X-Git-Url: https://git.carlh.net/gitweb/?a=blobdiff_plain;f=src%2Flib%2Fmaths_util.h;h=24c4b547f121fbee81cd066d88ae20a7ee79ff2f;hb=ff639b3cf30afcc097bfd21d39c8d15f466cadd6;hp=8adefbbc4e325c32ae35f4a4416cca8d0aa29dda;hpb=cf2ed48d21ddbc32bda262064480e88e69dc031a;p=dcpomatic.git

diff --git a/src/lib/maths_util.h b/src/lib/maths_util.h
index 8adefbbc4..24c4b547f 100644
--- a/src/lib/maths_util.h
+++ b/src/lib/maths_util.h
@@ -30,6 +30,21 @@
 extern double db_to_linear (double db);
 extern double linear_to_db (double linear);
 
+/** @return linear gain according to a logarithmic curve, for fading in.
+ *  t < 0:       linear gain of 0
+ *  0 >= t >= 1: logarithmic fade in curve
+ *  t > 1:       linear gain of 1
+ */
+extern float logarithmic_fade_in_curve (float t);
+
+
+/** @return linear gain according to a logarithmic curve, for fading out.
+ *  t > 1:       linear gain of 0
+ *  0 >= t >= 1: logarithmic fade out curve
+ *  t < 0:       linear gain of 1
+ */
+extern float logarithmic_fade_out_curve (float t);
+
 
 template <class T>
 T clamp (T val, T minimum, T maximum)