public function Temperature::convert in Physical Fields 8

Converts the current temperature measurement to a new unit.

Parameters

string $new_unit: The new unit.

Return value

static The resulting temperature.

Overrides Measurement::convert

File

src/Temperature.php, line 31

Class

Temperature

Provides a value object for temperature amounts.

Namespace

Drupal\physical

Code

public function convert($new_unit) {
  TemperatureUnit::assertExists($new_unit);

  // The base factors are not used because the formulas change depending
  // on the units being converted.
  $new_number = '0';
  switch ($this->unit) {
    case TemperatureUnit::KELVIN:
      if ($new_unit == TemperatureUnit::CELSIUS) {

        // http://www.rapidtables.com/convert/temperature/kelvin-to-celsius.htm
        $new_number = Calculator::subtract($this->number, '273.15');
      }
      else {

        // @see http://www.rapidtables.com/convert/temperature/kelvin-to-fahrenheit.htm
        $new_number = Calculator::subtract(Calculator::multiply($this->number, '1.8'), '459.67');
      }
      break;
    case TemperatureUnit::CELSIUS:
      if ($new_unit == TemperatureUnit::FAHRENHEIT) {

        // http://www.rapidtables.com/convert/temperature/how-celsius-to-fahrenheit.htm
        $new_number = Calculator::add(Calculator::multiply($this->number, '1.8'), '32');
      }
      else {

        // http://www.rapidtables.com/convert/temperature/celsius-to-kelvin.htm
        $new_number = Calculator::add($this->number, '273.15');
      }
      break;
    case TemperatureUnit::FAHRENHEIT:
      if ($new_unit == TemperatureUnit::CELSIUS) {

        // @see http://www.rapidtables.com/convert/temperature/fahrenheit-to-celsius.htm
        $new_number = Calculator::divide(Calculator::subtract($this->number, '32'), '1.8');
      }
      else {

        // http://www.rapidtables.com/convert/temperature/fahrenheit-to-kelvin.htm
        $new_number = Calculator::divide(Calculator::add($this->number, '459.67'), '1.8');
      }
      break;
  }
  return new static($new_number, $new_unit);
}