# HighlightPainter Demo

## What Is It

This demo features two simple new `HighlightPainters`: the `UnderlineHighlightPainter` and the `TextBoxHighlightPainter`.

## How To Use It

Swing already does all the heavy lifting here for us. We can add these just like any other `HighlightPainter`:

    UnderlineHighlightPainter painter =
        new UnderlineHighlightPainter(Color.red, 1, true);
    String word = "the";
    int i1 = textPane.getText().indexOf(word);
    if (i1 != -1) {
        int i2 = i1 + word.length();
        textPane.getHighlighter().addHighlight(i1, i2, painter);
    }

## Discussion

The "squiggly" underline has become the ubiquitous marker for cautionary flags in text panes. A decade or two ago it was only used to flag misspellings, but increasingly it's also used to flag grammatical warnings. You could also flag syntactical errors or warnings for a language like XML or Java.

The `TextBoxHighlightPainter` is a simpler upgrade to the `DefaultHighlightPainter` that offers a potential gradient or rounded corners.