svg_import_plugin.cpp

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/*
 * This program source code file is part of KICAD, a free EDA CAD application.
 *
 * Copyright (C) 2016 CERN
 * Copyright (C) 1992-2021 KiCad Developers, see AUTHORS.txt for contributors.
 * @author Janito V. Ferreira Filho
 *
 * 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 "svg_import_plugin.h"
 
#include <algorithm>
#include <cmath>
 
#include <math/vector2d.h>
 
#include <eda_item.h>
#include "graphics_importer.h"
 
static VECTOR2D calculateBezierBoundingBoxExtremity( const float* aCurvePoints,
 std::function< const float&( const float&, const float& ) > comparator );
static float calculateBezierSegmentationThreshold( const float* aCurvePoints );
static void segmentBezierCurve( const VECTOR2D& aStart, const VECTOR2D& aEnd, float aOffset,
 float aStep, const float* aCurvePoints, float aSegmentationThreshold,
 std::vector< VECTOR2D >& aGeneratedPoints );
static void createNewBezierCurveSegments( const VECTOR2D& aStart, const VECTOR2D& aMiddle,
 const VECTOR2D& aEnd, float aOffset, float aStep, const float* aCurvePoints,
 float aSegmentationThreshold, std::vector< VECTOR2D >& aGeneratedPoints );
static VECTOR2D getBezierPoint( const float* aCurvePoints, float aStep );
static VECTOR2D getPoint( const float* aPointCoordinates );
static VECTOR2D getPointInLine( const VECTOR2D& aLineStart, const VECTOR2D& aLineEnd,
 float aDistance );
static float distanceFromPointToLine( const VECTOR2D& aPoint, const VECTOR2D& aLineStart,
 const VECTOR2D& aLineEnd );
 
 
bool SVG_IMPORT_PLUGIN::Load( const wxString& aFileName )
{
 wxCHECK( m_importer, false );
 
 // 1- wxFopen takes care of unicode filenames across platforms
 // 2 - nanosvg (exactly nsvgParseFromFile) expects a binary file (exactly the CRLF eof must
 // not be replaced by LF and changes the byte count) in one validity test,
 // so open it in binary mode.
 FILE* fp = wxFopen( aFileName, wxT( "rb" ) );
 
 if( fp == nullptr )
 return false;
 
 // nsvgParseFromFile will close the file after reading
 m_parsedImage = nsvgParseFromFile( fp, "mm", 96 );
 
 wxCHECK( m_parsedImage, false );
 
 return true;
}
 
bool SVG_IMPORT_PLUGIN::Import()
{
 auto alpha =
 []( unsigned int color )
 {
 return color >> 24;
 };
 
 for( NSVGshape* shape = m_parsedImage->shapes; shape != nullptr; shape = shape->next )
 {
 double lineWidth = shape->strokeWidth;
 bool filled = shape->fill.type != NSVG_PAINT_NONE && alpha( shape->fill.color ) > 0;
 
 GRAPHICS_IMPORTER::POLY_FILL_RULE rule = GRAPHICS_IMPORTER::PF_NONZERO;
 
 switch( shape->fillRule )
 {
 case NSVG_FILLRULE_NONZERO: rule = GRAPHICS_IMPORTER::PF_NONZERO; break;
 case NSVG_FILLRULE_EVENODD: rule = GRAPHICS_IMPORTER::PF_EVEN_ODD; break;
 default: break;
 }
 
 m_internalImporter.NewShape( rule );
 
 for( NSVGpath* path = shape->paths; path != nullptr; path = path->next )
 {
 bool closed = path->closed || rule == GRAPHICS_IMPORTER::PF_EVEN_ODD;
 
 DrawPath( path->pts, path->npts, closed, filled, lineWidth );
 }
 }
 
 m_internalImporter.PostprocessNestedPolygons();
 wxCHECK( m_importer, false );
 m_internalImporter.ImportTo( *m_importer );
 
 return true;
}
 
 
double SVG_IMPORT_PLUGIN::GetImageHeight() const
{
 if( !m_parsedImage )
 {
 wxASSERT_MSG( false, wxT( "Image must have been loaded before checking height" ) );
 return 0.0;
 }
 
 return m_parsedImage->height;
}
 
 
double SVG_IMPORT_PLUGIN::GetImageWidth() const
{
 if( !m_parsedImage )
 {
 wxASSERT_MSG( false, wxT( "Image must have been loaded before checking width" ) );
 return 0.0;
 }
 
 return m_parsedImage->width;
}
 
 
void SVG_IMPORT_PLUGIN::DrawPath( const float* aPoints, int aNumPoints, bool aPoly, bool aFilled,
 double aLineWidth )
{
 std::vector< VECTOR2D > collectedPathPoints;
 
 if( aNumPoints > 0 )
 DrawCubicBezierPath( aPoints, aNumPoints, collectedPathPoints );
 
 if( aPoly && aFilled )
 DrawPolygon( collectedPathPoints, aLineWidth );
 else
 DrawLineSegments( collectedPathPoints, aLineWidth );
}
 
 
void SVG_IMPORT_PLUGIN::DrawCubicBezierPath( const float* aPoints, int aNumPoints,
 std::vector< VECTOR2D >& aGeneratedPoints )
{
 const int pointsPerSegment = 4;
 const int curveSpecificPointsPerSegment = 3;
 const int curveSpecificCoordinatesPerSegment = 2 * curveSpecificPointsPerSegment;
 const float* currentPoints = aPoints;
 int remainingPoints = aNumPoints;
 
 while( remainingPoints >= pointsPerSegment )
 {
 DrawCubicBezierCurve( currentPoints, aGeneratedPoints );
 currentPoints += curveSpecificCoordinatesPerSegment;
 remainingPoints -= curveSpecificPointsPerSegment;
 }
}
 
 
void SVG_IMPORT_PLUGIN::DrawCubicBezierCurve( const float* aPoints,
 std::vector< VECTOR2D >& aGeneratedPoints )
{
 auto start = getBezierPoint( aPoints, 0.0f );
 auto end = getBezierPoint( aPoints, 1.0f );
 auto segmentationThreshold = calculateBezierSegmentationThreshold( aPoints );
 
 aGeneratedPoints.push_back( start );
 segmentBezierCurve( start, end, 0.0f, 0.5f, aPoints, segmentationThreshold, aGeneratedPoints );
 aGeneratedPoints.push_back( end );
}
 
 
void SVG_IMPORT_PLUGIN::DrawPolygon( const std::vector< VECTOR2D >& aPoints, double aWidth )
{
 m_internalImporter.AddPolygon( aPoints, aWidth );
}
 
 
void SVG_IMPORT_PLUGIN::DrawLineSegments( const std::vector< VECTOR2D >& aPoints, double aWidth )
{
 unsigned int numLineStartPoints = aPoints.size() - 1;
 
 for( unsigned int pointIndex = 0; pointIndex < numLineStartPoints; ++pointIndex )
 m_internalImporter.AddLine( aPoints[ pointIndex ], aPoints[ pointIndex + 1 ], aWidth );
}
 
 
static VECTOR2D getPoint( const float* aPointCoordinates )
{
 return VECTOR2D( aPointCoordinates[0], aPointCoordinates[1] );
}
 
 
static VECTOR2D getBezierPoint( const float* aPoints, float aStep )
{
 const int coordinatesPerPoint = 2;
 
 auto firstCubicPoint = getPoint( aPoints );
 auto secondCubicPoint = getPoint( aPoints + 1 * coordinatesPerPoint );
 auto thirdCubicPoint = getPoint( aPoints + 2 * coordinatesPerPoint );
 auto fourthCubicPoint = getPoint( aPoints + 3 * coordinatesPerPoint );
 
 auto firstQuadraticPoint = getPointInLine( firstCubicPoint, secondCubicPoint, aStep );
 auto secondQuadraticPoint = getPointInLine( secondCubicPoint, thirdCubicPoint, aStep );
 auto thirdQuadraticPoint = getPointInLine( thirdCubicPoint, fourthCubicPoint, aStep );
 
 auto firstLinearPoint = getPointInLine( firstQuadraticPoint, secondQuadraticPoint, aStep );
 auto secondLinearPoint = getPointInLine( secondQuadraticPoint, thirdQuadraticPoint, aStep );
 
 return getPointInLine( firstLinearPoint, secondLinearPoint, aStep );
}
 
 
static VECTOR2D getPointInLine( const VECTOR2D& aLineStart, const VECTOR2D& aLineEnd,
 float aDistance )
{
 return aLineStart + ( aLineEnd - aLineStart ) * aDistance;
}
 
 
static float calculateBezierSegmentationThreshold( const float* aCurvePoints )
{
 using comparatorFunction = const float&(*)( const float&, const float& );
 
 auto minimumComparator = static_cast< comparatorFunction >( &std::min );
 auto maximumComparator = static_cast< comparatorFunction >( &std::max );
 
 VECTOR2D minimum = calculateBezierBoundingBoxExtremity( aCurvePoints, minimumComparator );
 VECTOR2D maximum = calculateBezierBoundingBoxExtremity( aCurvePoints, maximumComparator );
 VECTOR2D boundingBoxDimensions = maximum - minimum;
 
 return 0.001 * std::max( boundingBoxDimensions.x, boundingBoxDimensions.y );
}
 
 
static VECTOR2D calculateBezierBoundingBoxExtremity( const float* aCurvePoints,
 std::function< const float&( const float&, const float& ) > comparator )
{
 float x = aCurvePoints[0];
 float y = aCurvePoints[1];
 
 for( int pointIndex = 1; pointIndex < 3; ++pointIndex )
 {
 x = comparator( x, aCurvePoints[ 2 * pointIndex ] );
 y = comparator( y, aCurvePoints[ 2 * pointIndex + 1 ] );
 }
 
 return VECTOR2D( x, y );
}
 
 
static void segmentBezierCurve( const VECTOR2D& aStart, const VECTOR2D& aEnd, float aOffset,
 float aStep, const float* aCurvePoints,
 float aSegmentationThreshold,
 std::vector< VECTOR2D >& aGeneratedPoints )
{
 VECTOR2D middle = getBezierPoint( aCurvePoints, aOffset + aStep );
 float distanceToPreviousSegment = distanceFromPointToLine( middle, aStart, aEnd );
 
 if( distanceToPreviousSegment > aSegmentationThreshold )
 {
 createNewBezierCurveSegments( aStart, middle, aEnd, aOffset, aStep, aCurvePoints,
 aSegmentationThreshold, aGeneratedPoints );
 }
}
 
 
static void createNewBezierCurveSegments( const VECTOR2D& aStart, const VECTOR2D& aMiddle,
 const VECTOR2D& aEnd, float aOffset, float aStep,
 const float* aCurvePoints, float aSegmentationThreshold,
 std::vector< VECTOR2D >& aGeneratedPoints )
{
 float newStep = aStep / 2.f;
 float offsetAfterMiddle = aOffset + aStep;
 
 segmentBezierCurve( aStart, aMiddle, aOffset, newStep, aCurvePoints, aSegmentationThreshold,
 aGeneratedPoints );
 
 aGeneratedPoints.push_back( aMiddle );
 
 segmentBezierCurve( aMiddle, aEnd, offsetAfterMiddle, newStep, aCurvePoints,
 aSegmentationThreshold, aGeneratedPoints );
}
 
 
static float distanceFromPointToLine( const VECTOR2D& aPoint, const VECTOR2D& aLineStart,
 const VECTOR2D& aLineEnd )
{
 auto lineDirection = aLineEnd - aLineStart;
 auto lineNormal = lineDirection.Perpendicular().Resize( 1.f );
 auto lineStartToPoint = aPoint - aLineStart;
 
 auto distance = lineNormal.Dot( lineStartToPoint );
 
 return fabs( distance );
}