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__ */