discontinuedPackage jet_cad_floor_plan has been discontinued and replaced by jet_cad_2d_plan.

formatDimension function

String formatDimension(double mm, DisplayUnit unit, { DecimalSeparator decimalSeparator = DecimalSeparator.point, })

A dimension's text for a length of mm in the page's display unit (spec 11 D9, decision 7): no unit symbol, the page's decimalSeparator (spec Q0 T1; . in the examples below), no grouping, each unit at its plan precision:

• mm, to 1 mm: the integer (3450);
• cm, to 0.1 cm: one decimal, always (345.0, R-14);
• m, to 0.01 m: two decimals, always (3.45, 14.00);
• inches, to 1/8": whole inches then a reduced fraction, no mark (136 3/8, 136, 0 1/4, R-15);
• feet-inches, to 1/4": F'-I" or F'-I N/D", the fraction reduced (11'-4 1/4", 12'-0", 0'-0 1/2"); the marks are the notation that separates feet from inches, not a unit symbol (R-15).

The total is rounded (roundHalfUp) in quanta of the precision before it is split into whole units and a fraction, so a carry reaches the next unit: 143 7/8" is 575.5 quarters and prints 12'-0", never 11'-12". The magnitude of mm is formatted. Only cm and m print a decimal separator; mm prints an integer, inches and feet-inches fractions.

Implementation

String formatDimension(double mm, DisplayUnit unit,
    {DecimalSeparator decimalSeparator = DecimalSeparator.point}) {
  final v = mm.abs();
  switch (unit) {
    case DisplayUnit.millimeters:
      return '${roundHalfUp(v, 1)}';
    case DisplayUnit.centimeters:
      final n = roundHalfUp(v, 1); // millimetres, tenths of a cm
      return '${n ~/ 10}${decimalSeparator.char}${n % 10}';
    case DisplayUnit.meters:
      final n = roundHalfUp(v, 10); // hundredths of a metre
      return '${n ~/ 100}${decimalSeparator.char}'
          '${(n % 100).toString().padLeft(2, '0')}';
    case DisplayUnit.inches:
      final n = roundHalfUp(v, 25.4 / 8); // eighths of an inch
      return '${n ~/ 8}${_fraction(n % 8, 8)}';
    case DisplayUnit.feetInches:
      final n = roundHalfUp(v, 25.4 / 4); // quarters of an inch
      final feet = n ~/ 48, rest = n % 48;
      return "$feet'-${rest ~/ 4}${_fraction(rest % 4, 4)}\"";
  }
}