Initial import of gtk2_ardour.

git-svn-id: svn://localhost/trunk/ardour2@24 d708f5d6-7413-0410-9779-e7cbd77b26cf

1 files changed, 49 insertions, 0 deletions

diff --git a/gtk2_ardour/logmeter.h b/gtk2_ardour/logmeter.h
new file mode 100644
index 0000000000..f7ed1dd2be
--- /dev/null
+++ b/gtk2_ardour/logmeter.h
@@ -0,0 +1,49 @@
+#ifndef __ardour_gtk_log_meter_h__
+#define __ardour_gtk_log_meter_h__
+
+#if 0
+inline float
+_log_meter (float power, double lower_db, double upper_db, double non_linearity)
+{
+	return (power < lower_db ? 0.0 : pow((power-lower_db)/(upper_db-lower_db), non_linearity));
+}
+
+inline float
+log_meter (float power)
+{
+	return _log_meter (power, -192.0, 0.0, 8.0);
+}
+#endif
+
+inline float
+log_meter (float db)
+{
+         gfloat def = 0.0f; /* Meter deflection %age */
+ 
+         if (db < -70.0f) {
+                 def = 0.0f;
+         } else if (db < -60.0f) {
+                 def = (db + 70.0f) * 0.25f;
+         } else if (db < -50.0f) {
+                 def = (db + 60.0f) * 0.5f + 2.5f;
+         } else if (db < -40.0f) {
+                 def = (db + 50.0f) * 0.75f + 7.5f;
+         } else if (db < -30.0f) {
+                 def = (db + 40.0f) * 1.5f + 15.0f;
+         } else if (db < -20.0f) {
+                 def = (db + 30.0f) * 2.0f + 30.0f;
+         } else if (db < 6.0f) {
+                 def = (db + 20.0f) * 2.5f + 50.0f;
+         } else {
+		 def = 115.0f;
+	 }
+ 
+	 /* 115 is the deflection %age that would be 
+	    when db=6.0. this is an arbitrary
+	    endpoint for our scaling.
+	 */
+
+         return def/115.0f;
+}
+
+#endif /* __ardour_gtk_log_meter_h__ */