C++ DropDownList::Bottom方法代码示例

Pt ModalListPicker::DetermineListHeight(const Pt& _drop_down_size) {
    auto drop_down_size = _drop_down_size;

    // Determine the expected height
    auto border_thick = 2 * GG::Y(ListBox::BORDER_THICK);
    auto num_rows = std::min<int>(m_num_shown_rows, LB()->NumRows());
    auto row_height = (*LB()->FirstRowShown())->Height();
    auto expected_height = num_rows * row_height + border_thick;

    // Shrink the height if too near app edge.
    auto dist_to_app_edge = GUI::GetGUI()->AppHeight() - m_relative_to_wnd->Bottom();
    if (expected_height > dist_to_app_edge && row_height > 0) {
        auto reduced_num_rows = std::max(GG::Y(1), (dist_to_app_edge - border_thick) / row_height);
        expected_height = reduced_num_rows * row_height + border_thick;
    }

    drop_down_size.y = expected_height;

    LB()->Resize(drop_down_size);
    if (!LB()->Selections().empty())
        LB()->BringRowIntoView(*(LB()->Selections().begin()));
    GUI::GetGUI()->PreRenderWindow(LB());

    return drop_down_size;
}

void ModalListPicker::CompleteConstruction()
{
    m_lb_wnd->SelRowsChangedSignal.connect(
        boost::bind(&ModalListPicker::LBSelChangedSlot, this, _1));
    m_lb_wnd->LeftClickedRowSignal.connect(
        boost::bind(&ModalListPicker::LBLeftClickSlot, this, _1, _2, _3));
    GUI::GetGUI()->WindowResizedSignal.connect(
        boost::bind(&ModalListPicker::WindowResizedSlot, this, _1, _2));
    AttachChild(m_lb_wnd);
    m_lb_wnd->InstallEventFilter(shared_from_this());

    if (INSTRUMENT_ALL_SIGNALS)
        SelChangedSignal.connect(ModalListPickerSelChangedEcho(*this));

    if (m_relative_to_wnd)
        m_lb_wnd->MoveTo(Pt(m_relative_to_wnd->Left(), m_relative_to_wnd->Bottom()));

    m_lb_wnd->Hide();
}

void ModalListPicker::CorrectListSize() {
    // reset size of displayed drop list based on number of shown rows set.
    // assumes that all rows have the same height.
    // adds some magic padding for now to prevent the scroll bars showing up.

    if (!m_relative_to_wnd)
        return;

    if (LB()->Visible())
        return;

    LB()->MoveTo(Pt(m_relative_to_wnd->Left(), m_relative_to_wnd->Bottom()));

    Pt drop_down_size(m_relative_to_wnd->DroppedRowWidth(), m_relative_to_wnd->ClientHeight());

    if (LB()->Empty()) {
        LB()->Resize(drop_down_size);
    } else {
        LB()->Show();

        // The purpose of this code is to produce a drop down list that
        // will be exactly m_num_shown_rows high and make sure that the
        // selected row is prerendered in the same way when the drop down
        // list is open or closed.

        // The list needs to be resized twice.  The first resize with an
        // estimated row height will add any list box chrome, like scroll
        // bars to the list and may change the height of the row.  The
        // second resize uses the corrected row height to finalize the drop
        // down list size.

        // Note:  Placing a tighter constraint on valid DropDownList rows
        // of always returning the same fixed height regardless of status
        // (width, prerender etc.) would mean this code could be reduced to
        // check height and resize list just once.

        drop_down_size = DetermineListHeight(drop_down_size);
        DetermineListHeight(drop_down_size);

        LB()->Hide();
    }
}