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How to Change Font Color based on Background Color using ReactJS

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by Abdul Rawoof A R dot icon Updated: Feb 1, 2023

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We can change the font color based on the background color in react by few different ways: 

  • We can use a library that offers practical functions, including color contrast and brightness, to choose the best font color based on the background color. 
  • We may manually determine the contrast ratio between the background color and the text’s color. If the contrast ratio is below a certain threshold, you can choose a different font color to improve the contrast and readability of the text. This can be done by using a library ‘contrast.js.’ 
  • contrast.js: This is a library that helps in measuring the contrast between two colors. The contrast ratio gauges how simple it is to see text against a specific background color. 
  • We can use CSS ‘color’ function. 
  • color: This function allows you to use operations like lightening, darkening, and mixing to provide a color value that is generated from one or more other colors. 


For more information about changing font color based on the background color in React, refer to the code given below 

Fig : Preview of the output that you will get on running this code from your IDE.

Code

In this solution we're using React and styled-component library.

How to change font color based on background color using reactJs

JavaScriptdotLines of Code : 61dotLicense : Strong Copyleft (CC BY-SA 4.0)

Dependent Libraries : 
import React, { useState, useEffect } from "react";
import ReactDOM from "react-dom";
import DynamicContainer from "./style";

import "./styles.css";

function App() {
  const [bgColor, setBGColor] = useState("#422DAD");
  const [textColor, setTextColor] = useState("rgb(99,99,100)");

  function hexToRgb(hex) {
    // Expand shorthand form (e.g. "03F") to full form (e.g. "0033FF")
    var shorthandRegex = /^#?([a-f\d])([a-f\d])([a-f\d])$/i;
    hex = hex.replace(shorthandRegex, function(m, r, g, b) {
      return r + r + g + g + b + b;
    });

    var result = /^#?([a-f\d]{2})([a-f\d]{2})([a-f\d]{2})$/i.exec(hex);
    return result
      ? {
          r: parseInt(result[1], 16),
          g: parseInt(result[2], 16),
          b: parseInt(result[3], 16)
        }
      : null;
  }

  useEffect(() => {
    let { r, g, b } = hexToRgb(bgColor);
    let targetColor = `rgb(${r},${g},${b})`;
    var colors = targetColor.match(/^rgb\((\d+),\s*(\d+),\s*(\d+)\)$/);
    var brightness = 1;

    var R = colors[1];
    var G = colors[2];
    var B = colors[3];

    var ir = Math.floor((255 - R) * brightness);
    var ig = Math.floor((255 - G) * brightness);
    var ib = Math.floor((255 - B) * brightness);
    setTextColor(`rgb(${ir}, ${ig}, ${ib})`);
  }, [bgColor]);

  const handleBgChange = e => {
    setBGColor(e.target.value);
  };

  return (
    <>
      <DynamicContainer bgColor={bgColor} textColor={textColor}>
        Hello World!
      </DynamicContainer>
      <p>Choose Background color</p>
      <input type="color" value={bgColor} onChange={handleBgChange} />
    </>
  );
}

const rootElement = document.getElementById("root");
ReactDOM.render(<App />, rootElement);

Instructions

Follow the steps carefully to get the output easily.

  1. Install the Node.js and React on your IDE(preferable Visual Studio Code).
  2. Create React Application using npx create-react-app foldername.
  3. cd foldername.
  4. Open the folder in IDE.
  5. Copy the code using "copy" button above and paste it in index.js file(remove the earlier code from index.js) and refer demo for additional one file called style.js file.
  6. Add export default statement at end of the code(like 'export default App;').
  7. Open the terminal from IDE.
  8. npm start to run the file.


You can also refer this url 'DEMO' for getting the above output.

I hope you found this useful. I have added the link to dependent libraries, version information in the following sections.


I found this code snippet by searching for 'change the font color based on background color in React' in kandi. You can try any such use case!

Environment Tested

I tested this solution in the following versions. Be mindful of changes when working with other versions.

  1. The solution is created in Visual Studio Code 1.73.1.
  2. The solution is tested on node v18.12.1 and npm v8.19.2.
  3. React version-18.2.0.
  4. Styled-components version-6.0.0.


Using this solution, we are able to change the font color based on background color in React with simple steps. This process also facilities an easy way to use, hassle-free method to create a hands-on working version of code which would help us to change the font color based on background color in React.

Dependent Library

reactby facebook

JavaScript doticonstar image 209050 doticonVersion:v18.2.0doticon
License: Permissive (MIT)

The library for web and native user interfaces

Support
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            reactby facebook

            JavaScript doticon star image 209050 doticonVersion:v18.2.0doticon License: Permissive (MIT)

            The library for web and native user interfaces
            Support
              Quality
                Security
                  License
                    Reuse

                      styled-componentsby styled-components

                      TypeScript doticonstar image 39106 doticonVersion:v6.0.0-rc.3doticon
                      License: Permissive (MIT)

                      Visual primitives for the component age. Use the best bits of ES6 and CSS to style your apps without stress 💅

                      Support
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                          Security
                            License
                              Reuse

                                styled-componentsby styled-components

                                TypeScript doticon star image 39106 doticonVersion:v6.0.0-rc.3doticon License: Permissive (MIT)

                                Visual primitives for the component age. Use the best bits of ES6 and CSS to style your apps without stress 💅
                                Support
                                  Quality
                                    Security
                                      License
                                        Reuse

                                          You can also search for any dependent libraries on kandi like 'react' and 'styled-component'.

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