1 files changed, 112 insertions, 0 deletions
diff --git a/inputmethods/dasher/FrameRate.h b/inputmethods/dasher/FrameRate.h
new file mode 100644
index 0000000..2f86b03
--- a/dev/null
+++ b/inputmethods/dasher/FrameRate.h
@@ -0,0 +1,112 @@
+// FrameRate.h
+//
+/////////////////////////////////////////////////////////////////////////////
+//
+// Copyright (c) 2002 David Ward
+//
+/////////////////////////////////////////////////////////////////////////////
+
+#ifndef __FrameRate_h__
+#define __FrameRate_h__
+
+#include "MSVC_Unannoy.h"
+
+// keeps track of framerate
+// computes the Steps parameter
+// computes RXmax - which controls the maximum rate of zooming in
+
+const double LN2= log(2);
+
+class CFrameRate {
+	public:
+		CFrameRate() ;
+		~CFrameRate() {};
+		const double Rxmax() const {return m_dRXmax;}
+		const int Steps() const {return m_iSteps;}
+		const double Framerate() const {return m_dFr;}
+		void Reset(unsigned long Time);
+		void NewFrame(unsigned long Time);
+		
+		// TODO: These two shouldn't be the same thing:
+		void SetBitrate(double TargetRate);
+		void SetMaxBitrate(double MaxRate);
+	private:
+		double m_dFr;
+		double m_dMaxbitrate;    // the maximum rate of entering information
+		double m_dRXmax;         // the maximum zoomin per frame
+		int m_iFrames,m_iTime,m_iTime2,m_iSamples;
+		int m_iSteps;            // the 'Steps' parameter. See djw thesis.
+};
+	
+inline CFrameRate::CFrameRate() {
+
+ // maxbitrate should be user-defined and/or adaptive. Currently it is not.
+#if defined(_WIN32_WCE)
+	m_dMaxbitrate=5;
+#else
+	m_dMaxbitrate=5.5;
+#endif
+
+	m_dRXmax=2;  // only a transient effect
+	m_iFrames=0;
+	m_iSamples=1;
+
+	// we dont know the framerate yet - play it safe by setting it high
+	m_dFr=1<<5;
+
+	// start off very slow until we have sampled framerate adequately
+	m_iSteps=2000;
+	m_iTime=0; // Hmmm, User must reset framerate before starting.
+}
+
+inline void CFrameRate::NewFrame(unsigned long Time) 
+	// compute framerate if we have sampled enough frames
+{
+	
+	m_iFrames++;
+
+	if (m_iFrames==m_iSamples) {
+		m_iTime2=Time;
+		if (m_iTime2-m_iTime < 50) 
+			m_iSamples++;      // increase sample size
+		else if (m_iTime2-m_iTime > 80) {
+			m_iSamples--;
+			if (m_iSamples <2)
+				m_iSamples=2;
+		}
+		if (m_iTime2-m_iTime) {
+				m_dFr=m_iFrames*1000.0/(m_iTime2-m_iTime);
+				m_iTime=m_iTime2;
+				m_iFrames=0;
+
+			}
+		m_dRXmax=exp(m_dMaxbitrate*LN2/m_dFr);
+		m_iSteps=m_iSteps/2+(int)(-log(0.2)*m_dFr/LN2/m_dMaxbitrate)/2;
+	//	dchar debug[256];
+	//		_stprintf(debug,TEXT("fr %f Steps %d samples %d time2 %d rxmax %f\n"),fr,Steps,samples,time2,RXmax);
+	//	OutputDebugString(debug);
+	
+	}
+}
+
+inline void CFrameRate::Reset(unsigned long Time)
+{
+	m_iFrames=0;
+	m_iTime=Time;
+}
+
+
+inline void CFrameRate::SetBitrate(double TargetRate)
+{
+	m_dMaxbitrate = TargetRate;
+}
+
+
+inline void CFrameRate::SetMaxBitrate(double MaxRate)
+{
+	m_dMaxbitrate = MaxRate;
+}
+
+
+
+#endif /* #ifndef __FrameRate_h__ */