public void insertUpdate(DocumentEvent evt) {
documentChanged(evt);
int offset = evt.getOffset();
int length = evt.getLength();
int newStart;
int newEnd;
if (selectionStart > offset || (selectionStart == selectionEnd && selectionStart == offset))
newStart = selectionStart + length;
else newStart = selectionStart;
if (selectionEnd >= offset) newEnd = selectionEnd + length;
else newEnd = selectionEnd;
select(newStart, newEnd);
}
public void removeUpdate(DocumentEvent evt) {
documentChanged(evt);
int offset = evt.getOffset();
int length = evt.getLength();
int newStart;
int newEnd;
if (selectionStart > offset) {
if (selectionStart > offset + length) newStart = selectionStart - length;
else newStart = offset;
} else newStart = selectionStart;
if (selectionEnd > offset) {
if (selectionEnd > offset + length) newEnd = selectionEnd - length;
else newEnd = offset;
} else newEnd = selectionEnd;
select(newStart, newEnd);
}
protected void documentChanged(DocumentEvent evt) {
DocumentEvent.ElementChange ch = evt.getChange(document.getDefaultRootElement());
int count;
if (ch == null) count = 0;
else count = ch.getChildrenAdded().length - ch.getChildrenRemoved().length;
int line = getLineOfOffset(evt.getOffset());
if (count == 0) {
painter.invalidateLine(line);
}
// do magic stuff
else if (line < firstLine) {
setFirstLine(firstLine + count);
}
// end of magic stuff
else {
painter.invalidateLineRange(line, firstLine + visibleLines);
updateScrollBars();
}
}