/// <summary>
/// Returns the value range given a plot area coordinate.
/// </summary>
/// <param name="value">The plot area position.</param>
/// <returns>The value at that plot area coordinate.</returns>
protected override IComparable GetValueAtPosition(UnitValue value)
{
if (ActualRange.HasData && ActualLength != 0.0)
{
if (value.Unit == Unit.Pixels)
{
double coordinate = value.Value;
Range <double> actualDoubleRange = ActualRange.ToDoubleRange();
double output =
Math.Pow
(
10,
coordinate *
Math.Log10(actualDoubleRange.Maximum / actualDoubleRange.Minimum) /
ActualLength
)
*
actualDoubleRange.Minimum;
return(output);
}
else
{
throw new NotImplementedException();
}
}
return(null);
}
/// <summary>
/// Returns the actual interval to use to determine which values are
/// displayed in the axis.
/// </summary>
/// <param name="availableSize">The available size.</param>
/// <returns>Actual interval to use to determine which values are
/// displayed in the axis.
/// </returns>
protected virtual double CalculateActualInterval(Size availableSize)
{
if (Interval != null)
{
return(Interval.Value);
}
Range <double> doubleActualRange = ActualRange.ToDoubleRange();
// helper functions
Func <double, double> Exponent = x => Math.Ceiling(Math.Log(x, 10));
Func <double, double> Mantissa = x => x / Math.Pow(10, Exponent(x) - 1);
// reduce intervals for horizontal axis.
double maxIntervals = Orientation == AxisOrientation.X ? MaximumAxisIntervalsPer200Pixels * 0.8 : MaximumAxisIntervalsPer200Pixels;
// real maximum interval count
double maxIntervalCount = GetLength(availableSize) / 200 * maxIntervals;
double range = Math.Abs(doubleActualRange.Minimum - doubleActualRange.Maximum);
double interval = Math.Pow(10, Exponent(range));
double tempInterval = interval;
// decrease interval until interval count becomes less than maxIntervalCount
while (true)
{
int mantissa = (int)Mantissa(tempInterval);
if (mantissa == 5)
{
// reduce 5 to 2
tempInterval = ValueHelper.RemoveNoiseFromDoubleMath(tempInterval / 2.5);
}
else if (mantissa == 2 || mantissa == 1 || mantissa == 10)
{
// reduce 2 to 1,10 to 5,1 to 0.5
tempInterval = ValueHelper.RemoveNoiseFromDoubleMath(tempInterval / 2.0);
}
if (range / tempInterval > maxIntervalCount)
{
break;
}
interval = tempInterval;
}
return(interval);
}
/// <summary>
/// Returns the value range given a plot area coordinate.
/// </summary>
/// <param name="value">The plot area position.</param>
/// <returns>The value at that plot area coordinate.</returns>
protected override IComparable GetValueAtPosition(UnitValue value)
{
if (ActualRange.HasData && ActualLength != 0.0)
{
if (value.Unit == Unit.Pixels)
{
double coordinate = value.Value;
Range <double> actualDoubleRange = ActualRange.ToDoubleRange();
double rangelength = actualDoubleRange.Maximum - actualDoubleRange.Minimum;
double output = ((coordinate * (rangelength / ActualLength)) + actualDoubleRange.Minimum);
return(output);
}
else
{
throw new NotImplementedException();
}
}
return(null);
}
/// <summary>
/// Returns a sequence of major axis values.
/// </summary>
/// <param name="availableSize">The available size.</param>
/// <returns>A sequence of major axis values.
/// </returns>
private IEnumerable <double> GetMajorValues(Size availableSize)
{
if (!ActualRange.HasData || ValueHelper.Compare(ActualRange.Minimum, ActualRange.Maximum) == 0 || GetLength(availableSize) == 0.0)
{
yield break;
}
Range <double> typedActualRange = ActualRange.ToDoubleRange();
this.ActualInterval = CalculateActualInterval(availableSize);
double startValue = AlignToInterval(typedActualRange.Minimum, this.ActualInterval);
if (startValue < typedActualRange.Minimum)
{
startValue = AlignToInterval(typedActualRange.Minimum + this.ActualInterval, this.ActualInterval);
}
double nextValue = startValue;
for (int counter = 1; nextValue <= typedActualRange.Maximum; counter++)
{
yield return(nextValue);
nextValue = startValue + (counter * this.ActualInterval);
}
}