private void UpdateRange(long position, Origin origin, Origin watchRange)
{
int nextLines = bufferLines + (origin == Origin.Begin ? textViewLinesOnScreen : 0);
int prevLines = bufferLines + (origin == Origin.End ? textViewLinesOnScreen : 0);
LineRange newLineRange = lb.ReadRange(position, origin, prevLines, nextLines, 1000, 1000, watchRange);
if (origin == Origin.End)
{
newLineRange = ShiftLineRange(newLineRange, -(textViewLinesOnScreen - 1));
}
RangeUpdated(newLineRange);
}