src/java.desktop/share/classes/sun/java2d/marlin/MarlinTileGenerator.java

*** 29,44 ****
  import sun.java2d.pipe.AATileGenerator;
  import jdk.internal.misc.Unsafe;
  
  final class MarlinTileGenerator implements AATileGenerator, MarlinConst {
  
      private static final int MAX_TILE_ALPHA_SUM = TILE_W * TILE_H * MAX_AA_ALPHA;
  
      private static final int TH_AA_ALPHA_FILL_EMPTY = ((MAX_AA_ALPHA + 1) / 3); // 33%
      private static final int TH_AA_ALPHA_FILL_FULL  = ((MAX_AA_ALPHA + 1) * 2 / 3); // 66%
  
!     private static final int FILL_TILE_W = TILE_W >> 1; // half tile width
  
      static {
          if (MAX_TILE_ALPHA_SUM <= 0) {
              throw new IllegalStateException("Invalid MAX_TILE_ALPHA_SUM: " + MAX_TILE_ALPHA_SUM);
          }
--- 29,46 ----
  import sun.java2d.pipe.AATileGenerator;
  import jdk.internal.misc.Unsafe;
  
  final class MarlinTileGenerator implements AATileGenerator, MarlinConst {
  
+     private static final boolean DISABLE_BLEND = false;
+ 
      private static final int MAX_TILE_ALPHA_SUM = TILE_W * TILE_H * MAX_AA_ALPHA;
  
      private static final int TH_AA_ALPHA_FILL_EMPTY = ((MAX_AA_ALPHA + 1) / 3); // 33%
      private static final int TH_AA_ALPHA_FILL_FULL  = ((MAX_AA_ALPHA + 1) * 2 / 3); // 66%
  
!     private static final int FILL_TILE_W = Math.max(16, TILE_W >> 2); // 1/4th tile width
  
      static {
          if (MAX_TILE_ALPHA_SUM <= 0) {
              throw new IllegalStateException("Invalid MAX_TILE_ALPHA_SUM: " + MAX_TILE_ALPHA_SUM);
          }
*** 139,148 ****
--- 141,154 ----
       * @return 0x00 for no coverage, 0xff for total coverage, or any other
       *         value for partial coverage of the tile
       */
      @Override
      public int getTypicalAlpha() {
+         if (DISABLE_BLEND) {
+             // always return empty tiles to disable blending operations
+             return 0x00;
+         }
          int al = cache.alphaSumInTile(x);
          // Note: if we have a filled rectangle that doesn't end on a tile
          // border, we could still return 0xff, even though al!=maxTileAlphaSum
          // This is because if we return 0xff, our users will fill a rectangle
          // starting at x,y that has width = Math.min(TILE_SIZE, bboxX1-x),