100 lines
3.4 KiB
C++
100 lines
3.4 KiB
C++
/*
|
|
* 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) 1992-2018 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
|
|
*/
|
|
|
|
/**
|
|
* @file geometry_utils.h
|
|
* @brief a few functions useful in geometry calculations.
|
|
*/
|
|
|
|
#ifndef GEOMETRY_UTILS_H
|
|
#define GEOMETRY_UTILS_H
|
|
|
|
#include <math/vector2d.h>
|
|
|
|
/**
|
|
* @return the number of segments to approximate a arc by segments
|
|
* with a given max error (this number is >= 1)
|
|
* @param aRadius is the radius od the circle or arc
|
|
* @param aErrorMax is the max error
|
|
* This is the max distance between the middle of a segment and the circle.
|
|
* @param aArcAngleDegree is the arc angle in degrees
|
|
*/
|
|
int GetArcToSegmentCount( int aRadius, int aErrorMax, double aArcAngleDegree );
|
|
|
|
/**
|
|
* @return the correction factor to approximate a circle by segments
|
|
* @param aSegCountforCircle is the number of segments to approximate the circle
|
|
*
|
|
* When creating a polygon from a circle, the polygon is inside the circle.
|
|
* Only corners are on the circle.
|
|
* This is incorrect when building clearance areas of circles, that need to build
|
|
* the equivalent polygon outside the circle
|
|
* The correction factor is a scaling factor to apply to the radius to build a
|
|
* polygon outside the circle (only the middle of each segment is on the circle
|
|
*/
|
|
double GetCircletoPolyCorrectionFactor( int aSegCountforCircle );
|
|
|
|
/**
|
|
* Snap a vector onto the nearest 0, 45 or 90 degree line.
|
|
*
|
|
* The magnitude of the vector is NOT kept, instead the co-ordinates are
|
|
* set equal (and/or opposite) or to zero as needed. The effect of this is
|
|
* that if the starting vector is on a square grid, the resulting snapped
|
|
* vector will still be on the same grid.
|
|
|
|
* @param a vector to be snapped
|
|
* @return the snapped vector
|
|
*/
|
|
template<typename T>
|
|
VECTOR2<T> GetVectorSnapped45( const VECTOR2<T>& aVec )
|
|
{
|
|
auto newVec = aVec;
|
|
const VECTOR2<T> absVec { std::abs( aVec.x ), std::abs( aVec.y ) };
|
|
|
|
if ( absVec.x > absVec.y * 2 )
|
|
{
|
|
// snap along x-axis
|
|
newVec.y = 0;
|
|
}
|
|
else if ( absVec.y > absVec.x * 2 )
|
|
{
|
|
// snap onto y-axis
|
|
newVec.x = 0;
|
|
}
|
|
else if ( absVec.x > absVec.y )
|
|
{
|
|
// snap away from x-axis towards 45
|
|
newVec.y = std::copysign( aVec.x, aVec.y );
|
|
} else
|
|
{
|
|
// snap away from y-axis towards 45
|
|
newVec.x = std::copysign( aVec.y, aVec.x );
|
|
}
|
|
|
|
return newVec;
|
|
}
|
|
|
|
#endif // #ifndef GEOMETRY_UTILS_H
|
|
|