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151 lines
4.6 KiB
151 lines
4.6 KiB
/*
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This file is part of libkholidays.
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Copyright (c) 2004 Allen Winter <winter@kde.org>
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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This library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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In addition, as a special exception, the copyright holders give
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permission to link the code of this program with any edition of
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the Qt library by Trolltech AS, Norway (or with modified versions
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of Qt that use the same license as Qt), and distribute linked
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combinations including the two. You must obey the GNU General
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Public License in all respects for all of the code used other than
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Qt. If you modify this file, you may extend this exception to
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your version of the file, but you are not obligated to do so. If
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you do not wish to do so, delete this exception statement from
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your version.
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*/
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#ifndef KHOLIDAYS_LUNARPHASE_H
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#define KHOLIDAYS_LUNARPHASE_H
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/**
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Represents and manages a Lunar Phase
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A Lunar Phase can be one of the following:
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+ "new": the moon is not visible; or traditionally: first visible
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crescent of the Moon. For religious purposes, the new
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month begins when the first crescent moon can be seen.
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Thus, it is impossible to be certain in advance of when
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months will begin; in particular, the exact date on which
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Ramadan will begin is not known in advance. In Saudi Arabia,
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observers are sent up in airplanes if the weather is cloudy
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when the new moon is expected.
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+ "first quarter": the right 50% of the moon is visible.
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+ "full": the moon is fully visible.
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+ "last quarter": the left 50% of the moon is visible.
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A very good description of the lunar phases can be read at the Wikipedia,
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http://en.wikipedia.org/wiki/Lunar_phase
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In the southern hemisphere the order of the phases is reversed.
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So, to be accurate we need to know the hemisphere.
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Note that crescent and gibbous phases are not currently supported.
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*/
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#include <qstring.h>
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#include <qdatetime.h>
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#include <time.h>
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class LunarPhase
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{
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public:
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enum Phase { New, FirstQ, LastQ, Full, None };
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enum Hemisphere { Northern, Southern };
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LunarPhase( Hemisphere hemisphere = Northern );
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~LunarPhase();
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/**
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Return the lunar phase for the specified Gregorian date.
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The enum 'None' is returned if one of the supported phases
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does not occur on the date.
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@param date compute the lunar phase for the specified Gregorian date.
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*/
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Phase phase( const QDate &date ) const;
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/**
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Return the lunar phase as a text string for the specified date.
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A null string is returned if one of the supported phases does
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not occur on the date.
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@param date compute the lunar phase for the specified Gregorian date.
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*/
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QString phaseStr( const QDate &date ) const;
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/**
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Set the hemisphere.
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@param hemisphere Hemisphere
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*/
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void setHemisphere( Hemisphere hemisphere = Northern );
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/**
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Return the hemisphere.
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*/
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Hemisphere hemisphere() const;
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/**
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Return hemisphere as a clear text string.
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*/
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QString hemisphereStr() const;
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/**
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Return the string representation of hemisphere.
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*/
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static QString hemisphereName( Hemisphere hemisphere );
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/**
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Return the string representation of phase.
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@param phase the lunar phase.
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*/
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static QString phaseName( Phase phase );
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private:
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/**
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Return the phase of the moon as a percentage of full
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@param t is the time since the Epoch, measured in seconds.
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@return the percent fullness [0,100] of the moon.
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*/
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double percentFull( uint t ) const;
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/**
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Convert degrees to radians.
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@param degree degrees to convert.
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@return degrees in radians.
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*/
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double degreesToRadians( double degree ) const;
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/**
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Adjust value so that 0 <= degree <= 360.
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@param degree a pointer to the degree value.
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*/
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void adj360( double *degree ) const;
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Hemisphere mHemisphere;
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};
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#endif
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