/**
* Create a line number component for a text component.
*
* @param component the related text component
* @param minimumDisplayDigits the number of digits used to calculate the minimum width of the
* component
*/
public TextLineNumber(JTextComponent component, int minimumDisplayDigits) {
this.component = component;
setFont(component.getFont());
setBorderGap(5);
setCurrentLineForeground(Color.RED);
setDigitAlignment(RIGHT);
setMinimumDisplayDigits(minimumDisplayDigits);
component.getDocument().addDocumentListener(this);
component.addCaretListener(this);
component.addPropertyChangeListener("font", this);
}
/** Draw the line numbers */
@Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
// 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) {
}
}
}
