Simplify

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

1 files changed, 78 insertions, 108 deletions

diff --git a/blackbody.c b/blackbody.c
index 104e7da..9dfe1a8 100644
--- a/blackbody.c
+++ b/blackbody.c
@@ -4,173 +4,143 @@
 # pragma GCC diagnostic ignored "-Wunsuffixed-float-constants"
 #endif
 
-
 #ifndef LIBRED_COMPILING_PARSER
 #include "libred.h"
-#include "macros.h"
-#include <math.h>
 #include <errno.h>
-#include <fcntl.h>
-
-
-
-/**
- * The file descriptor to the colour lookup table.
- */
-int libred_fd = -1;
-
+#include <math.h>
+#include <stddef.h>
 
 
-/**
- * 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)
-{
-	libred_term_colour();
-	libred_fd = open(SYSDEPRESDIR "/" PACKAGE "/10deg", O_RDONLY);
-	return libred_fd < 0 ? -1 : 0;
-}
+struct xy {double x, y;};
+struct rgb {double r, g, b;};
 
+static struct xy xy_table[] = {
+#include "10deg-xy.i"
+};
 
-/**
- * Call this when the process will not
- * longer make calls to `libred_get_colour`.
- */
-void
-libred_term_colour(void)
-{
-	if (libred_fd >= 0)
-		close(libred_fd), libred_fd = -1;
-}
+static struct rgb rgb_table[] = {
+#include "10deg-rgb.i"
+};
 
 
 #endif
 /**
- * Convert from CIE xyY to [0, 1] sRGB.
+ * Convert from CIE xyY to [0, 1] sRGB
  * 
- * @param  x  The 'x' component.
- * @param  y  The 'y' component.
- * @param  Y  The 'Y' component.
- * @param  r  Output parameter for the “red” value.
- *            (Seriously, sRGB red is orange, just look at it fullscreen.)
- * @param  g  Output parameter for the green value.
- * @param  b  Output parameter for the blue value.
+ * @param  x  The 'x' component
+ * @param  y  The 'y' component
+ * @param  Y  The 'Y' component
+ * @param  r  Output parameter for the “red” value
+ *            (Seriously, sRGB red is orange, just look at it fullscreen)
+ * @param  g  Output parameter for the green value
+ * @param  b  Output parameter for the blue value
  */
 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))
-	double X, Z;
+	double X, Z, max;
   
 #if __GNUC__
 # pragma GCC diagnostic push
 # pragma GCC diagnostic ignored "-Wfloat-equal"
 #endif
-	/* Convert CIE xyY to CIE XYZ. */
+	/* Convert CIE xyY to CIE XYZ */
 	X = Y * (y == 0.0 ? 0.0 : (x / y));
 	Z = Y * (y == 0.0 ? 0.0 : ((1.0 - x - y) / y));
 #if __GNUC__
 # pragma GCC diagnostic pop
 #endif
   
-	/* Convert CIE XYZ to [0, 1] linear RGB. (ciexyz_to_linear) */
+	/* 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. */
+	/* Convert [0, 1] linear RGB to [0, 1] sRGB */
 	SRGB(*r), SRGB(*g), SRGB(*b);
+
+	/* Adjust colours for use */
+	max = fmax(fmax(fabs(*r), fabs(*g)), fabs(*b));
+#if __GNUC__
+# pragma GCC diagnostic push
+# pragma GCC diagnostic ignored "-Wfloat-equal"
+#endif
+	if (max != 0.0)  *r /= max, *g /= max, *b /= max;
+#if __GNUC__
+# pragma GCC diagnostic pop
+#endif
+	*r = *r > 0.0 ? *r : 0.0;
+	*g = *g > 0.0 ? *g : 0.0;
+	*b = *b > 0.0 ? *b : 0.0;
 }
 #ifndef LIBRED_COMPILING_PARSER
 
-
 /**
  * Perform linear interpolation (considered very good)
  * between the CIE xyY 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.
+ * and the closest above the desired colour temperature
  * 
- * @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  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
  */
 static void
 interpolate(double x1, double y1, double x2, double y2, double temp, double *r, double *g, double *b)
 {
-	double weight = fmod(temp, (double)LIBRED_DELTA_TEMPERATURE) / (double)LIBRED_DELTA_TEMPERATURE;
+	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);
 }
 
-
 /**
- * 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.
+ * Get the [0, 1] sRGB values of a colour temperature
  * 
- * @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).
+ * @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  EDOM  The selected temperature is below 1000 K
  */
 int
 libred_get_colour(long int temp, double *r, double *g, double *b)
 {
-	double values[10]; /* low:x,y,r,g,b + high:x,y,r,g,b */
-	off_t offset;
-	double max;
-
-	/* We do not have any values for above 40 000 K, but
-	 * the differences will be unnoticeable, perhaps even
-	 * unencodeable. */
-	if (temp > LIBRED_HIGHEST_TEMPERATURE)  temp = LIBRED_HIGHEST_TEMPERATURE;
-	/* Things do not glow below 1000 K. Yes, fire is hot! */
-	if (temp < LIBRED_LOWEST_TEMPERATURE)   t ((errno = EDOM));
-
-	/* Read table. */
-	offset = ((off_t)temp - LIBRED_LOWEST_TEMPERATURE) / LIBRED_DELTA_TEMPERATURE;
-	offset *= (off_t)(sizeof(values) / 2);
-	errno = EOVERFLOW; xpread(libred_fd, values, sizeof(values), offset);
-
-	/* Get colour. */
-	if (temp % LIBRED_DELTA_TEMPERATURE)
-		interpolate(values[0], values[1], values[6], values[7], (double)temp, r, g, b);
-	else
-		*r = values[2], *g = values[3], *b = values[4];
-
-	/* Adjust colours for use. */
-	max = fmax(fmax(fabs(*r), fabs(*g)), fabs(*b));
-#if __GNUC__
-# pragma GCC diagnostic push
-# pragma GCC diagnostic ignored "-Wfloat-equal"
-#endif
-	if (max != 0.0)  *r /= max, *g /= max, *b /= max;
-#if __GNUC__
-# pragma GCC diagnostic pop
-#endif
-	*r = *r > 0.0 ? *r : 0.0;
-	*g = *g > 0.0 ? *g : 0.0;
-	*b = *b > 0.0 ? *b : 0.0;
+	double x1, y1, x2, y2;
+	size_t i;
+
+	if (temp > LIBRED_HIGHEST_TEMPERATURE)
+		temp = LIBRED_HIGHEST_TEMPERATURE;
+
+	if (temp < LIBRED_LOWEST_TEMPERATURE) {
+		errno = EDOM;
+		return -1;
+	}
+
+	if (temp % LIBRED_DELTA_TEMPERATURE) { /* TODO make optional */
+		i = (temp - LIBRED_LOWEST_TEMPERATURE) / LIBRED_DELTA_TEMPERATURE;
+		x1 = xy_table[i].x;
+		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);
+	} else {
+		i = (temp - LIBRED_LOWEST_TEMPERATURE) / LIBRED_DELTA_TEMPERATURE;
+		*r = rgb_table[i].r;
+		*g = rgb_table[i].g;
+		*b = rgb_table[i].b;
+	}
 
 	return 0;
-fail:
-	return -1;
 }
 #endif