anchor.diff:      }
     }
   
  -  static bool __debug = false;
  -
     /**
      * Inverse prediction.
      */
  
positive.code:   // 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]);
    }
  
  
negative.code:     final int mask = (1 << bits) - 1;
      final int tilesPerRow = VP8L._subSampleSize(width, bits);
      int predModeBase = (y >> bits) * tilesPerRow; //this.data +
  
      while (y < yEnd) {
        final int pred2 = _predictor2(outData, outData[data - 1], data - width);
  