/*
* 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;
}
/**
* Draw the line numbers
*
* @param g
*/
@Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
((Graphics2D) g)
.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
// Determine the width of the space available to draw the line number
FontMetrics fontMetrics = component.getFontMetrics(component.getFont());
Insets insets = getInsets();
int availableWidth = getSize().width - insets.left - insets.right;
// Determine the rows to draw within the clipped bounds.
Rectangle clip = g.getClipBounds();
int rowStartOffset = component.viewToModel(new Point(0, clip.y));
int endOffset = component.viewToModel(new Point(0, clip.y + clip.height));
while (rowStartOffset <= endOffset) {
try {
if (isCurrentLine(rowStartOffset)) g.setColor(getCurrentLineForeground());
else g.setColor(getForeground());
// Get the line number as a string and then determine the
// "X" and "Y" offsets for drawing the string.
String lineNumber = getTextLineNumber(rowStartOffset);
int stringWidth = fontMetrics.stringWidth(lineNumber);
int x = getOffsetX(availableWidth, stringWidth) + insets.left;
int y = getOffsetY(rowStartOffset, fontMetrics);
g.drawString(lineNumber, x, y);
// Move to the next row
rowStartOffset = Utilities.getRowEnd(component, rowStartOffset) + 1;
} catch (Exception e) {
break;
}
}
}