8024767: [TEST] need test to cover JDK-7189452

Reviewed-by: ceisserer, bae
Contributed-by: alexander.v.stepanov@oracle.com

test/java/awt/Graphics2D/DrawString/TextRenderingTest.java

+/*
+ * Copyright (c) 2013, 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.Color;
+import java.awt.Graphics2D;
+import java.awt.GraphicsConfiguration;
+import java.awt.GraphicsEnvironment;
+import java.awt.GradientPaint;
+import java.awt.geom.Point2D;
+
+import java.awt.Font;
+
+import java.awt.image.BufferedImage;
+import java.awt.image.VolatileImage;
+
+
+/*
+ * @test
+ * @bug 7189452 8024767
+ * @summary Check if source offset for text rendering is handled correctly
+ *          (shouldn't see the text on a similarly colored background).
+ * @author a.stepanov
+ * @run main TextRenderingTest
+ */
+
+public class TextRenderingTest {
+
+    private static final int width  = 450;
+    private static final int height = 150;
+
+    public static void main(final String[] args) {
+
+        GraphicsEnvironment ge =
+            GraphicsEnvironment.getLocalGraphicsEnvironment();
+        GraphicsConfiguration gc =
+            ge.getDefaultScreenDevice().getDefaultConfiguration();
+        VolatileImage vi = gc.createCompatibleVolatileImage(width, height);
+
+        while (true) {
+            vi.validate(gc);
+            Graphics2D g2d = vi.createGraphics();
+            g2d.setColor(Color.white);
+            g2d.fillRect(0, 0, width, height);
+
+            g2d.setPaint(new GradientPaint(
+                             new Point2D.Float(0, height / 2), Color.white,
+                             new Point2D.Float(width, height / 2), Color.black));
+            g2d.fillRect(0, 0, width, height);
+
+            String fnt = g2d.getFont().getFamily();
+            g2d.setFont(new Font(fnt, Font.PLAIN, 100));
+            g2d.drawString("IIIIIIIIII", 100, 100); // draw text with offset
+
+            g2d.dispose();
+
+            if (vi.validate(gc) != VolatileImage.IMAGE_OK) {
+                try {
+                    Thread.sleep(100);
+                } catch (InterruptedException e) {}
+                continue;
+            }
+
+            if (vi.contentsLost()) {
+                try {
+                    Thread.sleep(100);
+                } catch (InterruptedException e) {}
+                continue;
+            }
+
+            break;
+        }
+
+        BufferedImage bi = vi.getSnapshot();
+
+        // the text shifted shouldn't be visible onto a painted rectangle!
+        // so the check: color component (blue) must decrease monotonously
+
+        int prev = Integer.MAX_VALUE;
+        for (int x = 0; x < width; ++x) {
+            int color = bi.getRGB(x, height / 2);
+            int b = color & 0xFF;
+
+            if (b > prev) {
+                throw new RuntimeException("test failed: can see the text rendered!");
+            }
+
+            prev = b;
+        }
+    }
+}