Title

How to set a single column color in a bar chart?

Description

How do I set the color of a specific column independently?

Solution

Different chart libraries have different solutions. VChart allows users to control styles through callback functions, including color, stroke, and other style configurations.
Bar charts can control colors by configuring bar.style.fill.
fill supports callback functions, which can modify the style of a certain column through datum, and other data can get the original grouped colors through the seriesColor interface.

Code Example

import { StrictMode, useEffect } from "react";
import { createRoot } from "react-dom/client";

const rootElement = document.getElementById("root");
const root = createRoot(rootElement);

import VChart from "@visactor/vchart";

const App = () => {
  useEffect(() => {
    const spec = {
      type: "bar",
      data: [
        {
          id: "barData",
          values: [
            { type: "Autocracies", year: "1930", value: 129 },
            { type: "Autocracies", year: "1940", value: 133 },
            { type: "Autocracies", year: "1950", value: 130 },
            { type: "Autocracies", year: "1960", value: 126 },
            { type: "Autocracies", year: "1970", value: 117 },
            { type: "Autocracies", year: "1980", value: 114 },
            { type: "Autocracies", year: "1990", value: 111 },
            { type: "Autocracies", year: "2000", value: 89 },
            { type: "Autocracies", year: "2010", value: 80 },
            { type: "Autocracies", year: "2018", value: 80 },
            { type: "Democracies", year: "1930", value: 22 },
            { type: "Democracies", year: "1940", value: 13 },
            { type: "Democracies", year: "1950", value: 25 },
            { type: "Democracies", year: "1960", value: 29 },
            { type: "Democracies", year: "1970", value: 38 },
            { type: "Democracies", year: "1980", value: 41 },
            { type: "Democracies", year: "1990", value: 57 },
            { type: "Democracies", year: "2000", value: 87 },
            { type: "Democracies", year: "2010", value: 98 },
            { type: "Democracies", year: "2018", value: 99 },
          ],
        },
      ],
      xField: ["year", "type"],
      yField: "value",
      seriesField: "type",
      bar: {
        style: {
          fill: (datum, chart) => {
            if (datum["year"] === "2000") {
              return "red";
            }
            // origin color
            return chart.seriesColor(datum["type"]);
          },
        },
      },
      legends: {
        visible: true,
        orient: "top",
        position: "start",
      },
    };

    const vchart = new VChart(spec, { dom: "chart" });
    vchart.renderSync();

    return () => {
      vchart.release();
    };
  }, []);

  return <div id="chart" style={{ width: 400 }}></div>;
};

root.render(
  <StrictMode>
    <App />
  </StrictMode>
);
</br>

Result

Online Demo: https://codesandbox.io/p/sandbox/vchart-single-bar-style-n9m6np?file=%2Fsrc%2Findex.js%3A7%2C39

Related Documentation

Bar Style API: https://visactor.io/vchart/option/barChart#bar.style.fill
Github: https://github.com/VisActor/VChart