Fix midi control for log plugin parameters.

git-svn-id: svn://localhost/ardour2/trunk@663 d708f5d6-7413-0410-9779-e7cbd77b26cf

1 files changed, 10 insertions, 4 deletions

diff --git a/libs/ardour/plugin.cc b/libs/ardour/plugin.cc
index 2d1f8ffcbd..9fc6c57909 100644
--- a/libs/ardour/plugin.cc
+++ b/libs/ardour/plugin.cc
@@ -127,10 +127,16 @@ Plugin::MIDIPortControl::set_value (float value)
 			value = 0.0;
 		}
 	} else {
-		value = lower + (range * value);
-		
-		if (logarithmic) {
-			value = exp(value);
+
+		if (!logarithmic) {
+			value = lower + (range * value);
+		} else {
+			float _lower = 0.0f;
+			if (lower > 0.0f) {
+				_lower = log(lower);
+			}
+
+			value = exp(_lower + log(range) * value);
 		}
 	}