libardour added.

git-svn-id: svn://localhost/trunk/ardour2@17 d708f5d6-7413-0410-9779-e7cbd77b26cf

1 files changed, 133 insertions, 0 deletions

diff --git a/libs/ardour/ardour/logcurve.h b/libs/ardour/ardour/logcurve.h
new file mode 100644
index 0000000000..84911b0369
--- /dev/null
+++ b/libs/ardour/ardour/logcurve.h
@@ -0,0 +1,133 @@
+/*
+    Copyright (C) 2001 Steve Harris & Paul Davis 
+
+    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 of the License, 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., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+    $Id$
+*/
+
+#ifndef __ardour_logcurve_h__
+#define __ardour_logcurve_h__
+
+#include <pbd/fastlog.h>
+#include <pbd/lockmonitor.h>
+
+namespace ARDOUR {
+
+class LogCurve {
+  public:
+	LogCurve (float steepness = 0.2, uint32_t len = 0) {
+		l = len;
+		S = steepness;
+		a = log(S);
+		b = 1.0f / log(1.0f + (1.0f / S));
+	}
+
+	bool operator== (const LogCurve& other) const {
+		return S == other.S && l == other.l;
+	}
+
+	bool operator!= (const LogCurve& other) const {
+		return S != other.S || l != other.l;
+	}
+	
+	float value (float frac) const {
+		return (fast_log(frac + S) - a) * b;
+	} 
+	
+	float value (uint32_t pos) const {
+		return (fast_log(((float) pos/l) + S) - a) * b;
+	} 
+
+	float invert_value (float frac) const {
+		return (a - fast_log(frac + S)) * b;
+	} 
+	
+	float invert_value (uint32_t pos) const {
+		return (a - fast_log(((float) pos/l) + S)) * b;
+	} 
+
+	void fill (float *vec, uint32_t veclen, bool invert) const {
+		float dx = 1.0f/veclen;
+		float x;
+		uint32_t i;
+
+		if (!invert) {
+
+			vec[0] = 0.0;
+			vec[veclen-1] = 1.0;
+
+			for (i = 1, x = 0; i < veclen - 1; x += dx, i++) {
+				vec[i] = value (x);
+			}
+
+		} else {
+
+			vec[0] = 1.0;
+			vec[veclen-1] = 0.0;
+
+			for (i = veclen-2, x = 0.0f; i > 0; x += dx, i--) {
+				vec[i] = value (x);
+			}
+		}
+	}
+
+	float steepness() const { return S; }
+	uint32_t length() const { return l; }
+	
+	void set_steepness (float steepness) { 
+		S = steepness; 
+		a = log(S); 		
+		b = 1.0f / log(1.0f + (1.0f / S));
+	}
+	void set_length (uint32_t len) { l = len; }
+
+	mutable PBD::NonBlockingLock lock;
+
+  protected:
+	float a;
+	float b;
+	float S;
+	uint32_t l;
+};
+
+class LogCurveIn : public LogCurve 
+{
+  public:
+	LogCurveIn (float steepness = 0.2, uint32_t len = 0) 
+		: LogCurve (steepness, len) {}
+
+	float value (float frac) const {
+		return (fast_log(frac + S) - a) * b;
+	} 
+	
+	float value (uint32_t pos) const {
+		return (fast_log(((float) pos/l) + S) - a) * b;
+	} 
+};
+
+class LogCurveOut : public LogCurve 
+{
+  public:
+	LogCurveOut (float steepness = 0.2, uint32_t len = 0) 
+		: LogCurve (steepness, len) {}
+
+};
+
+}; /* namespace ARDOUR */
+
+#endif /* __ardour_logcurve_h__ */
+
+