convertRange function

double convertRange(double value, double oldMin, double oldMax, double newMin, double newMax,)

Maps a value from one range to another and inverts the result.

This utility function takes a value from an original range (defined by oldMin and oldMax) and maps it to a new range (defined by newMin and newMax), then inverts the result within the new range.

The function performs the following steps:

1. Clamps the input value to ensure it's within the original range
2. Maps the clamped value from the original range to the new range using linear interpolation
3. Inverts the mapped value within the new range

This is particularly useful in chart visualization for:

• Scaling values between different coordinate systems
• Converting between data values and pixel positions
• Normalizing values for consistent visual representation
• Creating inverse relationships (e.g., when a smaller input should produce a larger output)

@param value The input value to be converted. @param oldMin The minimum value of the original range. @param oldMax The maximum value of the original range. @param newMin The minimum value of the target range. @param newMax The maximum value of the target range. @return The converted and inverted value in the new range.

Implementation

double convertRange(
  double value,
  double oldMin,
  double oldMax,
  double newMin,
  double newMax,
) {
  // Ensure the value is within the old range
  final double clampedValue = value.clamp(oldMin, oldMax);

  // Map the old range to the new range
  final double oldRange = oldMax - oldMin;
  final double newRange = newMax - newMin;

  // Calculate the scaled value in the new range
  final double newValue =
      (((clampedValue - oldMin) * newRange) / oldRange) + newMin;

  // Invert the value within the new range
  // This creates an inverse relationship where:
  // - When input is oldMin, output is newMax
  // - When input is oldMax, output is newMin
  return newMax - newValue + newMin;
}