units_converter 1.1.1+2

Simple and light units conversion package for all your needs.

units_converter

units_converter is a package written in dart for dart & flutter developers. You should not take care of unit conversion when you want to internationalize your app, everything is already done with this package! You can also add your own custom conversion!

This package is used by Converter NOW!

This documentation is structured in examples of incresing complexity. But don't worry, in most cases you will only need the first examples.

Table of Contents

• Convert a unit to another unit
• Convert a unit to all the another units
• Special type of conversion: numeral systems conversion
• Simple custom conversion
• Custom conversion
• Which conversions?

Convert a unit to another unit

Example 1: convert 1 meter in inches

// We give 1 meter as input
var length = Length()..convert(LENGTH.meters, 1);
// We get the inches
var unit = length.inches;
// We print the Unit
print('name:${unit.name}, value:${unit.value}, stringValue:${unit.stringValue}, symbol:${unit.symbol}');

Output:

name:LENGTH.inches, value:39.370078740157474, stringValue:39.37007874, symbol:in

Convert a unit to all the another units

Example 2: convert 1 degree in all the other angles units. This time we want also to specify that we just want 7 significant figures and we don't want trailing zeros (e.g. 1.000000 -> 1).

// Initialization of the object
var angle = Angle(significantFigures: 7, removeTrailingZeros: false); // conversion
angle.convert(ANGLE.degree, 1);
// We get all the units
var units = angle.getAll(); //We get all ther others units
// Let's print all of them
for (var unit in units) {
  print('name:${unit.name}, value:${unit.value}, stringValue:${unit.stringValue}, symbol:${unit.symbol}');
}

Output:

name:ANGLE.degree, value:1.0, stringValue:1.000000, symbol:°
name:ANGLE.minutes, value:60.0, stringValue:60.00000, symbol:'
name:ANGLE.seconds, value:3600.0, stringValue:3600.000, symbol:''

As you can see in this example if you specify removeTrailingZeros: false, the stringValue keeps all the trailing zeros (the default is true). You can also ask for an certain number of significant figures in the stringValue.

Special type of conversion: numeral systems conversion

Warning! Numeral systems conversion is the only conversion that need the input as a String, and not as a double / int for obvious reasons

Example 3: convert '100' (decimal) to binary and hexadecimal

// We give '100' decimal as input
var numeralSystems = NumeralSystems()..convert(NUMERAL_SYSTEMS.decimal, '100');
// We get the binary value
print('Binary: ${numeralSystems.binary.stringValue}');
// We get the hexadecimal value
print('Hexadecimal: ${numeralSystems.hexadecimal.stringValue}'); 

Output:

Binary: 1100100
Hexadecimal: 64

Simple custom conversion

Use SimpleCustomConversion when you are dealing with a linear conversion between the units, i.e. when a unit is x times a value. In SimpleCustomConversion we have to define a conversionMap between a base unit, which must have a value of 1, and all the other units. In the example below we say that 1€ is 1.2271$, but also 0.9033₤, and so on and so forth.

Example 4: define the currency exchange rate with their symbols (optional) and perform the conversion between two of them.

final Map<String, double> conversionMap = {
  'EUR': 1,
  'USD': 1.2271,
  'GBP': 0.9033,
  'JPY': 126.25,
  'CNY': 7.9315,
};
// The map of the symbols is optional but nice
final Map<String, String> mapSymbols = {
  'EUR': '€',
  'USD': '\$',
  'GBP': '₤',
  'JPY': '¥',
  'CNY': '¥',
};

var customConversion = SimpleCustomConversion(conversionMap, mapSymbols: mapSymbols);
customConversion.convert('EUR', 1);
Unit usd = customConversion.getUnit('USD');
print('1€ = ${usd.stringValue}${usd.symbol}');

Output:

1€ = 1.2271$

Custom conversion

In most cases, you will only need SimpleCustomConversion (see the previous section). SimpleCustomConversion allow you to define conversions in the for of y=ax. But if you need to define special relationship between units you need CustomConversion. This allow you to perform conversion like: y=ax+b and y=a/x+b (where y and x are the value of two units and a and b are two coefficient), for example the conversion between Celsius and Fahreneit use the first relation and the conversion between km/l and l/100km has to be done with the second relation. Both can't be done with SimpleCustomConversion.

Example 5: let's define the following imaginary units of measurement:

• KiloDash = 1000 * Dash
• DashPlus1 = Dash + 1
  • OneOver(DashPlus1) = 1 / (DashPlus1)

As you can see all this relations can be structured like a conversion tree. Now you can take a look at the example below: it does in the code what we have just said.

Node conversionTree = Node(
  name: 'Dash',
  leafNodes: [
    Node(
      name: 'KiloDash',
      coefficientProduct: 1000,
    ),
    Node(
      name: 'DashPlus1',
      coefficientSum: -1,
      leafNodes: [
        Node(
          name: 'OneOver(DashPlus1)',
          conversionType: CONVERSION_TYPE.reciprocalConversion,
        ),
      ],
    ),
  ],
);
final Map<String, String> symbolsMap = {
  'Dash': 'dsh',
  'KiloDash': 'kdsh',
  'DashPlus1': 'dsh+1',
  'OneOver(DashPlus1)': '1/(dsh+1)',
};
var dash = CustomConversion(
  conversionTree: conversionTree,
  mapSymbols: symbolsMap,
  name: 'Conversion of Dash',
);
dash.convert('Dash', 1);
var myUnits = dash.getAll();
for (var unit in myUnits) {
  print('name:${unit.name}, value:${unit.value}, stringValue:${unit.stringValue}, symbol:${unit.symbol}');
}

Output:

name:Dash, value:1.0, stringValue:1, symbol:dsh
name:KiloDash, value:0.001, stringValue:0.001, symbol:kdsh
name:DashPlus1, value:2.0, stringValue:2, symbol:dsh+1
name:OneOver(DashPlus1), value:0.5, stringValue:0.5, symbol:1/(dsh+1)

Which conversions?

• Angles (degree, radians, etc.)

• Area (hectares, acres, etc.)

• Digital data (byte, gigabit, etc.)

• Energy (Joule, kilowatt-hour, etc.)

• Force (Newton, kilogram-force, etc.)

• Fuel consumption (miles per hour, kilometers per hour, etc.)

• Length (meter, miles, etc)

• Mass (kilograms, ounces, etc.)

• Numeral systems (hexadecimal, binary, etc.)

• Power (kilowatt, horse power, etc.)

• Pressure (bar, psi, etc.)

• Shoe size (eu size, us size, etc.)

• SI prefixes (giga, tera, etc.)

• Speed (miles per hour, kilometers per hour, etc.)

• Temperature (celsius, fahreneit, etc.)

• Time (seconds, years, etc.)

• Torque (newtons per meter, dyne meter, etc.)

• Volume (liter, cubic meters, etc.)