double LIB_VIEW_FRAME::BestZoom()
{
    /* Please, note: wxMSW before version 2.9 seems have
     * problems with zoom values < 1 ( i.e. userscale > 1) and needs to be patched:
     * edit file <wxWidgets>/src/msw/dc.cpp
     * search for line static const int VIEWPORT_EXTENT = 1000;
     * and replace by static const int VIEWPORT_EXTENT = 10000;
     */

    LIB_COMPONENT*  component = NULL;
    double          bestzoom = 16.0;      // default value for bestzoom
    CMP_LIBRARY*    lib = CMP_LIBRARY::FindLibrary( m_libraryName );

    if( lib  )
        component = lib->FindComponent( m_entryName );

    if( component == NULL )
    {
        SetScrollCenterPosition( wxPoint( 0, 0 ) );
        return bestzoom;
    }

    wxSize size = m_canvas->GetClientSize();

    EDA_RECT BoundaryBox = component->GetBoundingBox( m_unit, m_convert );

    // Reserve a 10% margin around component bounding box.
    double margin_scale_factor = 0.8;
    double zx =(double) BoundaryBox.GetWidth() /
               ( margin_scale_factor * (double)size.x );
    double zy = (double) BoundaryBox.GetHeight() /
                ( margin_scale_factor * (double)size.y);

    // Calculates the best zoom
    bestzoom = std::max( zx, zy );

    // keep it >= minimal existing zoom (can happen for very small components
    // like small power symbols
    if( bestzoom  < GetScreen()->m_ZoomList[0] )
        bestzoom  = GetScreen()->m_ZoomList[0];

    SetScrollCenterPosition( BoundaryBox.Centre() );

    return bestzoom;
}
void LIB_VIEW_FRAME::ReCreateHToolbar()
{
    int  ii;
    wxString msg;
    CMP_LIBRARY* lib;
    LIB_COMPONENT* component = NULL;
    LIB_ALIAS* entry = NULL;
    bool asdeMorgan = false;

    if( m_mainToolBar  == NULL )
    {
        m_mainToolBar = new wxAuiToolBar( this, ID_H_TOOLBAR, wxDefaultPosition, wxDefaultSize,
                                          wxAUI_TB_DEFAULT_STYLE | wxAUI_TB_HORZ_LAYOUT );

        // Set up toolbar
        m_mainToolBar->AddTool( ID_LIBVIEW_SELECT_LIB, wxEmptyString,
                                KiBitmap( library_xpm ),
                                _( "Select library to browse" ) );

        m_mainToolBar->AddTool( ID_LIBVIEW_SELECT_PART, wxEmptyString,
                                KiBitmap( add_component_xpm ),
                                _( "Select component to browse" ) );

        m_mainToolBar->AddSeparator();
        m_mainToolBar->AddTool( ID_LIBVIEW_PREVIOUS, wxEmptyString,
                                KiBitmap( lib_previous_xpm ),
                                _( "Display previous component" ) );

        m_mainToolBar->AddTool( ID_LIBVIEW_NEXT, wxEmptyString,
                                KiBitmap( lib_next_xpm ),
                                _( "Display next component" ) );

        m_mainToolBar->AddSeparator();
        msg = AddHotkeyName( _( "Zoom in" ), s_Viewlib_Hokeys_Descr,
                             HK_ZOOM_IN, IS_COMMENT );
        m_mainToolBar->AddTool( ID_ZOOM_IN, wxEmptyString,
                                KiBitmap( zoom_in_xpm ), msg );

        msg = AddHotkeyName( _( "Zoom out" ), s_Viewlib_Hokeys_Descr,
                             HK_ZOOM_OUT, IS_COMMENT );
        m_mainToolBar->AddTool( ID_ZOOM_OUT, wxEmptyString,
                                KiBitmap( zoom_out_xpm ), msg );

        msg = AddHotkeyName( _( "Redraw view" ), s_Viewlib_Hokeys_Descr,
                             HK_ZOOM_REDRAW, IS_COMMENT );
        m_mainToolBar->AddTool( ID_ZOOM_REDRAW, wxEmptyString,
                             KiBitmap( zoom_redraw_xpm ), msg );

        msg = AddHotkeyName( _( "Zoom auto" ), s_Viewlib_Hokeys_Descr,
                             HK_ZOOM_AUTO, IS_COMMENT );
        m_mainToolBar->AddTool( ID_ZOOM_PAGE, wxEmptyString,
                                KiBitmap( zoom_fit_in_page_xpm ), msg );

        m_mainToolBar->AddSeparator();
        m_mainToolBar->AddTool( ID_LIBVIEW_DE_MORGAN_NORMAL_BUTT, wxEmptyString,
                                KiBitmap( morgan1_xpm ),
                                _( "Show as \"De Morgan\" normal part" ),
                                wxITEM_CHECK );

        m_mainToolBar->AddTool( ID_LIBVIEW_DE_MORGAN_CONVERT_BUTT, wxEmptyString,
                                KiBitmap( morgan2_xpm ),
                                _( "Show as \"De Morgan\" convert part" ),
                                wxITEM_CHECK );

        m_mainToolBar->AddSeparator();

        m_selpartBox = new wxComboBox( m_mainToolBar, ID_LIBVIEW_SELECT_PART_NUMBER,
                                       wxEmptyString, wxDefaultPosition,
                                       wxSize( 150, -1 ), 0, NULL, wxCB_READONLY );
        m_mainToolBar->AddControl( m_selpartBox );

        m_mainToolBar->AddSeparator();
        m_mainToolBar->AddTool( ID_LIBVIEW_VIEWDOC, wxEmptyString,
                                KiBitmap( datasheet_xpm ),
                                _( "View component documents" ) );
        m_mainToolBar->EnableTool( ID_LIBVIEW_VIEWDOC, false );

        if( m_semaphore )
        {
            // The library browser is called from a "load component" command
            m_mainToolBar->AddSeparator();
            m_mainToolBar->AddTool( ID_LIBVIEW_CMP_EXPORT_TO_SCHEMATIC,
                                    wxEmptyString, KiBitmap( export_xpm ),
                                    _( "Insert component in schematic" ) );
        }

        // after adding the buttons to the toolbar, must call Realize() to
        // reflect the changes
        m_mainToolBar->Realize();
    }

    if( (m_libraryName != wxEmptyString) && (m_entryName != wxEmptyString) )
    {
        lib = CMP_LIBRARY::FindLibrary( m_libraryName );

        if( lib != NULL )
        {
            component = lib->FindComponent( m_entryName );

            if( component && component->HasConversion() )
                asdeMorgan = true;

            entry = lib->FindEntry( m_entryName );
        }
    }

    // Must be AFTER Realize():
    m_mainToolBar->EnableTool( ID_LIBVIEW_DE_MORGAN_CONVERT_BUTT, asdeMorgan );
    m_mainToolBar->EnableTool( ID_LIBVIEW_DE_MORGAN_NORMAL_BUTT, asdeMorgan );

    if( asdeMorgan )
    {
        bool normal = m_convert <= 1;
        m_mainToolBar->ToggleTool( ID_LIBVIEW_DE_MORGAN_NORMAL_BUTT,normal );
        m_mainToolBar->ToggleTool( ID_LIBVIEW_DE_MORGAN_CONVERT_BUTT, !normal );
    }
    else
    {
        m_mainToolBar->ToggleTool( ID_LIBVIEW_DE_MORGAN_NORMAL_BUTT, true  );
        m_mainToolBar->ToggleTool( ID_LIBVIEW_DE_MORGAN_CONVERT_BUTT, false );
     }


    int parts_count = 1;

    if( component )
        parts_count = std::max( component->GetPartCount(), 1 );

    m_selpartBox->Clear();

    for( ii = 0; ii < parts_count; ii++ )
    {
        wxString msg;
        msg.Printf( _( "Unit %c" ), 'A' + ii );
        m_selpartBox->Append( msg );
    }

    m_selpartBox->SetSelection( (m_unit > 0 ) ? m_unit - 1 : 0 );
    m_selpartBox->Enable( parts_count > 1 );

    m_mainToolBar->EnableTool( ID_LIBVIEW_VIEWDOC,
                               entry && ( entry->GetDocFileName() != wxEmptyString ) );

    m_mainToolBar->Refresh();
}