string ResolveTextFromPreviousFrame(int frameId, double angle)
{
var frame = Timeline.Data[frameId];
var lastFrame = Timeline.LatestFrame(f => f.Heading.Value, frameId - 1);
if (lastFrame != null && (frame.Seconds - lastFrame.Seconds) < 1)
{
var lastFrameExtended = (ExtendedData)lastFrame.Heading.ForIndicatorUse;
var dN = Math.Abs(Math2.DiffAngles(angle, lastFrameExtended.LastN));
var dE = Math.Abs(Math2.DiffAngles(angle, lastFrameExtended.LastE));
var dS = Math.Abs(Math2.DiffAngles(angle, lastFrameExtended.LastS));
var dW = Math.Abs(Math2.DiffAngles(angle, lastFrameExtended.LastW));
var T = 15; // Degrees motion
var tx = 0;
if (dN < T)
{
tx++;
}
if (dE < T)
{
tx++;
}
if (dS < T)
{
tx++;
}
if (dW < T)
{
tx++;
}
if (tx == 1)
{
if (dN < T)
{
return("N");
}
if (dE < T)
{
return("E");
}
if (dS < T)
{
return("S");
}
if (dW < T)
{
return("W");
}
}
}
return(null);
}
private double CheckResultValidity(double ret, int frameId)
{
var prev = Timeline.LatestFrame(d => d.Heading.Value, frameId);
if (prev != null && !double.IsNaN(Timeline.Data[frameId].Heading.Value))
{
var dT = Timeline.Data[frameId].Heading.SecondsWhenComputed - prev.Heading.SecondsWhenComputed;
if (dT < 1)
{
var dX = Math2.DiffAngles(Timeline.Data[frameId].Heading.Value, prev.Heading.Value);
if (Math.Abs(dX) > 10)
{
// can't move more than 20 deg in one second
ret = double.NaN;
}
}
}
return(ret);
}
