anchor.diff:    // Predictors
   
     static int _predictor0(Data.Uint32List pixels, int left, int top) {
  -    if (__debug) {
  -      print('PRED0');
  -    }
       return VP8L.ARGB_BLACK;
     }
   
     static int _predictor1(Data.Uint32List pixels, int left, int top) {
  -    if (__debug) {
  -      print('PRED1 $left');
  -    }
       return left;
     }
   
     static int _predictor2(Data.Uint32List pixels, int left, int top) {
  -    if (__debug) {
  -          print('PRED2');
  -        }
       return pixels[top];
     }
   
     static int _predictor3(Data.Uint32List pixels, int left, int top) {
  -    if (__debug) {
  -          print('PRED3');
  -        }
       return pixels[top + 1];
     }
   
     static int _predictor4(Data.Uint32List pixels, int left, int top) {
  -    if (__debug) {
  -          print('PRED4');
  -        }
       return pixels[top -1];
     }
   
     static int _predictor5(Data.Uint32List pixels, int left, int top) {
  -    if (__debug) {
  -          print('PRED5');
  -        }
       return _average3(left, pixels[top], pixels[top + 1]);
     }
   
     static int _predictor6(Data.Uint32List pixels, int left, int top) {
  -    if (__debug) {
  -          print('PRED6');
  -        }
       return _average2(left, pixels[top - 1]);
     }
   
     static int _predictor7(Data.Uint32List pixels, int left, int top) {
  -    if (__debug) {
  -          print('PRED7');
  -        }
       return _average2(left, pixels[top]);
     }
   
     static int _predictor8(Data.Uint32List pixels, int left, int top) {
  -    if (__debug) {
  -          print('PRED8');
  -        }
       return _average2(pixels[top -1], pixels[top]);
     }
   
     static int _predictor9(Data.Uint32List pixels, int left, int top) {
  -    if (__debug) {
  -          print('PRED9');
  -        }
       return _average2(pixels[top], pixels[top + 1]);
     }
   
     static int _predictor10(Data.Uint32List pixels, int left, int top) {
  -    if (__debug) {
  -          print('PRED10');
  -        }
       return _average4(left, pixels[top -1], pixels[top], pixels[top + 1]);
     }
   
     static int _predictor11(Data.Uint32List pixels, int left, int top) {
  -    if (__debug) {
  -          print('PRED11');
  -        }
       return _select(pixels[top], left, pixels[top - 1]);
     }
   
     static int _predictor12(Data.Uint32List pixels, int left, int top) {
  -    if (__debug) {
  -          print('PRED12');
  -        }
       return _clampedAddSubtractFull(left, pixels[top], pixels[top - 1]);
     }
   
     static int _predictor13(Data.Uint32List pixels, int left, int top) {
  -    if (__debug) {
  -          print('PRED13');
  -        }
       return _clampedAddSubtractHalf(left, pixels[top], pixels[top - 1]);
     }
   
  
positive.code:   }
  
    static int _clampedAddSubtractFull(int c0, int c1, int c2) {
      //if (__debug) print('_clampedAddSubtractFull $c0 $c1 $c2');
      final int a = _addSubtractComponentFull(c0 >> 24, c1 >> 24, c2 >> 24);
      final int r = _addSubtractComponentFull((c0 >> 16) & 0xff,
          (c1 >> 16) & 0xff,
  
negative.code:     }
      // return 0, when a is a negative integer.
      // return 255, when a is positive.
      return _int32ToUint32((-a - 1)) >> 24;
    }
  
    static int _addSubtractComponentFull(int a, int b, int c) {
  