/// <summary>
/// Tests to see if the specified value falls in the range specified by this ColorCategory
/// </summary>
/// <param name="value">The value of type int to test</param>
/// <returns>Boolean, true if the value was found in the range</returns>
public bool Contains(double value)
{
return(Range == null || Range.Contains(value));
}
/// <summary>
/// This is primarily used in the BiValue situation where a color needs to be generated
/// somewhere between the start value and the end value.
/// </summary>
/// <param name="value">The value to be converted into a color from the range on this color break</param>
/// <returns>A color that is selected from the range values.</returns>
public virtual Color CalculateColor(double value)
{
if (!Range.Contains(value))
{
return(Color.Transparent);
}
if (Minimum == null || Maximum == null)
{
return(Range.Minimum == null ? HighColor : LowColor);
}
// From here on we have a double that falls in the range somewhere
double lowVal = Minimum.Value;
double range = Math.Abs(Maximum.Value - lowVal);
double p = 0; // the portion of the range, where 0 is LowValue & 1 is HighValue
double ht;
switch (GradientModel)
{
case GradientModel.Linear:
p = (value - lowVal) / range;
break;
case GradientModel.Exponential:
ht = value;
if (ht < 1)
{
ht = 1.0;
}
if (range > 1)
{
p = Math.Pow(ht - lowVal, 2) / Math.Pow(range, 2);
}
else
{
return(LowColor);
}
break;
case GradientModel.Logarithmic:
ht = value;
if (ht < 1)
{
ht = 1.0;
}
if (range > 1.0 && ht - lowVal > 1.0)
{
p = Math.Log(ht - lowVal) / Math.Log(range);
}
else
{
return(LowColor);
}
break;
}
int alpha = Utils.ByteRange(LowColor.A + Math.Round((HighColor.A - LowColor.A) * p));
int red = Utils.ByteRange(LowColor.R + Math.Round((HighColor.R - LowColor.R) * p));
int green = Utils.ByteRange(LowColor.G + Math.Round((HighColor.G - LowColor.G) * p));
int blue = Utils.ByteRange(LowColor.B + Math.Round((HighColor.B - LowColor.B) * p));
return(Color.FromArgb(alpha, red, green, blue));
}
