void PCB_EDIT_FRAME::Start_DragTrackSegmentAndKeepSlope( TRACK* track, wxDC*  DC )
{
    TRACK* TrackToStartPoint = NULL;
    TRACK* TrackToEndPoint   = NULL;
    bool   error = false;

    if( !track )
        return;

    // TODO: Use clenup functions to merge collinear segments if track
    // is connected to a collinear segment.

    s_StartSegmentPresent = s_EndSegmentPresent = true;

    if( ( track->start == NULL ) || ( track->start->Type() == PCB_TRACE_T ) )
        TrackToStartPoint = track->GetTrack( GetBoard()->m_Track, NULL, ENDPOINT_START, true, false );

    //  Test if more than one segment is connected to this point
    if( TrackToStartPoint )
    {
        TrackToStartPoint->SetState( BUSY, true );

        if( ( TrackToStartPoint->Type() == PCB_VIA_T )
           || track->GetTrack( GetBoard()->m_Track, NULL, ENDPOINT_START, true, false ) )
            error = true;

        TrackToStartPoint->SetState( BUSY, false );
    }

    if( ( track->end == NULL ) || ( track->end->Type() == PCB_TRACE_T ) )
        TrackToEndPoint = track->GetTrack( GetBoard()->m_Track, NULL, ENDPOINT_END, true, false );

    //  Test if more than one segment is connected to this point
    if( TrackToEndPoint )
    {
        TrackToEndPoint->SetState( BUSY, true );

        if( (TrackToEndPoint->Type() == PCB_VIA_T)
           || track->GetTrack( GetBoard()->m_Track, NULL, ENDPOINT_END, true, false ) )
            error = true;

        TrackToEndPoint->SetState( BUSY, false );
    }

    if( error )
    {
        DisplayError( this,
                      _( "Unable to drag this segment: too many segments connected" ) );
        return;
    }

    if( !TrackToStartPoint || ( TrackToStartPoint->Type() != PCB_TRACE_T ) )
        s_StartSegmentPresent = false;

    if( !TrackToEndPoint || ( TrackToEndPoint->Type() != PCB_TRACE_T ) )
        s_EndSegmentPresent = false;

    // Change high light net: the new one will be highlighted
    GetBoard()->PushHighLight();

    if( GetBoard()->IsHighLightNetON() )
        HighLight( DC );

    EraseDragList();

    track->SetFlags( IS_DRAGGED );

    if( TrackToStartPoint )
    {
        STATUS_FLAGS flag = STARTPOINT;

        if( track->GetStart() != TrackToStartPoint->GetStart() )
            flag = ENDPOINT;

        AddSegmentToDragList( flag, TrackToStartPoint );
        track->SetFlags( STARTPOINT );
    }

    if( TrackToEndPoint )
    {
        STATUS_FLAGS flag = STARTPOINT;

        if( track->GetEnd() != TrackToEndPoint->GetStart() )
            flag = ENDPOINT;

        AddSegmentToDragList( flag, TrackToEndPoint );
        track->SetFlags( ENDPOINT );
    }

    AddSegmentToDragList( track->GetFlags(), track );

    UndrawAndMarkSegmentsToDrag( m_canvas, DC );


    PosInit   = GetCrossHairPosition();
    s_LastPos = GetCrossHairPosition();
    m_canvas->SetMouseCapture( Show_Drag_Track_Segment_With_Cte_Slope, Abort_MoveTrack );

    GetBoard()->SetHighLightNet( track->GetNetCode() );
    GetBoard()->HighLightON();
    GetBoard()->DrawHighLight( m_canvas, DC, GetBoard()->GetHighLightNetCode() );

    // Prepare the Undo command
    ITEM_PICKER picker( NULL, UR_CHANGED );

    for( unsigned ii = 0; ii < g_DragSegmentList.size(); ii++ )
    {
        TRACK* draggedtrack = g_DragSegmentList[ii].m_Track;
        picker.SetItem( draggedtrack);
        picker.SetLink ( draggedtrack->Clone() );
        s_ItemsListPicker.PushItem( picker );
        draggedtrack = (TRACK*) picker.GetLink();
        draggedtrack->SetStatus( 0 );
        draggedtrack->ClearFlags();
    }

    if( !InitialiseDragParameters() )
    {
        DisplayError( this, _( "Unable to drag this segment: two collinear segments" ) );
        m_canvas->SetMouseCaptureCallback( NULL );
        Abort_MoveTrack( m_canvas, DC );
        return;
    }
}
void PCB_EDIT_FRAME::StartMoveOneNodeOrSegment( TRACK* aTrack, wxDC* aDC, int aCommand )
{
    if( !aTrack )
        return;

    EraseDragList();

    // Change highlighted net: the new one will be highlighted
    GetBoard()->PushHighLight();

    if( GetBoard()->IsHighLightNetON() )
        HighLight( aDC );

    PosInit = GetCrossHairPosition();

    if( aTrack->Type() == PCB_VIA_T )
    {
        aTrack->SetFlags( IS_DRAGGED | STARTPOINT | ENDPOINT );
        AddSegmentToDragList( aTrack->GetFlags(), aTrack );

        if( aCommand != ID_POPUP_PCB_MOVE_TRACK_SEGMENT )
        {
            Collect_TrackSegmentsToDrag( GetBoard(), aTrack->GetStart(),
                                         aTrack->GetLayerSet(),
                                         aTrack->GetNetCode(), aTrack->GetWidth() / 2 );
        }

        PosInit = aTrack->GetStart();
    }
    else
    {
        STATUS_FLAGS diag = aTrack->IsPointOnEnds( GetCrossHairPosition(), -1 );
        wxPoint pos;

        switch( aCommand )
        {
        case ID_POPUP_PCB_MOVE_TRACK_SEGMENT:   // Move segment
            aTrack->SetFlags( IS_DRAGGED | ENDPOINT | STARTPOINT );
            AddSegmentToDragList( aTrack->GetFlags(), aTrack );
            break;

        case ID_POPUP_PCB_DRAG_TRACK_SEGMENT:   // drag a segment
            pos = aTrack->GetStart();
            Collect_TrackSegmentsToDrag( GetBoard(), pos, aTrack->GetLayerSet(),
                                         aTrack->GetNetCode(), aTrack->GetWidth() / 2 );
            pos = aTrack->GetEnd();
            aTrack->SetFlags( IS_DRAGGED | ENDPOINT | STARTPOINT );
            Collect_TrackSegmentsToDrag( GetBoard(), pos, aTrack->GetLayerSet(),
                                         aTrack->GetNetCode(), aTrack->GetWidth() / 2 );
            break;

        case ID_POPUP_PCB_MOVE_TRACK_NODE:  // Drag via or move node
            pos = (diag & STARTPOINT) ? aTrack->GetStart() : aTrack->GetEnd();
            Collect_TrackSegmentsToDrag( GetBoard(), pos, aTrack->GetLayerSet(),
                                         aTrack->GetNetCode(), aTrack->GetWidth() / 2 );
            PosInit = pos;
            break;
        }

        aTrack->SetFlags( IS_DRAGGED );
    }

    // Prepare the Undo command
    ITEM_PICKER picker( aTrack, UR_CHANGED );
    picker.SetLink( aTrack->Clone() );
    s_ItemsListPicker.PushItem( picker );

    for( unsigned ii = 0; ii < g_DragSegmentList.size(); ii++ )
    {
        TRACK* draggedtrack = g_DragSegmentList[ii].m_Track;
        picker.SetItem( draggedtrack );
        picker.SetLink( draggedtrack->Clone() );
        s_ItemsListPicker.PushItem( picker );
        draggedtrack = (TRACK*) picker.GetLink();
        draggedtrack->SetStatus( 0 );
        draggedtrack->ClearFlags();
    }

    s_LastPos = PosInit;
    m_canvas->SetMouseCapture( Show_MoveNode, Abort_MoveTrack );

    GetBoard()->SetHighLightNet( aTrack->GetNetCode() );
    GetBoard()->HighLightON();

    GetBoard()->DrawHighLight( m_canvas, aDC, GetBoard()->GetHighLightNetCode() );
    m_canvas->CallMouseCapture( aDC, wxDefaultPosition, true );

    UndrawAndMarkSegmentsToDrag( m_canvas, aDC );
}