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/*
* angle_units.cc -- Implementation of ePiX's angular units
*
* This file is part of ePiX, a C++ library for creating high-quality
* figures in LaTeX
*
* Version 1.1.22
* Last Change: September 24, 2007
*/
/*
* Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007
* Andrew D. Hwang <ahwang -at- holycross -dot- edu>
* Department of Mathematics and Computer Science
* College of the Holy Cross
* Worcester, MA, 01610-2395, USA
*/
/*
* ePiX 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.
*
* ePiX 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 ePiX; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "constants.h"
#include "angle_units.h"
namespace ePiX {
angle_state::angle_state()
: m_rad_per_unit(1.0),
m_unit_per_deg(PI_180),
m_rev_per_unit(1.0/TWO_PI) { }
void angle_state::set_radians_mode()
{
m_rad_per_unit = 1.0;
m_unit_per_deg = PI_180;
m_rev_per_unit = 1.0/TWO_PI;
}
void angle_state::set_degrees_mode()
{
m_rad_per_unit = PI_180;
m_unit_per_deg = 1.0;
m_rev_per_unit = 1.0/360;
}
void angle_state::set_revolutions_mode()
{
m_rad_per_unit = TWO_PI;
m_unit_per_deg = 1.0/360;
m_rev_per_unit = 1.0;
}
double angle_state::to_radians(double t)
{
return t *= m_rad_per_unit;
}
// result lies in (-180, 180]
double angle_state::to_degrees(double t)
{
t *= m_rev_per_unit;
t -= 0.5; // shift half a turn
t -= ceil(t); // map to (-1,0]
t += 0.5; // shift to (-0.5, 0.5]
return t *= 360.0;
}
double angle_state::from_degrees(double t)
{
return t *= m_unit_per_deg;
}
angle_state& the_angle_style()
{
static angle_state* the_angle_state(new angle_state());
return *the_angle_state;
}
} // end of namespace
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