1 files changed, 97 insertions, 0 deletions
diff --git a/libs/surfaces/maschine2/m2_encoder.h b/libs/surfaces/maschine2/m2_encoder.h
new file mode 100644
index 0000000000..39032e62dd
--- /dev/null
+++ b/libs/surfaces/maschine2/m2_encoder.h
@@ -0,0 +1,97 @@
+/*
+ * Copyright (C) 2016 Robin Gareus <robin@gareus.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 2, 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, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+
+#ifndef _ardour_surfaces_m2encoder_h_
+#define _ardour_surfaces_m2encoder_h_
+
+#include <stdint.h>
+#include "pbd/signals.h"
+
+namespace ArdourSurface {
+
+class M2EncoderInterface
+{
+	public:
+		M2EncoderInterface () {}
+		virtual ~M2EncoderInterface () {}
+
+		/* user API */
+		PBD::Signal1<void, int> changed;
+		virtual float value () const { return 0.f; }
+		virtual float range () const { return 0.f; }
+
+		/* internal API - called from device thread */
+		virtual bool set_value (unsigned int v) { return false; }
+};
+
+class M2Encoder : public M2EncoderInterface
+{
+	public:
+		M2Encoder (unsigned int upper = 1000)
+			: M2EncoderInterface ()
+			, _upper (upper /* limit, exclusive. eg [0..15]: 16 */)
+			, _value (0)
+			, _initialized (false)
+		{
+			assert (_upper > 7);
+			_wrapcnt = std::max (3U, upper / 6);
+		}
+
+		float value () const { return _value / (_upper - 1.f); }
+		float range () const { return (_upper - 1.f); }
+
+		bool set_value (unsigned int v) {
+			if (!_initialized) {
+				_initialized = true;
+				_value = v;
+				return false;
+			}
+
+			if (v == _value) {
+				return false;
+			}
+
+			int delta;
+			if (v < _wrapcnt && _value > _upper - _wrapcnt) {
+				// wrap around max -> min
+				delta = v + _upper - _value;
+			}
+			else if (_value < _wrapcnt && v > _upper - _wrapcnt) {
+				// wrap around min -> max
+				delta = v - _upper - _value;
+			}
+			else {
+				delta = v - _value;
+			}
+
+			_value = v;
+			changed (delta);
+			return true;
+		}
+
+	protected:
+		unsigned int _upper;
+		unsigned int _value;
+		unsigned int _wrapcnt;
+		bool _initialized;
+};
+
+} /* namespace */
+#endif /* _ardour_surfaces_m2encoder_h_ */
+
+