eirikbakke/ScrollpaneTrackpadJitterBugExhibit.java

## ScrollpaneTrackpadJitterBugExhibit.java
package com.sieuferd.uiutil;

import java.awt.Dimension;
import java.awt.Font;
import java.awt.Rectangle;
import javax.swing.*;

public final class ScrollpaneTrackpadJitterBugExhibit extends JFrame {
  private static final class ViewportPanel extends JPanel implements Scrollable {
    public ViewportPanel() {
      setLayout(new java.awt.GridLayout(2, 0, 0, 800));
      //topLabel.setVerticalAlignment(SwingConstants.TOP);
      add(new JLabel("Top of Viewport"));
      //bottomLabel.setVerticalAlignment(SwingConstants.BOTTOM);
      JLabel bottomLabel = new JLabel(
          "<html>Line 1<br>Line 2<br>Line 3<br>Line 4<br>Line 5<br>Line 6<br>Bottom of Viewport</html>");
      bottomLabel.setFont(new Font("Dialog", Font.PLAIN, 18));
      add(bottomLabel);
    }

    @Override
    public Dimension getPreferredScrollableViewportSize() {
      return getPreferredSize();
    }

    @Override
    public int getScrollableUnitIncrement(Rectangle visibleRect, int orientation, int direction) {
      return 30;
    }

    @Override
    public int getScrollableBlockIncrement(Rectangle visibleRect, int orientation, int direction) {
      return 30;
    }

    @Override
    public boolean getScrollableTracksViewportWidth() {
      return true;
    }

    @Override
    public boolean getScrollableTracksViewportHeight() {
      return false;
    }
  }

  public ScrollpaneTrackpadJitterBugExhibit() {
    JScrollPane scrollPane = new JScrollPane(new ViewportPanel());

    scrollPane.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);
    scrollPane.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);

    getContentPane().add(scrollPane, java.awt.BorderLayout.CENTER);
    pack();
    setSize(300, 400);
  }

  public static void main(String args[]) {
    SwingUtilities.invokeLater(new Runnable() {
      public void run() {
        new ScrollpaneTrackpadJitterBugExhibit().setVisible(true);
      }
    });
  }
}
	package com.sieuferd.uiutil;

	import java.awt.Dimension;
	import java.awt.Font;
	import java.awt.Rectangle;
	import javax.swing.*;

	public final class ScrollpaneTrackpadJitterBugExhibit extends JFrame {
	private static final class ViewportPanel extends JPanel implements Scrollable {
	public ViewportPanel() {
	setLayout(new java.awt.GridLayout(2, 0, 0, 800));
	//topLabel.setVerticalAlignment(SwingConstants.TOP);
	add(new JLabel("Top of Viewport"));
	//bottomLabel.setVerticalAlignment(SwingConstants.BOTTOM);
	JLabel bottomLabel = new JLabel(
	"<html>Line 1<br>Line 2<br>Line 3<br>Line 4<br>Line 5<br>Line 6<br>Bottom of Viewport</html>");
	bottomLabel.setFont(new Font("Dialog", Font.PLAIN, 18));
	add(bottomLabel);
	}

	@Override
	public Dimension getPreferredScrollableViewportSize() {
	return getPreferredSize();
	}

	@Override
	public int getScrollableUnitIncrement(Rectangle visibleRect, int orientation, int direction) {
	return 30;
	}

	@Override
	public int getScrollableBlockIncrement(Rectangle visibleRect, int orientation, int direction) {
	return 30;
	}

	@Override
	public boolean getScrollableTracksViewportWidth() {
	return true;
	}

	@Override
	public boolean getScrollableTracksViewportHeight() {
	return false;
	}
	}

	public ScrollpaneTrackpadJitterBugExhibit() {
	JScrollPane scrollPane = new JScrollPane(new ViewportPanel());

	scrollPane.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);
	scrollPane.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);

	getContentPane().add(scrollPane, java.awt.BorderLayout.CENTER);
	pack();
	setSize(300, 400);
	}

	public static void main(String args[]) {
	SwingUtilities.invokeLater(new Runnable() {
	public void run() {
	new ScrollpaneTrackpadJitterBugExhibit().setVisible(true);
	}
	});
	}
	}