How to output a String on multiple lines using Graphics

graphics, java, string

Solution

Thanks to Epaga's hint and a couple of examples on the Net (not so obvious to find! I used mainly Break a Line for text layout), I could make a component to display wrapped text. It is incomplete, but at least it shows the intended effect.

class TextContainer extends JPanel
{
    private int m_width;
    private int m_height;
    private String m_text;
    private AttributedCharacterIterator m_iterator;
    private int m_start;
    private int m_end;

    public TextContainer(String text, int width, int height)
    {
        m_text = text;
        m_width = width;
        m_height = height;

        AttributedString styledText = new AttributedString(text);
        m_iterator = styledText.getIterator();
        m_start = m_iterator.getBeginIndex();
        m_end = m_iterator.getEndIndex();
    }

    public String getText()
    {
        return m_text;
    }

    public Dimension getPreferredSize()
    {
        return new Dimension(m_width, m_height);
    }

    public void paint(Graphics g)
    {
        super.paintComponent(g);

        Graphics2D g2 = (Graphics2D) g;
        FontRenderContext frc = g2.getFontRenderContext();

        LineBreakMeasurer measurer = new LineBreakMeasurer(m_iterator, frc);
        measurer.setPosition(m_start);

        float x = 0, y = 0;
        while (measurer.getPosition() < m_end)
        {
            TextLayout layout = measurer.nextLayout(m_width);

            y += layout.getAscent();
            float dx = layout.isLeftToRight() ?
                    0 : m_width - layout.getAdvance();

            layout.draw(g2, x + dx, y);
            y += layout.getDescent() + layout.getLeading();
        }
    }
}

Just for fun, I made it fitting a circle (alas, no justification, it seems):

public void paint(Graphics g)
{
    super.paintComponent(g);

    Graphics2D g2 = (Graphics2D) g;
    FontRenderContext frc = g2.getFontRenderContext();

    LineBreakMeasurer measurer = new LineBreakMeasurer(m_iterator, frc);
    measurer.setPosition(m_start);

    float y = 0;
    while (measurer.getPosition() < m_end)
    {
        double ix = Math.sqrt((m_width / 2 - y) * y);
        float x = m_width / 2.0F - (float) ix;
        int width = (int) ix * 2;

        TextLayout layout = measurer.nextLayout(width);

        y += layout.getAscent();
        float dx = layout.isLeftToRight() ?
                0 : width - layout.getAdvance();

        layout.draw(g2, x + dx, y);
        y += layout.getDescent() + layout.getLeading();
    }
}

I am not too sure about dx computation, though.

Problem

My Program overrides `public void paint(Graphics g, int x, int y);` in order to draw some stings using `g.drawString(someString, x+10, y+30);` Now someString can be quite long and thus, it may not fit on one line. What is the best way to write the text on multiple line. For instance, in a rectangle (x1, y1, x2, y2)?

Original source