C++ DLIST::GetFirst方法代码示例

/**
 * In a contiguous list of wires, remove wires that backtrack over the previous
 * wire. Example:
 *
 * Wire is added:
 * ---------------------------------------->
 *
 * A second wire backtracks over it:
 * -------------------<====================>
 *
 * RemoveBacktracks is called:
 * ------------------->
 */
static void RemoveBacktracks( DLIST<SCH_ITEM>& aWires )
{
    SCH_LINE* last_line = NULL;

    EDA_ITEM* first = aWires.GetFirst();
    for( EDA_ITEM* p = first; p; )
    {
        SCH_LINE *line = dynamic_cast<SCH_LINE*>( p );
        if( !line )
        {
            wxFAIL_MSG( "RemoveBacktracks() requires SCH_LINE items" );
            break;
        }
        p = line->Next();

        if( last_line )
        {
            wxASSERT_MSG( last_line->GetEndPoint() == line->GetStartPoint(),
                    "RemoveBacktracks() requires contiguous lines" );
            if( IsPointOnSegment( last_line->GetStartPoint(), line->GetStartPoint(),
                        line->GetEndPoint() ) )
            {
                last_line->SetEndPoint( line->GetEndPoint() );
                delete s_wires.Remove( line );
            }
            else
                last_line = line;
        }
        else
            last_line = line;
    }
}

/**
 * In a contiguous list of wires, remove wires that backtrack over the previous
 * wire. Example:
 *
 * Wire is added:
 * ---------------------------------------->
 *
 * A second wire backtracks over it:
 * -------------------<====================>
 *
 * RemoveBacktracks is called:
 * ------------------->
 */
static void RemoveBacktracks( DLIST<SCH_ITEM>& aWires )
{
    EDA_ITEM* first = aWires.GetFirst();
    std::vector<SCH_LINE*> last_lines;

    for( EDA_ITEM* p = first; p; )
    {
        SCH_LINE *line = static_cast<SCH_LINE*>( p );
        p = line->Next();

        if( !last_lines.empty() )
        {
            SCH_LINE* last_line = last_lines[last_lines.size() - 1];
            bool contiguous = ( last_line->GetEndPoint() == line->GetStartPoint() );
            bool backtracks = IsPointOnSegment( last_line->GetStartPoint(),
                    last_line->GetEndPoint(), line->GetEndPoint() );
            bool total_backtrack = ( last_line->GetStartPoint() == line->GetEndPoint() );

            if( contiguous && backtracks )
            {
                if( total_backtrack )
                {
                    delete s_wires.Remove( last_line );
                    delete s_wires.Remove( line );
                    last_lines.pop_back();
                }
                else
                {
                    last_line->SetEndPoint( line->GetEndPoint() );
                    delete s_wires.Remove( line );
                }
            }
            else
            {
                last_lines.push_back( line );
            }
        }
        else
        {
            last_lines.push_back( line );
        }
    }
}

void SCH_EDIT_FRAME::EndSegment( wxDC* DC )
{
    SCH_SCREEN* screen = GetScreen();
    SCH_LINE* segment = (SCH_LINE*) screen->GetCurItem();

    if( segment == NULL || segment->Type() != SCH_LINE_T || !segment->IsNew() )
        return;

    // Delete zero length segments and clear item flags.
    SCH_ITEM* item = s_wires.begin();

    while( item )
    {
        item->ClearFlags();

        wxCHECK_RET( item->Type() == SCH_LINE_T, wxT( "Unexpected object type in wire list." ) );

        segment = (SCH_LINE*) item;
        item = item->Next();

        if( segment->IsNull() )
            delete s_wires.Remove( segment );
    }

    if( s_wires.GetCount() == 0 )
        return;

    // Get the last non-null wire (this is the last created segment).
    SetRepeatItem( segment = (SCH_LINE*) s_wires.GetLast() );

    screen->SetCurItem( NULL );
    m_canvas->EndMouseCapture( -1, -1, wxEmptyString, false );

    // store the terminal point of this last segment: a junction could be needed
    // (the last wire could be merged/deleted/modified, and lost)
    wxPoint endpoint = segment->GetEndPoint();

    // store the starting point of this first segment: a junction could be needed
    SCH_LINE* firstsegment = (SCH_LINE*) s_wires.GetFirst();
    wxPoint startPoint = firstsegment->GetStartPoint();

    // Save the old wires for the undo command
    DLIST< SCH_ITEM > oldWires;                     // stores here the old wires
    GetScreen()->ExtractWires( oldWires, true );    // Save them in oldWires list
    // Put the snap shot of the previous wire, buses, and junctions in the undo/redo list.
    PICKED_ITEMS_LIST oldItems;
    oldItems.m_Status = UR_WIRE_IMAGE;

    while( oldWires.GetCount() != 0 )
    {
        ITEM_PICKER picker = ITEM_PICKER( oldWires.PopFront(), UR_WIRE_IMAGE );
        oldItems.PushItem( picker );
    }

    SaveCopyInUndoList( oldItems, UR_WIRE_IMAGE );

    // Remove segments backtracking over others
    RemoveBacktracks( s_wires );

    // Add the new wires
    screen->Append( s_wires );

    // Correct and remove segments that need to be merged.
    screen->SchematicCleanUp();

    // A junction could be needed to connect the end point of the last created segment.
    if( screen->IsJunctionNeeded( endpoint ) )
        screen->Append( AddJunction( DC, endpoint ) );

    // A junction could be needed to connect the start point of the set of new created wires
    if( screen->IsJunctionNeeded( startPoint ) )
        screen->Append( AddJunction( DC, startPoint ) );

    m_canvas->Refresh();

    OnModify();
}