Initial import.

1 files changed, 123 insertions, 0 deletions

diff --git a/redshift.c b/redshift.c
new file mode 100644
index 0000000..ef71609
--- /dev/null
+++ b/redshift.c
@@ -0,0 +1,123 @@
+/* redshift.c */
+/* Copyright (c) 2009, Jon Lund Steffensen <jonlst@gmail.com> */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+#include <locale.h>
+
+#include "solar.h"
+#include "colortemp.h"
+
+#define MIN_LAT   -90.0
+#define MAX_LAT    90.0
+#define MIN_LON  -180.0
+#define MAX_LON   180.0
+#define MIN_TEMP   1000
+#define MAX_TEMP  10000
+
+
+#define USAGE  \
+	"Usage: %s LAT LON DAY-TEMP NIGHT-TEMP [GAMMA]\n"
+
+#define DEG_CHAR  0xb0
+
+
+static void
+printtime(time_t time)
+{
+	char s[64];
+	strftime(s, 64, "%a, %d %b %Y %H:%M:%S %z", localtime(&time));
+	printf("%s\n", s);
+}
+
+int
+main(int argc, char *argv[])
+{
+	/* Check extensions needed for color temperature adjustment. */
+	int r = colortemp_check_extension();
+	if (r < 0) {
+		fprintf(stderr, "Unable to set color temperature.\n");
+		exit(EXIT_FAILURE);
+	}
+
+	/* Init locale for special symbols */
+	char *loc = setlocale(LC_CTYPE, "");
+	if (loc == NULL) {
+		fprintf(stderr, "Unable to set locale.\n");
+		exit(EXIT_FAILURE);
+	}
+
+	/* Load arguments */
+	if (argc < 5) {
+		printf(USAGE, argv[0]);
+		exit(EXIT_FAILURE);
+	}
+
+	/* Latitude */
+	float lat = atof(argv[1]);
+	if (lat < MIN_LAT || lat > MAX_LAT) {
+		fprintf(stderr,
+			"Latitude must be between %.1f%lc and %.1f%lc\n",
+			MIN_LAT, DEG_CHAR, MAX_LAT, DEG_CHAR);
+		exit(EXIT_FAILURE);
+	}
+
+	/* Longitude */
+	float lon = atof(argv[2]);
+	if (lon < MIN_LON || lon > MAX_LON) {
+		fprintf(stderr,
+			"Longitude must be between %.1f%lc and %.1f%lc\n",
+			MIN_LON, DEG_CHAR, MAX_LON, DEG_CHAR);
+		exit(EXIT_FAILURE);
+	}
+
+	/* Color temperature at daytime */
+	int temp_day = atoi(argv[3]);
+	if (temp_day < MIN_TEMP || temp_day >= MAX_TEMP) {
+		fprintf(stderr, "Temperature must be between %uK and %uK\n",
+			MIN_TEMP, MAX_TEMP);
+		exit(EXIT_FAILURE);
+	}
+
+	/* Color temperature at night */
+	int temp_night = atoi(argv[4]);
+	if (temp_night < MIN_TEMP || temp_night >= MAX_TEMP) {
+		fprintf(stderr, "Temperature must be between %uK and %uK\n",
+			MIN_TEMP, MAX_TEMP);
+		exit(EXIT_FAILURE);
+	}
+
+	/* Gamma value */
+	float gamma = 1.0;
+	if (argc > 5) gamma = atof(argv[5]);
+
+	/* Current angular elevation of the sun */
+	time_t now = time(NULL);
+	double elevation = solar_elevation(now, lat, lon);
+	printf("Solar elevation is %f\n", elevation);
+
+	/* Use elevation of sun to set color temperature */
+	int temp = 0;
+	if (elevation < SOLAR_CIVIL_TWILIGHT_ELEV) {
+		temp = temp_night;
+		printf("Set color temperature to %uK\n", temp_night);
+	} else if (elevation < SOLAR_DAYTIME_ELEV) {
+		float a = (SOLAR_DAYTIME_ELEV - elevation) /
+			(SOLAR_DAYTIME_ELEV - SOLAR_CIVIL_TWILIGHT_ELEV);
+		temp = (1.0-a)*temp_day + a*temp_night;
+		printf("Interpolated (%f) temperature is %uK\n", a, temp);
+	} else {
+		temp = temp_day;
+		printf("Set color temperature to %uK\n", temp_day);
+	}
+
+	/* Set color temperature */
+	r = colortemp_set_temperature(temp, gamma);
+	if (r < 0) {
+		fprintf(stderr, "Unable to set color temperature.\n");
+		exit(EXIT_FAILURE);
+	}
+
+	return EXIT_SUCCESS;
+}