dxf_import_plugin.cpp

Go to the documentation of this file.

/*
 * This program source code file is part of KiCad, a free EDA CAD application.
 *
 * Copyright (C) 2019 Jean-Pierre Charras, jp.charras at wanadoo.fr
 * Copyright (C) 2019-2024 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
 */
 
// The DXF reader lib (libdxfrw) comes from dxflib project used in QCAD
// See http://www.ribbonsoft.com
// Each time a dxf entity is read, a "call back" function is called
// like void DXF_IMPORT_PLUGIN::addLine( const DL_LineData& data ) when a line is read.
// this function just add the BOARD entity from dxf parameters (start and end point ...)
 
 
#include "dxf_import_plugin.h"
#include <wx/arrstr.h>
#include <wx/regex.h>
#include <geometry/ellipse.h>
#include <bezier_curves.h>
 
#include <trigo.h>
#include <macros.h>
#include <cmath> // isnan
#include <board.h>
#include "common.h"
 
 
/*
 * Important notes
 * 1. All output coordinates of this importer are in mm
 * 2. DXFs have a concept of world (WCS) and object coordinates (OCS)
 3. The following objects are world coordinates:
 - Line
 - Point
 - Polyline (3D)
 - Vertex (3D)
 - Polymesh
 - Polyface
 - Viewport
 4. The following entities are object coordinates
 - Circle
 - Arc
 - Solid
 - Trace
 - Attrib
 - Shape
 - Insert
 - Polyline (2D)
 - Vertex (2D)
 - LWPolyline
 - Hatch
 - Image
 - Text
 * 5. Object coordinates must be run through the arbitrary axis
 * translation even though they are 2D drawings and most of the time
 * the import is fine. Sometimes, against all logic, CAD tools like
 * SolidWorks may randomly insert circles "mirror" that must be unflipped
 * by following the object to world conversion
 * 6. Blocks are virtual groups, blocks must be placed by a INSERT entity
 * 7. Blocks may be repeated multiple times
 * 8. There is no sane way to make text look perfect like the original CAD.
 * DXF simply does mpt secifying text/font enough to make it portable.
 * We however make do try to get it somewhat close/visually appealing.
 * 9. We silently drop the z coordinate on 3d polylines
 */
 
 
// minimum bulge value before resorting to a line segment;
// the value 0.0218 is equivalent to about 5 degrees arc,
#define MIN_BULGE 0.0218
 
#define SCALE_FACTOR(x) (x)
 
 
DXF_IMPORT_PLUGIN::DXF_IMPORT_PLUGIN() : DL_CreationAdapter()
{
 m_xOffset = 0.0; // X coord offset for conversion (in mm)
 m_yOffset = 0.0; // Y coord offset for conversion (in mm)
 m_version = 0; // the dxf version, not yet used
 m_defaultThickness = 0.2; // default thickness (in mm)
 m_brdLayer = Dwgs_User; // The default import layer
 m_importAsFPShapes = true;
 m_minX = m_minY = std::numeric_limits<double>::max();
 m_maxX = m_maxY = std::numeric_limits<double>::lowest();
 m_currentUnit = DXF_IMPORT_UNITS::DEFAULT;
 
 m_importCoordinatePrecision = 4; // initial value per dxf spec
 m_importAnglePrecision = 0; // initial value per dxf spec
 
 // placeholder layer so we can fallback to something later
 auto layer0 = std::make_unique<DXF_IMPORT_LAYER>( "", DXF_IMPORT_LINEWEIGHT_BY_LW_DEFAULT );
 m_layers.push_back( std::move( layer0 ) );
 
 m_currentBlock = nullptr;
}
 
 
DXF_IMPORT_PLUGIN::~DXF_IMPORT_PLUGIN()
{
}
 
 
bool DXF_IMPORT_PLUGIN::Load( const wxString& aFileName )
{
 try
 {
 return ImportDxfFile( aFileName );
 }
 catch( const std::bad_alloc& )
 {
 m_layers.clear();
 m_blocks.clear();
 m_styles.clear();
 
 m_internalImporter.ClearShapes();
 
 ReportMsg( _( "Memory was exhausted trying to load the DXF, it may be too large." ) );
 return false;
 }
}
 
 
bool DXF_IMPORT_PLUGIN::LoadFromMemory( const wxMemoryBuffer& aMemBuffer )
{
 try
 {
 return ImportDxfFile( aMemBuffer );
 }
 catch( const std::bad_alloc& )
 {
 m_layers.clear();
 m_blocks.clear();
 m_styles.clear();
 
 m_internalImporter.ClearShapes();
 
 ReportMsg( _( "Memory was exhausted trying to load the DXF, it may be too large." ) );
 return false;
 }
}
 
 
bool DXF_IMPORT_PLUGIN::Import()
{
 wxCHECK( m_importer, false );
 m_internalImporter.ImportTo( *m_importer );
 
 return true;
}
 
 
double DXF_IMPORT_PLUGIN::GetImageWidth() const
{
 return m_maxX - m_minX;
}
 
 
double DXF_IMPORT_PLUGIN::GetImageHeight() const
{
 return m_maxY - m_minY;
}
 
 
BOX2D DXF_IMPORT_PLUGIN::GetImageBBox() const
{
 BOX2D bbox;
 bbox.SetOrigin( m_minX, m_minY );
 bbox.SetEnd( m_maxX, m_maxY );
 
 return bbox;
}
 
 
void DXF_IMPORT_PLUGIN::SetImporter( GRAPHICS_IMPORTER* aImporter )
{
 GRAPHICS_IMPORT_PLUGIN::SetImporter( aImporter );
 
 if( m_importer )
 SetDefaultLineWidthMM( m_importer->GetLineWidthMM() );
}
 
 
double DXF_IMPORT_PLUGIN::mapX( double aDxfCoordX )
{
 return SCALE_FACTOR( m_xOffset + ( aDxfCoordX * getCurrentUnitScale() ) );
}
 
 
double DXF_IMPORT_PLUGIN::mapY( double aDxfCoordY )
{
 return SCALE_FACTOR( m_yOffset - ( aDxfCoordY * getCurrentUnitScale() ) );
}
 
 
double DXF_IMPORT_PLUGIN::mapDim( double aDxfValue )
{
 return SCALE_FACTOR( aDxfValue * getCurrentUnitScale() );
}
 
 
bool DXF_IMPORT_PLUGIN::ImportDxfFile( const wxString& aFile )
{
 DL_Dxf dxf_reader;
 
 // wxFopen takes care of unicode filenames across platforms
 FILE* fp = wxFopen( aFile, wxT( "rt" ) );
 
 if( fp == nullptr )
 return false;
 
 // Note the dxf reader takes care of switching to "C" locale before reading the file
 // and will close the file after reading
 bool success = dxf_reader.in( fp, this );
 
 return success;
}
 
 
bool DXF_IMPORT_PLUGIN::ImportDxfFile( const wxMemoryBuffer& aMemBuffer )
{
 DL_Dxf dxf_reader;
 
 std::string str( reinterpret_cast<char*>( aMemBuffer.GetData() ), aMemBuffer.GetDataLen() );
 
 // Note the dxf reader takes care of switching to "C" locale before reading the file
 // and will close the file after reading
 bool success = dxf_reader.in( str, this );
 
 return success;
}
 
 
void DXF_IMPORT_PLUGIN::ReportMsg( const wxString& aMessage )
{
 // Add message to keep trace of not handled dxf entities
 m_messages += aMessage;
 m_messages += '\n';
}
 
 
void DXF_IMPORT_PLUGIN::addSpline( const DL_SplineData& aData )
{
 // Called when starting reading a spline
 m_curr_entity.Clear();
 m_curr_entity.m_EntityParseStatus = 1;
 m_curr_entity.m_EntityFlag = aData.flags;
 m_curr_entity.m_EntityType = DL_ENTITY_SPLINE;
 m_curr_entity.m_SplineDegree = aData.degree;
 m_curr_entity.m_SplineTangentStartX = aData.tangentStartX;
 m_curr_entity.m_SplineTangentStartY = aData.tangentStartY;
 m_curr_entity.m_SplineTangentEndX = aData.tangentEndX;
 m_curr_entity.m_SplineTangentEndY = aData.tangentEndY;
 m_curr_entity.m_SplineKnotsCount = aData.nKnots;
 m_curr_entity.m_SplineControlCount = aData.nControl;
 m_curr_entity.m_SplineFitCount = aData.nFit;
}
 
 
void DXF_IMPORT_PLUGIN::addControlPoint( const DL_ControlPointData& aData )
{
 // Called for every spline control point, when reading a spline entity
 m_curr_entity.m_SplineControlPointList.emplace_back( aData.x , aData.y, aData.w );
}
 
 
void DXF_IMPORT_PLUGIN::addFitPoint( const DL_FitPointData& aData )
{
 // Called for every spline fit point, when reading a spline entity
 // we store only the X,Y coord values in a VECTOR2D
 m_curr_entity.m_SplineFitPointList.emplace_back( aData.x, aData.y );
}
 
 
void DXF_IMPORT_PLUGIN::addKnot( const DL_KnotData& aData)
{
 // Called for every spline knot value, when reading a spline entity
 m_curr_entity.m_SplineKnotsList.push_back( aData.k );
}
 
 
void DXF_IMPORT_PLUGIN::addLayer( const DL_LayerData& aData )
{
 wxString name = wxString::FromUTF8( aData.name.c_str() );
 
 int lw = attributes.getWidth();
 
 if( lw == DXF_IMPORT_LINEWEIGHT_BY_LAYER )
 lw = DXF_IMPORT_LINEWEIGHT_BY_LW_DEFAULT;
 
 std::unique_ptr<DXF_IMPORT_LAYER> layer = std::make_unique<DXF_IMPORT_LAYER>( name, lw );
 
 m_layers.push_back( std::move( layer ) );
}
 
 
void DXF_IMPORT_PLUGIN::addLinetype( const DL_LinetypeData& data )
{
#if 0
 wxString name = From_UTF8( data.name.c_str() );
 wxString description = From_UTF8( data.description.c_str() );
#endif
}
 
 
double DXF_IMPORT_PLUGIN::lineWeightToWidth( int lw, DXF_IMPORT_LAYER* aLayer )
{
 if( lw == DXF_IMPORT_LINEWEIGHT_BY_LAYER && aLayer != nullptr )
 lw = aLayer->m_lineWeight;
 
 // All lineweights >= 0 are always in 100ths of mm
 double mm = m_defaultThickness;
 
 if( lw >= 0 )
 mm = lw / 100.0;
 
 return SCALE_FACTOR( mm );
}
 
 
DXF_IMPORT_LAYER* DXF_IMPORT_PLUGIN::getImportLayer( const std::string& aLayerName )
{
 DXF_IMPORT_LAYER* layer = m_layers.front().get();
 wxString layerName = wxString::FromUTF8( aLayerName.c_str() );
 
 if( !layerName.IsEmpty() )
 {
 auto resultIt = std::find_if( m_layers.begin(), m_layers.end(),
 [layerName]( const auto& it )
 {
 return it->m_layerName == layerName;
 } );
 
 if( resultIt != m_layers.end() )
 layer = resultIt->get();
 }
 
 return layer;
}
 
 
DXF_IMPORT_BLOCK* DXF_IMPORT_PLUGIN::getImportBlock( const std::string& aBlockName )
{
 DXF_IMPORT_BLOCK* block = nullptr;
 wxString blockName = wxString::FromUTF8( aBlockName.c_str() );
 
 if( !blockName.IsEmpty() )
 {
 auto resultIt = std::find_if( m_blocks.begin(), m_blocks.end(),
 [blockName]( const auto& it )
 {
 return it->m_name == blockName;
 } );
 
 if( resultIt != m_blocks.end() )
 block = resultIt->get();
 }
 
 return block;
}
 
 
DXF_IMPORT_STYLE* DXF_IMPORT_PLUGIN::getImportStyle( const std::string& aStyleName )
{
 DXF_IMPORT_STYLE* style = nullptr;
 wxString styleName = wxString::FromUTF8( aStyleName.c_str() );
 
 if( !styleName.IsEmpty() )
 {
 auto resultIt = std::find_if( m_styles.begin(), m_styles.end(),
 [styleName]( const auto& it )
 {
 return it->m_name == styleName;
 } );
 
 if( resultIt != m_styles.end() )
 style = resultIt->get();
 }
 
 return style;
}
 
 
void DXF_IMPORT_PLUGIN::addLine( const DL_LineData& aData )
{
 DXF_IMPORT_LAYER* layer = getImportLayer( attributes.getLayer() );
 double lineWidth = lineWeightToWidth( attributes.getWidth(), layer );
 
 VECTOR2D start( mapX( aData.x1 ), mapY( aData.y1 ) );
 VECTOR2D end( mapX( aData.x2 ), mapY( aData.y2 ) );
 
 GRAPHICS_IMPORTER_BUFFER* bufferToUse = m_currentBlock ? &m_currentBlock->m_buffer
 : &m_internalImporter;
 bufferToUse->AddLine( start, end, lineWidth );
 
 updateImageLimits( start );
 updateImageLimits( end );
}
 
 
void DXF_IMPORT_PLUGIN::addPolyline(const DL_PolylineData& aData )
{
 // Convert DXF Polylines into a series of KiCad Lines and Arcs.
 // A Polyline (as opposed to a LWPolyline) may be a 3D line or
 // even a 3D Mesh. The only type of Polyline which is guaranteed
 // to import correctly is a 2D Polyline in X and Y, which is what
 // we assume of all Polylines. The width used is the width of the Polyline.
 // per-vertex line widths, if present, are ignored.
 m_curr_entity.Clear();
 m_curr_entity.m_EntityParseStatus = 1;
 m_curr_entity.m_EntityFlag = aData.flags;
 m_curr_entity.m_EntityType = DL_ENTITY_POLYLINE;
}
 
 
void DXF_IMPORT_PLUGIN::addVertex( const DL_VertexData& aData )
{
 if( m_curr_entity.m_EntityParseStatus == 0 )
 return; // Error
 
 DXF_IMPORT_LAYER* layer = getImportLayer( attributes.getLayer() );
 double lineWidth = lineWeightToWidth( attributes.getWidth(), layer );
 
 /* support for per-vertex-encoded linewidth (Cadence uses it) */
 /* linewidths are scaled by 100 in DXF */
 if( aData.startWidth > 0.0 )
 lineWidth = aData.startWidth / 100.0;
 else if ( aData.endWidth > 0.0 )
 lineWidth = aData.endWidth / 100.0;
 
 const DL_VertexData* vertex = &aData;
 
 MATRIX3x3D arbAxis = getArbitraryAxis( getExtrusion() );
 VECTOR3D vertexCoords = ocsToWcs( arbAxis, VECTOR3D( vertex->x, vertex->y, vertex->z ) );
 
 if( m_curr_entity.m_EntityParseStatus == 1 ) // This is the first vertex of an entity
 {
 m_curr_entity.m_LastCoordinate.x = mapX( vertexCoords.x );
 m_curr_entity.m_LastCoordinate.y = mapY( vertexCoords.y );
 m_curr_entity.m_PolylineStart = m_curr_entity.m_LastCoordinate;
 m_curr_entity.m_BulgeVertex = vertex->bulge;
 m_curr_entity.m_EntityParseStatus = 2;
 return;
 }
 
 VECTOR2D seg_end( mapX( vertexCoords.x ), mapY( vertexCoords.y ) );
 
 if( std::abs( m_curr_entity.m_BulgeVertex ) < MIN_BULGE )
 insertLine( m_curr_entity.m_LastCoordinate, seg_end, lineWidth );
 else
 insertArc( m_curr_entity.m_LastCoordinate, seg_end, m_curr_entity.m_BulgeVertex, lineWidth );
 
 m_curr_entity.m_LastCoordinate = seg_end;
 m_curr_entity.m_BulgeVertex = vertex->bulge;
}
 
 
void DXF_IMPORT_PLUGIN::endEntity()
{
 DXF_IMPORT_LAYER* layer = getImportLayer( attributes.getLayer() );
 double lineWidth = lineWeightToWidth( attributes.getWidth(), layer );
 
 if( m_curr_entity.m_EntityType == DL_ENTITY_POLYLINE ||
 m_curr_entity.m_EntityType == DL_ENTITY_LWPOLYLINE )
 {
 // Polyline flags bit 0 indicates closed (1) or open (0) polyline
 if( m_curr_entity.m_EntityFlag & 1 )
 {
 if( std::abs( m_curr_entity.m_BulgeVertex ) < MIN_BULGE )
 {
 insertLine( m_curr_entity.m_LastCoordinate, m_curr_entity.m_PolylineStart,
 lineWidth );
 }
 else
 {
 insertArc( m_curr_entity.m_LastCoordinate, m_curr_entity.m_PolylineStart,
 m_curr_entity.m_BulgeVertex, lineWidth );
 }
 }
 }
 
 if( m_curr_entity.m_EntityType == DL_ENTITY_SPLINE )
 insertSpline( lineWidth );
 
 m_curr_entity.Clear();
}
 
 
void DXF_IMPORT_PLUGIN::addBlock( const DL_BlockData& aData )
{
 wxString name = wxString::FromUTF8( aData.name.c_str() );
 
 std::unique_ptr<DXF_IMPORT_BLOCK> block = std::make_unique<DXF_IMPORT_BLOCK>( name, aData.bpx,
 aData.bpy );
 
 m_blocks.push_back( std::move( block ) );
 
 m_currentBlock = m_blocks.back().get();
}
 
 
void DXF_IMPORT_PLUGIN::endBlock()
{
 m_currentBlock = nullptr;
}
 
void DXF_IMPORT_PLUGIN::addInsert( const DL_InsertData& aData )
{
 DXF_IMPORT_BLOCK* block = getImportBlock( aData.name );
 
 if( block == nullptr )
 return;
 
 MATRIX3x3D arbAxis = getArbitraryAxis( getExtrusion() );
 
 MATRIX3x3D rot;
 rot.SetRotation( DEG2RAD( -aData.angle ) ); // DL_InsertData angle is in degrees
 
 MATRIX3x3D scale;
 scale.SetScale( VECTOR2D( aData.sx, aData.sy ) );
 
 MATRIX3x3D trans = ( arbAxis * rot ) * scale;
 VECTOR3D insertCoords = ocsToWcs( arbAxis, VECTOR3D( aData.ipx, aData.ipy, aData.ipz ) );
 
 VECTOR2D translation( mapX( insertCoords.x ), mapY( insertCoords.y ) );
 translation -= VECTOR2D( mapX( block->m_baseX ), mapY( block->m_baseY ) );
 
 for( const std::unique_ptr<IMPORTED_SHAPE>& shape : block->m_buffer.GetShapes() )
 {
 std::unique_ptr<IMPORTED_SHAPE> newShape = shape->clone();
 
 newShape->Transform( trans, translation );
 
 m_internalImporter.AddShape( newShape );
 }
}
 
 
void DXF_IMPORT_PLUGIN::addCircle( const DL_CircleData& aData )
{
 MATRIX3x3D arbAxis = getArbitraryAxis( getExtrusion() );
 VECTOR3D centerCoords = ocsToWcs( arbAxis, VECTOR3D( aData.cx, aData.cy, aData.cz ) );
 
 VECTOR2D center( mapX( centerCoords.x ), mapY( centerCoords.y ) );
 DXF_IMPORT_LAYER* layer = getImportLayer( attributes.getLayer() );
 double lineWidth = lineWeightToWidth( attributes.getWidth(), layer );
 
 GRAPHICS_IMPORTER_BUFFER* bufferToUse = m_currentBlock ? &m_currentBlock->m_buffer
 : &m_internalImporter;
 bufferToUse->AddCircle( center, mapDim( aData.radius ), lineWidth, false );
 
 VECTOR2D radiusDelta( mapDim( aData.radius ), mapDim( aData.radius ) );
 
 updateImageLimits( center + radiusDelta );
 updateImageLimits( center - radiusDelta );
}
 
 
void DXF_IMPORT_PLUGIN::addArc( const DL_ArcData& aData )
{
 MATRIX3x3D arbAxis = getArbitraryAxis( getExtrusion() );
 VECTOR3D centerCoords = ocsToWcs( arbAxis, VECTOR3D( aData.cx, aData.cy, aData.cz ) );
 
 // Init arc centre:
 VECTOR2D center( mapX( centerCoords.x ), mapY( centerCoords.y ) );
 
 // aData.anglex is in degrees.
 EDA_ANGLE startangle( aData.angle1, DEGREES_T );
 EDA_ANGLE endangle( aData.angle2, DEGREES_T );
 
 if( ( arbAxis.GetScale().x < 0 ) != ( arbAxis.GetScale().y < 0 ) )
 {
 startangle = ANGLE_180 - startangle;
 endangle = ANGLE_180 - endangle;
 std::swap( startangle, endangle );
 }
 
 // Init arc start point
 VECTOR2D startPoint( aData.radius, 0.0 );
 RotatePoint( startPoint, -startangle );
 VECTOR2D arcStart( mapX( startPoint.x + centerCoords.x ),
 mapY( startPoint.y + centerCoords.y ) );
 
 // calculate arc angle (arcs are CCW, and should be < 0 in Pcbnew)
 EDA_ANGLE angle = -( endangle - startangle );
 
 if( angle > ANGLE_0 )
 angle -= ANGLE_360;
 
 DXF_IMPORT_LAYER* layer = getImportLayer( attributes.getLayer() );
 double lineWidth = lineWeightToWidth( attributes.getWidth(), layer );
 
 GRAPHICS_IMPORTER_BUFFER* bufferToUse = m_currentBlock ? &m_currentBlock->m_buffer
 : &m_internalImporter;
 bufferToUse->AddArc( center, arcStart, angle, lineWidth );
 
 VECTOR2D radiusDelta( mapDim( aData.radius ), mapDim( aData.radius ) );
 
 updateImageLimits( center + radiusDelta );
 updateImageLimits( center - radiusDelta );
}
 
 
void DXF_IMPORT_PLUGIN::addEllipse( const DL_EllipseData& aData )
{
 MATRIX3x3D arbAxis = getArbitraryAxis( getExtrusion() );
 VECTOR3D centerCoords = ocsToWcs( arbAxis, VECTOR3D( aData.cx, aData.cy, aData.cz ) );
 VECTOR3D majorCoords = ocsToWcs( arbAxis, VECTOR3D( aData.mx, aData.my, aData.mz ) );
 
 // DXF ellipses store the minor axis length as a ratio to the major axis.
 // The major coords are relative to the center point.
 // For now, we assume ellipses in the XY plane.
 
 VECTOR2D center( mapX( centerCoords.x ), mapY( centerCoords.y ) );
 VECTOR2D major( mapX( majorCoords.x ), mapY( majorCoords.y ) );
 
 // DXF elliptical arcs store their angles in radians (unlike circular arcs which use degrees)
 // The arcs wind CCW as in KiCad. The end angle must be greater than the start angle, and if
 // the extrusion direction is negative, the arc winding is CW instead! Note that this is a
 // simplification that assumes the DXF is representing a 2D drawing, and would need to be
 // revisited if we want to import true 3D drawings and "flatten" them to the 2D KiCad plane
 // internally.
 EDA_ANGLE startAngle( aData.angle1, RADIANS_T );
 EDA_ANGLE endAngle( aData.angle2, RADIANS_T );
 
 if( startAngle > endAngle )
 endAngle += ANGLE_360;
 
 if( aData.ratio == 1.0 )
 {
 double radius = major.EuclideanNorm();
 
 if( startAngle == endAngle )
 {
 DL_CircleData circle( aData.cx, aData.cy, aData.cz, radius );
 addCircle( circle );
 return;
 }
 else
 {
 // Angles are relative to major axis
 startAngle -= EDA_ANGLE( major );
 endAngle -= EDA_ANGLE( major );
 
 DL_ArcData arc( aData.cx, aData.cy, aData.cz, radius, startAngle.AsDegrees(),
 endAngle.AsDegrees() );
 addArc( arc );
 return;
 }
 }
 
 // TODO: testcases for negative extrusion vector; handle it here
 
 std::vector<BEZIER<double>> splines;
 ELLIPSE<double> ellipse( center, major, aData.ratio, startAngle, endAngle );
 
 TransformEllipseToBeziers( ellipse, splines );
 
 DXF_IMPORT_LAYER* layer = getImportLayer( attributes.getLayer() );
 double lineWidth = lineWeightToWidth( attributes.getWidth(), layer );
 
 GRAPHICS_IMPORTER_BUFFER* bufferToUse = m_currentBlock ? &m_currentBlock->m_buffer
 : &m_internalImporter;
 
 for( const BEZIER<double>& b : splines )
 bufferToUse->AddSpline( b.Start, b.C1, b.C2, b.End, lineWidth );
 
 // Naive bounding
 updateImageLimits( center + major );
 updateImageLimits( center - major );
}
 
 
void DXF_IMPORT_PLUGIN::addText( const DL_TextData& aData )
{
 MATRIX3x3D arbAxis = getArbitraryAxis( getExtrusion() );
 VECTOR3D refPointCoords = ocsToWcs( arbAxis, VECTOR3D( aData.ipx, aData.ipy, aData.ipz ) );
 VECTOR3D secPointCoords = ocsToWcs( arbAxis, VECTOR3D( std::isnan( aData.apx ) ? 0 : aData.apx,
 std::isnan( aData.apy ) ? 0 : aData.apy,
 std::isnan( aData.apz ) ? 0 : aData.apz ) );
 
 VECTOR2D refPoint( mapX( refPointCoords.x ), mapY( refPointCoords.y ) );
 VECTOR2D secPoint( mapX( secPointCoords.x ), mapY( secPointCoords.y ) );
 
 if( aData.vJustification != 0 || aData.hJustification != 0 || aData.hJustification == 4 )
 {
 if( aData.hJustification != 3 && aData.hJustification != 5 )
 {
 VECTOR2D tmp = secPoint;
 secPoint = refPoint;
 refPoint = tmp;
 }
 }
 
 wxString text = toNativeString( wxString::FromUTF8( aData.text.c_str() ) );
 
 DXF_IMPORT_STYLE* style = getImportStyle( aData.style.c_str() );
 
 double textHeight = mapDim( aData.height );
 // The 0.9 factor gives a better height/width base ratio with our font
 double charWidth = textHeight * 0.9;
 
 if( style != nullptr )
 charWidth *= style->m_widthFactor;
 
 double textWidth = charWidth * text.length(); // Rough approximation
 double textThickness = textHeight/8.0; // Use a reasonable line thickness for this text
 
 VECTOR2D bottomLeft(0.0, 0.0);
 VECTOR2D bottomRight(0.0, 0.0);
 VECTOR2D topLeft(0.0, 0.0);
 VECTOR2D topRight(0.0, 0.0);
 
 GR_TEXT_H_ALIGN_T hJustify = GR_TEXT_H_ALIGN_LEFT;
 GR_TEXT_V_ALIGN_T vJustify = GR_TEXT_V_ALIGN_BOTTOM;
 
 switch( aData.vJustification )
 {
 case 0: //DRW_Text::VBaseLine:
 case 1: //DRW_Text::VBottom:
 vJustify = GR_TEXT_V_ALIGN_BOTTOM;
 
 topLeft.y = textHeight;
 topRight.y = textHeight;
 break;
 
 case 2: //DRW_Text::VMiddle:
 vJustify = GR_TEXT_V_ALIGN_CENTER;
 
 bottomRight.y = -textHeight / 2.0;
 bottomLeft.y = -textHeight / 2.0;
 topLeft.y = textHeight / 2.0;
 topRight.y = textHeight / 2.0;
 break;
 
 case 3: //DRW_Text::VTop:
 vJustify = GR_TEXT_V_ALIGN_TOP;
 
 bottomLeft.y = -textHeight;
 bottomRight.y = -textHeight;
 break;
 }
 
 switch( aData.hJustification )
 {
 case 0: //DRW_Text::HLeft:
 case 3: //DRW_Text::HAligned: // no equivalent options in text pcb.
 case 5: //DRW_Text::HFit: // no equivalent options in text pcb.
 hJustify = GR_TEXT_H_ALIGN_LEFT;
 
 bottomRight.x = textWidth;
 topRight.x = textWidth;
 break;
 
 case 1: //DRW_Text::HCenter:
 case 4: //DRW_Text::HMiddle: // no equivalent options in text pcb.
 hJustify = GR_TEXT_H_ALIGN_CENTER;
 
 bottomLeft.x = -textWidth / 2.0;
 topLeft.x = -textWidth / 2.0;
 bottomRight.x = textWidth / 2.0;
 topRight.x = textWidth / 2.0;
 break;
 
 case 2: //DRW_Text::HRight:
 hJustify = GR_TEXT_H_ALIGN_RIGHT;
 
 bottomLeft.x = -textWidth;
 topLeft.x = -textWidth;
 break;
 }
 
#if 0
 wxString sty = wxString::FromUTF8( aData.style.c_str() );
 sty = sty.ToLower();
 
 if( aData.textgen == 2 )
 {
 // Text dir = left to right;
 } else if( aData.textgen == 4 )
 {
 // Text dir = top to bottom;
 } else
 {
 }
#endif
 
 // dxf_lib imports text angle in radians (although there are no comment about that.
 // So, for the moment, convert this angle to degrees
 double angle_degree = aData.angle * 180 / M_PI;
 // We also need the angle in radians. so convert angle_degree to radians
 // regardless the aData.angle unit
 double angleInRads = angle_degree * M_PI / 180.0;
 double cosine = cos(angleInRads);
 double sine = sin(angleInRads);
 
 GRAPHICS_IMPORTER_BUFFER* bufferToUse = m_currentBlock ? &m_currentBlock->m_buffer
 : &m_internalImporter;
 bufferToUse->AddText( refPoint, text, textHeight, charWidth, textThickness, angle_degree,
 hJustify, vJustify );
 
 // Calculate the boundary box and update the image limits:
 bottomLeft.x = bottomLeft.x * cosine - bottomLeft.y * sine;
 bottomLeft.y = bottomLeft.x * sine + bottomLeft.y * cosine;
 
 bottomRight.x = bottomRight.x * cosine - bottomRight.y * sine;
 bottomRight.y = bottomRight.x * sine + bottomRight.y * cosine;
 
 topLeft.x = topLeft.x * cosine - topLeft.y * sine;
 topLeft.y = topLeft.x * sine + topLeft.y * cosine;
 
 topRight.x = topRight.x * cosine - topRight.y * sine;
 topRight.y = topRight.x * sine + topRight.y * cosine;
 
 bottomLeft += refPoint;
 bottomRight += refPoint;
 topLeft += refPoint;
 topRight += refPoint;
 
 updateImageLimits( bottomLeft );
 updateImageLimits( bottomRight );
 updateImageLimits( topLeft );
 updateImageLimits( topRight );
}
 
 
void DXF_IMPORT_PLUGIN::addMTextChunk( const std::string& text )
{
 // If the text string is greater than 250 characters, the string is divided into 250-character
 // chunks, which appear in one or more group 3 codes. If group 3 codes are used, the last group
 // is a group 1 and has fewer than 250 characters
 
 m_mtextContent.append( text );
}
 
 
void DXF_IMPORT_PLUGIN::addMText( const DL_MTextData& aData )
{
 m_mtextContent.append( aData.text );
 
 // TODO: determine control codes applied to the whole text?
 wxString text = toNativeString( wxString::FromUTF8( m_mtextContent.c_str() ) );
 
 DXF_IMPORT_STYLE* style = getImportStyle( aData.style.c_str() );
 double textHeight = mapDim( aData.height );
 
 // The 0.9 factor gives a better height/width base ratio with our font
 double charWidth = textHeight * 0.9;
 
 if( style != nullptr )
 charWidth *= style->m_widthFactor;
 
 double textWidth = charWidth * text.length(); // Rough approximation
 double textThickness = textHeight/8.0; // Use a reasonable line thickness for this text
 
 VECTOR2D bottomLeft(0.0, 0.0);
 VECTOR2D bottomRight(0.0, 0.0);
 VECTOR2D topLeft(0.0, 0.0);
 VECTOR2D topRight(0.0, 0.0);
 
 MATRIX3x3D arbAxis = getArbitraryAxis( getExtrusion() );
 VECTOR3D textposCoords = ocsToWcs( arbAxis, VECTOR3D( aData.ipx, aData.ipy, aData.ipz ) );
 VECTOR2D textpos( mapX( textposCoords.x ), mapY( textposCoords.y ) );
 
 // Initialize text justifications:
 GR_TEXT_H_ALIGN_T hJustify = GR_TEXT_H_ALIGN_LEFT;
 GR_TEXT_V_ALIGN_T vJustify = GR_TEXT_V_ALIGN_BOTTOM;
 
 if( aData.attachmentPoint <= 3 )
 {
 vJustify = GR_TEXT_V_ALIGN_TOP;
 
 bottomLeft.y = -textHeight;
 bottomRight.y = -textHeight;
 }
 else if( aData.attachmentPoint <= 6 )
 {
 vJustify = GR_TEXT_V_ALIGN_CENTER;
 
 bottomRight.y = -textHeight / 2.0;
 bottomLeft.y = -textHeight / 2.0;
 topLeft.y = textHeight / 2.0;
 topRight.y = textHeight / 2.0;
 }
 else
 {
 vJustify = GR_TEXT_V_ALIGN_BOTTOM;
 
 topLeft.y = textHeight;
 topRight.y = textHeight;
 }
 
 if( aData.attachmentPoint % 3 == 1 )
 {
 hJustify = GR_TEXT_H_ALIGN_LEFT;
 
 bottomRight.x = textWidth;
 topRight.x = textWidth;
 }
 else if( aData.attachmentPoint % 3 == 2 )
 {
 hJustify = GR_TEXT_H_ALIGN_CENTER;
 
 bottomLeft.x = -textWidth / 2.0;
 topLeft.x = -textWidth / 2.0;
 bottomRight.x = textWidth / 2.0;
 topRight.x = textWidth / 2.0;
 }
 else
 {
 hJustify = GR_TEXT_H_ALIGN_RIGHT;
 
 bottomLeft.x = -textWidth;
 topLeft.x = -textWidth;
 }
 
#if 0 // These setting have no meaning in Pcbnew
 if( data.alignH == 1 )
 {
 // Text is left to right;
 }
 else if( data.alignH == 3 )
 {
 // Text is top to bottom;
 }
 else
 {
 // use ByStyle;
 }
 
 if( aData.alignV == 1 )
 {
 // use AtLeast;
 }
 else
 {
 // useExact;
 }
#endif
 
 // dxf_lib imports text angle in radians (although there are no comment about that.
 // So, for the moment, convert this angle to degrees
 double angle_degree = aData.angle * 180/M_PI;
 // We also need the angle in radians. so convert angle_degree to radians
 // regardless the aData.angle unit
 double angleInRads = angle_degree * M_PI / 180.0;
 double cosine = cos(angleInRads);
 double sine = sin(angleInRads);
 
 
 GRAPHICS_IMPORTER_BUFFER* bufferToUse = m_currentBlock ? &m_currentBlock->m_buffer
 : &m_internalImporter;
 bufferToUse->AddText( textpos, text, textHeight, charWidth, textThickness, angle_degree,
 hJustify, vJustify );
 
 bottomLeft.x = bottomLeft.x * cosine - bottomLeft.y * sine;
 bottomLeft.y = bottomLeft.x * sine + bottomLeft.y * cosine;
 
 bottomRight.x = bottomRight.x * cosine - bottomRight.y * sine;
 bottomRight.y = bottomRight.x * sine + bottomRight.y * cosine;
 
 topLeft.x = topLeft.x * cosine - topLeft.y * sine;
 topLeft.y = topLeft.x * sine + topLeft.y * cosine;
 
 topRight.x = topRight.x * cosine - topRight.y * sine;
 topRight.y = topRight.x * sine + topRight.y * cosine;
 
 bottomLeft += textpos;
 bottomRight += textpos;
 topLeft += textpos;
 topRight += textpos;
 
 updateImageLimits( bottomLeft );
 updateImageLimits( bottomRight );
 updateImageLimits( topLeft );
 updateImageLimits( topRight );
 
 m_mtextContent.clear();
}
 
 
double DXF_IMPORT_PLUGIN::getCurrentUnitScale()
{
 double scale = 1.0;
 
 switch( m_currentUnit )
 {
 case DXF_IMPORT_UNITS::INCHES: scale = 25.4; break;
 case DXF_IMPORT_UNITS::FEET: scale = 304.8; break;
 case DXF_IMPORT_UNITS::MILLIMETERS: scale = 1.0; break;
 case DXF_IMPORT_UNITS::CENTIMETERS: scale = 10.0; break;
 case DXF_IMPORT_UNITS::METERS: scale = 1000.0; break;
 case DXF_IMPORT_UNITS::MICROINCHES: scale = 2.54e-5; break;
 case DXF_IMPORT_UNITS::MILS: scale = 0.0254; break;
 case DXF_IMPORT_UNITS::YARDS: scale = 914.4; break;
 case DXF_IMPORT_UNITS::ANGSTROMS: scale = 1.0e-7; break;
 case DXF_IMPORT_UNITS::NANOMETERS: scale = 1.0e-6; break;
 case DXF_IMPORT_UNITS::MICRONS: scale = 1.0e-3; break;
 case DXF_IMPORT_UNITS::DECIMETERS: scale = 100.0; break;
 
 default:
 // use the default of 1.0 for:
 // 0: Unspecified Units
 // 3: miles
 // 7: kilometers
 // 15: decameters
 // 16: hectometers
 // 17: gigameters
 // 18: AU
 // 19: lightyears
 // 20: parsecs
 break;
 }
 
 return scale;
}
 
 
 
void DXF_IMPORT_PLUGIN::setVariableInt( const std::string& key, int value, int code )
{
 // Called for every int variable in the DXF file (e.g. "$INSUNITS").
 
 if( key == "$DWGCODEPAGE" )
 {
 m_codePage = value;
 return;
 }
 
 if( key == "$AUPREC" )
 {
 m_importAnglePrecision = value;
 return;
 }
 
 if( key == "$LUPREC" )
 {
 m_importCoordinatePrecision = value;
 return;
 }
 
 if( key == "$INSUNITS" ) // Drawing units
 {
 m_currentUnit = DXF_IMPORT_UNITS::DEFAULT;
 
 switch( value )
 {
 case 1: m_currentUnit = DXF_IMPORT_UNITS::INCHES; break;
 case 2: m_currentUnit = DXF_IMPORT_UNITS::FEET; break;
 case 4: m_currentUnit = DXF_IMPORT_UNITS::MILLIMETERS; break;
 case 5: m_currentUnit = DXF_IMPORT_UNITS::CENTIMETERS; break;
 case 6: m_currentUnit = DXF_IMPORT_UNITS::METERS; break;
 case 8: m_currentUnit = DXF_IMPORT_UNITS::MICROINCHES; break;
 case 9: m_currentUnit = DXF_IMPORT_UNITS::MILS; break;
 case 10: m_currentUnit = DXF_IMPORT_UNITS::YARDS; break;
 case 11: m_currentUnit = DXF_IMPORT_UNITS::ANGSTROMS; break;
 case 12: m_currentUnit = DXF_IMPORT_UNITS::NANOMETERS; break;
 case 13: m_currentUnit = DXF_IMPORT_UNITS::MICRONS; break;
 case 14: m_currentUnit = DXF_IMPORT_UNITS::DECIMETERS; break;
 
 default:
 // use the default for:
 // 0: Unspecified Units
 // 3: miles
 // 7: kilometers
 // 15: decameters
 // 16: hectometers
 // 17: gigameters
 // 18: AU
 // 19: lightyears
 // 20: parsecs
 break;
 }
 
 return;
 }
}
 
 
void DXF_IMPORT_PLUGIN::setVariableString( const std::string& key, const std::string& value,
 int code )
{
 // Called for every string variable in the DXF file (e.g. "$ACADVER").
}
 
 
wxString DXF_IMPORT_PLUGIN::toDxfString( const wxString& aStr )
{
 wxString res;
 int j = 0;
 
 for( unsigned i = 0; i<aStr.length(); ++i )
 {
 int c = aStr[i];
 
 if( c > 175 || c < 11 )
 {
 res.append( aStr.Mid( j, i - j ) );
 j = i;
 
 switch( c )
 {
 case 0x0A:
 res += wxT( "\\P" );
 break;
 
 // diameter:
#ifdef _WIN32
 // windows, as always, is special.
 case 0x00D8:
#else
 case 0x2205:
#endif
 res += wxT( "%%C" );
 break;
 
 // degree:
 case 0x00B0:
 res += wxT( "%%D" );
 break;
 
 // plus/minus
 case 0x00B1:
 res += wxT( "%%P" );
 break;
 
 default:
 j--;
 break;
 }
 
 j++;
 }
 }
 
 res.append( aStr.Mid( j ) );
 return res;
}
 
 
wxString DXF_IMPORT_PLUGIN::toNativeString( const wxString& aData )
{
 wxString res;
 size_t i = 0;
 int braces = 0;
 int overbarLevel = -1;
 
 // For description, see:
 // https://ezdxf.readthedocs.io/en/stable/dxfinternals/entities/mtext.html
 // https://www.cadforum.cz/en/text-formatting-codes-in-mtext-objects-tip8640
 
 for( i = 0; i < aData.length(); i++ )
 {
 switch( (wchar_t) aData[i] )
 {
 case '{': // Text area influenced by the code
 braces++;
 break;
 
 case '}':
 if( overbarLevel == braces )
 {
 res << '}';
 overbarLevel = -1;
 }
 braces--;
 break;
 
 case '^': // C0 control code
 if( ++i >= aData.length() )
 break;
 
 switch( (wchar_t) aData[i] )
 {
 case 'I': res << '\t'; break;
 case 'J': res << '\b'; break;
 case ' ': res << '^'; break;
 default: break;
 }
 break;
 
 case '\\':
 {
 if( ++i >= aData.length() )
 break;
 
 switch( (wchar_t) aData[i] )
 {
 case 'P': // New paragraph (new line)
 case 'X': // Paragraph wrap on the dimension line (only in dimensions)
 res << '\n';
 break;
 
 case '~': // Non-wrapping space, hard space
 res << L'\u00A0';
 break;
 
 case 'U': // Unicode character, e.g. \U+ff08
 {
 i += 2;
 wxString codeHex;
 
 for( ; codeHex.length() < 4 && i < aData.length(); i++ )
 codeHex << aData[i];
 
 unsigned long codeVal = 0;
 
 if( codeHex.ToCULong( &codeVal, 16 ) && codeVal != 0 )
 res << wxUniChar( codeVal );
 
 i--;
 }
 break;
 
 case 'S': // Stacking
 {
 i++;
 wxString stacked;
 
 for( ; i < aData.length(); i++ )
 {
 if( aData[i] == ';' )
 break;
 else
 stacked << aData[i];
 }
 
 if( stacked.Contains( wxS( "#" ) ) )
 {
 res << '^' << '{';
 res << stacked.BeforeFirst( '#' );
 res << '}' << '/' << '_' << '{';
 res << stacked.AfterFirst( '#' );
 res << '}';
 }
 else
 {
 stacked.Replace( wxS( "^ " ), wxS( "/" ) );
 res << stacked;
 }
 }
 break;
 
 case 'O': // Start overstrike
 if( overbarLevel == -1 )
 {
 res << '~' << '{';
 overbarLevel = braces;
 }
 break;
 case 'o': // Stop overstrike
 if( overbarLevel == braces )
 {
 res << '}';
 overbarLevel = -1;
 }
 break;
 
 case 'L': // Start underline
 case 'l': // Stop underline
 case 'K': // Start strike-through
 case 'k': // Stop strike-through
 case 'N': // New column
 // Ignore
 break;
 
 case 'p': // Control codes for bullets, numbered paragraphs, tab stops and columns
 case 'Q': // Slanting (obliquing) text by angle
 case 'H': // Text height
 case 'W': // Text width
 case 'F': // Font selection
 case 'f': // Font selection (alternative)
 case 'A': // Alignment
 case 'C': // Color change (ACI colors)
 case 'c': // Color change (truecolor)
 case 'T': // Tracking, char.spacing
 // Skip to ;
 for( ; i < aData.length(); i++ )
 {
 if( aData[i] == ';' )
 break;
 }
 break;
 
 default: // Escaped character
 if( ++i >= aData.length() )
 break;
 
 res << aData[i];
 break;
 }
 }
 break;
 
 default: res << aData[i];
 }
 }
 
 if( overbarLevel != -1 )
 {
 res << '}';
 overbarLevel = -1;
 }
 
#if 1
 wxRegEx regexp;
 
 // diameter:
 regexp.Compile( wxT( "%%[cC]" ) );
#ifdef __WINDOWS__
 // windows, as always, is special.
 regexp.Replace( &res, wxChar( 0xD8 ) );
#else
 // Empty_set, diameter is 0x2300
 regexp.Replace( &res, wxChar( 0x2205 ) );
#endif
 
 // degree:
 regexp.Compile( wxT( "%%[dD]" ) );
 regexp.Replace( &res, wxChar( 0x00B0 ) );
 // plus/minus
 regexp.Compile( wxT( "%%[pP]" ) );
 regexp.Replace( &res, wxChar( 0x00B1 ) );
#endif
 
 return res;
}
 
 
void DXF_IMPORT_PLUGIN::addTextStyle( const DL_StyleData& aData )
{
 wxString name = wxString::FromUTF8( aData.name.c_str() );
 
 auto style = std::make_unique<DXF_IMPORT_STYLE>( name, aData.fixedTextHeight, aData.widthFactor,
 aData.bold, aData.italic );
 
 m_styles.push_back( std::move( style ) );
}
 
 
void DXF_IMPORT_PLUGIN::addPoint( const DL_PointData& aData )
{
 MATRIX3x3D arbAxis = getArbitraryAxis( getExtrusion() );
 VECTOR3D centerCoords = ocsToWcs( arbAxis, VECTOR3D( aData.x, aData.y, aData.z ) );
 VECTOR2D center( mapX( centerCoords.x ), mapY( centerCoords.y ) );
 
 // we emulate points with filled circles
 // set the linewidth to something that even small circles look good with
 // thickness is optional for dxf points
 // note: we had to modify the dxf library to grab the attribute for thickness
 double lineWidth = 0.0001;
 double thickness = mapDim( std::max( aData.thickness, 0.01 ) );
 
 GRAPHICS_IMPORTER_BUFFER* bufferToUse = m_currentBlock ? &m_currentBlock->m_buffer
 : &m_internalImporter;
 bufferToUse->AddCircle( center, thickness, lineWidth, true );
 
 VECTOR2D radiusDelta( SCALE_FACTOR( thickness ), SCALE_FACTOR( thickness ) );
 
 updateImageLimits( center + radiusDelta );
 updateImageLimits( center - radiusDelta );
}
 
 
void DXF_IMPORT_PLUGIN::insertLine( const VECTOR2D& aSegStart,
 const VECTOR2D& aSegEnd, double aWidth )
{
 VECTOR2D origin( SCALE_FACTOR( aSegStart.x ), SCALE_FACTOR( aSegStart.y ) );
 VECTOR2D end( SCALE_FACTOR( aSegEnd.x ), SCALE_FACTOR( aSegEnd.y ) );
 
 GRAPHICS_IMPORTER_BUFFER* bufferToUse = m_currentBlock ? &m_currentBlock->m_buffer
 : &m_internalImporter;
 bufferToUse->AddLine( origin, end, aWidth );
 
 updateImageLimits( origin );
 updateImageLimits( end );
}
 
 
void DXF_IMPORT_PLUGIN::insertArc( const VECTOR2D& aSegStart, const VECTOR2D& aSegEnd,
 double aBulge, double aWidth )
{
 VECTOR2D segment_startpoint( SCALE_FACTOR( aSegStart.x ), SCALE_FACTOR( aSegStart.y ) );
 VECTOR2D segment_endpoint( SCALE_FACTOR( aSegEnd.x ), SCALE_FACTOR( aSegEnd.y ) );
 
 // ensure aBulge represents an angle from +/- ( 0 .. approx 359.8 deg )
 if( aBulge < -2000.0 )
 aBulge = -2000.0;
 else if( aBulge > 2000.0 )
 aBulge = 2000.0;
 
 double ang = 4.0 * atan( aBulge );
 
 // reflect the Y values to put everything in a RHCS
 VECTOR2D sp( aSegStart.x, -aSegStart.y );
 VECTOR2D ep( aSegEnd.x, -aSegEnd.y );
 // angle from end->start
 double offAng = atan2( ep.y - sp.y, ep.x - sp.x );
 // length of subtended segment = 1/2 distance between the 2 points
 double d = 0.5 * sqrt( (sp.x - ep.x) * (sp.x - ep.x) + (sp.y - ep.y) * (sp.y - ep.y) );
 // midpoint of the subtended segment
 double xm = ( sp.x + ep.x ) * 0.5;
 double ym = ( sp.y + ep.y ) * 0.5;
 double radius = d / sin( ang * 0.5 );
 
 if( radius < 0.0 )
 radius = -radius;
 
 // calculate the height of the triangle with base d and hypotenuse r
 double dh2 = radius * radius - d * d;
 
 // this should only ever happen due to rounding errors when r == d
 if( dh2 < 0.0 )
 dh2 = 0.0;
 
 double h = sqrt( dh2 );
 
 if( ang < 0.0 )
 offAng -= M_PI_2;
 else
 offAng += M_PI_2;
 
 // for angles greater than 180 deg we need to flip the
 // direction in which the arc center is found relative
 // to the midpoint of the subtended segment.
 if( ang < -M_PI )
 offAng += M_PI;
 else if( ang > M_PI )
 offAng -= M_PI;
 
 // center point
 double cx = h * cos( offAng ) + xm;
 double cy = h * sin( offAng ) + ym;
 VECTOR2D center( SCALE_FACTOR( cx ), SCALE_FACTOR( -cy ) );
 VECTOR2D arc_start;
 EDA_ANGLE angle( ang, RADIANS_T );
 
 if( ang < 0.0 )
 {
 arc_start = VECTOR2D( SCALE_FACTOR( ep.x ), SCALE_FACTOR( -ep.y ) );
 }
 else
 {
 arc_start = VECTOR2D( SCALE_FACTOR( sp.x ), SCALE_FACTOR( -sp.y ) );
 angle = -angle;
 }
 
 GRAPHICS_IMPORTER_BUFFER* bufferToUse = m_currentBlock ? &m_currentBlock->m_buffer
 : &m_internalImporter;
 bufferToUse->AddArc( center, arc_start, angle, aWidth );
 
 VECTOR2D radiusDelta( SCALE_FACTOR( radius ), SCALE_FACTOR( radius ) );
 
 updateImageLimits( center + radiusDelta );
 updateImageLimits( center - radiusDelta );
}
 
 
#include "tinysplinecxx.h"
 
void DXF_IMPORT_PLUGIN::insertSpline( double aWidth )
{
#if 0 // Debug only
 wxLogMessage("spl deg %d kn %d ctr %d fit %d",
 m_curr_entity.m_SplineDegree,
 m_curr_entity.m_SplineKnotsList.size(),
 m_curr_entity.m_SplineControlPointList.size(),
 m_curr_entity.m_SplineFitPointList.size() );
#endif
 
 unsigned imax = m_curr_entity.m_SplineControlPointList.size();
 
 if( imax < 2 ) // malformed spline
 return;
 
#if 0 // set to 1 to approximate the spline by segments between 2 control points
 VECTOR2D startpoint( mapX( m_curr_entity.m_SplineControlPointList[0].m_x ),
 mapY( m_curr_entity.m_SplineControlPointList[0].m_y ) );
 
 for( unsigned int ii = 1; ii < imax; ++ii )
 {
 VECTOR2D endpoint( mapX( m_curr_entity.m_SplineControlPointList[ii].m_x ),
 mapY( m_curr_entity.m_SplineControlPointList[ii].m_y ) );
 
 if( startpoint != endpoint )
 {
 m_internalImporter.AddLine( startpoint, endpoint, aWidth );
 
 updateImageLimits( startpoint );
 updateImageLimits( endpoint );
 
 startpoint = endpoint;
 }
 }
#else // Use bezier curves, supported by pcbnew, to approximate the spline
 std::vector<double> ctrlp;
 
 for( unsigned ii = 0; ii < imax; ++ii )
 {
 ctrlp.push_back( m_curr_entity.m_SplineControlPointList[ii].m_x );
 ctrlp.push_back( m_curr_entity.m_SplineControlPointList[ii].m_y );
 }
 
 tinyspline::BSpline beziers;
 std::vector<double> coords;
 
 try
 {
 tinyspline::BSpline dxfspline( m_curr_entity.m_SplineControlPointList.size(),
 /* coord dim */ 2, m_curr_entity.m_SplineDegree );
 
 dxfspline.setControlPoints( ctrlp );
 dxfspline.setKnots( m_curr_entity.m_SplineKnotsList );
 
 if( dxfspline.degree() < 3 )
 dxfspline = dxfspline.elevateDegree( 3 - dxfspline.degree() );
 
 beziers = dxfspline.toBeziers();
 coords = beziers.controlPoints();
 }
 catch( const std::runtime_error& ) // tinyspline throws everything including data validation
 // as runtime errors
 {
 // invalid spline definition, drop this block
 ReportMsg( _( "Invalid spline definition encountered" ) );
 return;
 }
 
 size_t order = beziers.order();
 size_t dim = beziers.dimension();
 size_t numBeziers = ( coords.size() / dim ) / order;
 
 for( size_t i = 0; i < numBeziers; i++ )
 {
 size_t ii = i * dim * order;
 VECTOR2D start( mapX( coords[ ii ] ), mapY( coords[ ii + 1 ] ) );
 VECTOR2D bezierControl1( mapX( coords[ii + 2] ), mapY( coords[ii + 3] ) );
 
 // not sure why this happens, but it seems to sometimes slip degree on the final bezier
 VECTOR2D bezierControl2;
 
 if( ii + 5 >= coords.size() )
 bezierControl2 = bezierControl1;
 else
 bezierControl2 = VECTOR2D( mapX( coords[ii + 4] ), mapY( coords[ii + 5] ) );
 
 VECTOR2D end;
 
 if( ii + 7 >= coords.size() )
 end = bezierControl2;
 else
 end = VECTOR2D( mapX( coords[ii + 6] ), mapY( coords[ii + 7] ) );
 
 GRAPHICS_IMPORTER_BUFFER* bufferToUse = m_currentBlock ? &m_currentBlock->m_buffer
 : &m_internalImporter;
 bufferToUse->AddSpline( start, bezierControl1, bezierControl2, end, aWidth );
 }
#endif
}
 
 
void DXF_IMPORT_PLUGIN::updateImageLimits( const VECTOR2D& aPoint )
{
 m_minX = std::min( aPoint.x, m_minX );
 m_maxX = std::max( aPoint.x, m_maxX );
 
 m_minY = std::min( aPoint.y, m_minY );
 m_maxY = std::max( aPoint.y, m_maxY );
}
 
 
MATRIX3x3D DXF_IMPORT_PLUGIN::getArbitraryAxis( DL_Extrusion* aData )
{
 VECTOR3D arbZ, arbX, arbY;
 
 double direction[3];
 aData->getDirection( direction );
 
 arbZ = VECTOR3D( direction[0], direction[1], direction[2] ).Normalize();
 
 if( ( abs( arbZ.x ) < ( 1.0 / 64.0 ) ) && ( abs( arbZ.y ) < ( 1.0 / 64.0 ) ) )
 arbX = VECTOR3D( 0, 1, 0 ).Cross( arbZ ).Normalize();
 else
 arbX = VECTOR3D( 0, 0, 1 ).Cross( arbZ ).Normalize();
 
 arbY = arbZ.Cross( arbX ).Normalize();
 
 return MATRIX3x3D{ arbX, arbY, arbZ };
}
 
 
VECTOR3D DXF_IMPORT_PLUGIN::wcsToOcs( const MATRIX3x3D& arbitraryAxis, VECTOR3D point )
{
 return arbitraryAxis * point;
}
 
 
VECTOR3D DXF_IMPORT_PLUGIN::ocsToWcs( const MATRIX3x3D& arbitraryAxis, VECTOR3D point )
{
 VECTOR3D worldX = wcsToOcs( arbitraryAxis, VECTOR3D( 1, 0, 0 ) );
 VECTOR3D worldY = wcsToOcs( arbitraryAxis, VECTOR3D( 0, 1, 0 ) );
 VECTOR3D worldZ = wcsToOcs( arbitraryAxis, VECTOR3D( 0, 0, 1 ) );
 
 MATRIX3x3 world( worldX, worldY, worldZ );
 
 return world * point;
}