/** * Copyright © 2016 Mattias Andrée * * 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 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 . */ #ifndef LIBRED_H #define LIBRED_H /** * Approximate apparent size of the Sun in degrees. */ #define LIBRED_SOLAR_APPARENT_RADIUS (32.0 / 60.0) /** * The Sun's elevation at sunset and sunrise, measured in degrees. */ #define LIBRED_SOLAR_ELEVATION_SUNSET_SUNRISE (-32.0 / 60.0) /** * The Sun's elevation at civil dusk and civil dawn, measured in degrees. */ #define LIBRED_SOLAR_ELEVATION_CIVIL_DUSK_DAWN (-6.0) /** * The Sun's elevation at nautical dusk and nautical dawn, measured in degrees. */ #define LIBRED_SOLAR_ELEVATION_NAUTICAL_DUSK_DAWN (-12.0) /** * The Sun's elevation at astronomical dusk and astronomical dawn, measured in degrees. */ #define LIBRED_SOLAR_ELEVATION_ASTRONOMICAL_DUSK_DAWN (-18.0) /** * The Sun's elevation at amateur astronomical dusk and amateur astronomical dawn, measured in degrees. */ #define LIBRED_SOLAR_ELEVATION_AMATEUR_ASTRONOMICAL_DUSK_DAWN (-15.0) /** * The Sun's lowest elevation during the golden hour, measured in degrees. */ #define LIBRED_SOLAR_ELEVATION_GOLDEN_HOUR_LOW (-4.0) /** * The Sun's highest elevation during the golden hour, measured in degrees. */ #define LIBRED_SOLAR_ELEVATION_GOLDEN_HOUR_HIGH (6.0) /** * The Sun's lowest elevation during the blue hour, measured in degrees. */ #define LIBRED_SOLAR_ELEVATION_BLUE_HOUR_LOW (-6.0) /** * The Sun's highest elevation during the blue hour, measured in degrees. */ #define LIBRED_SOLAR_ELEVATION_BLUE_HOUR_HIGH (-4.0) /** * Test whether it is twilight. * * @param ELEV:double The current elevation. * @return 1 if is twilight, 0 otherwise. */ #define LIBRED_IS_TWILIGHT(ELEV) ((-18.0 <= (ELEV)) && ((ELEV) <= -32.0 / 60.0)) /** * Test whether it is civil twilight. * * @param ELEV:double The current elevation. * @return 1 if is civil twilight, 0 otherwise. */ #define LIBRED_IS_CIVIL_TWILIGHT(ELEV) ((-6.0 <= (ELEV)) && ((ELEV) <= -32.0 / 60.0)) /** * Test whether it is nautical twilight. * * @param ELEV:double The current elevation. * @return 1 if is nautical twilight, 0 otherwise. */ #define LIBRED_IS_NAUTICAL_TWILIGHT(ELEV) ((-12.0 <= (ELEV)) && ((ELEV) <= -32.0 / 60.0)) /** * Test whether it is astronomical twilight. * * @param ELEV:double The current elevation. * @return 1 if is astronomical twilight, 0 otherwise. */ #define LIBRED_IS_ASTRONOMICAL_TWILIGHT(ELEV) ((-18.0 <= (ELEV)) && ((ELEV) <= -32.0 / 60.0)) /** * Test whether it is amateur astronomical twilight. * * @param ELEV:double The current elevation. * @return 1 if is amatuer astronomical twilight, 0 otherwise. */ #define LIBRED_IS_AMATEUR_ASTRONOMICAL_TWILIGHT(ELEV) ((-18.0 <= (ELEV)) && ((ELEV) <= -15.0)) /** * Test whether it is nighttime. * * @param ELEV:double The current elevation. * @return 1 if is nighttime, 0 otherwise. */ #define LIBRED_IS_NIGHTTIME(ELEV) ((ELEV) < -18.0) /** * Test whether it is daytime. * * @param ELEV:double The current elevation. * @return 1 if is daytime, 0 otherwise. */ #define LIBRED_IS_DAYTIME(ELEV) ((ELEV) > -32.0 / 60.0) /** * Test whether it is the golden hour. * * @param ELEV:double The current elevation. * @return 1 if is golden hour, 0 otherwise. */ #define LIBRED_IS_GOLDEN_HOUR(ELEV) ((-4.0 <= (ELEV)) && ((ELEV) <= 6.0)) /** * Test whether it is the blue hour. * * @param ELEV:double The current elevation. * @return 1 if is blue hour, 0 otherwise. */ #define LIBRED_IS_BLUE_HOUR(ELEV) ((-6.0 <= (ELEV)) && ((ELEV) <= -4.0)) /** * Calculates the Sun's elevation as apparent * from a geographical position. * * @param latitude The latitude in degrees northwards from * the equator, negative for southwards. * @param longitude The longitude in degrees eastwards from * Greenwich, negative for westwards. * @return The Sun's apparent elevation as seen, right now, * from the specified position, measured in degrees. * * @throws 0 On success. * @throws Any error specified for clock_gettime(3) on error. */ double libred_solar_elevation(double, double); /** * Exit if time the is before year 0 in J2000. * * @return 0 on success, -1 on error. */ int libred_check_timetravel(void); /** * The highest colour temperature in the table. */ #define LIBRED_HIGHEST_TEMPERATURE 40000 /** * The lowest colour temperature in the table. */ #define LIBRED_LOWEST_TEMPERATURE 1000 /** * The temperature difference between the colours in the table. * Note, `libred_get_colour` will make interpolation for colours * that are not in the table. */ #define LIBRED_DELTA_TEMPERATURE 100 /** * The file descriptor to the colour lookup table. * -1 if none is open. */ extern int libred_fd; /** * Iff this macro is define `libred_fd` is available. */ #define LIBRED_HAVE_FD 1 /** * This function must be called, once, * before calling `libred_get_colour`. * * @return 0 on success, -1 on error. * * @throws Any error specified for `open(3)`. */ int libred_init_colour(void); /** * Call this when the process will not * longer make calls to `libred_get_colour`. */ void libred_term_colour(void); /** * Get the [0, 1] sRGB values of a colour temperature. * * @param temp The desired colour temperature. * @param r Output parameter for the “red” value. * @param g Output parameter for the green value. * @param b Output parameter for the blue value. * @return 0 on succeess, -1 on error. * * @throws EOVERFLOW The file did not have the expected size. * @throws EDOM The selected temperature is below 1000 K. * @throws Any error specified for pread(3). */ int libred_get_colour(long int, double*, double*, double*); #endif