layoutText function

({int column, int row, List<String> rows}) layoutText(List<String> chars, int cursor, int width)

Text laid out in rows of at most width columns, with where the cursor falls.

Implementation

({List<String> rows, int row, int column}) layoutText(List<String> chars, int cursor, int width) {
  final rows = <StringBuffer>[StringBuffer()];
  var column = 0;
  var cursorRow = 0;
  var cursorColumn = 0;
  for (var index = 0; index <= chars.length; index++) {
    if (index == cursor) {
      if (column >= width) {
        rows.add(StringBuffer());
        column = 0;
      }
      cursorRow = rows.length - 1;
      cursorColumn = column;
    }
    if (index == chars.length) {
      break;
    }
    final char = chars[index];
    if (char == '\n') {
      rows.add(StringBuffer());
      column = 0;
      continue;
    }
    final charWidth = runeWidth(char.runes.first);
    if (column + charWidth > width) {
      rows.add(StringBuffer());
      column = 0;
    }
    rows.last.write(char);
    column += charWidth;
  }
  return (rows: rows.map((row) => row.toString()).toList(), row: cursorRow, column: cursorColumn);
}