                                   const wxControlAction& action,
                                   wxScrollBar *control)
{
    m_handler = handler;
    m_action = action;
    m_control = control;
}

bool wxScrollBarTimer::DoNotify()
{
    return m_handler->OnScrollTimer(m_control, m_action);
}

// ----------------------------------------------------------------------------
// wxStdScrollBarInputHandler
// ----------------------------------------------------------------------------

wxStdScrollBarInputHandler::wxStdScrollBarInputHandler(wxRenderer *renderer,
                                                       wxInputHandler *handler)
                          : wxStdInputHandler(handler)
{
    m_renderer = renderer;
    m_winCapture = NULL;
    m_htLast = wxHT_NOWHERE;
    m_timerScroll = NULL;
}

wxStdScrollBarInputHandler::~wxStdScrollBarInputHandler()
{
    // normally, it's NULL by now but just in case the user somehow managed to
    // keep the mouse captured until now...
    delete m_timerScroll;
}

void wxStdScrollBarInputHandler::SetElementState(wxScrollBar *control,
                                                 int flag,
                                                 bool doIt)
{
    if ( m_htLast > wxHT_SCROLLBAR_FIRST && m_htLast < wxHT_SCROLLBAR_LAST )
    {
        wxScrollBar::Element
            elem = (wxScrollBar::Element)(m_htLast - wxHT_SCROLLBAR_FIRST - 1);

        int flags = control->GetState(elem);
        if ( doIt )
            flags |= flag;
        else
            flags &= ~flag;
        control->SetState(elem, flags);
    }
}

bool wxStdScrollBarInputHandler::OnScrollTimer(wxScrollBar *scrollbar,
                                               const wxControlAction& action)
{
    int oldThumbPos = scrollbar->GetThumbPosition();
    scrollbar->PerformAction(action);
    if ( scrollbar->GetThumbPosition() != oldThumbPos )
        return true;

    // we scrolled till the end
    m_timerScroll->Stop();

    return false;
}

void wxStdScrollBarInputHandler::StopScrolling(wxScrollBar *control)
{
    // return everything to the normal state
    if ( m_winCapture )
    {
        m_winCapture->ReleaseMouse();
        m_winCapture = NULL;
    }

    m_btnCapture = -1;

    if ( m_timerScroll )
    {
        delete m_timerScroll;
        m_timerScroll = NULL;
    }

    // unpress the arrow and highlight the current element
    Press(control, false);
}

wxCoord
wxStdScrollBarInputHandler::GetMouseCoord(const wxScrollBar *scrollbar,
                                          const wxMouseEvent& event) const
{
    wxPoint pt = event.GetPosition();
    return scrollbar->GetWindowStyle() & wxVERTICAL ? pt.y : pt.x;
}

void wxStdScrollBarInputHandler::HandleThumbMove(wxScrollBar *scrollbar,
                                                 const wxMouseEvent& event)
{
    int thumbPos = GetMouseCoord(scrollbar, event) - m_ofsMouse;
    thumbPos = m_renderer->PixelToScrollbar(scrollbar, thumbPos);
    scrollbar->PerformAction(wxACTION_SCROLL_THUMB_MOVE, thumbPos);
}

bool wxStdScrollBarInputHandler::HandleKey(wxInputConsumer *consumer,
                                           const wxKeyEvent& event,
                                           bool pressed)
{
    // we only react to the key presses here
    if ( pressed )
    {
        wxControlAction action;
        switch ( event.GetKeyCode() )
        {
            case WXK_DOWN:
            case WXK_RIGHT:     action = wxACTION_SCROLL_LINE_DOWN; break;
            case WXK_UP:
            case WXK_LEFT:      action = wxACTION_SCROLL_LINE_UP;   break;
            case WXK_HOME:      action = wxACTION_SCROLL_START;     break;
            case WXK_END:       action = wxACTION_SCROLL_END;       break;
            case WXK_PAGEUP:
            case WXK_PRIOR:     action = wxACTION_SCROLL_PAGE_UP;   break;
            case WXK_PAGEDOWN:
            case WXK_NEXT:      action = wxACTION_SCROLL_PAGE_DOWN; break;
        }

        if ( !action.IsEmpty() )
        {
            consumer->PerformAction(action);

            return true;
        }
    }

    return wxStdInputHandler::HandleKey(consumer, event, pressed);
}

bool wxStdScrollBarInputHandler::HandleMouse(wxInputConsumer *consumer,
                                             const wxMouseEvent& event)
{
    // is this a click event from an acceptable button?
    int btn = event.GetButton();
    if ( (btn != -1) && IsAllowedButton(btn) )
    {
        // determine which part of the window mouse is in
        wxScrollBar *scrollbar = wxStaticCast(consumer->GetInputWindow(), wxScrollBar);
        wxHitTest ht = m_renderer->HitTestScrollbar
                                   (
                                    scrollbar,
                                    event.GetPosition()
                                   );

        // when the mouse is pressed on any scrollbar element, we capture it
        // and hold capture until the same mouse button is released
        if ( event.ButtonDown() || event.ButtonDClick() )
        {
            if ( !m_winCapture )
            {
                m_btnCapture = btn;
                m_winCapture = consumer->GetInputWindow();
                m_winCapture->CaptureMouse();

                // generate the command
                bool hasAction = true;
                wxControlAction action;
                switch ( ht )
                {
                    case wxHT_SCROLLBAR_ARROW_LINE_1:
                        action = wxACTION_SCROLL_LINE_UP;
                        break;

                    case wxHT_SCROLLBAR_ARROW_LINE_2:
                        action = wxACTION_SCROLL_LINE_DOWN;
                        break;

                    case wxHT_SCROLLBAR_BAR_1:
                        action = wxACTION_SCROLL_PAGE_UP;
                        m_ptStartScrolling = event.GetPosition();
                        break;

                    case wxHT_SCROLLBAR_BAR_2:
                        action = wxACTION_SCROLL_PAGE_DOWN;
                        m_ptStartScrolling = event.GetPosition();
                        break;

                    case wxHT_SCROLLBAR_THUMB:
                        consumer->PerformAction(wxACTION_SCROLL_THUMB_DRAG);
                        m_ofsMouse = GetMouseCoord(scrollbar, event) -
                                     m_renderer->ScrollbarToPixel(scrollbar);

                        // fall through: there is no immediate action

                    default:
                        hasAction = false;
                }

                // remove highlighting
                Highlight(scrollbar, false);
                m_htLast = ht;

                // and press the arrow or highlight thumb now instead
                if ( m_htLast == wxHT_SCROLLBAR_THUMB )
                    Highlight(scrollbar, true);
                else
                    Press(scrollbar, true);

                // start dragging
                if ( hasAction )
                {
                    m_timerScroll = new wxScrollBarTimer(this, action,
                                                         scrollbar);
                    m_timerScroll->StartAutoScroll();
                }
                //else: no (immediate) action

            }
            //else: mouse already captured, nothing to do
        }
        // release mouse if the *same* button went up
        else if ( btn == m_btnCapture )
        {
            if ( m_winCapture )
            {
                StopScrolling(scrollbar);

                // if we were dragging the thumb, send the last event
                if ( m_htLast == wxHT_SCROLLBAR_THUMB )
                {
                    scrollbar->PerformAction(wxACTION_SCROLL_THUMB_RELEASE);
                }

                m_htLast = ht;
                Highlight(scrollbar, true);
            }
            else
            {
                // this is not supposed to happen as the button can't go up
                // without going down previously and then we'd have
                // m_winCapture by now
                wxFAIL_MSG( _T("logic error in mouse capturing code") );
            }
        }
    }

    return wxStdInputHandler::HandleMouse(consumer, event);
}

bool wxStdScrollBarInputHandler::HandleMouseMove(wxInputConsumer *consumer,
                                                 const wxMouseEvent& event)
{
    wxScrollBar *scrollbar = wxStaticCast(consumer->GetInputWindow(), wxScrollBar);

    if ( m_winCapture )
    {
        if ( (m_htLast == wxHT_SCROLLBAR_THUMB) && event.Dragging() )
        {
            // make the thumb follow the mouse by keeping the same offset
            // between the mouse position and the top/left of the thumb
            HandleThumbMove(scrollbar, event);

            return true;
        }

        // no other changes are possible while the mouse is captured
        return false;
    }

    bool isArrow = scrollbar->GetArrows().HandleMouseMove(event);

    if ( event.Dragging() )
    {
        wxHitTest ht = m_renderer->HitTestScrollbar
                                   (
                                    scrollbar,
                                    event.GetPosition()
                                   );
        if ( ht == m_htLast )
        {
            // nothing changed
            return false;
        }

#ifdef DEBUG_MOUSE
        wxLogDebug("Scrollbar::OnMouseMove: ht = %d", ht);
#endif // DEBUG_MOUSE

        Highlight(scrollbar, false);
        m_htLast = ht;

        if ( !isArrow )
            Highlight(scrollbar, true);
        //else: already done by wxScrollArrows::HandleMouseMove
    }
    else if ( event.Leaving() )
    {
        if ( !isArrow )
            Highlight(scrollbar, false);

        m_htLast = wxHT_NOWHERE;
    }
    else // event.Entering()
    {
        // we don't process this event
        return false;
    }

    // we did something
    return true;
}

#endif // wxUSE_SCROLLBAR

// ----------------------------------------------------------------------------
// wxScrollTimer
// ----------------------------------------------------------------------------

wxScrollTimer::wxScrollTimer()
{
    m_skipNext = false;
}

void wxScrollTimer::StartAutoScroll()
{
    // start scrolling immediately
    if ( !DoNotify() )
    {
        // ... and end it too
        return;
    }

    // there is an initial delay before the scrollbar starts scrolling -
    // implement it by ignoring the first timer expiration and only start
    // scrolling from the second one
    m_skipNext = true;
    Start(200); // FIXME: hardcoded delay
}

void wxScrollTimer::Notify()
{
    if ( m_skipNext )
    {
        // scroll normally now - reduce the delay
        Stop();
        Start(50); // FIXME: hardcoded delay

        m_skipNext = false;
    }
    else
    {
        // if DoNotify() returns false, we're already deleted by the timer
        // event handler, so don't do anything else here
        (void)DoNotify();
    }
}