Swing HTML rendering shows very large bullet point

Asked 29/11, 2012 at 13:7 Answered 29/11, 2012 at 13:38

Solved java html swing rendering jeditorpane

I use a JEditorPane to render some HTML in a swing application. I use a bullet point list <ul><li>...</li></ul> and I obtain overly large bullet points in the output. The same HTML chunk will show normal sized bullet points in a real browser.

I observed this on Windows 7 / JDK 7 and iirc also on Ubuntu and OpenJDK 1.7.0_09.

Is this known? Is there a way around it?

Working example:

import javax.swing.JEditorPane;
import javax.swing.JFrame;
import javax.swing.WindowConstants;

/**
 *
 */
public class HTMLTest {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        // create new frame
        JFrame frame = new JFrame();
        frame.setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE);
        frame.setSize(500, 500);

        // create editor pane and fill with some html
        JEditorPane pane = new JEditorPane();
        pane.setContentType("text/html");
        pane.setEditable(false);
        pane.setText("<html><h1>Heading</h1>Text<ul><li>Bullet point</li></ul></html>");

        // add editor pane to frame and set frame visible
        frame.add(pane);
        frame.setVisible(true);
    }
}

P.S.: I am now using

ul {
    list-style-type: none;
    margin-left: 10px
}

in a css file and

<li>&bull; Item 1</li>

in the html to have a decent bullet point. Solution inspired by aterai.

Tva answered 29/11, 2012 at 13:7 Comment(1)

This combines favorably with something like text-indent: -20px; padding-left: 20px to indent the text to theright of the bullet symbol. I haven't found out how to automatically align the indent with the bullet size though. – Knawel 3/5, 2019 at 16:56

+1 @StanislavL and here is another example(use css list-style-image property):

screenshot

bullet.png:

import java.awt.*;
import javax.swing.*;
import javax.swing.text.*;
import javax.swing.text.html.*;

public class HTMLTest2 {
  public JComponent makeEditorPane(String bullet) {
    // create editor pane and fill with some html
    JEditorPane pane = new JEditorPane();
    pane.setContentType("text/html");
    pane.setEditable(false);
    if(bullet!=null) {
      HTMLEditorKit htmlEditorKit = (HTMLEditorKit)pane.getEditorKit();
      StyleSheet styleSheet = htmlEditorKit.getStyleSheet();
      //String u = getClass().getResource(bullet).toString();
      String u = "https://i.sstatic.net/jV29K.png";
      styleSheet.addRule(String.format("ul{list-style-image:url(%s);margin:0px 20px;", u));
      //styleSheet.addRule("ul{list-style-type:circle;margin:0px 20px;}");
      //styleSheet.addRule("ul{list-style-type:disc;margin:0px 20px;}");
      //styleSheet.addRule("ul{list-style-type:decimal;margin:0px 20px;}");
    }
    pane.setText("<html><h1>Heading</h1>Text<ul><li>Bullet point</li></ul></html>");
    return pane;
  }
  public JComponent makeUI() {
    JPanel p = new JPanel(new GridLayout(2,1));
    p.add(new JScrollPane(makeEditorPane(null)));
    p.add(new JScrollPane(makeEditorPane("bullet.png")));
    return p;
  }
  public static void main(String[] args) {
    EventQueue.invokeLater(new Runnable() {
      @Override public void run() {
        createAndShowGUI();
      }
    });
  }
  public static void createAndShowGUI() {
    JFrame f = new JFrame();
    f.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
    f.getContentPane().add(new HTMLTest2().makeUI());
    f.setSize(320, 320);
    f.setLocationRelativeTo(null);
    f.setVisible(true);
  }
}

Merge answered 29/11, 2012 at 13:38 Comment(3)

I marked this answer as solution because it seem a bit easier to realize than the other from StanislavL, although both are good. – Tva 30/11, 2012 at 9:29

@Merge Is there a simpler solution to this now five years on, have Oracle addressed this is any way. – Whinstone 27/7, 2017 at 10:24

@PaulTaylor CSS support in the Swing component has not changed since 5 years ago. – Merge 27/7, 2017 at 13:51

See ListView source code

public void paint(Graphics g, Shape allocation) {
    super.paint(g, allocation);
    Rectangle alloc = allocation.getBounds();
    Rectangle clip = g.getClipBounds();
    // Since listPainter paints in the insets we have to check for the
    // case where the child is not painted because the paint region is
    // to the left of the child. This assumes the ListPainter paints in
    // the left margin.
    if ((clip.x + clip.width) < (alloc.x + getLeftInset())) {
        Rectangle childRect = alloc;
        alloc = getInsideAllocation(allocation);
        int n = getViewCount();
        int endY = clip.y + clip.height;
        for (int i = 0; i < n; i++) {
        childRect.setBounds(alloc);
        childAllocation(i, childRect);
        if (childRect.y < endY) {
            if ((childRect.y + childRect.height) >= clip.y) {
            listPainter.paint(g, childRect.x, childRect.y,
                      childRect.width, childRect.height,
                      this, i);
            }
        }
        else {
            break;
        }
        }
    }
}

The listPainter uses the past arguments as

    if (childtype == CSS.Value.SQUARE || childtype == CSS.Value.CIRCLE
        || childtype == CSS.Value.DISC) {
    drawShape(g, childtype, (int) x, (int) y, 
          (int) w, (int) h, align);
    }

And the drawShape is following as you can see the size is hardcoded there to be 8

void drawShape(Graphics g, CSS.Value type, int ax, int ay, int aw, 
               int ah, float align) {
            // Align to bottom of shape.
            int gap = isLeftToRight ? - (bulletgap + 8) : (aw + bulletgap);
            int x = ax + gap;
            int y = Math.max(ay, ay + (int)(align * ah) - 8);

        if (type == CSS.Value.SQUARE) {
        g.drawRect(x, y, 8, 8);
        } else if (type == CSS.Value.CIRCLE) {
        g.drawOval(x, y, 8, 8);
        } else {
        g.fillOval(x, y, 8, 8);
        }
    }

You can try to replace the StyleSheet's ListPainter in the method provided your own painter

public ListPainter getListPainter(AttributeSet a) {
    return new ListPainter(a, this);
}

where you can change the rendering of bullets

Osswald answered 29/11, 2012 at 13:24 Comment(3)

Thank you for that very nice search. That effectively makes all list shapes ugly in html rendering in swing. I think in browsers the size of the bullet migt depend on the actual font size. – Tva 29/11, 2012 at 13:31

You can override ListView's 'public void paint(Graphics g, Shape allocation)' method and provide own painting there instead of replacing 'ListPainter' – Osswald 29/11, 2012 at 13:36

But why is the default so ugly ? – Whinstone 27/7, 2017 at 10:23