The SSH host key has changed on 8 April, 2022 to this one: SHA256:573uTBSeh74kvOo0HJXi5ijdzRm8me27suzNEDlGyrQ
A GLib style wrapper library around the Swiss Ephemeris library, created by Astrodienst.
You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
 
 
 
 
swe-glib/src/gswe-moon-phase-data.c

206 lines
5.4 KiB

/* gswe-moon-phase-data.c: Moon phase representation
*
* Copyright © 2013 Gergely Polonkai
*
* SWE-GLib 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 3 of the License, or
* (at your option) any later version.
*
* SWE-GLib 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 library; if not, see <http://www.gnu.org/licenses/>.
*/
#include <math.h>
#include "gswe-types.h"
#include "swe-glib-private.h"
#include "gswe-moon-phase-data.h"
#include "gswe-moon-phase-data-private.h"
#include "gswe-timestamp.h"
#define SYNODIC 29.53058867
/**
* SECTION:gswe-moon-phase-data
* @short_description: a structure representing the phase of the Moon
* @title: GsweMoonPhaseData
* @stability: Stable
* @include: swe-glib.h
* @see_also: #GsweMoonPhase
*
* #GsweMoonPhaseData is a structure that represents the actual phase of the
* Moon, including its illumination percentage.
*/
G_DEFINE_BOXED_TYPE(
GsweMoonPhaseData,
gswe_moon_phase_data,
(GBoxedCopyFunc)gswe_moon_phase_data_ref,
(GBoxedFreeFunc)gswe_moon_phase_data_unref);
/**
* gswe_moon_phase_data_new:
*
* Creates a new #GsweMoonPhaseData object with reference count set to 1.
*
* Returns: (transfer full): a new #GsweMoonPhaseData object
*/
GsweMoonPhaseData *
gswe_moon_phase_data_new(void)
{
GsweMoonPhaseData *ret;
ret = g_new0(GsweMoonPhaseData, 1);
ret->refcount = 1;
return ret;
}
/**
* gswe_moon_phase_data_ref:
* @moon_phase_data: (in): a #GsweMoonPhaseData
*
* Increases reference count on @moon_phase_data by one.
*
* Returns: (transfer none): the same #GsweMoonPhaseData
*/
GsweMoonPhaseData *
gswe_moon_phase_data_ref(GsweMoonPhaseData *moon_phase_data)
{
moon_phase_data->refcount++;
return moon_phase_data;
}
/**
* gswe_moon_phase_data_unref:
* @moon_phase_data: (in): a #GsweMoonPhaseData
*
* Decreases reference count on @moon_phase_data by one. If reference count
* drops to zero, @moon_phase_data is freed.
*/
void
gswe_moon_phase_data_unref(GsweMoonPhaseData *moon_phase_data)
{
if (moon_phase_data == NULL) {
return;
}
if (--moon_phase_data->refcount == 0) {
g_free(moon_phase_data);
}
}
/**
* gswe_moon_phase_data_calculate_by_jd:
* @moon_phase_data: a #GsweMoonPhaseData
* @jd: a Julian Day number, with hours as fractions
* @err: a #GError
*
* Calculates the moon at a given time, specified by @jd.
*/
void
gswe_moon_phase_data_calculate_by_jd(
GsweMoonPhaseData *moon_phase_data,
gdouble jd,
GError **err)
{
gdouble jdb,
phase_percent;
jdb = gswe_timestamp_get_julian_day_et(gswe_full_moon_base_date, err);
if ((err) && (*err)) {
return;
}
if ((phase_percent = fmod(((jd - jdb) * 100) / SYNODIC, 100)) < 0) {
phase_percent += 100.0;
}
if ((phase_percent < 0) || (phase_percent > 100)) {
g_error("Error during Moon phase calculation!");
}
moon_phase_data->illumination = (50.0 - fabs(phase_percent - 50.0)) * 2;
if (phase_percent == 0) {
moon_phase_data->phase = GSWE_MOON_PHASE_NEW;
} else if (phase_percent < 25) {
moon_phase_data->phase = GSWE_MOON_PHASE_WAXING_CRESCENT;
} else if (phase_percent == 25) {
moon_phase_data->phase = GSWE_MOON_PHASE_WAXING_HALF;
} else if (phase_percent < 50) {
moon_phase_data->phase = GSWE_MOON_PHASE_WAXING_GIBBOUS;
} else if (phase_percent == 50) {
moon_phase_data->phase = GSWE_MOON_PHASE_FULL;
} else if (phase_percent < 75) {
moon_phase_data->phase = GSWE_MOON_PHASE_WANING_GIBBOUS;
} else if (phase_percent == 75) {
moon_phase_data->phase = GSWE_MOON_PHASE_WANING_HALF;
} else if (phase_percent < 100) {
moon_phase_data->phase = GSWE_MOON_PHASE_WANING_CRESCENT;
} else {
moon_phase_data->phase = GSWE_MOON_PHASE_DARK;
}
}
/**
* gswe_moon_phase_data_calculate_by_timestamp:
* @moon_phase_data: a #GsweMoonPhaseData
* @timestamp: a #GsweTimestamp with a valid timestamp set
* @err: a #GError
*
* Calculates the moon at a given time, specified by @timestamp.
*/
void
gswe_moon_phase_data_calculate_by_timestamp(
GsweMoonPhaseData *moon_phase_data,
GsweTimestamp *timestamp,
GError **err)
{
gdouble jd;
jd = gswe_timestamp_get_julian_day_et(timestamp, err);
if (err && *err) {
return;
}
gswe_moon_phase_data_calculate_by_jd(moon_phase_data, jd, err);
}
/**
* gswe_moon_phase_data_get_phase:
* @moon_phase_data: (in): a GsweMoonPhaseData
*
* Gets the phase of the Moon in the given GsweMoonPhaseData.
*
* Returns: the Moon phase
*/
GsweMoonPhase
gswe_moon_phase_data_get_phase(GsweMoonPhaseData *moon_phase_data)
{
return moon_phase_data->phase;
}
/**
* gswe_moon_phase_data_get_illumination:
* @moon_phase_data: (in): a GsweMoonPhaseData
*
* Gets the illumination percentage from the given GsweMoonPhaseData.
*
* Returns: the illumination percentage
*/
gdouble
gswe_moon_phase_data_get_illumination(GsweMoonPhaseData *moon_phase_data)
{
return moon_phase_data->illumination;
}