Add modulus operator to MIDI transformer.

Useful for doing things like making alternating bowing patterns.

gtk2_ardour/transform_dialog.cc

@@ -69,7 +69,7 @@ TransformDialog::Model::Model()
 	}
 
 	static const char* operator_labels[] = {
-		/* no PUSH */ "+", "-", "*", "/", NULL
+		/* no PUSH */ "+", "-", "*", "/", "mod", NULL
 	};
 	for (int o = 0; operator_labels[o]; ++o) {
 		Gtk::TreeModel::Row row = *(operator_list->append());

libs/ardour/ardour/transform.h

@@ -106,7 +106,8 @@ public:
 			ADD,   ///< Add top two values
 			SUB,   ///< Subtract top from second-top
 			MULT,  ///< Multiply top two values
-			DIV    ///< Divide second-top by top
+			DIV,   ///< Divide second-top by top
+			MOD    ///< Modulus (division remainder)
 		};
 
 		Operation(Operator o, const Value& a=Value()) : op(o), arg(a) {}

libs/ardour/transform.cc

@@ -106,6 +106,12 @@ Transform::Operation::eval(Context& ctx) const
 		}
 		value /= rhs.to_double();
 		break;
+	case MOD:
+		if (rhs.to_double() == 0.0) {
+			return;  // Program will fail safely
+		}
+		value = fmod(value, rhs.to_double());
+		break;
 	default: break;
 	}