public @Nullable Integer convertImpl(int lineNumber, boolean hideFoldingLines) {
    int zeroBaseNumber = lineNumber - 1;
    if (hideFoldingLines && myFoldingHiddenLines != null && myFoldingHiddenLines.test(zeroBaseNumber)) {
      return null;
    }
    if (myLineConverter != null) {
      zeroBaseNumber = myLineConverter.applyAsInt(zeroBaseNumber);
    }
    return zeroBaseNumber < 0 ? null : zeroBaseNumber + 1;
  }
public @Nullable Integer convertImpl(int lineNumber, boolean hideFoldingLines)