Improve quality, fix errors, update comments, update man pages, add new man pagesHEAD1.1master

Signed-off-by: Mattias Andrée <m@maandree.se>

1 files changed, 93 insertions, 77 deletions

diff --git a/blackbody.c b/blackbody.c
index 78608c1..1abf133 100644
--- a/blackbody.c
+++ b/blackbody.c
@@ -11,6 +11,7 @@
 # include <stddef.h>
 
 
+
 /**
  * Colour temperatures in CIE xy (xyY without Y)
  */
@@ -26,6 +27,7 @@ static struct rgb {double r, g, b;} rgb_table[] = {
 };
 
 
+
 #endif
 /**
  * Convert from CIE xyY to [0, 1] sRGB
@@ -41,9 +43,16 @@ static struct rgb {double r, g, b;} rgb_table[] = {
 static void
 ciexyy_to_srgb(double x, double y, double Y, double *r, double *g, double *b)
 {
-#define SRGB(C)  (((C) <= 0.0031308) ? (12.92 * (C)) : ((1.0 + 0.055) * pow((C), 1.0 / 2.4) - 0.055))
+#define LINEAR_TO_SRGB(C)\
+	do {\
+		double sign = (C) < 0 ? -1 : 1;\
+		(C) *= sign;\
+		(C) = (((C) <= 0.0031306684425217108) ? (12.92 * (C)) : (1.055 * pow((C), 1.0 / 2.4) - 0.055));\
+		(C) *= sign;\
+	} while (0)
+
 	double X, Z, max;
-  
+
 #if __GNUC__
 # pragma GCC diagnostic push
 # pragma GCC diagnostic ignored "-Wfloat-equal"
@@ -55,13 +64,16 @@ ciexyy_to_srgb(double x, double y, double Y, double *r, double *g, double *b)
 # pragma GCC diagnostic pop
 #endif
   
-	/* Convert CIE XYZ to [0, 1] linear RGB (ciexyz_to_linear) */
-	*r = ( 3.240450 * X) + (-1.537140 * Y) + (-0.4985320 * Z);
-	*g = (-0.969266 * X) + ( 1.876010 * Y) + ( 0.0415561 * Z);
-	*b = (0.0556434 * X) + (-0.204026 * Y) + ( 1.0572300 * Z);
-  
-	/* Convert [0, 1] linear RGB to [0, 1] sRGB */
-	SRGB(*r), SRGB(*g), SRGB(*b);
+	/* Convert CIE XYZ to [0, 1] linear RGB */
+	*r = ( 3.24044625464773750067593027779366821050643920898438 * X)
+	   + (-1.53713476182008057513428411766653880476951599121094 * Y)
+	   + (-0.49853019302272871815517873983480967581272125244141 * Z);
+	*g = (-0.96926660624467975146956177923129871487617492675781 * X)
+	   + ( 1.87601195978837020916785149893257766962051391601562 * Y)
+	   + ( 0.04155604221443006535130493261931405868381261825562 * Z);
+	*b = ( 0.05564350356435283223577314970498264301568269729614 * X)
+	   + (-0.20402617973596023914772956686647376045584678649902 * Y)
+	   + ( 1.05722656772270329206264705135254189372062683105469 * Z);
 
 	/* Adjust colours for use */
 	max = fmax(fmax(fabs(*r), fabs(*g)), fabs(*b));
@@ -76,35 +88,66 @@ ciexyy_to_srgb(double x, double y, double Y, double *r, double *g, double *b)
 	*r = *r > 0.0 ? *r : 0.0;
 	*g = *g > 0.0 ? *g : 0.0;
 	*b = *b > 0.0 ? *b : 0.0;
+
+	/* Convert [0, 1] linear RGB to [0, 1] sRGB */
+	LINEAR_TO_SRGB(*r);
+	LINEAR_TO_SRGB(*g);
+	LINEAR_TO_SRGB(*b);
 }
 #ifndef LIBRED_COMPILING_PARSER
 
+
 /**
- * Perform linear interpolation (considered very good)
- * between the CIE xy values for two colour temperatures
- * and convert the result to sRGB. The two colours should
- * be the closest below the desired colour temperature,
- * and the closest above the desired colour temperature
+ * Convert from [0, 1] sRGB to CIE xyY
  * 
- * @param  x1    The 'x' component for the low colour
- * @param  y1    The 'y' component for the low colour
- * @param  x2    The 'x' component for the high colour
- * @param  y2    The 'y' component for the high colour
- * @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
+ * @param  r  The “red” value
+ *            (Seriously, sRGB red is orange, just look at it fullscreen)
+ * @param  g  The green value
+ * @param  b  The blue value
+ * @param  x  Output parameter for The 'x' component
+ * @param  y  Output parameter for The 'y' component
+ * @param  Y  Output parameter for The 'Y' component
  */
 static void
-interpolate(double x1, double y1, double x2, double y2, double temp, double *r, double *g, double *b)
+srgb_to_ciexyy(double r, double g, double b, double *x, double *y, double *Y)
 {
-	double weight = fmod(temp - (LIBRED_LOWEST_TEMPERATURE % LIBRED_DELTA_TEMPERATURE),
-	                     (double)LIBRED_DELTA_TEMPERATURE) / (double)LIBRED_DELTA_TEMPERATURE;
-	double x = x1 * (1 - weight) + x2 * weight;
-	double y = y1 * (1 - weight) + y2 * weight;
-	ciexyy_to_srgb(x, y, 1.0, r, g, b);
+#define SRGB_TO_LINEAR(C)\
+	do {\
+		double sign = (C) < 0 ? -1 : 1;\
+		(C) *= sign;\
+		(C) = (((C) <= 0.0031306684425217108 * 12.92) ? ((C) / 12.92) : pow(((C) + 0.055) / 1.055, 2.4));\
+		(C) *= sign;\
+	} while (0)
+
+	/* Convert [0, 1] sRGB to [0, 1] linear RGB */
+	double s, z;
+
+	SRGB_TO_LINEAR(r);
+	SRGB_TO_LINEAR(g);
+	SRGB_TO_LINEAR(b);
+
+	/* Convert [0, 1] linear RGB to CIE XYZ */
+	*x = 0.41245744558236757670854899515688885003328323364258 * r
+	   + 0.35757586524551587814357844763435423374176025390625 * g
+	   + 0.18043724782639966597308500695362454280257225036621 * b;
+	*y = 0.21267337037840827740353688568575307726860046386719 * r
+	   + 0.71515173049103175628715689526870846748352050781250 * g
+	   + 0.07217489913055986916479156434434116818010807037354 * b;
+	z  = 0.01933394276167346020889326041469757910817861557007 * r
+	   + 0.11919195508183859366635459764438564889132976531982 * g
+	   + 0.95030283855237174250873977143783122301101684570312 * b;
+	*Y = z;
+
+	/* Convert CIE XYZ to CIE xyY */
+	*Y = *y;
+	s = *x + *y + z;
+	*x /= s;
+	*y /= s;
+	if (!isfinite(*x) || !isfinite(*y))
+		*x = *y = 0;
 }
 
+
 /**
  * Perform linear interpolation (considered very good)
  * between the CIE xy values for two colour temperatures.
@@ -121,7 +164,7 @@ interpolate(double x1, double y1, double x2, double y2, double temp, double *r,
  * @param  y     Output parameter for the CIE y value
  */
 static void
-interpolate_xy(double x1, double y1, double x2, double y2, double temp, double *x, double *y)
+interpolate(double x1, double y1, double x2, double y2, double temp, double *x, double *y)
 {
 	double weight = fmod(temp - (LIBRED_LOWEST_TEMPERATURE % LIBRED_DELTA_TEMPERATURE),
 	                     (double)LIBRED_DELTA_TEMPERATURE) / (double)LIBRED_DELTA_TEMPERATURE;
@@ -129,8 +172,9 @@ interpolate_xy(double x1, double y1, double x2, double y2, double temp, double *
 	*y = y1 * (1 - weight) + y2 * weight;
 }
 
+
 int
-libred_get_colour(long int temp, double *r, double *g, double *b)
+libred_get_colour_xy(long int temp, double *x, double *y)
 {
 	double x1, y1, x2, y2;
 	size_t i;
@@ -152,18 +196,18 @@ libred_get_colour(long int temp, double *r, double *g, double *b)
 		y1 = xy_table[i].y;
 		x2 = xy_table[i + 1].x;
 		y2 = xy_table[i + 1].y;
-		interpolate(x1, y1, x2, y2, (double)temp, r, g, b);
+		interpolate(x1, y1, x2, y2, (double)temp, x, y);
 	} else {
-		*r = rgb_table[i].r;
-		*g = rgb_table[i].g;
-		*b = rgb_table[i].b;
+		*x = xy_table[i].x;
+		*y = xy_table[i].y;
 	}
 
 	return 0;
 }
 
+
 int
-libred_get_colour_xy(long int temp, double *x, double *y) /* TODO test */
+libred_get_colour(long int temp, double *r, double *g, double *b)
 {
 	double x1, y1, x2, y2;
 	size_t i;
@@ -181,25 +225,29 @@ libred_get_colour_xy(long int temp, double *x, double *y) /* TODO test */
 
 	i = (size_t)(tmp / LIBRED_DELTA_TEMPERATURE);
 	if (tmp % LIBRED_DELTA_TEMPERATURE) {
+		double x, y;
 		x1 = xy_table[i].x;
 		y1 = xy_table[i].y;
 		x2 = xy_table[i + 1].x;
 		y2 = xy_table[i + 1].y;
-		interpolate_xy(x1, y1, x2, y2, (double)temp, x, y);
+		interpolate(x1, y1, x2, y2, (double)temp, &x, &y);
+		ciexyy_to_srgb(x, y, 1, r, g, b);
 	} else {
-		*x = xy_table[i].x;
-		*y = xy_table[i].y;
+		*r = rgb_table[i].r;
+		*g = rgb_table[i].g;
+		*b = rgb_table[i].b;
 	}
 
 	return 0;
 }
 
+
 double
-libred_get_temperature_xy(double x, double y, double *x_error, double *y_error) /* TODO man, test */
+libred_get_temperature_xy(double x, double y, double *x_error, double *y_error)
 {
-	size_t i, j;
+	size_t i = 0, j;
 	double x1, y1, x2, y2, dx, dy, xd, yd, t, d2;
-	double best_temp = 0, best_d2 = INFINITY;
+	double best_temp = -1, best_d2 = INFINITY;
 
 	if (!x_error)
 		x_error = &dx;
@@ -232,55 +280,23 @@ libred_get_temperature_xy(double x, double y, double *x_error, double *y_error)
 			t *= (double)(j - i);
 			best_temp = (double)i + t;
 		}
+
+		i = j;
 	}
 
 	return best_temp * LIBRED_DELTA_TEMPERATURE + LIBRED_LOWEST_TEMPERATURE;
 }
 
-/**
- * Convert from [0, 1] sRGB to CIE xyY
- * 
- * @param  r  The “red” value
- *            (Seriously, sRGB red is orange, just look at it fullscreen)
- * @param  g  The green value
- * @param  b  The blue value
- * @param  x  Output parameter for The 'x' component
- * @param  y  Output parameter for The 'y' component
- * @param  Y  Output parameter for The 'Y' component
- */
-static void
-srgb_to_ciexyy(double r, double g, double b, double *x, double *y, double *Y)
-{
-	double s, z;
-
-	r *= s = r < 0 ? -1 : 1;
-	r = s * (r <= 0.0031306684425217108 * 12.92 ? r * 12.92 : pow((r + 0.055) / 1.055, 2.4));
-	g *= s = g < 0 ? -1 : 1;
-	g = s * (g <= 0.0031306684425217108 * 12.92 ? g * 12.92 : pow((g + 0.055) / 1.055, 2.4));
-	b *= s = b < 0 ? -1 : 1;
-	b = s * (g <= 0.0031306684425217108 * 12.92 ? b * 12.92 : pow((b + 0.055) / 1.055, 2.4));
-
-	*x = (0.41245744558236758 * r) + (0.35757586524551588 * g) + (0.18043724782639967 * b);
-	*y = (0.21267337037840828 * r) + (0.71515173049103176 * g) + (0.07217489913055987 * b);
-	z  = (0.01933394276167346 * r) + (0.11919195508183859 * g) + (0.95030283855237174 * b);
-
-	*Y = *y;
-	s = *x + *y + z;
-	*x /= s;
-	*y /= s;
-	if (!isfinite(*x) || !isfinite(*y))
-		*x = *y = 0;
-}
 
 double
-libred_get_temperature(double r, double g, double b, double *y, /* TODO man, test */
+libred_get_temperature(double r, double g, double b, double *y,
                        double *r_error, double *g_error, double *b_error)
 {
 	double tx, ty, luma, x_error, y_error, ret;
 
 	srgb_to_ciexyy(r, g, b, &tx, &ty, &luma);
 	ret = libred_get_temperature_xy(tx, ty, &x_error, &y_error);
-	ciexyy_to_srgb(x_error, y_error, luma, &r, &g, &b);
+	ciexyy_to_srgb(x_error, y_error, 1, &r, &g, &b);
 
 	if (y)
 		*y = luma;