/*
* We need to know if the caret is currently positioned on the line we
* are about to paint so the line number can be highlighted.
*/
private boolean isCurrentLine(int rowStartOffset) {
int caretPosition = component.getCaretPosition();
Element root = component.getDocument().getDefaultRootElement();
if (root.getElementIndex(rowStartOffset) == root.getElementIndex(caretPosition)) return true;
else return false;
}
/*
* Get the line number to be drawn. The empty string will be returned
* when a line of text has wrapped.
*/
protected String getTextLineNumber(int rowStartOffset) {
Element root = component.getDocument().getDefaultRootElement();
int index = root.getElementIndex(rowStartOffset);
Element line = root.getElement(index);
if (line.getStartOffset() == rowStartOffset) return String.valueOf(index + 1);
else return "";
}
//
// Implement CaretListener interface
//
@Override
public void caretUpdate(CaretEvent e) {
// Get the line the caret is positioned on
int caretPosition = component.getCaretPosition();
Element root = component.getDocument().getDefaultRootElement();
int currentLine = root.getElementIndex(caretPosition);
// Need to repaint so the correct line number can be highlighted
if (lastLine != currentLine) {
repaint();
lastLine = currentLine;
}
}
/*
* Determine the Y offset for the current row
*/
private int getOffsetY(int rowStartOffset, FontMetrics fontMetrics) throws BadLocationException {
// Get the bounding rectangle of the row
Rectangle r = component.modelToView(rowStartOffset);
int lineHeight = fontMetrics.getHeight();
int y = r.y + r.height;
int descent = 0;
// The text needs to be positioned above the bottom of the bounding
// rectangle based on the descent of the font(s) contained on the row.
if (r.height == lineHeight) {
// default font is being used
descent = fontMetrics.getDescent();
} else {
// We need to check all the attributes for font changes
if (fonts == null) {
fonts = new HashMap<String, FontMetrics>();
}
Element root = component.getDocument().getDefaultRootElement();
int index = root.getElementIndex(rowStartOffset);
Element line = root.getElement(index);
for (int i = 0; i < line.getElementCount(); i++) {
Element child = line.getElement(i);
AttributeSet as = child.getAttributes();
String fontFamily = (String) as.getAttribute(StyleConstants.FontFamily);
Integer fontSize = (Integer) as.getAttribute(StyleConstants.FontSize);
String key = fontFamily + fontSize;
FontMetrics fm = fonts.get(key);
if (fm == null) {
Font font = new Font(fontFamily, Font.PLAIN, fontSize);
fm = component.getFontMetrics(font);
fonts.put(key, fm);
}
descent = Math.max(descent, fm.getDescent());
}
}
return y - descent;
}