8139183: drawImage misses background's alpha channel
Reviewed-by: flar, psadhukhan
--- a/jdk/src/java.desktop/share/classes/sun/java2d/pipe/DrawImage.java Wed Mar 09 14:23:20 2016 +0300
+++ b/jdk/src/java.desktop/share/classes/sun/java2d/pipe/DrawImage.java Thu Mar 10 14:14:28 2016 +0530
@@ -340,8 +340,8 @@
* <li> Image will be used only once and acceleration caching wouldn't help
* </ul>
*/
- BufferedImage makeBufferedImage(Image img, Color bgColor, int type,
- int sx1, int sy1, int sx2, int sy2)
+ private BufferedImage makeBufferedImage(Image img, Color bgColor, int type,
+ int sx1, int sy1, int sx2, int sy2)
{
final int width = sx2 - sx1;
final int height = sy2 - sy1;
@@ -430,10 +430,16 @@
if (isBgOperation(srcData, bgColor)) {
// We cannot perform bg operations during transform so make
- // an opaque temp image with the appropriate background
- // and work from there.
- img = makeBufferedImage(img, bgColor, BufferedImage.TYPE_INT_RGB,
- sx1, sy1, sx2, sy2);
+ // a temp image with the appropriate background based on
+ // background alpha value and work from there. If background
+ // alpha is opaque use INT_RGB else use INT_ARGB so that we
+ // will not lose translucency of background.
+
+ int bgAlpha = bgColor.getAlpha();
+ int type = ((bgAlpha == 255)
+ ? BufferedImage.TYPE_INT_RGB
+ : BufferedImage.TYPE_INT_ARGB);
+ img = makeBufferedImage(img, bgColor, type, sx1, sy1, sx2, sy2);
// Temp image has appropriate subimage at 0,0 now.
sx2 -= sx1;
sy2 -= sy1;
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/test/java/awt/image/DrawImage/ScaledImageAlphaTest.java Thu Mar 10 14:14:28 2016 +0530
@@ -0,0 +1,154 @@
+/*
+ * Copyright (c) 2016, 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
+ * @bug 8139183
+ * @summary Test verifies whether alpha channel of a translucent
+ * image is proper or not after scaling through drawImage.
+ * @run main ScaledImageAlphaTest
+ */
+
+import java.awt.AlphaComposite;
+import java.awt.Color;
+import java.awt.Graphics2D;
+import java.awt.GraphicsConfiguration;
+import java.awt.GraphicsEnvironment;
+import java.awt.Transparency;
+import java.awt.image.BufferedImage;
+import java.awt.image.VolatileImage;
+
+public class ScaledImageAlphaTest {
+
+ static final int translucentAlpha = 128, opaqueAlpha = 255;
+ static final int[] translucentVariants = new int[] {
+ BufferedImage.TYPE_INT_ARGB,
+ BufferedImage.TYPE_INT_ARGB_PRE,
+ BufferedImage.TYPE_4BYTE_ABGR,
+ BufferedImage.TYPE_4BYTE_ABGR_PRE
+ };
+ static final int[] alphaValues = new int[] {
+ translucentAlpha,
+ opaqueAlpha
+ };
+ static int width = 50, height = 50;
+ static int scaleX = 5, scaleY = 5, scaleWidth = 40, scaleHeight = 40;
+
+ private static void verifyAlpha(Color color, int alpha) {
+
+ /* if extracted alpha value is equal alpha that we set
+ * for background color, alpha channel is not lost
+ * while scaling otherwise we have lost alpha channel.
+ */
+ int extractedAlpha = color.getAlpha();
+
+ if (extractedAlpha != alpha) {
+ throw new RuntimeException("Alpha channel for background"
+ + " is lost while scaling");
+ }
+ }
+
+ private static void validateBufferedImageAlpha() {
+
+ Color backgroundColor, extractedColor;
+ // verify for all translucent buffered image types
+ for (int type : translucentVariants) {
+ // verify for both opaque and translucent background color
+ for (int alpha : alphaValues) {
+ // create BufferedImage of dimension (50,50)
+ BufferedImage img = new
+ BufferedImage(width, height, type);
+ Graphics2D imgGraphics = (Graphics2D)img.getGraphics();
+ /* scale image to smaller dimension and set any
+ * background color with alpha.
+ */
+ backgroundColor = new Color(0, 255, 0, alpha);
+ imgGraphics.
+ drawImage(img, scaleX, scaleY, scaleWidth, scaleHeight,
+ backgroundColor, null);
+ imgGraphics.dispose();
+
+ /* get pixel information for background color with
+ * scaled coordinates.
+ */
+ extractedColor = new Color(img.getRGB(scaleX, scaleY), true);
+ verifyAlpha(extractedColor, alpha);
+ }
+ }
+ }
+
+ private static void validateVolatileImageAlpha() {
+
+ Color backgroundColor, extractedColor;
+ VolatileImage img;
+ BufferedImage bufImg = new
+ BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);
+ for (int alpha : alphaValues) {
+ backgroundColor = new Color(0, 255, 0, alpha);
+ do {
+ img = createVolatileImage(width, height,
+ Transparency.TRANSLUCENT);
+ Graphics2D imgGraphics = (Graphics2D)img.getGraphics();
+ // clear VolatileImage as by default it has white opaque image
+ imgGraphics.setComposite(AlphaComposite.Clear);
+ imgGraphics.fillRect(0,0, width, height);
+
+ imgGraphics.setComposite(AlphaComposite.SrcOver);
+ /* scale image to smaller dimension and set background color
+ * to green with translucent alpha.
+ */
+ imgGraphics.
+ drawImage(img, scaleX, scaleY, scaleWidth, scaleHeight,
+ backgroundColor, null);
+ //get BufferedImage out of VolatileImage
+ bufImg = img.getSnapshot();
+ imgGraphics.dispose();
+ } while (img.contentsLost());
+
+ /* get pixel information for background color with
+ * scaled coordinates.
+ */
+ extractedColor = new Color(bufImg.getRGB(scaleX, scaleY), true);
+ verifyAlpha(extractedColor, alpha);
+ }
+ }
+
+ private static VolatileImage createVolatileImage(int width, int height,
+ int transparency) {
+ GraphicsEnvironment ge = GraphicsEnvironment.
+ getLocalGraphicsEnvironment();
+ GraphicsConfiguration gc = ge.getDefaultScreenDevice().
+ getDefaultConfiguration();
+
+ VolatileImage image = gc.createCompatibleVolatileImage(width, height,
+ transparency);
+ return image;
+ }
+
+ public static void main(String[] args) {
+ // test alpha channel with different types of BufferedImage
+ validateBufferedImageAlpha();
+ // test alpha channel with VolatileImage
+ validateVolatileImageAlpha();
+ }
+}