areaScrollDown method
Implementation
void areaScrollDown(int lines) {
final scrollRange = getAreaScrollRange();
for (var i = scrollRange.bottom; i > scrollRange.top;) {
i--;
if (i >= scrollRange.top + lines) {
this.lines[i] = this.lines[i - lines];
} else {
this.lines[i] = _newEmptyLine();
}
}
}