/**
* Ensures that the specified line and offset is visible by scrolling the text area if necessary.
*
* @param line The line to scroll to
* @param offset The offset in the line to scroll to
* @return True if scrolling was actually performed, false if the line and offset was already
* visible
*/
public boolean scrollTo(int line, int offset) {
// visibleLines == 0 before the component is realized
// we can't do any proper scrolling then, so we have
// this hack...
if (visibleLines == 0) {
setFirstLine(Math.max(0, line - electricScroll));
return true;
}
int newFirstLine = firstLine;
int newHorizontalOffset = horizontalOffset;
if (line < firstLine + electricScroll) {
newFirstLine = Math.max(0, line - electricScroll);
} else if (line + electricScroll >= firstLine + visibleLines) {
newFirstLine = (line - visibleLines) + electricScroll + 1;
if (newFirstLine + visibleLines >= getLineCount())
newFirstLine = getLineCount() - visibleLines;
if (newFirstLine < 0) newFirstLine = 0;
}
int x = _offsetToX(line, offset);
int width = painter.getFontMetrics().charWidth('w');
if (x < 0) {
newHorizontalOffset = Math.min(0, horizontalOffset - x + width + 5);
} else if (x + width >= painter.getWidth()) {
newHorizontalOffset = horizontalOffset + (painter.getWidth() - x) - width - 5;
}
return setOrigin(newFirstLine, newHorizontalOffset);
}
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();
}
}
