1 /*
   2  * Copyright (c) 2016, 2017, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
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  23 
  24 /**
  25  * @test
  26  * @key headful
  27  * @bug 8160246
  28  * @summary Regression: 4410243 reproducible with GTK LaF
  29  * @run main ScrollFlickerTest
  30  */
  31 
  32 import javax.swing.*;
  33 import java.awt.*;
  34 
  35 public class ScrollFlickerTest {
  36 
  37     private static JFrame frame;
  38     private static JScrollPane scroll;
  39     private static int cnt = 0;
  40 
  41     public static void main(String[] args) throws Exception {
  42         SwingUtilities.invokeAndWait(() -> {
  43             frame = new JFrame();
  44             frame.setSize(300, 200);
  45             frame.getContentPane().setLayout(null);
  46             JTextArea text = new JTextArea("Test test test test");
  47             text.setLineWrap(true);
  48             scroll = new JScrollPane(text);
  49             frame.getContentPane().add(scroll);
  50             scroll.setBounds(1, 1, 100, 50);
  51             frame.setVisible(true);
  52         });
  53 
  54         Robot robot = new Robot();
  55         robot.waitForIdle();
  56         robot.delay(200);
  57 
  58         SwingUtilities.invokeAndWait(() -> {
  59             Insets insets = scroll.getInsets();
  60             scroll.setSize(insets.left + insets.right +
  61                     scroll.getVerticalScrollBar().getPreferredSize().width, 50);
  62             scroll.revalidate();
  63         });
  64         robot.delay(200);
  65         SwingUtilities.invokeAndWait(() ->
  66                           scroll.getViewport().addChangeListener((e) -> cnt++));
  67         robot.delay(1000);
  68 
  69         SwingUtilities.invokeLater(frame::dispose);
  70 
  71         if (cnt > 0) {
  72             throw new RuntimeException("Scroll bar flickers");
  73         }
  74     }
  75 }