shape_utils.cpp

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/*
 * This program source code file is part of KiCad, a free EDA CAD application.
 *
 * Copyright (C) 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
 */
 
#include "geometry/shape_utils.h"
 
#include <geometry/circle.h>
#include <geometry/seg.h>
#include <geometry/half_line.h>
#include <geometry/line.h>
#include <geometry/point_types.h>
#include <geometry/shape_rect.h>
 
 
SEG KIGEOM::NormalisedSeg( const SEG& aSeg )
{
 if( LexicographicalCompare( aSeg.A, aSeg.B ) <= 0 )
 {
 return aSeg;
 }
 return aSeg.Reversed();
}
 
 
const VECTOR2I& KIGEOM::GetOtherEnd( const SEG& aSeg, const VECTOR2I& aPoint )
{
 return ( aSeg.A == aPoint ) ? aSeg.B : aSeg.A;
}
 
 
OPT_VECTOR2I KIGEOM::GetSharedEndpoint( const SEG& aSegA, const SEG& aSegB )
{
 if( aSegA.A == aSegB.A || aSegA.A == aSegB.B )
 {
 return aSegA.A;
 }
 else if( aSegA.B == aSegB.A || aSegA.B == aSegB.B )
 {
 return aSegA.B;
 }
 
 return std::nullopt;
}
 
 
std::array<SEG, 4> KIGEOM::BoxToSegs( const BOX2I& aBox )
{
 const std::array<VECTOR2I, 4> corners = {
 VECTOR2I{ aBox.GetLeft(), aBox.GetTop() },
 VECTOR2I{ aBox.GetRight(), aBox.GetTop() },
 VECTOR2I{ aBox.GetRight(), aBox.GetBottom() },
 VECTOR2I{ aBox.GetLeft(), aBox.GetBottom() },
 };
 
 return {
 SEG{ corners[0], corners[1] },
 SEG{ corners[1], corners[2] },
 SEG{ corners[2], corners[3] },
 SEG{ corners[3], corners[0] },
 };
}
 
 
std::optional<SEG> KIGEOM::ClipHalfLineToBox( const HALF_LINE& aRay, const BOX2I& aBox )
{
 // Do the naive implementation - if this really is done in a tight loop,
 // the Cohen-Sutherland implementation in ClipLine could be faster, but
 // needs to be adapted to work with half-lines.
 const std::array<SEG, 4> boxSegs = KIGEOM::BoxToSegs( aBox );
 
 std::optional<VECTOR2I> ptA, ptB;
 
 for( const SEG& boxSeg : boxSegs )
 {
 OPT_VECTOR2I intersection = aRay.Intersect( boxSeg );
 
 if( !intersection )
 {
 continue;
 }
 
 // Init the first point or eat it if it's the same
 if( !ptA || *intersection == *ptA )
 {
 ptA = *intersection;
 }
 else
 {
 ptB = *intersection;
 }
 }
 
 // If we have exactly two intersections, the ray crossed twice
 // so take the segment between the two points
 if( ptA && ptB )
 {
 return SEG( *ptA, *ptB );
 }
 
 // It only crosses once, so the start is in the box. Take the segment from
 // the start point to the intersection
 if( ptA && *ptA != aRay.GetStart() )
 {
 return SEG( aRay.GetStart(), *ptA );
 }
 
 // It didn't cross at all
 return std::nullopt;
}
 
 
std::optional<SEG> KIGEOM::ClipLineToBox( const LINE& aLine, const BOX2I& aBox )
{
 // As above, maybe can be optimised?
 const std::array<SEG, 4> boxSegs = KIGEOM::BoxToSegs( aBox );
 
 std::optional<VECTOR2I> ptA, ptB;
 
 for( const SEG& boxSeg : boxSegs )
 {
 OPT_VECTOR2I intersection = aLine.Intersect( boxSeg );
 
 // Reject intersections that are not on the actual box boundary
 if( intersection && boxSeg.Contains( *intersection ) )
 {
 // Init the first point or eat it if it's the same
 if( !ptA || *intersection == *ptA )
 {
 ptA = *intersection;
 }
 else
 {
 ptB = *intersection;
 }
 }
 }
 
 // If we have exactly two intersections, we have a segment
 // (zero is no intersection, and one is a just crossing a corner exactly)
 if( ptA && ptB )
 {
 return SEG( *ptA, *ptB );
 }
 
 return std::nullopt;
}
 
 
SHAPE_ARC KIGEOM::MakeArcCw90( const VECTOR2I& aCenter, int aRadius, DIRECTION_45::Directions aDir )
{
 switch( aDir )
 {
 case DIRECTION_45::NW:
 return SHAPE_ARC{
 aCenter,
 aCenter + VECTOR2I( -aRadius, 0 ),
 ANGLE_90,
 };
 case DIRECTION_45::NE:
 return SHAPE_ARC{
 aCenter,
 aCenter + VECTOR2I( 0, -aRadius ),
 ANGLE_90,
 };
 case DIRECTION_45::SW:
 return SHAPE_ARC{
 aCenter,
 aCenter + VECTOR2I( 0, aRadius ),
 ANGLE_90,
 };
 case DIRECTION_45::SE:
 return SHAPE_ARC{
 aCenter,
 aCenter + VECTOR2I( aRadius, 0 ),
 ANGLE_90,
 };
 default: wxFAIL_MSG( "Invalid direction" ); return SHAPE_ARC();
 }
}
 
 
SHAPE_ARC KIGEOM::MakeArcCw180( const VECTOR2I& aCenter, int aRadius,
 DIRECTION_45::Directions aDir )
{
 switch( aDir )
 {
 case DIRECTION_45::N:
 return SHAPE_ARC{
 aCenter,
 aCenter + VECTOR2I( -aRadius, 0 ),
 ANGLE_180,
 };
 case DIRECTION_45::E:
 return SHAPE_ARC{
 aCenter,
 aCenter + VECTOR2I( 0, -aRadius ),
 ANGLE_180,
 };
 case DIRECTION_45::S:
 return SHAPE_ARC{
 aCenter,
 aCenter + VECTOR2I( aRadius, 0 ),
 ANGLE_180,
 };
 case DIRECTION_45::W:
 return SHAPE_ARC{
 aCenter,
 aCenter + VECTOR2I( 0, aRadius ),
 ANGLE_180,
 };
 default: wxFAIL_MSG( "Invalid direction" );
 }
 
 return SHAPE_ARC();
}
 
 
VECTOR2I KIGEOM::GetPoint( const SHAPE_RECT& aRect, DIRECTION_45::Directions aDir )
{
 const VECTOR2I nw = aRect.GetPosition();
 switch( aDir )
 {
 // clang-format off
 case DIRECTION_45::N: return nw + VECTOR2I( aRect.GetWidth() / 2, 0 );
 case DIRECTION_45::E: return nw + VECTOR2I( aRect.GetWidth(), aRect.GetHeight() / 2 );
 case DIRECTION_45::S: return nw + VECTOR2I( aRect.GetWidth() / 2, aRect.GetHeight() );
 case DIRECTION_45::W: return nw + VECTOR2I( 0, aRect.GetHeight() / 2 );
 case DIRECTION_45::NW: return nw;
 case DIRECTION_45::NE: return nw + VECTOR2I( aRect.GetWidth(), 0 );
 case DIRECTION_45::SW: return nw + VECTOR2I( 0, aRect.GetHeight() );
 case DIRECTION_45::SE: return nw + VECTOR2I( aRect.GetWidth(), aRect.GetHeight() );
 default: wxFAIL_MSG( "Invalid direction" );
 // clang-format on
 }
 return VECTOR2I();
}
 
 
std::vector<TYPED_POINT2I> KIGEOM::GetCircleKeyPoints( const CIRCLE& aCircle, bool aIncludeCenter )
{
 std::vector<TYPED_POINT2I> pts;
 
 if( aIncludeCenter )
 {
 pts.emplace_back( VECTOR2I{ 0, 0 }, POINT_TYPE::PT_CENTER );
 }
 
 pts.emplace_back( VECTOR2I{ 0, aCircle.Radius }, POINT_TYPE::PT_QUADRANT );
 pts.emplace_back( VECTOR2I{ aCircle.Radius, 0 }, POINT_TYPE::PT_QUADRANT );
 pts.emplace_back( VECTOR2I{ 0, -aCircle.Radius }, POINT_TYPE::PT_QUADRANT );
 pts.emplace_back( VECTOR2I{ -aCircle.Radius, 0 }, POINT_TYPE::PT_QUADRANT );
 
 // Shift the points to the circle center
 for( TYPED_POINT2I& pt : pts )
 {
 pt.m_point += aCircle.Center;
 }
 
 return pts;
}