private static void CalculateComponents(long totalTicks,
TimeSignature timeSignature,
short ticksPerQuarterNote,
out long bars,
out long beats,
out long ticks)
{
var barLength = BarBeatUtilities.GetBarLength(timeSignature, ticksPerQuarterNote);
bars = Math.DivRem(totalTicks, barLength, out ticks);
var beatLength = BarBeatUtilities.GetBeatLength(timeSignature, ticksPerQuarterNote);
beats = Math.DivRem(ticks, beatLength, out ticks);
}
public ITimeSpan ConvertTo(long timeSpan, long time, TempoMap tempoMap)
{
var ticksPerQuarterNoteTimeDivision = tempoMap.TimeDivision as TicksPerQuarterNoteTimeDivision;
if (ticksPerQuarterNoteTimeDivision == null)
{
throw new ArgumentException("Time division is not supported for time span conversion.", nameof(tempoMap));
}
if (timeSpan == 0)
{
return(new BarBeatFractionTimeSpan());
}
var ticksPerQuarterNote = ticksPerQuarterNoteTimeDivision.TicksPerQuarterNote;
var endTime = time + timeSpan;
//
var timeSignatureLine = tempoMap.TimeSignature;
var timeSignatureChanges = timeSignatureLine
.Where(v => v.Time > time && v.Time < endTime)
.ToList();
var bars = 0L;
// Calculate count of complete bars between time signature changes
for (int i = 0; i < timeSignatureChanges.Count - 1; i++)
{
var timeSignatureChange = timeSignatureChanges[i];
var nextTime = timeSignatureChanges[i + 1].Time;
var barLength = BarBeatUtilities.GetBarLength(timeSignatureChange.Value, ticksPerQuarterNote);
bars += (nextTime - timeSignatureChange.Time) / barLength;
}
// Calculate components before first time signature change and after last time signature change
var firstTime = timeSignatureChanges.FirstOrDefault()?.Time ?? time;
var lastTime = timeSignatureChanges.LastOrDefault()?.Time ?? time;
var firstTimeSignature = timeSignatureLine.AtTime(time);
var lastTimeSignature = timeSignatureLine.AtTime(lastTime);
long barsBefore, beatsBefore;
double fractionBefore;
CalculateComponents(firstTime - time,
firstTimeSignature,
ticksPerQuarterNote,
out barsBefore,
out beatsBefore,
out fractionBefore);
long barsAfter, beatsAfter;
double fractionAfter;
CalculateComponents(time + timeSpan - lastTime,
lastTimeSignature,
ticksPerQuarterNote,
out barsAfter,
out beatsAfter,
out fractionAfter);
bars += barsBefore + barsAfter;
// Try to complete a bar
var beats = beatsBefore + beatsAfter;
if (beats > 0)
{
if (beatsBefore > 0 && beats >= firstTimeSignature.Numerator)
{
bars++;
beats -= firstTimeSignature.Numerator;
}
}
// Try to complete a beat
var fraction = fractionBefore + fractionAfter;
beats += (long)Math.Truncate(fraction);
fraction -= Math.Truncate(fraction);
//
return(new BarBeatFractionTimeSpan(bars, beats + fraction));
}
public long ConvertFrom(ITimeSpan timeSpan, long time, TempoMap tempoMap)
{
var ticksPerQuarterNoteTimeDivision = tempoMap.TimeDivision as TicksPerQuarterNoteTimeDivision;
if (ticksPerQuarterNoteTimeDivision == null)
{
throw new ArgumentException("Time division is not supported for time span conversion.", nameof(tempoMap));
}
var barBeatFractionTimeSpan = (BarBeatFractionTimeSpan)timeSpan;
// TODO: epsilon
if (barBeatFractionTimeSpan.Bars == 0 && barBeatFractionTimeSpan.Beats == 0)
{
return(0);
}
var ticksPerQuarterNote = ticksPerQuarterNoteTimeDivision.TicksPerQuarterNote;
var timeSignatureLine = tempoMap.TimeSignature;
//
double fractionalBeats = barBeatFractionTimeSpan.Beats;
long bars = barBeatFractionTimeSpan.Bars;
long beats = (long)Math.Truncate(fractionalBeats);
double fraction = fractionalBeats - Math.Truncate(fractionalBeats);
var startTimeSignature = timeSignatureLine.AtTime(time);
var startBarLength = BarBeatUtilities.GetBarLength(startTimeSignature, ticksPerQuarterNote);
var startBeatLength = BarBeatUtilities.GetBeatLength(startTimeSignature, ticksPerQuarterNote);
var totalTicks = bars * startBarLength + beats * startBeatLength + ConvertFractionToTicks(fraction, startBeatLength);
var timeSignatureChanges = timeSignatureLine.Where(v => v.Time > time && v.Time < time + totalTicks).ToList();
var lastBarLength = 0L;
var lastBeatLength = 0L;
var firstTimeSignatureChange = timeSignatureChanges.FirstOrDefault();
var lastTimeSignature = firstTimeSignatureChange?.Value ?? startTimeSignature;
var lastTime = firstTimeSignatureChange?.Time ?? time;
long barsBefore, beatsBefore;
double fractionBefore;
CalculateComponents(lastTime - time,
startTimeSignature,
ticksPerQuarterNote,
out barsBefore,
out beatsBefore,
out fractionBefore);
bars -= barsBefore;
// Balance bars
if (bars > 0)
{
foreach (var timeSignatureChange in timeSignatureLine.Where(v => v.Time > lastTime).ToList())
{
var deltaTime = timeSignatureChange.Time - lastTime;
lastBarLength = BarBeatUtilities.GetBarLength(lastTimeSignature, ticksPerQuarterNote);
lastBeatLength = BarBeatUtilities.GetBeatLength(lastTimeSignature, ticksPerQuarterNote);
var currentBars = Math.Min(deltaTime / lastBarLength, bars);
bars -= currentBars;
lastTime += currentBars * lastBarLength;
if (bars == 0)
{
break;
}
lastTimeSignature = timeSignatureChange.Value;
}
if (bars > 0)
{
lastBarLength = BarBeatUtilities.GetBarLength(lastTimeSignature, ticksPerQuarterNote);
lastBeatLength = BarBeatUtilities.GetBeatLength(lastTimeSignature, ticksPerQuarterNote);
lastTime += bars * lastBarLength;
}
}
if (beats == beatsBefore && fraction == fractionBefore)
{
return(lastTime - time);
}
// Balance beats
if (beatsBefore > beats && lastBarLength > 0)
{
lastTime += -lastBarLength + (startTimeSignature.Numerator - beatsBefore) * lastBeatLength;
beatsBefore = 0;
}
if (beatsBefore < beats)
{
lastBeatLength = BarBeatUtilities.GetBeatLength(timeSignatureLine.AtTime(lastTime), ticksPerQuarterNote);
lastTime += (beats - beatsBefore) * lastBeatLength;
}
// Balance cents
if (fractionBefore > fraction && lastBeatLength > 0)
{
lastTime += -lastBeatLength + ConvertFractionToTicks(fraction + 1.0 - fractionBefore, lastBeatLength);
}
if (fractionBefore < fraction)
{
if (lastBeatLength == 0)
{
lastBeatLength = BarBeatUtilities.GetBeatLength(timeSignatureLine.AtTime(lastTime), ticksPerQuarterNote);
}
lastTime += ConvertFractionToTicks(fraction - fractionBefore, lastBeatLength);
}
//
return(lastTime - time);
}
