src/java.desktop/share/classes/sun/java2d/pipe/DrawImage.java

*** 1,7 ****
  /*
!  * Copyright (c) 2001, 2014, 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.  Oracle designates this
--- 1,7 ----
  /*
!  * Copyright (c) 2001, 2015, 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.  Oracle designates this
*** 952,961 ****
--- 952,967 ----
               (bgColor != null &&
                bgColor.getTransparency() == Transparency.OPAQUE)))
          {
              comp = CompositeType.SrcNoEa;
          }
+         if (srcData == dstData && sx == dx && sy == dy
+                 && CompositeType.SrcNoEa.equals(comp)) {
+             // Performance optimization. We skip the Blit/BlitBG if we know that
+             // it will be noop.
+             return;
+         }
          if (!isBgOperation(srcData, bgColor)) {
              Blit blit = Blit.getFromCache(srcType, comp, dstType);
              blit.Blit(srcData, dstData, sg.composite, clipRegion,
                        sx, sy, dx, dy, w, h);
          } else {