kicad/pcbnew/plot_board_layers.cpp

/**
 * @file plot_board_layers.cpp
 * @brief Functions to plot one board layer (silkscreen layers or other layers).
 * Silkscreen layers have specific requirement for pads (not filled) and texts
 * (with option to remove them from some copper areas (pads...)
 */

/*
 * This program source code file is part of KiCad, a free EDA CAD application.
 *
 * Copyright (C) 1992-2022 KiCad Developers, see AUTHORS.txt for contributors.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, you may find one here:
 * http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
 * or you may search the http://www.gnu.org website for the version 2 license,
 * or you may write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
 */


#include <eda_item.h>
#include <layer_ids.h>
#include <geometry/geometry_utils.h>
#include <geometry/shape_segment.h>
#include <pcb_base_frame.h>
#include <math/util.h>      // for KiROUND

#include <board.h>
#include <board_design_settings.h>
#include <core/arraydim.h>
#include <footprint.h>
#include <pcb_track.h>
#include <fp_shape.h>
#include <pad.h>
#include <pcb_text.h>
#include <zone.h>
#include <pcb_shape.h>
#include <pcb_target.h>
#include <pcb_dimension.h>

#include <pcbplot.h>
#include <plotters/plotter_dxf.h>
#include <plotters/plotter_hpgl.h>
#include <plotters/plotter_gerber.h>
#include <plotters/plotters_pslike.h>
#include <pcb_painter.h>
#include <gbr_metadata.h>
#include <advanced_config.h>

/*
 * Plot a solder mask layer.  Solder mask layers have a minimum thickness value and cannot be
 * drawn like standard layers, unless the minimum thickness is 0.
 */
static void PlotSolderMaskLayer( BOARD *aBoard, PLOTTER* aPlotter, LSET aLayerMask,
                                 const PCB_PLOT_PARAMS& aPlotOpt, int aMinThickness );


void PlotBoardLayers( BOARD* aBoard, PLOTTER* aPlotter, const LSEQ& aLayers,
                      const PCB_PLOT_PARAMS& aPlotOptions )
{
    wxCHECK( aBoard && aPlotter && aLayers.size(), /* void */ );

    for( LSEQ seq = aLayers; seq; ++seq )
        PlotOneBoardLayer( aBoard, aPlotter, *seq, aPlotOptions );
}


void PlotOneBoardLayer( BOARD *aBoard, PLOTTER* aPlotter, PCB_LAYER_ID aLayer,
                        const PCB_PLOT_PARAMS& aPlotOpt )
{
    PCB_PLOT_PARAMS plotOpt = aPlotOpt;
    int soldermask_min_thickness = aBoard->GetDesignSettings().m_SolderMaskMinWidth;

    // Set a default color and the text mode for this layer
    aPlotter->SetColor( BLACK );
    aPlotter->SetTextMode( aPlotOpt.GetTextMode() );

    // Specify that the contents of the "Edges Pcb" layer are to be plotted in addition to the
    // contents of the currently specified layer.
    LSET    layer_mask( aLayer );

    if( IsCopperLayer( aLayer ) )
    {
        // Skip NPTH pads on copper layers ( only if hole size == pad size ):
        // Drill mark will be plotted if drill mark is SMALL_DRILL_SHAPE  or FULL_DRILL_SHAPE
        if( plotOpt.GetFormat() == PLOT_FORMAT::DXF )
        {
            plotOpt.SetSkipPlotNPTH_Pads( false );
            PlotLayerOutlines( aBoard, aPlotter, layer_mask, plotOpt );
        }
        else
        {
            plotOpt.SetSkipPlotNPTH_Pads( true );
            PlotStandardLayer( aBoard, aPlotter, layer_mask, plotOpt );
        }
    }
    else
    {
        switch( aLayer )
        {
        case B_Mask:
        case F_Mask:
            plotOpt.SetSkipPlotNPTH_Pads( false );

            // Disable plot pad holes
            plotOpt.SetDrillMarksType( PCB_PLOT_PARAMS::NO_DRILL_SHAPE );

            // Plot solder mask:
            if( soldermask_min_thickness == 0 )
            {
                if( plotOpt.GetFormat() == PLOT_FORMAT::DXF )
                    PlotLayerOutlines( aBoard, aPlotter, layer_mask, plotOpt );
                else
                    PlotStandardLayer( aBoard, aPlotter, layer_mask, plotOpt );
            }
            else
            {
                PlotSolderMaskLayer( aBoard, aPlotter, layer_mask, plotOpt,
                                     soldermask_min_thickness );
            }

            break;

        case B_Adhes:
        case F_Adhes:
        case B_Paste:
        case F_Paste:
            plotOpt.SetSkipPlotNPTH_Pads( false );

            // Disable plot pad holes
            plotOpt.SetDrillMarksType( PCB_PLOT_PARAMS::NO_DRILL_SHAPE );

            if( plotOpt.GetFormat() == PLOT_FORMAT::DXF )
                PlotLayerOutlines( aBoard, aPlotter, layer_mask, plotOpt );
            else
                PlotStandardLayer( aBoard, aPlotter, layer_mask, plotOpt );

            break;

        case F_SilkS:
        case B_SilkS:
            if( plotOpt.GetFormat() == PLOT_FORMAT::DXF && plotOpt.GetDXFPlotPolygonMode() )
                // PlotLayerOutlines() is designed only for DXF plotters.
                // and must not be used for other plot formats
                PlotLayerOutlines( aBoard, aPlotter, layer_mask, plotOpt );
            else
                PlotStandardLayer( aBoard, aPlotter, layer_mask, plotOpt );

            // Gerber: Subtract soldermask from silkscreen if enabled
            if( aPlotter->GetPlotterType() == PLOT_FORMAT::GERBER
                    && plotOpt.GetSubtractMaskFromSilk() )
            {
                if( aLayer == F_SilkS )
                    layer_mask = LSET( F_Mask );
                else
                    layer_mask = LSET( B_Mask );

                // Create the mask to subtract by creating a negative layer polarity
                aPlotter->SetLayerPolarity( false );

                // Disable plot pad holes
                plotOpt.SetDrillMarksType( PCB_PLOT_PARAMS::NO_DRILL_SHAPE );

                // Plot the mask
                PlotStandardLayer( aBoard, aPlotter, layer_mask, plotOpt );
            }

            break;

        // These layers are plotted like silk screen layers.
        // Mainly, pads on these layers are not filled.
        // This is not necessary the best choice.
        case Dwgs_User:
        case Cmts_User:
        case Eco1_User:
        case Eco2_User:
        case Edge_Cuts:
        case Margin:
        case F_CrtYd:
        case B_CrtYd:
        case F_Fab:
        case B_Fab:
            plotOpt.SetSkipPlotNPTH_Pads( false );
            plotOpt.SetDrillMarksType( PCB_PLOT_PARAMS::NO_DRILL_SHAPE );

            if( plotOpt.GetFormat() == PLOT_FORMAT::DXF && plotOpt.GetDXFPlotPolygonMode() )
                // PlotLayerOutlines() is designed only for DXF plotters.
                // and must not be used for other plot formats
                PlotLayerOutlines( aBoard, aPlotter, layer_mask, plotOpt );
            else
                PlotStandardLayer( aBoard, aPlotter, layer_mask, plotOpt );

            break;

        default:
            plotOpt.SetSkipPlotNPTH_Pads( false );
            plotOpt.SetDrillMarksType( PCB_PLOT_PARAMS::NO_DRILL_SHAPE );

            if( plotOpt.GetFormat() == PLOT_FORMAT::DXF && plotOpt.GetDXFPlotPolygonMode() )
                // PlotLayerOutlines() is designed only for DXF plotters.
                // and must not be used for other plot formats
                PlotLayerOutlines( aBoard, aPlotter, layer_mask, plotOpt );
            else
                PlotStandardLayer( aBoard, aPlotter, layer_mask, plotOpt );

            break;
        }
    }
}


/**
 * Plot a copper layer or mask.
 *
 * Silk screen layers are not plotted here.
 */
void PlotStandardLayer( BOARD* aBoard, PLOTTER* aPlotter, LSET aLayerMask,
                        const PCB_PLOT_PARAMS& aPlotOpt )
{
    BRDITEMS_PLOTTER itemplotter( aPlotter, aBoard, aPlotOpt );

    itemplotter.SetLayerSet( aLayerMask );

    OUTLINE_MODE plotMode = aPlotOpt.GetPlotMode();
    bool onCopperLayer = ( LSET::AllCuMask() & aLayerMask ).any();
    bool onSolderMaskLayer = ( LSET( 2, F_Mask, B_Mask ) & aLayerMask ).any();
    bool onSolderPasteLayer = ( LSET( 2, F_Paste, B_Paste ) & aLayerMask ).any();
    bool onFrontFab = ( LSET(  F_Fab ) & aLayerMask ).any();
    bool onBackFab  = ( LSET( B_Fab ) & aLayerMask ).any();
    bool sketchPads = ( onFrontFab || onBackFab ) && aPlotOpt.GetSketchPadsOnFabLayers();

     // Plot edge layer and graphic items
    itemplotter.PlotBoardGraphicItems();

    // Draw footprint texts:
    for( const FOOTPRINT* footprint : aBoard->Footprints() )
        itemplotter.PlotFootprintTextItems( footprint );

    // Draw footprint other graphic items:
    for( const FOOTPRINT* footprint : aBoard->Footprints() )
        itemplotter.PlotFootprintGraphicItems( footprint );

    // Plot footprint pads
    for( FOOTPRINT* footprint : aBoard->Footprints() )
    {
        aPlotter->StartBlock( nullptr );

        for( PAD* pad : footprint->Pads() )
        {
            OUTLINE_MODE padPlotMode = plotMode;

            if( !( pad->GetLayerSet() & aLayerMask ).any() )
            {
                if( sketchPads &&
                        ( ( onFrontFab && pad->GetLayerSet().Contains( F_Cu ) ) ||
                          ( onBackFab && pad->GetLayerSet().Contains( B_Cu ) ) ) )
                {
                    padPlotMode = SKETCH;
                }
                else
                {
                    continue;
                }
            }

            /// pads not connected to copper are optionally not drawn
            if( onCopperLayer && !pad->FlashLayer( aLayerMask ) )
                continue;

            COLOR4D color = COLOR4D::BLACK;

            if( ( pad->GetLayerSet() & aLayerMask )[B_Cu] )
               color = aPlotOpt.ColorSettings()->GetColor( B_Cu );

            if( ( pad->GetLayerSet() & aLayerMask )[F_Cu] )
                color = color.LegacyMix( aPlotOpt.ColorSettings()->GetColor( F_Cu ) );

            if( sketchPads && aLayerMask[F_Fab] )
                color = aPlotOpt.ColorSettings()->GetColor( F_Fab );
            else if( sketchPads && aLayerMask[B_Fab] )
                color = aPlotOpt.ColorSettings()->GetColor( B_Fab );

            VECTOR2I margin;
            int width_adj = 0;

            if( onCopperLayer )
                width_adj = itemplotter.getFineWidthAdj();

            if( onSolderMaskLayer )
                margin.x = margin.y = pad->GetSolderMaskExpansion();

            if( onSolderPasteLayer )
                margin = pad->GetSolderPasteMargin();

            // not all shapes can have a different margin for x and y axis
            // in fact only oval and rect shapes can have different values.
            // Round shape have always the same x,y margin
            // so define a unique value for other shapes that do not support different values
            int mask_clearance = margin.x;

            // Now offset the pad size by margin + width_adj
            VECTOR2I padPlotsSize = pad->GetSize() + margin * 2 + VECTOR2I( width_adj, width_adj );

            // Store these parameters that can be modified to plot inflated/deflated pads shape
            PAD_SHAPE padShape = pad->GetShape();
            VECTOR2I  padSize = pad->GetSize();
            VECTOR2I  padDelta = pad->GetDelta(); // has meaning only for trapezoidal pads
            double    padCornerRadius = pad->GetRoundRectCornerRadius();

            // Don't draw a 0 sized pad.
            // Note: a custom pad can have its pad anchor with size = 0
            if( pad->GetShape() != PAD_SHAPE::CUSTOM
                && ( padPlotsSize.x <= 0 || padPlotsSize.y <= 0 ) )
                continue;

            switch( pad->GetShape() )
            {
            case PAD_SHAPE::CIRCLE:
            case PAD_SHAPE::OVAL:
                pad->SetSize( padPlotsSize );

                if( aPlotOpt.GetSkipPlotNPTH_Pads() &&
                    ( aPlotOpt.GetDrillMarksType() == PCB_PLOT_PARAMS::NO_DRILL_SHAPE ) &&
                    ( pad->GetSize() == pad->GetDrillSize() ) &&
                    ( pad->GetAttribute() == PAD_ATTRIB::NPTH ) )
                {
                    break;
                }

                itemplotter.PlotPad( pad, color, padPlotMode );
                break;

            case PAD_SHAPE::RECT:
                pad->SetSize( padPlotsSize );

                if( mask_clearance > 0 )
                {
                    pad->SetShape( PAD_SHAPE::ROUNDRECT );
                    pad->SetRoundRectCornerRadius( mask_clearance );
                }

                itemplotter.PlotPad( pad, color, padPlotMode );
                break;

            case PAD_SHAPE::TRAPEZOID:
                // inflate/deflate a trapezoid is a bit complex.
                // so if the margin is not null, build a similar polygonal pad shape,
                // and inflate/deflate the polygonal shape
                // because inflating/deflating using different values for y and y
                // we are using only margin.x as inflate/deflate value
                if( mask_clearance == 0 )
                {
                    itemplotter.PlotPad( pad, color, padPlotMode );
                }
                else
                {
                    PAD dummy( *pad );
                    dummy.SetAnchorPadShape( PAD_SHAPE::CIRCLE );
                    dummy.SetShape( PAD_SHAPE::CUSTOM );
                    SHAPE_POLY_SET outline;
                    outline.NewOutline();
                    int dx = padSize.x / 2;
                    int dy = padSize.y / 2;
                    int ddx = padDelta.x / 2;
                    int ddy = padDelta.y / 2;

                    outline.Append( -dx - ddy,  dy + ddx );
                    outline.Append(  dx + ddy,  dy - ddx );
                    outline.Append(  dx - ddy, -dy + ddx );
                    outline.Append( -dx + ddy, -dy - ddx );

                    // Shape polygon can have holes so use InflateWithLinkedHoles(), not Inflate()
                    // which can create bad shapes if margin.x is < 0
                    int maxError = aBoard->GetDesignSettings().m_MaxError;
                    int numSegs = GetArcToSegmentCount( mask_clearance, maxError, FULL_CIRCLE );
                    outline.InflateWithLinkedHoles( mask_clearance, numSegs,
                                                    SHAPE_POLY_SET::PM_FAST );
                    dummy.DeletePrimitivesList();
                    dummy.AddPrimitivePoly( outline, 0, true );

                    // Be sure the anchor pad is not bigger than the deflated shape because this
                    // anchor will be added to the pad shape when plotting the pad. So now the
                    // polygonal shape is built, we can clamp the anchor size
                    dummy.SetSize( wxSize( 0,0 ) );

                    itemplotter.PlotPad( &dummy, color, padPlotMode );
                }

                break;

            case PAD_SHAPE::ROUNDRECT:
            {
                // rounding is stored as a percent, but we have to change the new radius
                // to initial_radius + clearance to have a inflated/deflated similar shape
                int initial_radius = pad->GetRoundRectCornerRadius();
                pad->SetSize( padPlotsSize );
                pad->SetRoundRectCornerRadius( std::max( initial_radius + mask_clearance, 0 ) );

                itemplotter.PlotPad( pad, color, padPlotMode );
                break;
            }

            case PAD_SHAPE::CHAMFERED_RECT:
                if( mask_clearance == 0 )
                {
                    // the size can be slightly inflated by width_adj (PS/PDF only)
                    pad->SetSize( padPlotsSize );
                    itemplotter.PlotPad( pad, color, padPlotMode );
                }
                else
                {
                    // Due to the polygonal shape of a CHAMFERED_RECT pad, the best way is to
                    // convert the pad shape to a full polygon, inflate/deflate the polygon
                    // and use a dummy  CUSTOM pad to plot the final shape.
                    PAD dummy( *pad );
                    // Build the dummy pad outline with coordinates relative to the pad position
                    // and orientation 0. The actual pos and rotation will be taken in account
                    // later by the plot function
                    dummy.SetPosition( VECTOR2I( 0, 0 ) );
                    dummy.SetOrientation( ANGLE_0 );
                    SHAPE_POLY_SET outline;
                    int maxError = aBoard->GetDesignSettings().m_MaxError;
                    int numSegs = GetArcToSegmentCount( mask_clearance, maxError, FULL_CIRCLE );
                    dummy.TransformShapeWithClearanceToPolygon( outline, UNDEFINED_LAYER, 0,
                                                                maxError, ERROR_INSIDE );
                    outline.InflateWithLinkedHoles( mask_clearance, numSegs,
                                                    SHAPE_POLY_SET::PM_FAST );

                    // Initialize the dummy pad shape:
                    dummy.SetAnchorPadShape( PAD_SHAPE::CIRCLE );
                    dummy.SetShape( PAD_SHAPE::CUSTOM );
                    dummy.DeletePrimitivesList();
                    dummy.AddPrimitivePoly( outline, 0, true );

                    // Be sure the anchor pad is not bigger than the deflated shape because this
                    // anchor will be added to the pad shape when plotting the pad.
                    // So we set the anchor size to 0
                    dummy.SetSize( wxSize( 0,0 ) );
                    dummy.SetPosition( pad->GetPosition() );
                    dummy.SetOrientation( pad->GetOrientation() );

                    itemplotter.PlotPad( &dummy, color, padPlotMode );
                }

                break;

            case PAD_SHAPE::CUSTOM:
            {
                // inflate/deflate a custom shape is a bit complex.
                // so build a similar pad shape, and inflate/deflate the polygonal shape
                PAD dummy( *pad );
                SHAPE_POLY_SET shape;
                pad->MergePrimitivesAsPolygon( &shape );

                // Shape polygon can have holes so use InflateWithLinkedHoles(), not Inflate()
                // which can create bad shapes if margin.x is < 0
                int maxError = aBoard->GetDesignSettings().m_MaxError;
                int numSegs = GetArcToSegmentCount( mask_clearance, maxError, FULL_CIRCLE );
                shape.InflateWithLinkedHoles( mask_clearance, numSegs, SHAPE_POLY_SET::PM_FAST );
                dummy.DeletePrimitivesList();
                dummy.AddPrimitivePoly( shape, 0, true );

                // Be sure the anchor pad is not bigger than the deflated shape because this
                // anchor will be added to the pad shape when plotting the pad. So now the
                // polygonal shape is built, we can clamp the anchor size
                if( mask_clearance < 0 )  // we expect margin.x = margin.y for custom pads
                    dummy.SetSize( padPlotsSize );

                itemplotter.PlotPad( &dummy, color, padPlotMode );
                break;
            }
            }

            // Restore the pad parameters modified by the plot code
            pad->SetSize( padSize );
            pad->SetDelta( padDelta );
            pad->SetShape( padShape );
            pad->SetRoundRectCornerRadius( padCornerRadius );
        }

        aPlotter->EndBlock( nullptr );
    }

    // Plot vias on copper layers, and if aPlotOpt.GetPlotViaOnMaskLayer() is true,
    // plot them on solder mask

    GBR_METADATA gbr_metadata;

    bool isOnCopperLayer = ( aLayerMask & LSET::AllCuMask() ).any();

    if( isOnCopperLayer )
    {
        gbr_metadata.SetApertureAttrib( GBR_APERTURE_METADATA::GBR_APERTURE_ATTRIB_VIAPAD );
        gbr_metadata.SetNetAttribType( GBR_NETLIST_METADATA::GBR_NETINFO_NET );
    }

    aPlotter->StartBlock( nullptr );

    for( const PCB_TRACK* track : aBoard->Tracks() )
    {
        const PCB_VIA* via = dyn_cast<const PCB_VIA*>( track );

        if( !via )
            continue;

        // vias are not plotted if not on selected layer, but if layer is SOLDERMASK_LAYER_BACK
        // or SOLDERMASK_LAYER_FRONT, vias are drawn only if they are on the corresponding
        // external copper layer
        LSET via_mask_layer = via->GetLayerSet();

        if( aPlotOpt.GetPlotViaOnMaskLayer() )
        {
            if( via_mask_layer[B_Cu] )
                via_mask_layer.set( B_Mask );

            if( via_mask_layer[F_Cu] )
                via_mask_layer.set( F_Mask );
        }

        if( !( via_mask_layer & aLayerMask ).any() )
            continue;

        int via_margin = 0;
        double width_adj = 0;

        if( aLayerMask[B_Mask] || aLayerMask[F_Mask] )
            via_margin = via->GetSolderMaskExpansion();

        if( ( aLayerMask & LSET::AllCuMask() ).any() )
            width_adj = itemplotter.getFineWidthAdj();

        int diameter = via->GetWidth() + 2 * via_margin + width_adj;

        /// Vias not connected to copper are optionally not drawn
        if( onCopperLayer && !via->FlashLayer( aLayerMask ) )
            continue;

        // Don't draw a null size item :
        if( diameter <= 0 )
            continue;

        // Some vias can be not connected (no net).
        // Set the m_NotInNet for these vias to force a empty net name in gerber file
        gbr_metadata.m_NetlistMetadata.m_NotInNet = via->GetNetname().IsEmpty();

        gbr_metadata.SetNetName( via->GetNetname() );

        COLOR4D color = aPlotOpt.ColorSettings()->GetColor(
                LAYER_VIAS + static_cast<int>( via->GetViaType() ) );

        // Set plot color (change WHITE to LIGHTGRAY because the white items are not seen on a
        // white paper or screen
        aPlotter->SetColor( color != WHITE ? color : LIGHTGRAY );
        aPlotter->FlashPadCircle( via->GetStart(), diameter, plotMode, &gbr_metadata );
    }

    aPlotter->EndBlock( nullptr );
    aPlotter->StartBlock( nullptr );
    gbr_metadata.SetApertureAttrib( GBR_APERTURE_METADATA::GBR_APERTURE_ATTRIB_CONDUCTOR );

    // Plot tracks (not vias) :
    for( const PCB_TRACK* track : aBoard->Tracks() )
    {
        if( track->Type() == PCB_VIA_T )
            continue;

        if( !aLayerMask[track->GetLayer()] )
            continue;

        // Some track segments can be not connected (no net).
        // Set the m_NotInNet for these segments to force a empty net name in gerber file
        gbr_metadata.m_NetlistMetadata.m_NotInNet = track->GetNetname().IsEmpty();

        gbr_metadata.SetNetName( track->GetNetname() );
        int width = track->GetWidth() + itemplotter.getFineWidthAdj();
        aPlotter->SetColor( itemplotter.getColor( track->GetLayer() ) );

        if( track->Type() == PCB_ARC_T )
        {
            const     PCB_ARC* arc = static_cast<const PCB_ARC*>( track );

            // ThickArc expects only positive angle arcs, so flip start/end if
            // we are negative
            if( arc->GetAngle() < ANGLE_0 )
            {
                aPlotter->ThickArc( arc->GetCenter(), arc->GetEnd(), arc->GetStart(),
                                    width, plotMode, &gbr_metadata );
            }
            else
            {
                aPlotter->ThickArc( arc->GetCenter(), arc->GetStart(), arc->GetEnd(),
                                    width, plotMode, &gbr_metadata );
            }
        }
        else
        {
            aPlotter->ThickSegment( track->GetStart(), track->GetEnd(), width, plotMode,
                                    &gbr_metadata );
        }
    }

    aPlotter->EndBlock( nullptr );

    // Plot filled ares
    aPlotter->StartBlock( nullptr );

    NETINFO_ITEM nonet( aBoard );

    for( const ZONE* zone : aBoard->Zones() )
    {
        for( PCB_LAYER_ID layer : zone->GetLayerSet().Seq() )
        {
            if( !aLayerMask[layer] )
                continue;

            SHAPE_POLY_SET mainArea = zone->GetFilledPolysList( layer )->CloneDropTriangulation();
            SHAPE_POLY_SET islands;

            for( int i = mainArea.OutlineCount() - 1; i >= 0; i-- )
            {
                if( zone->IsIsland( layer, i ) )
                {
                    islands.AddOutline( mainArea.CPolygon( i )[0] );
                    mainArea.DeletePolygon( i );
                }
            }

            itemplotter.PlotFilledAreas( zone, layer, mainArea );

            if( !islands.IsEmpty() )
            {
                ZONE dummy( *zone );
                dummy.SetNet( &nonet );
                itemplotter.PlotFilledAreas( &dummy, layer, islands );
            }
        }
    }

    aPlotter->EndBlock( nullptr );

    // Adding drill marks, if required and if the plotter is able to plot them:
    if( aPlotOpt.GetDrillMarksType() != PCB_PLOT_PARAMS::NO_DRILL_SHAPE )
        itemplotter.PlotDrillMarks();
}


/**
 * Plot outlines of copper layer.
 */
void PlotLayerOutlines( BOARD* aBoard, PLOTTER* aPlotter, LSET aLayerMask,
                        const PCB_PLOT_PARAMS& aPlotOpt )
{
    BRDITEMS_PLOTTER itemplotter( aPlotter, aBoard, aPlotOpt );
    itemplotter.SetLayerSet( aLayerMask );

    SHAPE_POLY_SET outlines;

    for( LSEQ seq = aLayerMask.Seq( aLayerMask.SeqStackupBottom2Top() );  seq;  ++seq )
    {
        PCB_LAYER_ID layer = *seq;

        outlines.RemoveAllContours();
        aBoard->ConvertBrdLayerToPolygonalContours( layer, outlines );

        outlines.Simplify( SHAPE_POLY_SET::PM_FAST );

        // Plot outlines
        std::vector<VECTOR2I> cornerList;

        // Now we have one or more basic polygons: plot each polygon
        for( int ii = 0; ii < outlines.OutlineCount(); ii++ )
        {
            for( int kk = 0; kk <= outlines.HoleCount(ii); kk++ )
            {
                cornerList.clear();
                const SHAPE_LINE_CHAIN& path =
                        ( kk == 0 ) ? outlines.COutline( ii ) : outlines.CHole( ii, kk - 1 );

                aPlotter->PlotPoly( path, FILL_T::NO_FILL );
            }
        }

        // Plot pad holes
        if( aPlotOpt.GetDrillMarksType() != PCB_PLOT_PARAMS::NO_DRILL_SHAPE )
        {
            int smallDrill = ( aPlotOpt.GetDrillMarksType() == PCB_PLOT_PARAMS::SMALL_DRILL_SHAPE )
                             ? Millimeter2iu( ADVANCED_CFG::GetCfg().m_SmallDrillMarkSize ) :
                             INT_MAX;

            for( FOOTPRINT* footprint : aBoard->Footprints() )
            {
                for( PAD* pad : footprint->Pads() )
                {
                    if( pad->HasHole() )
                    {
                        std::shared_ptr<SHAPE_SEGMENT> slot = pad->GetEffectiveHoleShape();

                        if( slot->GetSeg().A == slot->GetSeg().B )  // circular hole
                        {
                            int drill = std::min( smallDrill, slot->GetWidth() );
                            aPlotter->Circle( pad->GetPosition(), drill, FILL_T::NO_FILL );
                        }
                        else
                        {
                            // Note: small drill marks have no significance when applied to slots
                            aPlotter->ThickSegment( slot->GetSeg().A,
                                                    slot->GetSeg().B,
                                                    slot->GetWidth(), SKETCH, nullptr );
                        }
                    }
                }
            }
        }

        // Plot vias holes
        for( PCB_TRACK* track : aBoard->Tracks() )
        {
            const PCB_VIA* via = dyn_cast<const PCB_VIA*>( track );

            if( via && via->IsOnLayer( layer ) )    // via holes can be not through holes
                aPlotter->Circle( via->GetPosition(), via->GetDrillValue(), FILL_T::NO_FILL );
        }
    }
}


/**
 * Plot a solder mask layer.
 *
 * Solder mask layers have a minimum thickness value and cannot be drawn like standard layers,
 * unless the minimum thickness is 0.
 * Currently the algo is:
 * 1 - build all pad shapes as polygons with a size inflated by
 *      mask clearance + (min width solder mask /2)
 * 2 - Merge shapes
 * 3 - deflate result by (min width solder mask /2)
 * 4 - ORing result by all pad shapes as polygons with a size inflated by
 *      mask clearance only (because deflate sometimes creates shape artifacts)
 * 5 - draw result as polygons
 *
 * We have 2 algos:
 * the initial algo, that create polygons for every shape, inflate and deflate polygons
 * with Min Thickness/2, and merges the result.
 * Drawback: pads attributes are lost (annoying in Gerber)
 * the new algo:
 * create initial polygons for every shape (pad or polygon),
 * inflate and deflate polygons
 * with Min Thickness/2, and merges the result (like initial algo)
 * remove all initial polygons.
 * The remaining polygons are areas with thickness < min thickness
 * plot all initial shapes by flashing (or using regions) for pad and polygons
 * (shapes will be better) and remaining polygons to
 * remove areas with thickness < min thickness from final mask
 *
 * TODO: remove old code after more testing.
 */
#define NEW_ALGO 1

void PlotSolderMaskLayer( BOARD *aBoard, PLOTTER* aPlotter, LSET aLayerMask,
                          const PCB_PLOT_PARAMS& aPlotOpt, int aMinThickness )
{
    int             maxError = aBoard->GetDesignSettings().m_MaxError;
    PCB_LAYER_ID    layer = aLayerMask[B_Mask] ? B_Mask : F_Mask;
    SHAPE_POLY_SET  buffer;
    SHAPE_POLY_SET* boardOutline = nullptr;

    if( aBoard->GetBoardPolygonOutlines( buffer ) )
        boardOutline = &buffer;

    // We remove 1nm as we expand both sides of the shapes, so allowing for a strictly greater
    // than or equal comparison in the shape separation (boolean add)
    int inflate = aMinThickness / 2 - 1;

    BRDITEMS_PLOTTER itemplotter( aPlotter, aBoard, aPlotOpt );
    itemplotter.SetLayerSet( aLayerMask );

    for( FOOTPRINT* footprint : aBoard->Footprints() )
        itemplotter.PlotFootprintTextItems( footprint );

    // Build polygons for each pad shape.  The size of the shape on solder mask should be size
    // of pad + clearance around the pad, where clearance = solder mask clearance + extra margin.
    // Extra margin is half the min width for solder mask, which is used to merge too-close shapes
    // (distance < aMinThickness), and will be removed when creating the actual shapes.

    // Will contain shapes inflated by inflate value that will be merged and deflated by
    // inflate value to build final polygons
    // After calculations the remaining polygons are polygons to plot
    SHAPE_POLY_SET areas;

    // Will contain exact shapes of all items on solder mask
    SHAPE_POLY_SET initialPolys;

#if NEW_ALGO
    // Generate polygons with arcs inside the shape or exact shape to minimize shape changes
    // created by arc to segment size correction.
    DISABLE_ARC_RADIUS_CORRECTION disabler;
#endif
    {
        // Plot footprint pads and graphics
        for( const FOOTPRINT* footprint : aBoard->Footprints() )
        {
            // add shapes with their exact mask layer size in initialPolys
            footprint->TransformPadsWithClearanceToPolygon( initialPolys, layer, 0, maxError,
                                                            ERROR_OUTSIDE );
            // add shapes inflated by aMinThickness/2 in areas
            footprint->TransformPadsWithClearanceToPolygon( areas, layer, inflate, maxError,
                                                            ERROR_OUTSIDE );

            for( const BOARD_ITEM* item : footprint->GraphicalItems() )
            {
                if( item->Type() == PCB_FP_SHAPE_T && item->IsOnLayer( layer ) )
                {
                    // add shapes with their exact mask layer size in initialPolys
                    item->TransformShapeWithClearanceToPolygon( initialPolys, layer, 0, maxError,
                                                                ERROR_OUTSIDE );

                    // add shapes inflated by aMinThickness/2 in areas
                    item->TransformShapeWithClearanceToPolygon( areas, layer, inflate, maxError,
                                                                ERROR_OUTSIDE );
                }
                else if( item->Type() == PCB_FP_SHAPE_T && item->IsOnLayer( Edge_Cuts ) )
                {
                   itemplotter.PlotFootprintShape( static_cast<const FP_SHAPE*>( item ) );
                }
            }
        }

        // Plot (untented) vias
        for( const PCB_TRACK* track : aBoard->Tracks() )
        {
            const PCB_VIA* via = dyn_cast<const PCB_VIA*>( track );

            // Note: IsOnLayer() checks relevant mask layers of untented vias
            if( !via || !via->IsOnLayer( layer ) )
                continue;

            int            clearance = via->GetSolderMaskExpansion();

            // add shapes with their exact mask layer size in initialPolys
            via->TransformShapeWithClearanceToPolygon( initialPolys, layer, clearance, maxError,
                                                       ERROR_OUTSIDE );

            // add shapes inflated by aMinThickness/2 in areas
            via->TransformShapeWithClearanceToPolygon( areas, layer, clearance + inflate, maxError,
                                                       ERROR_OUTSIDE );
        }

        // Add filled zone areas.
#if 0   // Set to 1 if a solder mask expansion must be applied to zones on solder mask
        int zone_margin = aBoard->GetDesignSettings().m_SolderMaskExpansion;
#else
        int zone_margin = 0;
#endif

        for( const BOARD_ITEM* item : aBoard->Drawings() )
        {
            if( item->IsOnLayer( layer ) )
            {
                // add shapes with their exact mask layer size in initialPolys
                item->TransformShapeWithClearanceToPolygon( initialPolys, layer, 0, maxError,
                                                            ERROR_OUTSIDE );
                // add shapes inflated by aMinThickness/2 in areas
                item->TransformShapeWithClearanceToPolygon( areas, layer, inflate, maxError,
                                                            ERROR_OUTSIDE );
            }
            else if( item->IsOnLayer( Edge_Cuts ) )
            {
                itemplotter.PlotPcbGraphicItem( item );
            }
        }

        for( ZONE* zone : aBoard->Zones() )
        {
            if( !zone->IsOnLayer( layer ) )
                continue;

            // add shapes inflated by aMinThickness/2 in areas
            zone->TransformSmoothedOutlineToPolygon( areas, inflate + zone_margin, maxError,
                                                     ERROR_OUTSIDE, boardOutline );

            // add shapes with their exact mask layer size in initialPolys
            zone->TransformSmoothedOutlineToPolygon( initialPolys, zone_margin, maxError,
                                                     ERROR_OUTSIDE, boardOutline );
        }
    }

    int numSegs = GetArcToSegmentCount( inflate, maxError, FULL_CIRCLE );

    // Merge all polygons: After deflating, not merged (not overlapping) polygons
    // will have the initial shape (with perhaps small changes due to deflating transform)
    areas.Simplify( SHAPE_POLY_SET::PM_STRICTLY_SIMPLE );
    areas.Deflate( inflate, numSegs );

#if !NEW_ALGO
    // To avoid a lot of code, use a ZONE to handle and plot polygons, because our polygons look
    // exactly like filled areas in zones.
    // Note, also this code is not optimized: it creates a lot of copy/duplicate data.
    // However it is not complex, and fast enough for plot purposes (copy/convert data is only a
    // very small calculation time for these calculations).
    ZONE zone( aBoard );
    zone.SetMinThickness( 0 );      // trace polygons only
    zone.SetLayer( layer );

    // Combine the current areas to initial areas. This is mandatory because inflate/deflate
    // transform is not perfect, and we want the initial areas perfectly kept
    areas.BooleanAdd( initialPolys, SHAPE_POLY_SET::PM_FAST );
    areas.Fracture( SHAPE_POLY_SET::PM_STRICTLY_SIMPLE );

    itemplotter.PlotFilledAreas( &zone, layer, areas );
#else

    // Remove initial shapes: each shape will be added later, as flashed item or region
    // with a suitable attribute.
    // Do not merge pads is mandatory in Gerber files: They must be identified as pads

    // we deflate areas in polygons, to avoid after subtracting initial shapes
    // having small artifacts due to approximations during polygon transforms
    areas.BooleanSubtract( initialPolys, SHAPE_POLY_SET::PM_STRICTLY_SIMPLE );

    // Slightly inflate polygons to avoid any gap between them and other shapes,
    // These gaps are created by arc to segments approximations
    areas.Inflate( Millimeter2iu( 0.002 ), 6 );

    // Now, only polygons with a too small thickness are stored in areas.
    areas.Fracture( SHAPE_POLY_SET::PM_STRICTLY_SIMPLE );

    // Plot each initial shape (pads and polygons on mask layer), with suitable attributes:
    PlotStandardLayer( aBoard, aPlotter, aLayerMask, aPlotOpt );

    for( int ii = 0; ii < areas.OutlineCount(); ii++ )
    {
        const SHAPE_LINE_CHAIN& path = areas.COutline( ii );

        // polygon area in mm^2 :
        double curr_area = path.Area() / ( IU_PER_MM * IU_PER_MM );

        // Skip very small polygons: they are certainly artifacts created by
        // arc approximations and polygon transforms
        // (inflate/deflate transforms)
        constexpr double poly_min_area_mm2 = 0.01;     // 0.01 mm^2 gives a good filtering

        if( curr_area < poly_min_area_mm2 )
            continue;

        aPlotter->PlotPoly( path, FILL_T::FILLED_SHAPE );
    }
#endif
}


/**
 * Set up most plot options for plotting a board (especially the viewport)
 * Important thing:
 *      page size is the 'drawing' page size,
 *      paper size is the physical page size
 */
static void initializePlotter( PLOTTER* aPlotter, const BOARD* aBoard,
                               const PCB_PLOT_PARAMS* aPlotOpts )
{
    PAGE_INFO pageA4( wxT( "A4" ) );
    const PAGE_INFO& pageInfo = aBoard->GetPageSettings();
    const PAGE_INFO* sheet_info;
    double paperscale; // Page-to-paper ratio
    wxSize paperSizeIU;
    wxSize pageSizeIU( pageInfo.GetSizeIU() );
    bool autocenter = false;

    // Special options: to fit the sheet to an A4 sheet replace the paper size. However there
    // is a difference between the autoscale and the a4paper option:
    //  - Autoscale fits the board to the paper size
    //  - A4paper fits the original paper size to an A4 sheet
    //  - Both of them fit the board to an A4 sheet
    if( aPlotOpts->GetA4Output() )
    {
        sheet_info  = &pageA4;
        paperSizeIU = pageA4.GetSizeIU();
        paperscale  = (double) paperSizeIU.x / pageSizeIU.x;
        autocenter  = true;
    }
    else
    {
        sheet_info  = &pageInfo;
        paperSizeIU = pageSizeIU;
        paperscale  = 1;

        // Need autocentering only if scale is not 1:1
        autocenter  = (aPlotOpts->GetScale() != 1.0);
    }

    EDA_RECT bbox = aBoard->ComputeBoundingBox();
    VECTOR2I boardCenter = bbox.Centre();
    VECTOR2I boardSize = bbox.GetSize();

    double compound_scale;

    // Fit to 80% of the page if asked; it could be that the board is empty, in this case
    // regress to 1:1 scale
    if( aPlotOpts->GetAutoScale() && boardSize.x > 0 && boardSize.y > 0 )
    {
        double xscale = (paperSizeIU.x * 0.8) / boardSize.x;
        double yscale = (paperSizeIU.y * 0.8) / boardSize.y;

        compound_scale = std::min( xscale, yscale ) * paperscale;
    }
    else
    {
        compound_scale = aPlotOpts->GetScale() * paperscale;
    }

    // For the plot offset we have to keep in mind the auxiliary origin too: if autoscaling is
    // off we check that plot option (i.e. autoscaling overrides auxiliary origin)
    VECTOR2I offset( 0, 0);

    if( autocenter )
    {
        offset.x = KiROUND( boardCenter.x - ( paperSizeIU.x / 2.0 ) / compound_scale );
        offset.y = KiROUND( boardCenter.y - ( paperSizeIU.y / 2.0 ) / compound_scale );
    }
    else
    {
        if( aPlotOpts->GetUseAuxOrigin() )
            offset = aBoard->GetDesignSettings().GetAuxOrigin();
    }

    aPlotter->SetPageSettings( *sheet_info );

    aPlotter->SetViewport( offset, IU_PER_MILS/10, compound_scale, aPlotOpts->GetMirror() );

    // Has meaning only for gerber plotter. Must be called only after SetViewport
    aPlotter->SetGerberCoordinatesFormat( aPlotOpts->GetGerberPrecision() );

    // Has meaning only for SVG plotter. Must be called only after SetViewport
    aPlotter->SetSvgCoordinatesFormat( aPlotOpts->GetSvgPrecision() );

    aPlotter->SetCreator( wxT( "PCBNEW" ) );
    aPlotter->SetColorMode( false );        // default is plot in Black and White.
    aPlotter->SetTextMode( aPlotOpts->GetTextMode() );
}


/**
 * Prefill in black an area a little bigger than the board to prepare for the negative plot
 */
static void FillNegativeKnockout( PLOTTER *aPlotter, const EDA_RECT &aBbbox )
{
    const int margin = 5 * IU_PER_MM;   // Add a 5 mm margin around the board
    aPlotter->SetNegative( true );
    aPlotter->SetColor( WHITE );        // Which will be plotted as black
    EDA_RECT area = aBbbox;
    area.Inflate( margin );
    aPlotter->Rect( area.GetOrigin(), area.GetEnd(), FILL_T::FILLED_SHAPE );
    aPlotter->SetColor( BLACK );
}


/**
 * Calculate the effective size of HPGL pens and set them in the plotter object
 */
static void ConfigureHPGLPenSizes( HPGL_PLOTTER *aPlotter, const PCB_PLOT_PARAMS *aPlotOpts )
{
    // Compute penDiam (the value is given in mils) in pcb units, with plot scale (if Scale is 2,
    // penDiam value is always m_HPGLPenDiam so apparent penDiam is actually penDiam / Scale
    int penDiam = KiROUND( aPlotOpts->GetHPGLPenDiameter() * IU_PER_MILS / aPlotOpts->GetScale() );

    // Set HPGL-specific options and start
    aPlotter->SetPenSpeed( aPlotOpts->GetHPGLPenSpeed() );
    aPlotter->SetPenNumber( aPlotOpts->GetHPGLPenNum() );
    aPlotter->SetPenDiameter( penDiam );
}


/**
 * Open a new plotfile using the options (and especially the format) specified in the options
 * and prepare the page for plotting.
 *
 * @return the plotter object if OK, NULL if the file is not created (or has a problem).
 */
PLOTTER* StartPlotBoard( BOARD *aBoard, const PCB_PLOT_PARAMS *aPlotOpts, int aLayer,
                         const wxString& aFullFileName, const wxString& aSheetName,
                         const wxString& aSheetPath )
{
    // Create the plotter driver and set the few plotter specific options
    PLOTTER*    plotter = nullptr;

    switch( aPlotOpts->GetFormat() )
    {
    case PLOT_FORMAT::DXF:
        DXF_PLOTTER* DXF_plotter;
        DXF_plotter = new DXF_PLOTTER();
        DXF_plotter->SetUnits( aPlotOpts->GetDXFPlotUnits() );

        plotter = DXF_plotter;
        break;

    case PLOT_FORMAT::POST:
        PS_PLOTTER* PS_plotter;
        PS_plotter = new PS_PLOTTER();
        PS_plotter->SetScaleAdjust( aPlotOpts->GetFineScaleAdjustX(),
                                    aPlotOpts->GetFineScaleAdjustY() );
        plotter = PS_plotter;
        break;

    case PLOT_FORMAT::PDF:
        plotter = new PDF_PLOTTER();
        break;

    case PLOT_FORMAT::HPGL:
        HPGL_PLOTTER* HPGL_plotter;
        HPGL_plotter = new HPGL_PLOTTER();

        // HPGL options are a little more convoluted to compute, so they get their own function
        ConfigureHPGLPenSizes( HPGL_plotter, aPlotOpts );
        plotter = HPGL_plotter;
        break;

    case PLOT_FORMAT::GERBER:
        plotter = new GERBER_PLOTTER();
        break;

    case PLOT_FORMAT::SVG:
        plotter = new SVG_PLOTTER();
        break;

    default:
        wxASSERT( false );
        return nullptr;
    }

    KIGFX::PCB_RENDER_SETTINGS* renderSettings = new KIGFX::PCB_RENDER_SETTINGS();
    renderSettings->LoadColors( aPlotOpts->ColorSettings() );
    renderSettings->SetDefaultPenWidth( Millimeter2iu( 0.0212 ) );  // Hairline at 1200dpi

    if( aLayer < GAL_LAYER_ID_END )
        renderSettings->SetLayerName( aBoard->GetLayerName( ToLAYER_ID( aLayer ) ) );

    plotter->SetRenderSettings( renderSettings );

    // Compute the viewport and set the other options

    // page layout is not mirrored, so temporarily change mirror option for the page layout
    PCB_PLOT_PARAMS plotOpts = *aPlotOpts;

    if( plotOpts.GetPlotFrameRef() && plotOpts.GetMirror() )
        plotOpts.SetMirror( false );

    initializePlotter( plotter, aBoard, &plotOpts );

    if( plotter->OpenFile( aFullFileName ) )
    {
        plotter->ClearHeaderLinesList();

        // For the Gerber "file function" attribute, set the layer number
        if( plotter->GetPlotterType() == PLOT_FORMAT::GERBER )
        {
            bool useX2mode = plotOpts.GetUseGerberX2format();

            GERBER_PLOTTER* gbrplotter = static_cast <GERBER_PLOTTER*> ( plotter );
            gbrplotter->DisableApertMacros( plotOpts.GetDisableGerberMacros() );
            gbrplotter->UseX2format( useX2mode );
            gbrplotter->UseX2NetAttributes( plotOpts.GetIncludeGerberNetlistInfo() );

            // Attributes can be added using X2 format or as comment (X1 format)
            AddGerberX2Attribute( plotter, aBoard, aLayer, not useX2mode );
        }

        plotter->StartPlot();

        // Plot the frame reference if requested
        if( aPlotOpts->GetPlotFrameRef() )
        {
            PlotDrawingSheet( plotter, aBoard->GetProject(), aBoard->GetTitleBlock(),
                              aBoard->GetPageSettings(), wxT( "1" ), 1, aSheetName, aSheetPath,
                              aBoard->GetFileName() );

            if( aPlotOpts->GetMirror() )
                initializePlotter( plotter, aBoard, aPlotOpts );
        }

        // When plotting a negative board: draw a black rectangle (background for plot board
        // in white) and switch the current color to WHITE; note the color inversion is actually
        // done in the driver (if supported)
        if( aPlotOpts->GetNegative() )
        {
            EDA_RECT bbox = aBoard->ComputeBoundingBox();
            FillNegativeKnockout( plotter, bbox );
        }

        return plotter;
    }

    delete plotter->RenderSettings();
    delete plotter;
    return nullptr;
}