src/share/classes/sun/awt/image/SurfaceManager.java

*** 29,38 ****
--- 29,39 ----
  import java.awt.GraphicsEnvironment;
  import java.awt.GraphicsConfiguration;
  import java.awt.Image;
  import java.awt.ImageCapabilities;
  import java.awt.image.BufferedImage;
+ import java.awt.image.VolatileImage;
  import java.util.concurrent.ConcurrentHashMap;
  import java.util.Iterator;
  import sun.java2d.SurfaceData;
  import sun.java2d.SurfaceDataProxy;
  import sun.java2d.loops.CompositeType;
*** 285,290 ****
--- 286,305 ----
      public void setAccelerationPriority(float priority) {
          if (priority == 0.0f) {
              flush(true);
          }
      }
+ 
+     /**
+      * Returns a scale factor of the image. This is utility method, which
+      * fetches information from the SurfaceData of the image.
+      *
+      * @see SurfaceData#getDefaultScale
+      */
+     public static int getImageScale(final Image img) {
+         if (!(img instanceof VolatileImage)) {
+             return 1;
+         }
+         final SurfaceManager sm = getManager(img);
+         return sm.getPrimarySurfaceData().getDefaultScale();
+     }
  }