text

Allows to get detailed information about the text (number of lines, lines at positions, characters at locations, locations at positions, positions at locations, and vice versa).

It is much faster than you could possibly imagine, thanks to the sparse lists.

import 'package:text/text.dart';

void main() {
  final text = Text(string);
  var position = text.length ~/ 2;
  // Get the line by the character position
  var line = text.lineAt(position)!;
  print('#${line.number}: ${toStr(line.characters)}');

  // Get the location by the character position
  var location = text.locationAt(position);
  print('pos: $position => loc: ${location.line}:${location.column}');

  // Get the character position by the location
  position = text.position(location);
  print('loc: ${location.line}:${location.column} => pos: $position');

  // Get the line by index (line.number - 1)
  final line2 = text.line(line.number - 1);
  print('#${line.number} = #${line2.number}');

  // Search the Unicode character and display it location and string
  const char = 65504; // ￠
  position = text.characters.indexOf(char);
  location = text.locationAt(position);
  line = text.lineAt(position)!;
  print('${toStr([char])} found at pos: $position');
  print('${toStr([char])} found at loc: ${location.line}:${location.column}');
  print('${toStr([char])} found in line: ${toStr(line.characters)}');
}

String toStr(List<int> characters) => String.fromCharCodes(characters);

String string = '''
1. Line 1
2. Line 2
3. Line 3
4. Line 4
5. Line 5 🚀￠
''';

Output:

#3: 3. Line 3

pos: 27 => loc: 3:8
loc: 3:8 => pos: 27
#3 = #3
￠ found at pos: 51
￠ found at loc: 5:12
￠ found in line: 5. Line 5 🚀￠