en/builder/src/echarts3/visual/dataColor.js

// Pick color from palette for each data item.
// Applicable for charts that require applying color palette
// in data level (like pie, funnel, chord).
export default function (seriesType, ecModel) {
  // Pie and funnel may use diferrent scope
  var paletteScope = {};
  ecModel.eachRawSeriesByType(seriesType, function (seriesModel) {
    var dataAll = seriesModel.getRawData();
    var idxMap = {};

    if (!ecModel.isSeriesFiltered(seriesModel)) {
      var data = seriesModel.getData();
      data.each(function (idx) {
        var rawIdx = data.getRawIndex(idx);
        idxMap[rawIdx] = idx;
      });
      dataAll.each(function (rawIdx) {
        var filteredIdx = idxMap[rawIdx]; // If series.itemStyle.normal.color is a function. itemVisual may be encoded

        var singleDataColor = filteredIdx != null && data.getItemVisual(filteredIdx, 'color', true);

        if (!singleDataColor) {
          // FIXME Performance
          var itemModel = dataAll.getItemModel(rawIdx);
          var color = itemModel.get('itemStyle.normal.color') || seriesModel.getColorFromPalette(dataAll.getName(rawIdx), paletteScope); // Legend may use the visual info in data before processed

          dataAll.setItemVisual(rawIdx, 'color', color); // Data is not filtered

          if (filteredIdx != null) {
            data.setItemVisual(filteredIdx, 'color', color);
          }
        } else {
          // Set data all color for legend
          dataAll.setItemVisual(rawIdx, 'color', singleDataColor);
        }
      });
    }
  });
}