validationError property

PaperFormatError? get validationError

Why the measures cannot print, or null when they are valid.

Implementation

PaperFormatError? get validationError {
  if (pageWidthMm <= 0 ||
      pageHeightMm <= 0 ||
      cellWidthMm <= 0 ||
      cellHeightMm <= 0) {
    return PaperFormatError.sizeMissing;
  }
  if (columns < 1 || rows < 1 || columns > 20 || rows > 40) {
    return PaperFormatError.gridOutOfRange;
  }
  final usedWidth =
      marginLeftMm + columns * cellWidthMm + (columns - 1) * gapXMm;
  final usedHeight = marginTopMm + rows * cellHeightMm + (rows - 1) * gapYMm;
  if (usedWidth > pageWidthMm + 0.5 || usedHeight > pageHeightMm + 0.5) {
    return PaperFormatError.cellsOutsidePage;
  }
  return null;
}