Adjusting the font size based on the text length and the size of the parent div

Question

Adjusting the font size based on the text length and the size of the parent div

React/Javascript

I am working on a challenge involving a div element that contains a paragraph. This paragraph may vary in length, so I need to find a way to dynamically adjust the font size based on its length. If the paragraph is longer, I want to scale down the font size to ensure it fits within the div. Conversely, if the paragraph is shorter, I need to scale up the font size.

I have attempted using Scaletext for this purpose, but unfortunately, I was not able to achieve the desired outcome. It seems that Scaletext may not be suitable for solving my specific issue.

The parent div has predefined max width and height, making it responsive to different screen sizes.

javascript css reactjs

Answer 1

Answer №1

To determine if a div has overflow, compare its boundaries (defined by its CSS width and height properties) with its current scrollHeight:

This involves setting a fixed height and hiding overflows using overflow:hidden.

We then iterate over all question divs
Check if they have an overflow
If so – reduce font-size (in another loop) until scrollHeight is less than or equal to divHeight

let questions = document.querySelectorAll(".question");
let resize = document.querySelector(".resize");

//Initial font size adjustment
fixOverflow();

//Resize observer
const resizeObserver = new ResizeObserver(() => {
  resetFontSizes();
  fixOverflow();
});
resizeObserver.observe(resize);

function fixOverflow() {
  questions.forEach(function (question, i) {
    let divHeight = question.getBoundingClientRect().height;
    let scrollHeight = question.scrollHeight;
    let style = window.getComputedStyle(question);
    let fontSize = parseFloat(style.fontSize);
    //Shrink font size if text overflows
    if (scrollHeight > divHeight) {
      for (let i = 0; scrollHeight > divHeight; i++) {
        fontSize--;
        question.style.fontSize = fontSize + "px";
        scrollHeight = question.scrollHeight;
      }
    }
    //Optional: Increase font size if there is free space available
    if (scrollHeight < divHeight) {
      for (let i = 0; scrollHeight < divHeight; i++) {
        fontSize++;
        question.style.fontSize = fontSize + "px";
        scrollHeight = question.scrollHeight;
      }
    }
  });
}

//Reset previously changed font sizes
function resetFontSizes() {
  let questions = document.querySelectorAll(".question");
  questions.forEach(function (question, i) {
    question.style.removeProperty("font-size");
  });
}

.resize{
  overflow:auto;
  padding:1rem;
  border:1px solid #ccc;
  resize:both;
}

.question p{
  margin-top:0;
}

.question{
  font-size:20px;
  line-height:1.2em;
  max-width:calc(100% - 2rem);
  width:500px;
  height:120px;
  border:1px solid #ccc;
  overflow:hidden;
  padding:1rem;
}

<div class="resize">
  <div class="question">
    <p>One morning, when Gregor Samsa woke from troubled dreams, he found himself transformed in his bed into a horrible vermin. </p>
  </div>
  <div class="question">
    <p>One morning, when Gregor Samsa woke from troubled dreams, he found himself transformed in his bed into a horrible vermin. He lay on his armour-like back, and if he lifted his head a little he could see his brown belly, slightly domed and divided by arches into stiff sections. The bedding was hardly able to cover it and seemed ready to slide off any moment. His many legs, pitifully thin compared with the size of the rest of him, waved about helplessly as he looked. </p>
  </div>
</div>
<h3 style="text-align:right">Resize parent div</h3>

To update/reset the font-size after resizing the window, you will need either a ResizeObserver() or a simple resize eventListener.

Answer 2

To determine if a div has overflow, compare its boundaries (defined by its CSS width and height properties) with its current scrollHeight:

This involves setting a fixed height and hiding overflows using overflow:hidden.

We then iterate over all question divs
Check if they have an overflow
If so – reduce font-size (in another loop) until scrollHeight is less than or equal to divHeight

let questions = document.querySelectorAll(".question");
let resize = document.querySelector(".resize");

//Initial font size adjustment
fixOverflow();

//Resize observer
const resizeObserver = new ResizeObserver(() => {
  resetFontSizes();
  fixOverflow();
});
resizeObserver.observe(resize);

function fixOverflow() {
  questions.forEach(function (question, i) {
    let divHeight = question.getBoundingClientRect().height;
    let scrollHeight = question.scrollHeight;
    let style = window.getComputedStyle(question);
    let fontSize = parseFloat(style.fontSize);
    //Shrink font size if text overflows
    if (scrollHeight > divHeight) {
      for (let i = 0; scrollHeight > divHeight; i++) {
        fontSize--;
        question.style.fontSize = fontSize + "px";
        scrollHeight = question.scrollHeight;
      }
    }
    //Optional: Increase font size if there is free space available
    if (scrollHeight < divHeight) {
      for (let i = 0; scrollHeight < divHeight; i++) {
        fontSize++;
        question.style.fontSize = fontSize + "px";
        scrollHeight = question.scrollHeight;
      }
    }
  });
}

//Reset previously changed font sizes
function resetFontSizes() {
  let questions = document.querySelectorAll(".question");
  questions.forEach(function (question, i) {
    question.style.removeProperty("font-size");
  });
}

.resize{
  overflow:auto;
  padding:1rem;
  border:1px solid #ccc;
  resize:both;
}

.question p{
  margin-top:0;
}

.question{
  font-size:20px;
  line-height:1.2em;
  max-width:calc(100% - 2rem);
  width:500px;
  height:120px;
  border:1px solid #ccc;
  overflow:hidden;
  padding:1rem;
}

<div class="resize">
  <div class="question">
    <p>One morning, when Gregor Samsa woke from troubled dreams, he found himself transformed in his bed into a horrible vermin. </p>
  </div>
  <div class="question">
    <p>One morning, when Gregor Samsa woke from troubled dreams, he found himself transformed in his bed into a horrible vermin. He lay on his armour-like back, and if he lifted his head a little he could see his brown belly, slightly domed and divided by arches into stiff sections. The bedding was hardly able to cover it and seemed ready to slide off any moment. His many legs, pitifully thin compared with the size of the rest of him, waved about helplessly as he looked. </p>
  </div>
</div>
<h3 style="text-align:right">Resize parent div</h3>

To update/reset the font-size after resizing the window, you will need either a ResizeObserver() or a simple resize eventListener.

Answer 3

Answer №2

It appears as though you are looking to dynamically adjust the font size depending on the screen width, if I have understood your question correctly.

If this is indeed what you need, perhaps considering utilizing the 'resize' JavaScript event to scale up the font-size based on the innerWidth of the parent element could be a solution worth exploring.

This approach may prove to be effective in achieving your desired outcome.

For more information, please refer to the MDN Docs on the resize event

Answer 4

It appears as though you are looking to dynamically adjust the font size depending on the screen width, if I have understood your question correctly.

If this is indeed what you need, perhaps considering utilizing the 'resize' JavaScript event to scale up the font-size based on the innerWidth of the parent element could be a solution worth exploring.

This approach may prove to be effective in achieving your desired outcome.

For more information, please refer to the MDN Docs on the resize event

Answer 5

Answer №3

Consider utilizing the "vw" unit - A measurement equivalent to a percentage of the viewport width

div{ font-size: 10vw; white-space: nowrap; }

Answer 6

Consider utilizing the "vw" unit - A measurement equivalent to a percentage of the viewport width

div{ font-size: 10vw; white-space: nowrap; }

Answer 7

Answer №4

It's important to note that the font-size CSS property exists. You can implement it in your code like this:

function adjustFontSize(element) {
    let map = [
        {start: 0, end: 10, fontSize: "60pt"},
        {start: 10, end: 20, fontSize: "40pt"},
        {start: 20, end: 30, fontSize: "20pt"},
        //...
    ]; //You can customize these values.

    let length = element.innerText.length;
    element.style.fontSize = map.filter(item => (item.start <= length && item.end > length))[0].fontSize;
}

function changeTextAndSize(text) {
    let element = document.getElementById("youritem");
    element.innerText = text;
    adjustFontSize(element);
}

<div id="youritem"></div>
<input type="button" value="Large" onclick="changeTextAndSize('abc')">
<input type="button" value="Medium" onclick="changeTextAndSize('abc0123456789')">
<input type="button" value="Small" onclick="changeTextAndSize('abc01234567890123456789')">

Try clicking the buttons to see the font size adjustment in action. Another option is using SVG and its font-size attribute, for example:

<svg viewBox="0 0 200 30" xmlns="http://www.w3.org/2000/svg">
  <text y="20" font-size="smaller">smaller</text>
  <text x="100" y="20" font-size="2em">2em</text>
</svg>

Answer 8

It's important to note that the font-size CSS property exists. You can implement it in your code like this:

function adjustFontSize(element) {
    let map = [
        {start: 0, end: 10, fontSize: "60pt"},
        {start: 10, end: 20, fontSize: "40pt"},
        {start: 20, end: 30, fontSize: "20pt"},
        //...
    ]; //You can customize these values.

    let length = element.innerText.length;
    element.style.fontSize = map.filter(item => (item.start <= length && item.end > length))[0].fontSize;
}

function changeTextAndSize(text) {
    let element = document.getElementById("youritem");
    element.innerText = text;
    adjustFontSize(element);
}

<div id="youritem"></div>
<input type="button" value="Large" onclick="changeTextAndSize('abc')">
<input type="button" value="Medium" onclick="changeTextAndSize('abc0123456789')">
<input type="button" value="Small" onclick="changeTextAndSize('abc01234567890123456789')">

Try clicking the buttons to see the font size adjustment in action. Another option is using SVG and its font-size attribute, for example:

<svg viewBox="0 0 200 30" xmlns="http://www.w3.org/2000/svg">
  <text y="20" font-size="smaller">smaller</text>
  <text x="100" y="20" font-size="2em">2em</text>
</svg>

Adjusting the font size based on the text length and the size of the parent div

Answer №1

Answer №2

Answer №3

Answer №4

Similar questions

Can two Angular element components be utilized simultaneously on a single page in Angular 6?

Ways to incorporate external JavaScript files into a React component

Removing the transparent section of an image: A step-by-step guide

Automatically load file and play audio when the page is loaded

Troubleshooting: Unusual Page Loaded on Webpack Dev Server

Is it possible to invoke an AngularJs service by clicking a button?

Route is searching for static files in the incorrect directory

Using Laravel Mix to implement a Datatable

Express-minify is having trouble loading the CSS file. If we remove a portion of the file, it should be able

appearing like a straightforward process of creating strings in JavaScript

Unique solution: "Using CSS to ensure the overflow document always scrolls to the bottom

Tips for retaining a number even when the page is refreshed

What could be causing errors with my addrole command in discord.jsV12?

What is the best way to implement CSS rules for a hidden submenu?

Linking a Checkbox to a Field's Value in AngularJS

Is it possible to export all types/interfaces from .d.ts files within multiple folders using index.ts in a React TypeScript project?

What is the best way to achieve a column layout using Bootstrap?

Having difficulties adjusting the margin for a JSX element directly within the code

Looking to run JavaScript code during an Ajax request?

Using javascript to generate fresh dictionaries