8139178: Wrong fontMetrics when printing in Landscape (OpenJDK)

Reviewed-by: prr
Contributed-by: alvdavi@amazon.com

src/share/native/sun/font/freetypeScaler.c

@@ -562,6 +562,14 @@ Java_sun_font_FreetypeFontScaler_getFontMetricsNative(
     /* See https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=657854 */
 #define FT_MulFixFloatShift6(a, b) (((float) (a)) * ((float) (b)) / 65536.0 / 64.0)
 
+#define contextAwareMetricsX(x, y) \
+    (FTFixedToFloat(context->transform.xx) * (x) - \
+     FTFixedToFloat(context->transform.xy) * (y))
+
+#define contextAwareMetricsY(x, y) \
+    (-FTFixedToFloat(context->transform.yx) * (x) + \
+     FTFixedToFloat(context->transform.yy) * (y))
+
     /*
      * See FreeType source code: src/base/ftobjs.c ft_recompute_scaled_metrics()
      * http://icedtea.classpath.org/bugzilla/show_bug.cgi?id=1659
@@ -596,7 +604,11 @@ Java_sun_font_FreetypeFontScaler_getFontMetricsNative(
     metrics = (*env)->NewObject(env,
         sunFontIDs.strikeMetricsClass,
         sunFontIDs.strikeMetricsCtr,
-                                ax, ay, dx, dy, bx, by, lx, ly, mx, my);
+        contextAwareMetricsX(ax, ay), contextAwareMetricsY(ax, ay),
+        contextAwareMetricsX(dx, dy), contextAwareMetricsY(dx, dy),
+        bx, by,
+        contextAwareMetricsX(lx, ly), contextAwareMetricsY(lx, ly),
+        contextAwareMetricsX(mx, my), contextAwareMetricsY(mx, my));
 
     return metrics;
 }

test/java/awt/font/Rotate/RotatedFontMetricsTest.java

+/*
+ * Copyright (c) 2018, 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.
+ */
+
+/*
+ * @test    RotatedFontMetricsTest
+ * @bug     8139178
+ * @summary This test verifies that rotation does not affect font metrics.
+ * @run     main RotatedFontMetricsTest
+ */
+
+import java.awt.Font;
+import java.awt.FontMetrics;
+import java.awt.Graphics2D;
+import java.awt.image.BufferedImage;
+
+public class RotatedFontMetricsTest {
+    static final int FONT_SIZE = Integer.getInteger("font.size", 20);
+
+    public static void main(String ... args) {
+        Font font = new Font(Font.DIALOG, Font.PLAIN, FONT_SIZE);
+        Graphics2D g2d = createGraphics();
+
+        FontMetrics ref = null;
+        RuntimeException failure = null;
+        for (int a = 0; a < 360; a += 15) {
+            Graphics2D g = (Graphics2D)g2d.create();
+            g.rotate(Math.toRadians(a));
+            FontMetrics m = g.getFontMetrics(font);
+            g.dispose();
+
+            boolean status = true;
+            if (ref == null) {
+                ref = m;
+            } else {
+                status = ref.getAscent() == m.getAscent() &&
+                        ref.getDescent() == m.getDescent() &&
+                        ref.getLeading() == m.getLeading() &&
+                        ref.getMaxAdvance() == m.getMaxAdvance();
+            }
+
+            System.out.printf("Metrics a%d, d%d, l%d, m%d (%d) %s\n",
+                    m.getAscent(), m.getDescent(), m.getLeading(), m.getMaxAdvance(),
+                    (int)a, status ? "OK" : "FAIL");
+
+            if (!status && failure == null) {
+                failure = new RuntimeException("Font metrics differ for angle " + a);
+            }
+        }
+        if (failure != null) {
+            throw failure;
+        }
+        System.out.println("done");
+    }
+
+    private static Graphics2D createGraphics() {
+        BufferedImage dst = new BufferedImage(100, 100, BufferedImage.TYPE_INT_RGB);
+        return dst.createGraphics();
+    }
+}