split out from radharc

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

1 files changed, 51 insertions, 0 deletions

diff --git a/src/blackbody.h b/src/blackbody.h
new file mode 100644
index 0000000..499e9b8
--- /dev/null
+++ b/src/blackbody.h
@@ -0,0 +1,51 @@
+/**
+ * Copyright © 2016  Mattias Andrée <maandree@member.fsf.org>
+ * 
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ * 
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+
+
+/**
+ * The highest colour temperature in the table.
+ */
+#define LIBRED_HIGHEST_TEMPERATURE  40000
+
+/**
+ * The lowest colour temperature in the table.
+ */
+#define LIBRED_LOWEST_TEMPERATURE  1000
+
+/**
+ * The temperature difference between the colours in the table.
+ */
+#define LIBRED_DELTA_TEMPERATURE  100
+
+
+
+/**
+ * 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.
+ * @param   b     Output parameter for the blue value.
+ * @return        0 on succeess, -1 on error.
+ * 
+ * @throws  0     The file did not have the expected size.
+ * @throws  EDOM  The selected temperature is below 1000 K.
+ */
+int libred_get_colour(int fd, long int temp, double *r, double *g, double *b);
+