AngleComputer.ih

/**
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU Lesser General Public License as
 *  published by the Free Software Foundation, either version 3 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, see <http://www.gnu.org/licenses/>.
 *
 **/
 
/**
 * @file AngleComputer.ih
 *
 * @author Jacques-Olivier Lachaud (\c jacques-olivier.lachaud@univ-savoie.fr )
 * Laboratory of Mathematics (CNRS, UMR 5807), University of Savoie, France
 *
 * @author (backported by) Bertrand Kerautret (\c kerautre@loria.fr )
 * LORIA (CNRS, UMR 7503), University of Nancy, France
 *
 * @date 2011/08/31
 *
 * Implementation of inline methods defined in AngleComputer.h
 *
 * This file is part of the DGtal library.
 */
 
///////////////////////////////////////////////////////////////////////////////
// IMPLEMENTATION of inline methods.
///////////////////////////////////////////////////////////////////////////////
 
//////////////////////////////////////////////////////////////////////////////
#include <cstdlib>
//////////////////////////////////////////////////////////////////////////////
 
 
 
///////////////////////////////////////////////////////////////////////////////
// Implementation of inline methods                                          //
 
 
 
/**
 * @param i any angle.
 * @return the corresponding angle in [0:2pi[
 */
inline
float 
DGtal::AngleComputer::cast( float i )
{
  while ( i < 0.0f ) i += (float) (M_PI*2.0);
  while ( i > (double)(M_PI*2.0) ) i -= (float)(M_PI*2.0);
  return i;
}
 
    
/**
 * Less comparator modulo. Be careful, modulo comparisons have no
 * sense when the absolute difference of the values are around pi.
 *
 * @param i any angle in [0:2pi[
 * @param j any angle in [0:2pi[
 * @return 'true' if [i] strictly precedes [j] in a window 'pi'.
 */
inline
bool
DGtal::AngleComputer::less( float i, float j )
{
  float d = j - i;
  if ( d > 0.0f )
    return d < M_PI;
  else
    return (-d) >= M_PI;
}
 
 
/**
 * Performs j - i modulo 2pi, assuming less(i,j) is true.
 *
 * @param j any angle in [0:2pi[
 * @param i any angle in [0:2pi[
 * @return the value j - i, always positive. 
 */
inline
float 
DGtal::AngleComputer::posDiff( float j, float i )
{
  return ( i <= j ) ? j - i : j + (float)(M_PI*2.0) - i;
}
 
/**
 * Performs j - i, assuming th result is in [-pi:pi[
 *
 * @param j any angle in [0:2pi[
 * @param i any angle in [0:2pi[
 * @return the value j - i, always positive. 
 */
inline
float 
DGtal::AngleComputer::deviation( float j, float i )
{
  return less( i, j ) ? posDiff( j, i ) : -posDiff( i, j );
}
 
 
/**
 * Equivalent to 'less( i, j ) ? i : j'.
 *
 * @param i any angle in [0:2pi[
 * @param j any angle in [0:2pi[
 * @return the smallest angle of [i] and [j] in a window 'pi'.
 */
inline
float 
DGtal::AngleComputer::min( float i, float j )
{
  return less( i, j ) ? i : j;
}
 
/**
 * Equivalent to 'less( i, j ) ? j : i'.
 *
 * @param i any angle in [0:2pi[
 * @param j any angle in [0:2pi[
 * @return the greatest angle of [i] and [j] in a window 'pi'.
 */
inline
float 
DGtal::AngleComputer::max( float i, float j )
{
  return less( i, j ) ? j : i;
}
 
 
 
/**
 * @param i any angle.
 * @return the corresponding angle in [0:2pi[
 */
inline
double 
DGtal::AngleComputer::cast( double i )
{
  while ( i < 0.0 ) i += (float)(M_PI*2.0);
  while ( i > (float)(M_PI*2.0) ) i -= (float)(M_PI*2.0);
  return i;
}
 
    
/**
 * Less comparator modulo. Be careful, modulo comparisons have no
 * sense when the absolute difference of the values are around pi.
 *
 * @param i any angle in [0:2pi[
 * @param j any angle in [0:2pi[
 * @return 'true' if [i] strictly precedes [j] in a window 'pi'.
 */
inline
bool
DGtal::AngleComputer::less( double i, double j )
{
  double d = j - i;
  if ( d > 0.0 )
    return d < M_PI;
  else
    return (-d) >= M_PI;
}
 
 
/**
 * Performs j - i modulo 2pi, assuming less(i,j) is true.
 *
 * @param j any angle in [0:2pi[
 * @param i any angle in [0:2pi[
 * @return the value j - i, always positive. 
 */
inline
double 
DGtal::AngleComputer::posDiff( double j, double i )
{
  return ( i <= j ) ? j - i : j + (float)(M_PI*2.0) - i;
}
 
/**
 * Performs j - i, assuming th result is in [-pi:pi[
 *
 * @param j any angle in [0:2pi[
 * @param i any angle in [0:2pi[
 * @return the value j - i, always positive. 
 */
inline
double 
DGtal::AngleComputer::deviation( double j, double i )
{
  return less( i, j ) ? posDiff( j, i ) : -posDiff( i, j );
}
 
 
/**
 * Equivalent to 'less( i, j ) ? i : j'.
 *
 * @param i any angle in [0:2pi[
 * @param j any angle in [0:2pi[
 * @return the smallest angle of [i] and [j] in a window 'pi'.
 */
inline
double 
DGtal::AngleComputer::min( double i, double j )
{
  return less( i, j ) ? i : j;
}
 
/**
 * Equivalent to 'less( i, j ) ? j : i'.
 *
 * @param i any angle in [0:2pi[
 * @param j any angle in [0:2pi[
 * @return the greatest angle of [i] and [j] in a window 'pi'.
 */
inline
double 
DGtal::AngleComputer::max( double i, double j )
{
  return less( i, j ) ? j : i;
}
 
 
 
 
//                                                                           //
///////////////////////////////////////////////////////////////////////////////