anchor.diff:      int count = 0;
       for (int i = _lowerIndex; i <= _upperIndex; i++) {
         final Color color = colors[i];
  -      count += histogram[color];
  +      count += histogram[color].value;
         if (color.red > maxRed) {
           maxRed = color.red;
         }
  
positive.code:       // the colors.
        _paletteColors.clear();
        for (Color color in hist.keys) {
          _paletteColors.add(PaletteColor(color, hist[color]));
        }
      } else {
        // We need use quantization to reduce the number of colors
  
negative.code: // found in the LICENSE file.
  
  import 'dart:async';
  import 'dart:collection';
  import 'dart:math' as math;
  import 'dart:typed_data';
  import 'dart:ui' as ui;
  