8239502: [TEST_BUG] Test javax/swing/text/FlowView/6318524/bug6318524…

….java never fails

Backport-of: b7425b63f6b69ba8709664377b4e037176ab6139

test/jdk/javax/swing/text/FlowView/6318524/bug6318524.java

@@ -0,0 +1,194 @@
+/*
+ * Copyright (c) 2005, 2021, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+import java.awt.Dimension;
+import java.awt.FontMetrics;
+import java.awt.Graphics;
+import java.awt.Rectangle;
+import java.awt.Shape;
+import java.awt.image.BufferedImage;
+import java.io.File;
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.List;
+import javax.imageio.ImageIO;
+import javax.swing.JFrame;
+import javax.swing.JTextPane;
+import javax.swing.SwingUtilities;
+import javax.swing.text.BadLocationException;
+import javax.swing.text.Caret;
+import javax.swing.text.Document;
+import javax.swing.text.Position;
+import javax.swing.text.SimpleAttributeSet;
+import javax.swing.text.StyleConstants;
+import javax.swing.text.View;
+
+import static java.awt.image.BufferedImage.TYPE_INT_RGB;
+
+/*
+ * @test
+ * @bug 6318524 8239502
+ * @summary Tests that children of ParagraphView do not mess up their parents
+ * @run main bug6318524
+ */
+/*
+ * Test parameters:
+ * -show: Show frame for visual inspection
+ * -save: Save the start image after the first paragraph is justified,
+ *        and the last image before it's checked that the first paragraph
+ *        remains justified
+ * -saveAll: Save images for all the intermediate steps
+ */
+public class bug6318524 {
+    private static final String LONG_WORD = "consequences";
+    private static final String TEXT = "Justified: "
+            + LONG_WORD + " " + LONG_WORD;
+    private static final int REPEAT_COUNT = 18;
+
+    private static JTextPane textPane;
+    private static Dimension bounds;
+
+    private static int step = 0;
+
+    private static Shape firstLineEndsAt;
+
+    public static void main(String[] args) throws Throwable {
+        List<String> argList = Arrays.asList(args);
+
+        // Show frame for visual inspection
+        final boolean showFrame = argList.contains("-show");
+        // Save images for all the intermediate steps
+        final boolean saveAllImages = argList.contains("-saveAll");
+        // Save the start and last image only
+        final boolean saveImage = saveAllImages || argList.contains("-save");
+
+        SwingUtilities.invokeAndWait(() -> {
+            createUI(showFrame);
+            paintToImage(step++, saveAllImages);
+            makeLineJustified();
+            paintToImage(step++, saveImage);
+
+            firstLineEndsAt = getEndOfFirstLine();
+
+            moveCursorToStart();
+            pressEnter(saveAllImages);
+
+            paintToImage(step++, saveImage);
+            checkLineJustified();
+        });
+    }
+
+    private static void createUI(boolean showFrame) {
+        textPane = new JTextPane();
+        textPane.setText(TEXT);
+
+        FontMetrics fm = textPane.getFontMetrics(textPane.getFont());
+        int textWidth = fm.stringWidth(LONG_WORD);
+        int textHeight = fm.getHeight();
+        bounds = new Dimension(2 * textWidth,
+                               (REPEAT_COUNT + 3) * textHeight);
+        textPane.setPreferredSize(bounds);
+        textPane.setSize(bounds);
+
+        if (showFrame) {
+            JFrame frame = new JFrame("bug6318524");
+            frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
+
+            frame.getContentPane().add(textPane);
+
+            frame.pack();
+            frame.setLocationRelativeTo(null);
+            frame.setVisible(true);
+        }
+    }
+
+    private static void makeLineJustified() {
+        SimpleAttributeSet sas = new SimpleAttributeSet();
+        StyleConstants.setAlignment(sas, StyleConstants.ALIGN_JUSTIFIED);
+        textPane.setParagraphAttributes(sas, false);
+    }
+
+    private static void moveCursorToStart() {
+        // Move cursor to the beginning
+        Caret caret = textPane.getCaret();
+        caret.setDot(0);
+    }
+
+    private static void pressEnter(boolean saveImages) {
+        Document doc = textPane.getDocument();
+        try {
+            for (int i = 0; i < REPEAT_COUNT; i++) {
+                // Add a new paragraph at the beginning
+                doc.insertString(0, "\n", null);
+                // Paint the textPane after each change
+                paintToImage(step++, saveImages);
+            }
+        } catch (BadLocationException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    private static void checkLineJustified() {
+        Shape newPosition = getEndOfFirstLine();
+        if (((Rectangle) firstLineEndsAt).x != ((Rectangle) newPosition).x) {
+            System.err.println("Old: " + firstLineEndsAt);
+            System.err.println("New: " + newPosition);
+            throw new RuntimeException("The first line of the paragraph is not justified");
+        }
+    }
+
+    private static Shape getEndOfFirstLine() {
+        try {
+            final View rootView = textPane.getUI().getRootView(textPane);
+            final View boxView = rootView.getView(0);
+            final View paragraphView = boxView.getView(boxView.getViewCount() - 1);
+            assert paragraphView.getViewCount() == 2;
+            final View rowView = paragraphView.getView(0);
+            return rowView.getView(0)
+                          .modelToView(rowView.getEndOffset() - 1,
+                                       textPane.getBounds(),
+                                       Position.Bias.Backward);
+        } catch (BadLocationException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    private static void paintToImage(final int step, boolean saveImage) {
+        BufferedImage im = new BufferedImage(bounds.width, bounds.height,
+                TYPE_INT_RGB);
+        Graphics g = im.getGraphics();
+        textPane.paint(g);
+        g.dispose();
+        if (saveImage) {
+            saveImage(im, String.format("%02d.png", step));
+        }
+    }
+
+    private static void saveImage(BufferedImage image, String fileName) {
+        try {
+            ImageIO.write(image, "png", new File(fileName));
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
+    }
+}