cl-react-graph/src/components/Bars/barHelper.ts

React D3 Charts

import { ScaleBand, ScaleLinear } from "d3-scale";

import { SpringConfig } from "@react-spring/web";

import { EChartDirection } from "../../BarChart";
import {
  BarChartDataSet,
  EGroupedBarLayout,
  HistogramBar,
} from "../../Histogram";
import { ColorScheme, getFill } from "../../utils/colorScheme";
import { ExtendedGroupItem } from "./Bars";

/**
 * Calculate the bar's band position based in the axis layout type.
 * This is the offset applied depending on the group layout setting.
 * x for vertical
 * y for horizontal
 */
const getBandPosition = (
  item: ExtendedGroupItem,
  props: BarSpringProps,
  itemWidths: number[],
) => {
  const { innerScaleBand, innerDomain, groupLayout, paddings } = props;
  const groupLabel = item.groupLabel ?? "main";
  let bandX = 0;
  switch (groupLayout) {
    case EGroupedBarLayout.OVERLAID:
      // Move to the right for each subsequent dataset to reveal the previous dataset's bars.
      const overlaidOffset =
        item.datasetIndex === 0
          ? 0
          : Math.floor(
              (itemWidths[item.datasetIndex - 1] -
                itemWidths[item.datasetIndex]) /
                2,
            );

      bandX = Number(innerScaleBand(String(innerDomain[0]))) + overlaidOffset;
      break;
    case EGroupedBarLayout.STACKED:
      // Each bar will be on top of the other, so they should all have the same starting x value
      bandX = Number(innerScaleBand(String(innerDomain[0])));
      break;
    case EGroupedBarLayout.GROUPED:
      // Position bars next to each other using the x axis inner scale band
      bandX = Number(innerScaleBand(String(groupLabel)));
      break;
  }

  return bandX;
};

export type BarSpringProps = {
  values: BarChartDataSet[];
  height: number;
  width: number;
  dataSets: ExtendedGroupItem[];
  numericScale: ScaleLinear<any, any>;
  bandScale: ScaleBand<string>;
  colorScheme: ColorScheme;
  hoverColorScheme?: readonly string[];
  innerDomain: string[];
  innerScaleBand: ScaleBand<string>;
  groupLayout: EGroupedBarLayout;
  paddings: HistogramBar;
  config: SpringConfig;
  direction: EChartDirection;
  /** @description - inverse the bars e.g if direction = horizontal run the bars from right to left */
  inverse?: boolean;
  itemWidths: number[];
};
/**
 * Build the from / to spring animation properties to animate the bars.
 */
export const buildBarSprings = (props: BarSpringProps) => {
  const {
    direction,
    config,
    height,
    dataSets,
    numericScale,
    bandScale,
    colorScheme,
    hoverColorScheme,
    inverse = false,
    itemWidths,
  } = props;
  const [_, width] = numericScale.range();

  const s = dataSets.map((item) => {
    const bandValue = Number(bandScale(item.label));
    const bandPosition = getBandPosition(item, props, itemWidths);
    const valueOffset = getValueOffset(item, props);
    const itemWidth = itemWidths[item.datasetIndex];
    const itemHeight = numericScale(item.value);
    const hoverFill = getFill(
      hoverColorScheme
        ? hoverColorScheme[item.datasetIndex]
        : colorScheme[item.datasetIndex],
    );
    const fill = getFill(colorScheme[item.datasetIndex]);
    if (direction === EChartDirection.HORIZONTAL) {
      return {
        from: {
          width: 0,
          fill,
          hoverFill,
          x: inverse ? width : 0,
          y: bandPosition + bandValue,
          height: itemWidth,
        },
        to: {
          width: itemHeight,
          fill,
          hoverFill,
          x: inverse ? width - itemHeight - valueOffset : valueOffset,
          y: bandPosition + bandValue,
          height: itemWidth,
        },
        config,
      };
    }
    return {
      from: {
        height: 0,
        fill,
        hoverFill,
        x: bandPosition + bandValue,
        y: inverse ? 0 : height,
        width: itemWidth,
      },
      to: {
        height: itemHeight,
        fill,
        hoverFill,
        x: bandPosition + bandValue,
        y: inverse ? 0 : valueOffset,
        width: itemWidth,
      },
      config,
    };
  });
  return s;
};

/**
 * If we are using a STACKED group layout the work out the total height
 * of the bars which should be stacked under the current item.
 * This should provide us with the finishing location for the bar's y position.
 */
export const getValueOffset = (
  item: ExtendedGroupItem,
  props: BarSpringProps,
) => {
  const { direction, numericScale, groupLayout, height, dataSets } = props;
  const offSet = dataSets
    .filter((d) => d.label === item.label)
    .filter((_, i) =>
      direction === EChartDirection.HORIZONTAL
        ? i < item.datasetIndex
        : i <= item.datasetIndex,
    )
    .reduce((p, n) => p + n.value, 0);

  if (direction === EChartDirection.HORIZONTAL) {
    if (groupLayout !== EGroupedBarLayout.STACKED) {
      return 0;
    }
    return numericScale(offSet);
  }

  if (groupLayout !== EGroupedBarLayout.STACKED) {
    return height - numericScale(item.value);
  }

  return height - numericScale(offSet);
};