C++ SCH_ITEM::GetClass方法代码示例

void SCH_EDIT_FRAME::OnDragItem( wxCommandEvent& aEvent )
{
    SCH_SCREEN* screen = GetScreen();
    SCH_ITEM* item = screen->GetCurItem();

    INSTALL_UNBUFFERED_DC( dc, m_canvas );

    if( item == NULL )
    {
        // If we didn't get here by a hot key, then something has gone wrong.
        if( aEvent.GetInt() == 0 )
            return;

        EDA_HOTKEY_CLIENT_DATA* data = (EDA_HOTKEY_CLIENT_DATA*) aEvent.GetClientObject();

        wxCHECK_RET( data != NULL, wxT( "Invalid hot key client object." ) );

        item = LocateAndShowItem( data->GetPosition(), SCH_COLLECTOR::DraggableItems,
                                  aEvent.GetInt() );

        // Exit if no item found at the current location or the item is already being edited.
        if( (item == NULL) || (item->GetFlags() != 0) )
            return;
    }

    switch( item->Type() )
    {
    case SCH_BUS_BUS_ENTRY_T:
    case SCH_BUS_WIRE_ENTRY_T:
    case SCH_LINE_T:
    case SCH_JUNCTION_T:
        if( item->GetLayer() == LAYER_BUS )
            break;

        // Fall thru if item is not on bus layer.
    case SCH_COMPONENT_T:
    case SCH_LABEL_T:
    case SCH_GLOBAL_LABEL_T:
    case SCH_HIERARCHICAL_LABEL_T:
    case SCH_SHEET_T:
        m_canvas->MoveCursorToCrossHair();

        // The easiest way to handle a drag component or sheet command
        // is to simulate a block drag command
        if( screen->m_BlockLocate.GetState() == STATE_NO_BLOCK )
        {
            if( !HandleBlockBegin( &dc, BLOCK_DRAG, GetCrossHairPosition() ) )
                break;

            // Give a non null size to the search block:
            screen->m_BlockLocate.Inflate( 1 );
            HandleBlockEnd( &dc );
        }

        break;

    default:
        wxFAIL_MSG( wxString::Format( wxT( "Cannot drag schematic item type %s." ),
                                      GetChars( item->GetClass() ) ) );
    }
}

void SCH_EDIT_FRAME::OnOrient( wxCommandEvent& aEvent )
{
    SCH_SCREEN* screen = GetScreen();
    SCH_ITEM*   item   = screen->GetCurItem();

    INSTALL_UNBUFFERED_DC( dc, m_canvas );

    // Allows block rotate operation on hot key.
    if( screen->m_BlockLocate.GetState() != STATE_NO_BLOCK )
    {
        if( aEvent.GetId() == ID_SCH_MIRROR_X )
        {
            m_canvas->MoveCursorToCrossHair();
            screen->m_BlockLocate.SetMessageBlock( this );
            screen->m_BlockLocate.SetCommand( BLOCK_MIRROR_X );
            HandleBlockEnd( &dc );
        }
        else if( aEvent.GetId() == ID_SCH_MIRROR_Y )
        {
            m_canvas->MoveCursorToCrossHair();
            screen->m_BlockLocate.SetMessageBlock( this );
            screen->m_BlockLocate.SetCommand( BLOCK_MIRROR_Y );
            HandleBlockEnd( &dc );
        }
        else
        {
            wxFAIL_MSG( wxT( "Unknown block oriention command ID." ) );
        }

        return;
    }

    if( item == NULL )
    {
        // If we didn't get here by a hot key, then something has gone wrong.
        if( aEvent.GetInt() == 0 )
            return;

        EDA_HOTKEY_CLIENT_DATA* data = (EDA_HOTKEY_CLIENT_DATA*) aEvent.GetClientObject();

        wxCHECK_RET( data != NULL, wxT( "Invalid hot key client object." ) );

        item = LocateAndShowItem( data->GetPosition(), SCH_COLLECTOR::OrientableItems,
                                  aEvent.GetInt() );

        // Exit if no item found at the current location or the item is already being edited.
        if( (item == NULL) || (item->GetFlags() != 0) )
            return;
    }


    switch( item->Type() )
    {
    case SCH_COMPONENT_T:
        if( aEvent.GetId() == ID_SCH_MIRROR_X )
            OrientComponent( CMP_MIRROR_X );
        else if( aEvent.GetId() == ID_SCH_MIRROR_Y )
            OrientComponent( CMP_MIRROR_Y );
        else if( aEvent.GetId() == ID_SCH_ORIENT_NORMAL )
            OrientComponent( CMP_NORMAL );
        else
            wxFAIL_MSG( wxT( "Invalid orient schematic component command ID." ) );

        break;

    case SCH_BITMAP_T:
        if( aEvent.GetId() == ID_SCH_MIRROR_X )
            MirrorImage( (SCH_BITMAP*) item, true );
        else if( aEvent.GetId() == ID_SCH_MIRROR_Y )
            MirrorImage( (SCH_BITMAP*) item, false );

        break;

    default:
        wxFAIL_MSG( wxString::Format( wxT( "Schematic object type %s cannot be oriented." ),
                                      GetChars( item->GetClass() ) ) );
    }

    if( item->GetFlags() == 0 )
        screen->SetCurItem( NULL );
}

void SCH_EDIT_FRAME::OnRotate( wxCommandEvent& aEvent )
{
    SCH_SCREEN* screen = GetScreen();
    SCH_ITEM*   item = screen->GetCurItem();

    INSTALL_UNBUFFERED_DC( dc, m_canvas );

    // Allows block rotate operation on hot key.
    if( screen->m_BlockLocate.GetState() != STATE_NO_BLOCK )
    {
        screen->m_BlockLocate.SetCommand( BLOCK_ROTATE );
        HandleBlockEnd( &dc );
        return;
    }

    if( item == NULL )
    {
        // If we didn't get here by a hot key, then something has gone wrong.
        if( aEvent.GetInt() == 0 )
            return;

        EDA_HOTKEY_CLIENT_DATA* data = (EDA_HOTKEY_CLIENT_DATA*) aEvent.GetClientObject();

        wxCHECK_RET( data != NULL, wxT( "Invalid hot key client object." ) );

        item = LocateAndShowItem( data->GetPosition(), SCH_COLLECTOR::RotatableItems,
                                  aEvent.GetInt() );

        // Exit if no item found at the current location or the item is already being edited.
        if( (item == NULL) || (item->GetFlags() != 0) )
            return;
    }

    switch( item->Type() )
    {
    case SCH_COMPONENT_T:
        if( aEvent.GetId() == ID_SCH_ROTATE_CLOCKWISE )
            OrientComponent( CMP_ROTATE_CLOCKWISE );
        else if( aEvent.GetId() == ID_SCH_ROTATE_COUNTERCLOCKWISE )
            OrientComponent( CMP_ROTATE_COUNTERCLOCKWISE );
        else
            wxFAIL_MSG( wxT( "Unknown rotate item command ID." ) );

        break;

    case SCH_TEXT_T:
    case SCH_LABEL_T:
    case SCH_GLOBAL_LABEL_T:
    case SCH_HIERARCHICAL_LABEL_T:
        m_canvas->MoveCursorToCrossHair();
        ChangeTextOrient( (SCH_TEXT*) item, &dc );
        break;

    case SCH_FIELD_T:
        m_canvas->MoveCursorToCrossHair();
        RotateField( (SCH_FIELD*) item, &dc );
        break;

    case SCH_BITMAP_T:
        RotateImage( (SCH_BITMAP*) item );
        break;

    case SCH_SHEET_T:           /// @todo allow sheet rotate on hotkey
    default:
        wxFAIL_MSG( wxString::Format( wxT( "Cannot rotate schematic item type %s." ),
                                      GetChars( item->GetClass() ) ) );
    }

    if( item->GetFlags() == 0 )
        screen->SetCurItem( NULL );
}

//.........这里部分代码省略.........

        wxCHECK_RET( data != NULL, wxT( "Invalid hot key client object." ) );

        // Set the locat filter, according to the edit command
        const KICAD_T* filterList = SCH_COLLECTOR::EditableItems;
        const KICAD_T* filterListAux = NULL;

        switch( aEvent.GetId() )
        {
        case ID_SCH_EDIT_COMPONENT_REFERENCE:
            filterList = SCH_COLLECTOR::CmpFieldReferenceOnly;
            filterListAux = SCH_COLLECTOR::ComponentsOnly;
            break;

        case ID_SCH_EDIT_COMPONENT_VALUE:
            filterList = SCH_COLLECTOR::CmpFieldValueOnly;
            filterListAux = SCH_COLLECTOR::ComponentsOnly;
            break;

        case ID_SCH_EDIT_COMPONENT_FOOTPRINT:
            filterList = SCH_COLLECTOR::CmpFieldFootprintOnly;
            filterListAux = SCH_COLLECTOR::ComponentsOnly;
            break;

        default:
            break;
        }

        item = LocateAndShowItem( data->GetPosition(), filterList, aEvent.GetInt() );

        // If no item found, and if an auxiliary filter exists, try to use it
        if( !item && filterListAux )
            item = LocateAndShowItem( data->GetPosition(), filterListAux, aEvent.GetInt() );

        // Exit if no item found at the current location or the item is already being edited.
        if( (item == NULL) || (item->GetFlags() != 0) )
            return;
    }

    switch( item->Type() )
    {
    case SCH_COMPONENT_T:
    {
        switch( aEvent.GetId() )
        {
        case ID_SCH_EDIT_COMPONENT_REFERENCE:
            EditComponentFieldText( ( (SCH_COMPONENT*) item )->GetField( REFERENCE ) );
            break;

        case ID_SCH_EDIT_COMPONENT_VALUE:
            EditComponentFieldText( ( (SCH_COMPONENT*) item )->GetField( VALUE ) );
            break;

        case ID_SCH_EDIT_COMPONENT_FOOTPRINT:
            EditComponentFieldText( ( (SCH_COMPONENT*) item )->GetField( FOOTPRINT ) );
            break;

        case ID_SCH_EDIT_ITEM:
            EditComponent( (SCH_COMPONENT*) item );
            break;

        default:
            wxFAIL_MSG( wxString::Format( wxT( "Invalid schematic component edit command ID %d" ),
                                          aEvent.GetId() ) );
        }

        break;
    }

    case SCH_SHEET_T:
        EditSheet( (SCH_SHEET*) item, &dc );
        break;

    case SCH_SHEET_PIN_T:
        EditSheetPin( (SCH_SHEET_PIN*) item, &dc );
        break;

    case SCH_TEXT_T:
    case SCH_LABEL_T:
    case SCH_GLOBAL_LABEL_T:
    case SCH_HIERARCHICAL_LABEL_T:
        EditSchematicText( (SCH_TEXT*) item );
        break;

    case SCH_FIELD_T:
        EditComponentFieldText( (SCH_FIELD*) item );
        break;

    case SCH_BITMAP_T:
        EditImage( (SCH_BITMAP*) item );
        break;

    default:
        wxFAIL_MSG( wxString::Format( wxT( "Cannot edit schematic item type %s." ),
                                      GetChars( item->GetClass() ) ) );
    }

    if( item->GetFlags() == 0 )
        screen->SetCurItem( NULL );
}

void SCH_EDIT_FRAME::OnMoveItem( wxCommandEvent& aEvent )
{
    SCH_SCREEN* screen = GetScreen();
    SCH_ITEM*   item = screen->GetCurItem();

    if( screen->m_BlockLocate.GetState() != STATE_NO_BLOCK )
    {
        // trying to move an item when there is a block at the same time is not acceptable
        return;
    }

    if( item == NULL )
    {
        // If we didn't get here by a hot key, then something has gone wrong.
        if( aEvent.GetInt() == 0 )
            return;

        EDA_HOTKEY_CLIENT_DATA* data = (EDA_HOTKEY_CLIENT_DATA*) aEvent.GetClientObject();

        wxCHECK_RET( data != NULL, wxT( "Invalid hot key client object." ) );

        item = LocateAndShowItem( data->GetPosition(), SCH_COLLECTOR::MovableItems,
                                  aEvent.GetInt() );

        // Exit if no item found at the current location or the item is already being edited.
        if( (item == NULL) || (item->GetFlags() != 0) )
            return;
    }

    INSTALL_UNBUFFERED_DC( dc, m_canvas );

    switch( item->Type() )
    {
    case SCH_LINE_T:
        break;

    case SCH_JUNCTION_T:
    case SCH_NO_CONNECT_T:
    case SCH_BUS_BUS_ENTRY_T:
    case SCH_BUS_WIRE_ENTRY_T:
    case SCH_LABEL_T:
    case SCH_GLOBAL_LABEL_T:
    case SCH_HIERARCHICAL_LABEL_T:
    case SCH_TEXT_T:
    case SCH_COMPONENT_T:
    case SCH_SHEET_PIN_T:
    case SCH_FIELD_T:
        MoveItem( item, &dc );
        break;

    case SCH_BITMAP_T:
        MoveImage( (SCH_BITMAP*) item, &dc );
        break;

    case SCH_SHEET_T:
        StartMoveSheet( (SCH_SHEET*) item, &dc );
        break;

    case SCH_MARKER_T:
    default:
        wxFAIL_MSG( wxString::Format( wxT( "Cannot move item type %s" ),
                                      GetChars( item->GetClass() ) ) );
        break;
    }

    if( GetToolId() == ID_NO_TOOL_SELECTED )
        SetRepeatItem( NULL );
}

void SCH_EDIT_FRAME::OnLeftClick( wxDC* aDC, const wxPoint& aPosition )
{
    SCH_ITEM*   item = GetScreen()->GetCurItem();
    wxPoint     gridPosition = GetGridPosition( aPosition );

    if( ( GetToolId() == ID_NO_TOOL_SELECTED ) || ( item && item->GetFlags() ) )
    {
        m_canvas->SetAutoPanRequest( false );
        SetRepeatItem( NULL );

        if( item && item->GetFlags() )
        {
            switch( item->Type() )
            {
            case SCH_LABEL_T:
            case SCH_GLOBAL_LABEL_T:
            case SCH_HIERARCHICAL_LABEL_T:
            case SCH_TEXT_T:
            case SCH_SHEET_PIN_T:
            case SCH_SHEET_T:
            case SCH_BUS_WIRE_ENTRY_T:
            case SCH_BUS_BUS_ENTRY_T:
            case SCH_JUNCTION_T:
            case SCH_COMPONENT_T:
            case SCH_FIELD_T:
            case SCH_BITMAP_T:
            case SCH_NO_CONNECT_T:
                addCurrentItemToList();
                return;

            case SCH_LINE_T:    // May already be drawing segment.
                break;

            default:
                wxFAIL_MSG( wxT( "SCH_EDIT_FRAME::OnLeftClick error.  Item type <" ) +
                            item->GetClass() + wxT( "> is already being edited." ) );
                item->ClearFlags();
                break;
            }
        }
        else
        {
            item = LocateAndShowItem( aPosition );
        }
    }

    switch( GetToolId() )
    {
    case ID_NO_TOOL_SELECTED:
        break;

    case ID_HIGHLIGHT:
        HighlightConnectionAtPosition( aPosition );
        break;

    case ID_HIERARCHY_PUSH_POP_BUTT:
        if( ( item && item->GetFlags() ) || ( g_RootSheet->CountSheets() == 0 ) )
            break;

        item = LocateAndShowItem( aPosition, SCH_COLLECTOR::SheetsOnly );

        if( item )  // The user has clicked on a sheet: this is an enter sheet command
        {
            m_CurrentSheet->push_back( (SCH_SHEET*) item );
            DisplayCurrentSheet();
        }
        else if( m_CurrentSheet->Last() != g_RootSheet )
        {   // The user has clicked ouside a sheet:this is an leave sheet command
            m_CurrentSheet->pop_back();
            DisplayCurrentSheet();
        }
        break;

    case ID_NOCONN_BUTT:
        if( ( item == NULL ) || ( item->GetFlags() == 0 ) )
        {
            if( GetScreen()->GetItem( gridPosition, 0, SCH_NO_CONNECT_T ) == NULL )
            {
                SCH_NO_CONNECT*  no_connect = AddNoConnect( aDC, gridPosition );
                SetRepeatItem( no_connect );
                GetScreen()->SetCurItem( no_connect );
                m_canvas->SetAutoPanRequest( true );
            }
        }
        else
        {
            addCurrentItemToList();
        }
        break;

    case ID_JUNCTION_BUTT:
        if( ( item == NULL ) || ( item->GetFlags() == 0 ) )
        {
            if( GetScreen()->GetItem( gridPosition, 0, SCH_JUNCTION_T ) == NULL )
            {
                SCH_JUNCTION* junction = AddJunction( aDC, gridPosition, true );
                SetRepeatItem( junction );
                GetScreen()->SetCurItem( junction );
                m_canvas->SetAutoPanRequest( true );
            }
//.........这里部分代码省略.........

void SCH_EDIT_FRAME::OnLeftClick( wxDC* aDC, const wxPoint& aPosition )
{
    SCH_ITEM*   item = GetScreen()->GetCurItem();
    wxPoint     gridPosition = GetGridPosition( aPosition );

    if( ( GetToolId() == ID_NO_TOOL_SELECTED ) || ( item && item->GetFlags() ) )
    {
        m_canvas->SetAutoPanRequest( false );
        SetRepeatItem( NULL );

        if( item && item->GetFlags() )
        {
            switch( item->Type() )
            {
            case SCH_LABEL_T:
            case SCH_GLOBAL_LABEL_T:
            case SCH_HIERARCHICAL_LABEL_T:
            case SCH_TEXT_T:
            case SCH_SHEET_PIN_T:
            case SCH_SHEET_T:
            case SCH_BUS_WIRE_ENTRY_T:
            case SCH_BUS_BUS_ENTRY_T:
            case SCH_JUNCTION_T:
            case SCH_COMPONENT_T:
            case SCH_FIELD_T:
            case SCH_BITMAP_T:
            case SCH_NO_CONNECT_T:
                addCurrentItemToList( aDC );
                return;

            case SCH_LINE_T:    // May already be drawing segment.
                break;

            default:
                wxFAIL_MSG( wxT( "SCH_EDIT_FRAME::OnLeftClick error.  Item type <" ) +
                            item->GetClass() + wxT( "> is already being edited." ) );
                item->ClearFlags();
                break;
            }
        }
        else
        {
            item = LocateAndShowItem( aPosition );
        }
    }

    switch( GetToolId() )
    {
    case ID_NO_TOOL_SELECTED:
        break;

    case ID_HIERARCHY_PUSH_POP_BUTT:
        if( ( item && item->GetFlags() ) || ( g_RootSheet->CountSheets() == 0 ) )
            break;

        item = LocateAndShowItem( aPosition, SCH_COLLECTOR::SheetsOnly );

        if( item )  // The user has clicked on a sheet: this is an enter sheet command
        {
            m_CurrentSheet->Push( (SCH_SHEET*) item );
            DisplayCurrentSheet();
        }
        else if( m_CurrentSheet->Last() != g_RootSheet )
        {   // The user has clicked ouside a sheet:this is an leave sheet command
            m_CurrentSheet->Pop();
            DisplayCurrentSheet();
        }
        break;

    case ID_NOCONN_BUTT:
        if( ( item == NULL ) || ( item->GetFlags() == 0 ) )
        {
            if( false == GetScreen()->GetItem( gridPosition, 0, SCH_NO_CONNECT_T ) )
            {
                SCH_NO_CONNECT*  no_connect = AddNoConnect( aDC, gridPosition );
                SetRepeatItem( no_connect );
                GetScreen()->SetCurItem( no_connect );
                m_canvas->SetAutoPanRequest( true );
            }
        }
        else
        {
            addCurrentItemToList( aDC );
        }
        break;

    case ID_JUNCTION_BUTT:
        if( ( item == NULL ) || ( item->GetFlags() == 0 ) )
        {
            if( false == GetScreen()->GetItem( gridPosition, 0, SCH_JUNCTION_T ) )
            {
                SCH_JUNCTION* junction = AddJunction( aDC, gridPosition, true );
                SetRepeatItem( junction );
                GetScreen()->SetCurItem( junction );
                m_canvas->SetAutoPanRequest( true );
            }
        }
        else
        {
            addCurrentItemToList( aDC );
//.........这里部分代码省略.........

void SCH_EDIT_FRAME::OnRotate( wxCommandEvent& aEvent )
{
    SCH_SCREEN* screen = GetScreen();
    SCH_ITEM*   item = screen->GetCurItem();

    INSTALL_UNBUFFERED_DC( dc, m_canvas );

    // Allows block rotate operation on hot key.
    if( screen->m_BlockLocate.GetState() != STATE_NO_BLOCK )
    {
        screen->m_BlockLocate.SetCommand( BLOCK_ROTATE );
        HandleBlockEnd( &dc );
        return;
    }

    if( item == NULL )
    {
        // If we didn't get here by a hot key, then something has gone wrong.
        if( aEvent.GetInt() == 0 )
            return;

        EDA_HOTKEY_CLIENT_DATA* data = (EDA_HOTKEY_CLIENT_DATA*) aEvent.GetClientObject();

        wxCHECK_RET( data != NULL, wxT( "Invalid hot key client object." ) );

        item = LocateAndShowItem( data->GetPosition(), SCH_COLLECTOR::RotatableItems,
                                  aEvent.GetInt() );

        // Exit if no item found at the current location or the item is already being edited.
        if( (item == NULL) || (item->GetFlags() != 0) )
            return;
    }

    switch( item->Type() )
    {
    case SCH_COMPONENT_T:
        {
            SCH_COMPONENT* component = static_cast<SCH_COMPONENT*>( item );
            if( aEvent.GetId() == ID_SCH_ROTATE_CLOCKWISE )
                OrientComponent( CMP_ROTATE_CLOCKWISE );
            else if( aEvent.GetId() == ID_SCH_ROTATE_COUNTERCLOCKWISE )
                OrientComponent( CMP_ROTATE_COUNTERCLOCKWISE );
            else
                wxFAIL_MSG( wxT( "Unknown rotate item command ID." ) );

            if( m_autoplaceFields )
                component->AutoAutoplaceFields( GetScreen() );

            m_canvas->Refresh();

            break;
        }

    case SCH_TEXT_T:
    case SCH_LABEL_T:
    case SCH_GLOBAL_LABEL_T:
    case SCH_HIERARCHICAL_LABEL_T:
        m_canvas->MoveCursorToCrossHair();
        ChangeTextOrient( (SCH_TEXT*) item );
        m_canvas->Refresh();
        break;

    case SCH_FIELD_T:
        m_canvas->MoveCursorToCrossHair();
        RotateField( (SCH_FIELD*) item );
        if( item->GetParent()->Type() == SCH_COMPONENT_T )
        {
            // Now that we're moving a field, they're no longer autoplaced.
            SCH_COMPONENT *parent = static_cast<SCH_COMPONENT*>( item->GetParent() );
            parent->ClearFieldsAutoplaced();
        }
        m_canvas->Refresh();
        break;

    case SCH_BITMAP_T:
        RotateImage( (SCH_BITMAP*) item );
        break;

    case SCH_SHEET_T:
        if( !item->IsNew() )    // rotate a sheet during its creation has no sense
        {
            bool retCCW = ( aEvent.GetId() == ID_SCH_ROTATE_COUNTERCLOCKWISE );
            RotateHierarchicalSheet( static_cast<SCH_SHEET*>( item ), retCCW );
        }

        break;

    case SCH_JUNCTION_T:
    case SCH_NO_CONNECT_T:
        // these items are not rotated, because rotation does not change them.
        break;

    default:
        // Other items (wires...) cannot be rotated, at least during creation
        if( item->IsNew() )
            break;

        wxFAIL_MSG( wxString::Format( wxT( "Cannot rotate schematic item type %s." ),
                                      GetChars( item->GetClass() ) ) );
    }
//.........这里部分代码省略.........

void SCH_EDIT_FRAME::OnDragItem( wxCommandEvent& aEvent )
{
    SCH_SCREEN* screen = GetScreen();
    SCH_ITEM* item = screen->GetCurItem();

    // The easiest way to handle a menu or a hot key drag command
    // is to simulate a block drag command
    //
    // When a drag item is requested, some items use a BLOCK_DRAG_ITEM drag type
    // an some items use a BLOCK_DRAG drag type  (mainly a junction)
    // a BLOCK_DRAG collects all items in a block (here a 2x2 rect centered on the cursor)
    // and BLOCK_DRAG_ITEM drag only the selected item
    BLOCK_COMMAND_T dragType = BLOCK_DRAG_ITEM;

    if( item == NULL )
    {
        // If we didn't get here by a hot key, then something has gone wrong.
        if( aEvent.GetInt() == 0 )
            return;

        EDA_HOTKEY_CLIENT_DATA* data = (EDA_HOTKEY_CLIENT_DATA*) aEvent.GetClientObject();

        wxCHECK_RET( data != NULL, wxT( "Invalid hot key client object." ) );

        item = LocateAndShowItem( data->GetPosition(), SCH_COLLECTOR::DraggableItems,
                                  aEvent.GetInt() );

        // Exit if no item found at the current location or the item is already being edited.
        if( (item == NULL) || (item->GetFlags() != 0) )
            return;

        // When a junction or a node is found, a BLOCK_DRAG is better
        if( m_collectedItems.IsCorner() || m_collectedItems.IsNode( false )
            || m_collectedItems.IsDraggableJunction() )
            dragType = BLOCK_DRAG;
    }

    switch( item->Type() )
    {
    case SCH_BUS_BUS_ENTRY_T:
    case SCH_BUS_WIRE_ENTRY_T:
    case SCH_LINE_T:
    case SCH_JUNCTION_T:
    case SCH_COMPONENT_T:
    case SCH_LABEL_T:
    case SCH_GLOBAL_LABEL_T:
    case SCH_HIERARCHICAL_LABEL_T:
    case SCH_SHEET_T:
        m_canvas->MoveCursorToCrossHair();

        if( screen->m_BlockLocate.GetState() == STATE_NO_BLOCK )
        {
            INSTALL_UNBUFFERED_DC( dc, m_canvas );

            if( !HandleBlockBegin( &dc, dragType, GetCrossHairPosition() ) )
                break;

            // Give a non null size to the search block:
            screen->m_BlockLocate.Inflate( 1 );
            HandleBlockEnd( &dc );
        }

        break;

    default:
        wxFAIL_MSG( wxString::Format( wxT( "Cannot drag schematic item type %s." ),
                                      GetChars( item->GetClass() ) ) );
    }
}