Newbie Questions on dataViewMappings and ColorHelper

Hi jonnyglass 

You may refer to this blog to get more details about ColorHelper : ColorHelper Class

For more details about data view mapping, you can refer to this code: PowerBI-visuals

 public static customizeQuery(options: CustomizeQueryOptions): void {
            var dataViewMapping = options.dataViewMappings[0];
            if (!dataViewMapping || !dataViewMapping.categorical || !dataViewMapping.categorical.categories)
                return;

            if (options.preferHigherDataVolume) {
                dataViewMapping.categorical.dataVolume = 4;
            }

            var dataViewCategories = <data.CompiledDataViewRoleForMappingWithReduction>dataViewMapping.categorical.categories;
            var categoryItems = dataViewCategories.for.in.items;
            if (!ArrayExtensions.isUndefinedOrEmpty(categoryItems)) {
                var categoryType = categoryItems[0].type;

                var objects: DataViewObjects;
                if (dataViewMapping.metadata)
                    objects = dataViewMapping.metadata.objects;

                if (CartesianChart.getIsScalar(objects, columnChartProps.categoryAxis.axisType, categoryType))
                    dataViewCategories.dataReductionAlgorithm = { sample: {} };
            }
        }

Best Regards,

Rico Zhou

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