misc

Signed-off-by: Mattias Andrée <maandree@member.fsf.org>

1 files changed, 88 insertions, 57 deletions

diff --git a/src/blackbody.c b/src/blackbody.c
index abe03a9..f45ead4 100644
--- a/src/blackbody.c
+++ b/src/blackbody.c
@@ -14,7 +14,7 @@
  * You should have received a copy of the GNU General Public License
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
-#include "blackbody.h"
+#include "libred.h"
 #include "macros.h"
 #include <math.h>
 #include <errno.h>
@@ -22,6 +22,40 @@
 
 
 /**
+ * The file descriptor to the colour lookup table.
+ */
+static int 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)
+{
+  libred_term_colour();
+  fd = open(SYSDEPRESDIR "/" PACKAGE "/10deg", O_RDONLY);
+  return fd < 0 ? -1 : 0;
+}
+
+
+/**
+ * Call this when the process will not
+ * longer make calls to `libred_get_colour`.
+ */
+void libred_term_colour(void)
+{
+  if (fd >= 0)
+    close(fd), fd = -1;
+}
+
+
+/**
  * Convert from CIE xyY to [0, 1] sRGB.
  * 
  * @param  x  The 'x' component.
@@ -32,23 +66,22 @@
  * @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)
+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;
-
-	/* 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));
-
-	/* 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);
+  double X, Z;
+  
+  /* 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));
+  
+  /* 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);
 }
 
 
@@ -68,20 +101,18 @@ ciexyy_to_srgb(double x, double y, double Y, double *r, double *g, double *b)
  * @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)
+static void interpolate(double x1, double y1, double x2, double y2, double temp, double *r, double *g, double *b)
 {
-	double weight = fmod(temp, (double)DELTA_TEMPERATURE) / (double)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);
+  double weight = fmod(temp, (double)DELTA_TEMPERATURE) / (double)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   fd    File descriptor for the colour table.
  * @param   temp  The desired colour temperature.
  * @param   r     Output parameter for the “red” value.
  * @param   g     Output parameter for the green value.
@@ -90,41 +121,41 @@ interpolate(double x1, double y1, double x2, double y2, double temp, double *r,
  * 
  * @throws  0     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
-get_colour(int fd, long int temp, double *r, double *g, double *b)
+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 > HIGHEST_TEMPERATURE)  temp = HIGHEST_TEMPERATURE;
-	/* Things do not glow below 1000 K. Yes, fire is hot! */
-	if (temp < LOWEST_TEMPERATURE)   t ((errno = EDOM));
-
-	/* Read table. */
-	offset = ((off_t)temp - LOWEST_TEMPERATURE) / DELTA_TEMPERATURE;
-	offset *= (off_t)(sizeof(values) / 2);
-	errno = 0; xpread(fd, values, sizeof(values), offset);
-
-	/* Get colour. */
-	if (temp % 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 (max != 0)  *r /= max, *g /= max, *b /= max;
-	*r = *r > 0.0 ? *r : 0.0;
-	*g = *g > 0.0 ? *g : 0.0;
-	*b = *b > 0.0 ? *b : 0.0;
-
-	return 0;
-fail:
-	return -1;
+  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 > HIGHEST_TEMPERATURE)  temp = HIGHEST_TEMPERATURE;
+  /* Things do not glow below 1000 K. Yes, fire is hot! */
+  if (temp < LOWEST_TEMPERATURE)   t ((errno = EDOM));
+  
+  /* Read table. */
+  offset = ((off_t)temp - LOWEST_TEMPERATURE) / DELTA_TEMPERATURE;
+  offset *= (off_t)(sizeof(values) / 2);
+  errno = 0; xpread(fd, values, sizeof(values), offset);
+  
+  /* Get colour. */
+  if (temp % 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 (max != 0)  *r /= max, *g /= max, *b /= max;
+  *r = *r > 0.0 ? *r : 0.0;
+  *g = *g > 0.0 ? *g : 0.0;
+  *b = *b > 0.0 ? *b : 0.0;
+  
+  return 0;
+ fail:
+  return -1;
 }