kicad/libs/kimath/src/convert_basic_shapes_to_polygon.cpp

/**
 * @file convert_basic_shapes_to_polygon.cpp
 */
/*
 * This program source code file is part of KiCad, a free EDA CAD application.
 *
 * Copyright (C) 2018 Jean-Pierre Charras, jp.charras at wanadoo.fr
 * Copyright (C) 1992-2020 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 <algorithm>                    // for max, min
#include <math.h>                       // for atan2
#include <type_traits>                  // for swap

#include <convert_basic_shapes_to_polygon.h>
#include <geometry/geometry_utils.h>
#include <geometry/shape_line_chain.h>  // for SHAPE_LINE_CHAIN
#include <geometry/shape_poly_set.h>    // for SHAPE_POLY_SET, SHAPE_POLY_SE...
#include <math/util.h>
#include <math/vector2d.h>              // for VECTOR2I
#include <trigo.h>


void TransformCircleToPolygon( SHAPE_LINE_CHAIN& aCornerBuffer, wxPoint aCenter, int aRadius,
                               int aError )
{
    wxPoint corner_position;
    int     numSegs = GetArcToSegmentCount( aRadius, aError, 360.0 );
    int     delta = 3600 / numSegs;           // rotate angle in 0.1 degree
    int     correction = GetCircleToPolyCorrection( aError );
    int     radius = aRadius + correction;    // make segments outside the circles
    double  halfstep = delta / 2.0;           // the starting value for rot angles

    for( int angle = 0; angle < 3600; angle += delta )
    {
        corner_position.x   = radius;
        corner_position.y   = 0;
        RotatePoint( &corner_position, angle );
        corner_position += aCenter;
        aCornerBuffer.Append( corner_position.x, corner_position.y );
    }

    aCornerBuffer.SetClosed( true );
}


void TransformCircleToPolygon( SHAPE_POLY_SET& aCornerBuffer, wxPoint aCenter, int aRadius,
                               int aError )
{
    wxPoint corner_position;
    int     numSegs = GetArcToSegmentCount( aRadius, aError, 360.0 );
    int     delta = 3600 / numSegs;           // rotate angle in 0.1 degree
    int     correction = GetCircleToPolyCorrection( aError );
    int     radius = aRadius + correction;    // make segments outside the circles

    aCornerBuffer.NewOutline();

    for( int angle = 0; angle < 3600; angle += delta )
    {
        corner_position.x = radius;
        corner_position.y = 0;
        RotatePoint( &corner_position, angle );
        corner_position += aCenter;
        aCornerBuffer.Append( corner_position.x, corner_position.y );
    }

    // Finish circle
    corner_position.x = radius;
    corner_position.y = 0;
    corner_position += aCenter;
    aCornerBuffer.Append( corner_position.x, corner_position.y );
}


void TransformOvalToPolygon( SHAPE_POLY_SET& aCornerBuffer, wxPoint aStart, wxPoint aEnd,
                             int aWidth, int aError )
{
    // To build the polygonal shape outside the actual shape, we use a bigger
    // radius to build rounded ends.
    // However, the width of the segment is too big.
    // so, later, we will clamp the polygonal shape with the bounding box
    // of the segment.
    int radius  = aWidth / 2;
    int numSegs = GetArcToSegmentCount( radius, aError, 360.0 );
    int delta = 3600 / numSegs;   // rotate angle in 0.1 degree
    int correction = GetCircleToPolyCorrection( aError );

    radius += correction;         // make segments outside the circles

    // end point is the coordinate relative to aStart
    wxPoint        endp = aEnd - aStart;
    wxPoint        startp = aStart;
    wxPoint        corner;
    SHAPE_POLY_SET polyshape;

    polyshape.NewOutline();

    // normalize the position in order to have endp.x >= 0
    // it makes calculations more easy to understand
    if( endp.x < 0 )
    {
        endp    = aStart - aEnd;
        startp  = aEnd;
    }

    // delta_angle is in radian
    double delta_angle = atan2( (double)endp.y, (double)endp.x );
    int    seg_len     = KiROUND( EuclideanNorm( endp ) );


    // Compute the outlines of the segment, and creates a polygon
    // Note: the polygonal shape is built from the equivalent horizontal
    // segment starting at {0,0}, and ending at {seg_len,0}

    // add right rounded end:

    for( int angle = 0; angle < 1800; angle += delta )
    {
        corner = wxPoint( 0, radius );
        RotatePoint( &corner, angle );
        corner.x += seg_len;
        polyshape.Append( corner.x, corner.y );
    }

    // Finish arc:
    corner = wxPoint( seg_len, -radius );
    polyshape.Append( corner.x, corner.y );

    // add left rounded end:
    for( int angle = 0; angle < 1800; angle += delta )
    {
        corner = wxPoint( 0, -radius );
        RotatePoint( &corner, angle );
        polyshape.Append( corner.x, corner.y );
    }

    // Finish arc:
    corner = wxPoint( 0, radius );
    polyshape.Append( corner.x, corner.y );

    // Now trim the edges of the polygonal shape which will be slightly outside the
    // track width.
    SHAPE_POLY_SET bbox;
    bbox.NewOutline();
    // Build the bbox (a horizontal rectangle).
    int halfwidth = aWidth / 2;     // Use the exact segment width for the bbox height
    corner.x = -radius - 2;         // use a bbox width slightly bigger to avoid
                                    // creating useless corner at segment ends
    corner.y = halfwidth;
    bbox.Append( corner.x, corner.y );
    corner.y = -halfwidth;
    bbox.Append( corner.x, corner.y );
    corner.x = radius + seg_len + 2;
    bbox.Append( corner.x, corner.y );
    corner.y = halfwidth;
    bbox.Append( corner.x, corner.y );

    // Now, clamp the shape
    polyshape.BooleanIntersection( bbox, SHAPE_POLY_SET::PM_STRICTLY_SIMPLE );
    // Note the final polygon is a simple, convex polygon with no hole
    // due to the shape of initial polygons

    // Rotate and move the polygon to its right location
    polyshape.Rotate( delta_angle, VECTOR2I( 0, 0 ) );
    polyshape.Move( startp );

    aCornerBuffer.Append( polyshape);
}


void GetRoundRectCornerCenters( wxPoint aCenters[4], int aRadius, const wxPoint& aPosition,
                                const wxSize& aSize, double aRotation )
{
    wxSize size( aSize/2 );

    size.x -= aRadius;
    size.y -= aRadius;

    // Ensure size is > 0, to avoid generating unusable shapes
    // which can crash kicad.
    size.x = std::max( 1, size.x );
    size.y = std::max( 1, size.y );

    aCenters[0] = wxPoint( -size.x,  size.y );
    aCenters[1] = wxPoint(  size.x,  size.y );
    aCenters[2] = wxPoint(  size.x, -size.y );
    aCenters[3] = wxPoint( -size.x, -size.y );

    // Rotate the polygon
    if( aRotation != 0.0 )
    {
        for( int ii = 0; ii < 4; ii++ )
            RotatePoint( &aCenters[ii], aRotation );
    }

    // move the polygon to the position
    for( int ii = 0; ii < 4; ii++ )
        aCenters[ii] += aPosition;
}


void TransformRoundChamferedRectToPolygon( SHAPE_POLY_SET& aCornerBuffer, const wxPoint& aPosition,
                                           const wxSize& aSize, double aRotation,
                                           int aCornerRadius, double aChamferRatio,
                                           int aChamferCorners, int aError )
{
    // Build the basic shape in orientation 0.0, position 0,0 for chamfered corners
    // or in actual position/orientation for round rect only
    wxPoint corners[4];
    GetRoundRectCornerCenters( corners, aCornerRadius,
                               aChamferCorners ? wxPoint( 0, 0 ) : aPosition,
                               aSize, aChamferCorners ? 0.0 : aRotation );

    SHAPE_POLY_SET outline;
    outline.NewOutline();

    for( const wxPoint& corner : corners)
        outline.Append( corner );

    int numSegs = GetArcToSegmentCount( aCornerRadius, aError, 360.0 );

    // To build the polygonal shape outside the actual shape, we use a bigger
    // radius to build rounded corners.

    int correction = GetCircleToPolyCorrection( aError );
    int radius = aCornerRadius + correction;    // make segments outside the circles
    outline.Inflate( radius, numSegs );

    if( correction > 1.0 )
    {
        // Refinement: clamp the inflated polygonal shape by the rectangular shape
        // containing the rounded polygon
        SHAPE_POLY_SET bbox;    // the rectangular shape
        bbox.NewOutline();

        for( const wxPoint& corner : corners )
            bbox.Append( corner );

        // Just build the rectangular bbox
        bbox.Inflate( aCornerRadius, 1, SHAPE_POLY_SET::CORNER_STRATEGY::ALLOW_ACUTE_CORNERS );

        // Now, clamp the shape
        outline.BooleanIntersection( bbox, SHAPE_POLY_SET::PM_STRICTLY_SIMPLE );
        // Note the final polygon is a simple, convex polygon with no hole
        // due to the shape of initial polygons
    }

    if( aChamferCorners == RECT_NO_CHAMFER )      // no chamfer
    {
        // Add the outline:
        aCornerBuffer.Append( outline );
        return;
    }

    // Now we have the round rect outline, in position 0,0 orientation 0.0.
    // Chamfer the corner(s).
    int chamfer_value = aChamferRatio * std::min( aSize.x, aSize.y );

    SHAPE_POLY_SET chamfered_corner;    // corner shape for the current corner to chamfer

    int corner_id[4] =
    {
        RECT_CHAMFER_TOP_LEFT, RECT_CHAMFER_TOP_RIGHT,
        RECT_CHAMFER_BOTTOM_LEFT, RECT_CHAMFER_BOTTOM_RIGHT
    };
    // Depending on the corner position, signX[] and signY[] give the sign of chamfer
    // coordinates relative to the corner position
    // The first corner is the top left corner, then top right, bottom left and bottom right
    int signX[4] = {1, -1, 1,-1 };
    int signY[4] = {1, 1, -1,-1 };

    for( int ii = 0; ii < 4; ii++ )
    {
        if( (corner_id[ii] & aChamferCorners) == 0 )
            continue;

        VECTOR2I corner_pos( -signX[ii]*aSize.x/2, -signY[ii]*aSize.y/2 );

        if( aCornerRadius )
        {
            // We recreate a rectangular area covering the full rounded corner (max size = aSize/2)
            // to rebuild the corner before chamfering, to be sure the rounded corner shape does not
            // overlap the chamfered corner shape:
            chamfered_corner.RemoveAllContours();
            chamfered_corner.NewOutline();
            chamfered_corner.Append( 0, 0 );
            chamfered_corner.Append( 0, signY[ii] * aSize.y / 2 );
            chamfered_corner.Append( signX[ii] * aSize.x / 2, signY[ii] * aSize.y / 2 );
            chamfered_corner.Append( signX[ii] * aSize.x / 2, 0 );
            chamfered_corner.Move( corner_pos );
            outline.BooleanAdd( chamfered_corner, SHAPE_POLY_SET::PM_STRICTLY_SIMPLE );
        }

        // Now chamfer this corner
        chamfered_corner.RemoveAllContours();
        chamfered_corner.NewOutline();
        chamfered_corner.Append( 0, 0 );
        chamfered_corner.Append( 0, signY[ii] * chamfer_value );
        chamfered_corner.Append( signX[ii] * chamfer_value, 0 );
        chamfered_corner.Move( corner_pos );
        outline.BooleanSubtract( chamfered_corner, SHAPE_POLY_SET::PM_STRICTLY_SIMPLE );
    }

    // Rotate and move the outline:
    if( aRotation != 0.0 )
        outline.Rotate( DECIDEG2RAD( -aRotation ), VECTOR2I( 0, 0 ) );

    outline.Move( VECTOR2I( aPosition ) );

    // Add the outline:
    aCornerBuffer.Append( outline );
}


void TransformArcToPolygon( SHAPE_POLY_SET& aCornerBuffer, wxPoint aCentre, wxPoint aStart,
                            double aArcAngle, int aError, int aWidth )
{
    wxPoint arc_start, arc_end;
    int     dist = EuclideanNorm( aCentre - aStart );
    int     numSegs = GetArcToSegmentCount( dist, aError, 360.0 );
    int     delta = 3600 / numSegs;   // rotate angle in 0.1 degree

    arc_end = arc_start = aStart;

    if( aArcAngle != 3600 )
        RotatePoint( &arc_end, aCentre, -aArcAngle );

    if( aArcAngle < 0 )
    {
        std::swap( arc_start, arc_end );
        aArcAngle = -aArcAngle;
    }

    // Compute the ends of segments and creates poly
    wxPoint curr_end    = arc_start;
    wxPoint curr_start  = arc_start;

    for( int ii = delta; ii < aArcAngle; ii += delta )
    {
        curr_end = arc_start;
        RotatePoint( &curr_end, aCentre, -ii );
        TransformOvalToPolygon( aCornerBuffer, curr_start, curr_end, aWidth, aError );
        curr_start = curr_end;
    }

    if( curr_end != arc_end )
        TransformOvalToPolygon( aCornerBuffer, curr_end, arc_end, aWidth, aError );
}


void TransformRingToPolygon( SHAPE_POLY_SET& aCornerBuffer, wxPoint aCentre, int aRadius,
                             int aError, int aWidth )
{
    int inner_radius = aRadius - ( aWidth / 2 );
    int outer_radius = inner_radius + aWidth;

    if( inner_radius <= 0 )
    {   //In this case, the ring is just a circle (no hole inside)
        TransformCircleToPolygon( aCornerBuffer, aCentre, aRadius + ( aWidth / 2 ), aError );
        return;
    }

    SHAPE_POLY_SET buffer;

    TransformCircleToPolygon( buffer, aCentre, outer_radius, aError );

    // Build the hole:
    buffer.NewHole();
    TransformCircleToPolygon( buffer.Hole( 0, 0 ), aCentre, inner_radius, aError );

    buffer.Fracture( SHAPE_POLY_SET::PM_FAST );
    aCornerBuffer.Append( buffer );
}