LUMIERA.clone/src/lib/time/quantiser.hpp

136 lines
4.1 KiB
C++

/*
QUANTISER.hpp - aligning time values to a time grid
Copyright (C) Lumiera.org
2010, Hermann Vosseler <Ichthyostega@web.de>
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.
*/
#ifndef LIB_TIME_QUANTISER_H
#define LIB_TIME_QUANTISER_H
#include "lib/error.hpp"
#include "lib/time/grid.hpp"
#include "lib/time/formats.hpp"
#include "lib/time/timevalue.hpp"
#include "lib/iter-adapter.hpp"
//#include <boost/operators.hpp>
#include <vector>
#include <string>
#include <cmath>
namespace lib {
namespace time {
LUMIERA_ERROR_DECLARE (UNKNOWN_GRID); ///< referring to an undefined grid or scale in value quantisation
namespace { // stashed here for later
template<typename NUM>
struct ValTrait;
template<>
struct ValTrait<int>
{
static int asInt (int val) { return val; }
static double asDouble (int val) { return val; }
};
template<>
struct ValTrait<double>
{
static int asInt (double val) { return std::floor(0.5+val); } ///< in accordance with Lumiera's time handling RfC
static double asDouble (double val) { return val; }
};
}
/**
* Facility to create grid-aligned time values.
* Effectively, a quantiser exposes the value Grid API, but
* additionally also manages a set of supported (display) formats or
* "time code" formats. Plus there is an static API to fetch a suitable
* quantiser instance by-name; actually this utilises a hidden link to
* the Lumiera session. Time quantisation and timecode handling explicitly
* relies on this Quantiser interface.
*
*/
class Quantiser
: public virtual Grid
{
protected:
format::Supported supportedFormats_;
Quantiser()
: supportedFormats_(format::SupportStandardTimecode())
{ }
public:
template<class FMT>
bool
supports() const
{
return supportedFormats_.check<FMT>();
}
//------Grid-API----------------------------------------------
virtual long gridPoint (TimeValue const& raw) const =0;
virtual TimeValue gridAlign (TimeValue const& raw) const =0;
virtual TimeValue timeOf (long gridPoint) const =0;
virtual TimeValue timeOf (FSecs, int =0) const =0;
};
/**
* Simple stand-alone Quantiser implementation based on a constant sized gird.
* This is a self-contained quantiser implementation without any implicit referral
* to the Lumiera session. As such it is suited for simplified unit testing.
* @warning real GUI and Proc-Layer code should always fetch a quantiser from the
* Session, referring to a pre defined TimeGrid. Basically, the overall purpose of
* the time-quantisation framework is to enforce such a link to a distinct time scale
* and quantisation, so to prevent "wild and uncoordinated" rounding attempts.
*/
class FixedFrameQuantiser
: public Quantiser
{
Time origin_;
Duration raster_;
public:
FixedFrameQuantiser (FrameRate const& frames_per_second, TimeValue referencePoint =TimeValue(0));
FixedFrameQuantiser (Duration const& frame_duration, TimeValue referencePoint =TimeValue(0));
long gridPoint (TimeValue const&) const;
TimeValue gridAlign (TimeValue const&) const;
TimeValue timeOf (long gridPoint) const;
TimeValue timeOf (FSecs, int =0) const;
};
}} // lib::time
#endif