Allow brightness to be adjusted (between 10% and 100%, the latter being the default).

src/colorramp.c

@@ -128,7 +128,7 @@ interpolate_color(float a, const float *c1, const float *c2, float *c)
 
 void
 colorramp_fill(uint16_t *gamma_r, uint16_t *gamma_g, uint16_t *gamma_b,
-	       int size, int temp, float gamma[3])
+	       int size, int temp, float brightness, float gamma[3])
 {
 	/* Approximate white point */
 	float white_point[3];
@@ -139,10 +139,10 @@ colorramp_fill(uint16_t *gamma_r, uint16_t *gamma_g, uint16_t *gamma_b,
 
 	for (int i = 0; i < size; i++) {
 		gamma_r[i] = pow((float)i/size, 1.0/gamma[0]) *
-			UINT16_MAX * white_point[0];
+			UINT16_MAX * brightness * white_point[0];
 		gamma_g[i] = pow((float)i/size, 1.0/gamma[1]) *
-			UINT16_MAX * white_point[1];
+			UINT16_MAX * brightness * white_point[1];
 		gamma_b[i] = pow((float)i/size, 1.0/gamma[2]) *
-			UINT16_MAX * white_point[2];
+			UINT16_MAX * brightness * white_point[2];
 	}
 }

src/colorramp.h

@@ -23,6 +23,6 @@
 #include <stdint.h>
 
 void colorramp_fill(uint16_t *gamma_r, uint16_t *gamma_g, uint16_t *gamma_b,
-		    int size, int temp, float gamma[3]);
+		    int size, int temp, float brightness, float gamma[3]);
 
 #endif /* ! _REDSHIFT_COLORRAMP_H */

src/gamma-randr.c

@@ -301,7 +301,7 @@ randr_set_option(randr_state_t *state, const char *key, const char *value)
 
 static int
 randr_set_temperature_for_crtc(randr_state_t *state, int crtc_num, int temp,
-			       float gamma[3])
+			       float brightness, float gamma[3])
 {
 	xcb_generic_error_t *error;
 	
@@ -333,7 +333,7 @@ randr_set_temperature_for_crtc(randr_state_t *state, int crtc_num, int temp,
 	uint16_t *gamma_b = &gamma_ramps[2*ramp_size];
 
 	colorramp_fill(gamma_r, gamma_g, gamma_b, ramp_size,
-		       temp, gamma);
+		       temp, brightness, gamma);
 
 	/* Set new gamma ramps */
 	xcb_void_cookie_t gamma_set_cookie =
@@ -355,7 +355,8 @@ randr_set_temperature_for_crtc(randr_state_t *state, int crtc_num, int temp,
 }
 
 int
-randr_set_temperature(randr_state_t *state, int temp, float gamma[3])
+randr_set_temperature(randr_state_t *state, int temp, float brightness,
+		      float gamma[3])
 {
 	int r;
 
@@ -364,12 +365,13 @@ randr_set_temperature(randr_state_t *state, int temp, float gamma[3])
 	if (state->crtc_num < 0) {
 		for (int i = 0; i < state->crtc_count; i++) {
 			r = randr_set_temperature_for_crtc(state, i,
-							   temp, gamma);
+							   temp, brightness,
+							   gamma);
 			if (r < 0) return -1;
 		}
 	} else {
 		return randr_set_temperature_for_crtc(state, state->crtc_num,
-						      temp, gamma);
+						      temp, brightness, gamma);
 	}
 
 	return 0;

src/gamma-randr.h

@@ -54,7 +54,8 @@ void randr_print_help(FILE *f);
 int randr_set_option(randr_state_t *state, const char *key, const char *value);
 
 void randr_restore(randr_state_t *state);
-int randr_set_temperature(randr_state_t *state, int temp, float gamma[3]);
+int randr_set_temperature(randr_state_t *state, int temp, float brightness,
+			  float gamma[3]);
 
 
 #endif /* ! _REDSHIFT_GAMMA_RANDR_H */

src/gamma-vidmode.c

@@ -169,7 +169,8 @@ vidmode_restore(vidmode_state_t *state)
 }
 
 int
-vidmode_set_temperature(vidmode_state_t *state, int temp, float gamma[3])
+vidmode_set_temperature(vidmode_state_t *state, int temp, float brightness,
+			float gamma[3])
 {
 	int r;
 
@@ -185,7 +186,7 @@ vidmode_set_temperature(vidmode_state_t *state, int temp, float gamma[3])
 	uint16_t *gamma_b = &gamma_ramps[2*state->ramp_size];
 
 	colorramp_fill(gamma_r, gamma_g, gamma_b, state->ramp_size,
-		       temp, gamma);
+		       temp, brightness, gamma);
 
 	/* Set new gamma ramps */
 	r = XF86VidModeSetGammaRamp(state->display, state->screen_num,

src/gamma-vidmode.h

@@ -42,7 +42,8 @@ int vidmode_set_option(vidmode_state_t *state, const char *key,
 		       const char *value);
 
 void vidmode_restore(vidmode_state_t *state);
-int vidmode_set_temperature(vidmode_state_t *state, int temp, float gamma[3]);
+int vidmode_set_temperature(vidmode_state_t *state, int temp, float brightness,
+			    float gamma[3]);
 
 
 #endif /* ! _REDSHIFT_GAMMA_VIDMODE_H */

src/gamma-w32gdi.c

@@ -129,7 +129,8 @@ w32gdi_restore(w32gdi_state_t *state)
 }
 
 int
-w32gdi_set_temperature(w32gdi_state_t *state, int temp, float gamma[3])
+w32gdi_set_temperature(w32gdi_state_t *state, int temp, float brightness,
+		       float gamma[3])
 {
 	BOOL r;
 
@@ -153,7 +154,7 @@ w32gdi_set_temperature(w32gdi_state_t *state, int temp, float gamma[3])
 	WORD *gamma_b = &gamma_ramps[2*GAMMA_RAMP_SIZE];
 
 	colorramp_fill(gamma_r, gamma_g, gamma_b, GAMMA_RAMP_SIZE,
-		       temp, gamma);
+		       temp, brightness, gamma);
 
 	/* Set new gamma ramps */
 	r = SetDeviceGammaRamp(hDC, gamma_ramps);
@@ -161,7 +162,7 @@ w32gdi_set_temperature(w32gdi_state_t *state, int temp, float gamma[3])
 		/* TODO it happens that SetDeviceGammaRamp returns FALSE on
 		   occasions where the adjustment seems to be successful.
 		   Does this only happen with multiple monitors connected? */
-		fputs(_("Unable to set gamma ramps.\n"), stderr);s
+		fputs(_("Unable to set gamma ramps.\n"), stderr);
 		free(gamma_ramps);
 		ReleaseDC(NULL, hDC);
 		return -1;

src/gamma-w32gdi.h

@@ -38,7 +38,8 @@ int w32gdi_set_option(w32gdi_state_t *state, const char *key,
 		      const char *value);
 
 void w32gdi_restore(w32gdi_state_t *state);
-int w32gdi_set_temperature(w32gdi_state_t *state, int temp, float gamma[3]);
+int w32gdi_set_temperature(w32gdi_state_t *state, int temp, float brightness,
+			   float gamma[3]);
 
 
 #endif /* ! _REDSHIFT_GAMMA_W32GDI_H */

src/redshift.c

@@ -201,12 +201,15 @@ static const location_provider_t location_providers[] = {
 #define MAX_LON   180.0
 #define MIN_TEMP   1000
 #define MAX_TEMP  10000
+#define MIN_BRIGHTNESS  0.1
+#define MAX_BRIGHTNESS  1.0
 #define MIN_GAMMA   0.1
 #define MAX_GAMMA  10.0
 
 /* Default values for parameters. */
 #define DEFAULT_DAY_TEMP    5500
 #define DEFAULT_NIGHT_TEMP  3700
+#define DEFAULT_BRIGHTNESS   1.0
 #define DEFAULT_GAMMA        1.0
 
 /* The color temperature when no adjustment is applied. */
@@ -610,6 +613,7 @@ main(int argc, char *argv[])
 	int temp_day = -1;
 	int temp_night = -1;
 	float gamma[3] = { NAN, NAN, NAN };
+	float brightness = NAN;
 
 	const gamma_method_t *method = NULL;
 	char *method_args = NULL;
@@ -624,8 +628,11 @@ main(int argc, char *argv[])
 
 	/* Parse command line arguments. */
 	int opt;
-	while ((opt = getopt(argc, argv, "c:g:hl:m:ort:vx")) != -1) {
+	while ((opt = getopt(argc, argv, "b:c:g:hl:m:ort:vx")) != -1) {
 		switch (opt) {
+		case 'b':
+			brightness = atof(optarg);
+			break;
 		case 'c':
 			if (config_filepath != NULL) free(config_filepath);
 			config_filepath = strdup(optarg);
@@ -781,6 +788,11 @@ main(int argc, char *argv[])
 				if (transition < 0) {
 					transition = !!atoi(setting->value);
 				}
+			} else if (strcasecmp(setting->name,
+					      "brightness") == 0) {
+				if (isnan(brightness)) {
+					brightness = atof(setting->value);
+				}
 			} else if (strcasecmp(setting->name, "gamma") == 0) {
 				if (isnan(gamma[0])) {
 					r = parse_gamma_string(setting->value,
@@ -833,6 +845,7 @@ main(int argc, char *argv[])
 	   the config file nor on the command line. */
 	if (temp_day < 0) temp_day = DEFAULT_DAY_TEMP;
 	if (temp_night < 0) temp_night = DEFAULT_NIGHT_TEMP;
+	if (isnan(brightness)) brightness = DEFAULT_BRIGHTNESS;
 	if (isnan(gamma[0])) gamma[0] = gamma[1] = gamma[2] = DEFAULT_GAMMA;
 	if (transition < 0) transition = 1;
 
@@ -931,6 +944,18 @@ main(int argc, char *argv[])
 		exit(EXIT_FAILURE);
 	}
 
+	/* Brightness */
+	if (brightness < MIN_BRIGHTNESS || brightness > MAX_BRIGHTNESS) {
+		fprintf(stderr,
+			_("Brightness value must be between %.1f and %.1f.\n"),
+			MIN_BRIGHTNESS, MAX_BRIGHTNESS);
+		exit(EXIT_FAILURE);
+	}
+
+	if (verbose) {
+		printf(_("Brightness: %.2f\n"), brightness);
+	}
+
 	/* Gamma */
 	if (gamma[0] < MIN_GAMMA || gamma[0] > MAX_GAMMA ||
 	    gamma[1] < MIN_GAMMA || gamma[1] > MAX_GAMMA ||
@@ -1004,7 +1029,7 @@ main(int argc, char *argv[])
 		if (verbose) printf(_("Color temperature: %uK\n"), temp);
 
 		/* Adjust temperature */
-		r = method->set_temperature(&state, temp, gamma);
+		r = method->set_temperature(&state, temp, brightness, gamma);
 		if (r < 0) {
 			fputs(_("Temperature adjustment failed.\n"), stderr);
 			method->free(&state);
@@ -1015,7 +1040,7 @@ main(int argc, char *argv[])
 	case PROGRAM_MODE_RESET:
 	{
 		/* Reset screen */
-		r = method->set_temperature(&state, NEUTRAL_TEMP, gamma);
+		r = method->set_temperature(&state, NEUTRAL_TEMP, 1.0, gamma);
 		if (r < 0) {
 			fputs(_("Temperature adjustment failed.\n"), stderr);
 			method->free(&state);
@@ -1179,7 +1204,8 @@ main(int argc, char *argv[])
 			/* Adjust temperature */
 			if (!disabled || short_trans) {
 				r = method->set_temperature(&state,
-							    temp, gamma);
+							    temp, brightness,
+							    gamma);
 				if (r < 0) {
 					fputs(_("Temperature adjustment"
 						" failed.\n"), stderr);

src/redshift.h

@@ -33,6 +33,7 @@ typedef int gamma_method_set_option_func(void *state, const char *key,
 					 const char *value);
 typedef void gamma_method_restore_func(void *state);
 typedef int gamma_method_set_temperature_func(void *state, int temp,
+					      float brightness,
 					      float gamma[3]);
 
 typedef struct {