151 lines
3.8 KiB
C++
151 lines
3.8 KiB
C++
/**********************************************************************
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Audacity - A Digital Audio Editor
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Copyright 1999-2009 Audacity Team
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License: GPL v2 - see LICENSE.txt
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Dan Horgan
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******************************************************************//**
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\file TimeWarper.h
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\brief Contains declarations for TimeWarper, IdentityTimeWarper,
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ShiftTimeWarper, LinearTimeWarper, LogarithmicTimeWarper classes
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\class TimeWarper
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\brief Transforms one point in time to another point. For example, a time
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stretching effect might use one to keep track of what happens to labels and
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split points in the input.
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\class IdentityTimeWarper
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\brief No change to time at all
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\class ShiftTimeWarper
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\brief Behaves like another, given TimeWarper, except shifted by a fixed amount
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\class LinearTimeWarper
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\brief Linear scaling, initialised by giving two points on the line
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\class LogarithmicTimeWarper
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\brief TimeScale - rate varies linearly, so time changes logarithmically.
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\class StepTimeWarper
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\brief Like identity but with a jump
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\class RegionTimeWarper
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\brief No change before the specified region; during the region, warp according
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to the given warper; after the region, constant shift so as to match at the end
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of the warped region.
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*//*******************************************************************/
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#ifndef __TIMEWARPER__
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#define __TIMEWARPER__
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class TimeWarper
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{
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public:
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virtual ~TimeWarper() { }
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virtual double Warp(double originalTime) const = 0;
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};
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class IdentityTimeWarper : public TimeWarper
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{
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public:
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virtual double Warp(double originalTime) const;
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};
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class ShiftTimeWarper : public TimeWarper
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{
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private:
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TimeWarper *mWarper;
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double mShift;
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public:
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ShiftTimeWarper(TimeWarper *warper, double shiftAmount)
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: mWarper(warper), mShift(shiftAmount) { }
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virtual ~ShiftTimeWarper()
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{ delete mWarper; }
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virtual double Warp(double originalTime) const;
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};
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class LinearTimeWarper : public TimeWarper
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{
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private:
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double mScale;
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double mShift;
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public:
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LinearTimeWarper(double tBefore0, double tAfter0,
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double tBefore1, double tAfter1)
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: mScale((tAfter1 - tAfter0)/(tBefore1 - tBefore0)),
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mShift(tAfter0 - mScale*tBefore0)
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{ }
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virtual double Warp(double originalTime) const;
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};
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class LogarithmicTimeWarper : public TimeWarper
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{
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private:
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LinearTimeWarper mRateWarper;
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double mRStart;
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double mTStart;
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double mScale;
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public:
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LogarithmicTimeWarper(double tStart, double tEnd,
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double rStart, double rEnd);
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virtual double Warp(double originalTime) const;
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};
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class StepTimeWarper : public TimeWarper
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{
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private:
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double mTStep;
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double mOffset;
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public:
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StepTimeWarper(double tStep, double offset);
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virtual double Warp(double originalTime) const;
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};
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// Note: this assumes that tStart is a fixed point of warper->warp()
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class RegionTimeWarper : public TimeWarper
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{
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private:
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TimeWarper *mWarper;
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double mTStart;
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double mTEnd;
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double mOffset;
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public:
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RegionTimeWarper(double tStart, double tEnd, TimeWarper *warper)
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: mWarper(warper), mTStart(tStart), mTEnd(tEnd),
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mOffset(mWarper->Warp(mTEnd)-mTEnd)
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{ }
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virtual ~RegionTimeWarper()
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{ delete mWarper; }
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virtual double Warp(double originalTime) const
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{
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if (originalTime < mTStart)
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{
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return originalTime;
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} else if (originalTime < mTEnd)
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{
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return mWarper->Warp(originalTime);
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} else
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{
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return mOffset + originalTime;
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}
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}
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};
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#endif /* End of include guard: __TIMEWARPER__ */
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// Indentation settings for Vim and Emacs and unique identifier for Arch, a
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// version control system. Please do not modify past this point.
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//
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// Local Variables:
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// c-basic-offset: 3
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// indent-tabs-mode: nil
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// End:
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//
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// vim: et sts=3 sw=3
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// arch-tag: TBD
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