Cross-browser multi-line text overflow with ellips

Question

I made an image for this question to make it easier to understand.

Is it possible to create an ellipsis on a <div> with a fixed width and multiple lines?

I’ve tried some jQuery plugins out here and there, but cannot find the one I’m looking for. Any recommendation? Ideas?

Answer 1

EDIT: Came across Shave which is JS plugin that does multi line text truncation based on a given max-height really well. It uses binary search to find the optimum break point. Definitely worth investigating.

---

ORIGINAL ANSWER:

I had to come up with a vanilla JS solution for this problem. In the case that I had worked on, I had to fit a long product name into limited width and over two lines; truncated by ellipsis if needed.

I used answers from various SO posts to cook up something that fit my needs. The strategy is as follows:

1. Calculate the average character width of the font variant for the desired font size.
2. Calculate the width of the container
3. Calculate number of characters which fit on one line in the container
4. Calculate the number of characters to truncate the string to based on the number of characters that fit on a line and the number of lines the text is supposed to wrap over.
5. Truncate the input text based on the previous calculation (factoring in for extra characters added by ellipsis) and append "..." to the end

Code sample:

/**
 * Helper to get the average width of a character in px
 * NOTE: Ensure this is used only AFTER font files are loaded (after page load)
 * @param {DOM element} parentElement 
 * @param {string} fontSize 
 */
function getAverageCharacterWidth(parentElement, fontSize) {
    var textSample = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890!@#$%^&*()";
    parentElement = parentElement || document.body;
    fontSize = fontSize || "1rem";
    var div = document.createElement('div');
    div.style.width = "auto";
    div.style.height = "auto";
    div.style.fontSize = fontSize;
    div.style.whiteSpace = "nowrap";
    div.style.position = "absolute";
    div.innerHTML = textSample;
    parentElement.appendChild(div);

    var pixels = Math.ceil((div.clientWidth + 1) / textSample.length);
    parentElement.removeChild(div);
    return pixels;
}

/**
 * Helper to truncate text to fit into a given width over a specified number of lines
 * @param {string} text Text to truncate
 * @param {string} oneChar Average width of one character in px
 * @param {number} pxWidth Width of the container (adjusted for padding)
 * @param {number} lineCount Number of lines to span over
 * @param {number} pad Adjust this to ensure optimum fit in containers. Use a negative value to Increase length of truncation, positive values to decrease it.
 */
function truncateTextForDisplay(text, oneChar, pxWidth, lineCount, pad) {
    var ellipsisPadding = isNaN(pad) ? 0 : pad;
    var charsPerLine = Math.floor(pxWidth / oneChar);
    var allowedCount = (charsPerLine * (lineCount)) - ellipsisPadding;
    return text.substr(0, allowedCount) + "...";
}


//SAMPLE USAGE:
var rawContainer = document.getElementById("raw");
var clipContainer1 = document.getElementById("clip-container-1");
var clipContainer2 = document.getElementById("clip-container-2");

//Get the text to be truncated
var text=rawContainer.innerHTML;

//Find the average width of a character
//Note: Ideally, call getAverageCharacterWidth only once and reuse the value for the same font and font size as this is an expensive DOM operation
var oneChar = getAverageCharacterWidth();

//Get the container width
var pxWidth = clipContainer1.clientWidth;

//Number of lines to span over
var lineCount = 2;

//Truncate without padding
clipContainer1.innerHTML = truncateTextForDisplay(text, oneChar, pxWidth, lineCount);

//Truncate with negative padding value to adjust for particular font and font size
clipContainer2.innerHTML = truncateTextForDisplay(text, oneChar, pxWidth, lineCount,-10);

.container{
  display: inline-block;
  width: 200px;
  overflow: hidden;
  height: auto;
  border: 1px dotted black;
  padding: 10px;
  }

<h4>Untruncated</h4>
<div id="raw" class="container">
This is super long text which needs to be clipped to the correct length with ellipsis spanning over two lines
</div>
<h4>Truncated</h4>
<div id="clip-container-1" class="container">
</div>
<h4>Truncated with Padding Tweak</h4>
<div id="clip-container-2" class="container">
</div>

PS:

1. If the truncation is to be on only one line, the pure CSS method of using text-overflow: ellipsis is neater
2. Fonts which don't have a fixed width may cause the truncation to happen too early or too late (as different characters have different widths). Using the pad parameter helps mitigate this in some cases but will not be fool proof :)
3. Will add in links and references to the original posts after I get laptop back (need history)

PPS: Just realised this is very similar to the approach as suggested by @DanMan and @st.never. Checkout the code snippets for an implementation example.

Answer 2

I wrote an angular component that solves the problem. It splits a given text into span elements. After rendering, it removes all overflowing elements and places the ellipsis right after the last visible element.

Usage example:

<app-text-overflow-ellipsis [text]="someText" style="max-height: 50px"></app-text-overflow-ellipsis>

Stackblitz demo: https://stackblitz.com/edit/angular-wfdqtd

The component:

import {
  ChangeDetectionStrategy,
  ChangeDetectorRef,
  Component,
  ElementRef, HostListener,
  Input,
  OnChanges,
  ViewChild
} from '@angular/core';

@Component({
  changeDetection: ChangeDetectionStrategy.OnPush,
  selector: 'app-text-overflow-ellipsis',
  template: `
    <span *ngFor="let word of words; let i = index" [innerHTML]="word + (!endsWithHyphen(i) ? ' ' : '')"></span>
    <span #ellipsis [hidden]="!showEllipsis && !initializing" [class.initializing]="initializing" [innerHTML]="'...' + (initializing ? '&nbsp;' : '')"></span>
  `,
  styles: [`
    :host {
      display: block; 
      position: relative;
    }
    .initializing {
      opacity: 0;
    }
  `
  ]
})

export class TextOverflowEllipsisComponent implements OnChanges {
  @Input()
  text: string;

  showEllipsis: boolean;
  initializing: boolean;

  words: string[];

  @ViewChild('ellipsis')
  ellipsisElement: ElementRef;

  constructor(private element: ElementRef, private cdRef: ChangeDetectorRef) {}

  ngOnChanges(){
    this.init();
  }

  @HostListener('window:resize')
  init(){
    // add space after hyphens
    let text = this.text.replace(/-/g, '- ') ;

    this.words = text.split(' ');
    this.initializing = true;
    this.showEllipsis = false;
    this.cdRef.detectChanges();

    setTimeout(() => {
      this.initializing = false;
      let containerElement = this.element.nativeElement;
      let containerWidth = containerElement.clientWidth;
      let wordElements = (<HTMLElement[]>Array.from(containerElement.childNodes)).filter((element) =>
        element.getBoundingClientRect && element !== this.ellipsisElement.nativeElement
      );
      let lines = this.getLines(wordElements, containerWidth);
      let indexOfLastLine = lines.length - 1;
      let lineHeight = this.deductLineHeight(lines);
      if (!lineHeight) {
        return;
      }
      let indexOfLastVisibleLine = Math.floor(containerElement.clientHeight / lineHeight) - 1;

      if (indexOfLastVisibleLine < indexOfLastLine) {

        // remove overflowing lines
        for (let i = indexOfLastLine; i > indexOfLastVisibleLine; i--) {
          for (let j = 0; j < lines[i].length; j++) {
            this.words.splice(-1, 1);
          }
        }

        // make ellipsis fit into last visible line
        let lastVisibleLine = lines[indexOfLastVisibleLine];
        let indexOfLastWord = lastVisibleLine.length - 1;
        let lastVisibleLineWidth = lastVisibleLine.map(
          (element) => element.getBoundingClientRect().width
        ).reduce(
          (width, sum) => width + sum, 0
        );
        let ellipsisWidth = this.ellipsisElement.nativeElement.getBoundingClientRect().width;
        for (let i = indexOfLastWord; lastVisibleLineWidth + ellipsisWidth >= containerWidth; i--) {
          let wordWidth = lastVisibleLine[i].getBoundingClientRect().width;
          lastVisibleLineWidth -= wordWidth;
          this.words.splice(-1, 1);
        }


        this.showEllipsis = true;
      }
      this.cdRef.detectChanges();

      // delay is to prevent from font loading issues
    }, 1000);

  }

  deductLineHeight(lines: HTMLElement[][]): number {
    try {
      let rect0 = lines[0][0].getBoundingClientRect();
      let y0 = rect0['y'] || rect0['top'] || 0;
      let rect1 = lines[1][0].getBoundingClientRect();
      let y1 = rect1['y'] || rect1['top'] || 0;
      let lineHeight = y1 - y0;
      if (lineHeight > 0){
        return lineHeight;
      }
    } catch (e) {}

    return null;
  }

  getLines(nodes: HTMLElement[], clientWidth: number): HTMLElement[][] {
    let lines = [];
    let currentLine = [];
    let currentLineWidth = 0;

    nodes.forEach((node) => {
      if (!node.getBoundingClientRect){
        return;
      }

      let nodeWidth = node.getBoundingClientRect().width;
      if (currentLineWidth + nodeWidth > clientWidth){
        lines.push(currentLine);
        currentLine = [];
        currentLineWidth = 0;
      }
      currentLine.push(node);
      currentLineWidth += nodeWidth;
    });
    lines.push(currentLine);

    return lines;
  }

  endsWithHyphen(index: number): boolean {
    let length = this.words[index].length;
    return this.words[index][length - 1] === '-' && this.words[index + 1] && this.words[index + 1][0];
  }
}

Answer 3

Just a quick basic idea.

I was testing with the following markup:

<div id="fos">
<p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Proin nisi ligula, dapibus a volutpat sit amet, mattis et dui. Nunc porttitor accumsan orci id luctus. Phasellus ipsum metus, tincidunt non rhoncus id, dictum a lectus. Nam sed ipsum a lacus sodales eleifend. Vestibulum lorem felis, rhoncus elementum vestibulum eget, dictum ut velit. Nullam venenatis, elit in suscipit imperdiet, orci purus posuere mauris, quis adipiscing ipsum urna ac quam.</p>  
</div>

And CSS:

#fos { width: 300px; height: 190px; overflow: hidden; }
#fos p { padding: 10px; margin: 0; }

Applying this jQuery will accomplish the desired result:

var $p = $('#fos p');
var divh = $('#fos').height();
while ($p.outerHeight() > divh) {
    $p.text(function (index, text) {
        return text.replace(/\W*\s(\S)*$/, '...');
    });
}

It repeatedly tries to remove the last word of the text until it reaches the desired size. Because of the overflow: hidden; the process remains invisible and even with JS turned off the result remains 'visually correct' (without the "..." of course).

If you combine this with a sensible truncation on the server-side (that leaves only a small overhead) then it will run quicker :).

Again, this is not a complete solution, just an idea.

UPDATE: Added a jsFiddle Demo.

Answer 4

Here's a vanilla JavaScript solution you can use in a pinch:

// @param 1 = element containing text to truncate
// @param 2 = the maximum number of lines to show
function limitLines(el, nLines) {
  var nHeight,
    el2 = el.cloneNode(true);
  // Create clone to determine line height
  el2.style.position = 'absolute';
  el2.style.top = '0';
  el2.style.width = '10%';
  el2.style.overflow = 'hidden';
  el2.style.visibility = 'hidden';
  el2.style.whiteSpace = 'nowrap';
  el.parentNode.appendChild(el2);
  nHeight = (el2.clientHeight+2)*nLines; // Add 2 pixels of slack
  // Clean up
  el.parentNode.removeChild(el2);
  el2 = null;
  // Truncate until desired nLines reached
  if (el.clientHeight > nHeight) {
    var i = 0,
      imax = nLines * 35;
    while (el.clientHeight > nHeight) {
      el.innerHTML = el.textContent.slice(0, -2) + '…';
      ++i;
      // Prevent infinite loop in "print" media query caused by
      // Bootstrap 3 CSS: a[href]:after { content:" (" attr(href) ")"; }
      if (i===imax) break;
    }
  }
}

limitLines(document.getElementById('target'), 7);

#test {
  width: 320px;
  font-size: 18px;
}

<div id="test">
  <p>Paragraph 1</p>
  <p id="target">Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.</p>
  <p>Paragraph 3</p>
</div>

You can play around with it in the codepen below. Try changing the font size in the CSS panel and make a minor edit in the HTML panel (e.g., add an extra space somewhere) to update the results. Regardless of the font size, the middle paragraph should always be truncated to the number of lines in the second parameter passed to limitLines().

Codepen: http://codepen.io/thdoan/pen/BoXbEK

Answer 5

Here I made another library with faster algorithm. Please check:

https://github.com/i-ahmed-biz/fast-ellipsis

To install using bower:

bower install fast-ellipsis

To install using npm:

bower install fast-ellipsis 

Hope you enjoy!

Answer 6

Not an exact answer to the question, but I came across this page when trying to do very similar, but wanting to add a link to "view more" rather than just a straightforward ellipsis. This is a jQuery function that will add a "more" link to text that is overflowing a container. Personally I'm using this with Bootstrap, but of course it will work without.

To use, put your text in a container as follows:

<div class="more-less">
    <div class="more-block">
        <p>The long text goes in here</p>
    </div>
</div>

When the following jQuery function is added, any of the divs that are larger than the adjustheight value will be truncated and have a "More" link added.

$(function(){
    var adjustheight = 60;
    var moreText = '+ More';
    var lessText = '- Less';
    $(".more-less .more-block").each(function(){
        if ($(this).height() > adjustheight){
            $(this).css('height', adjustheight).css('overflow', 'hidden');
            $(this).parent(".more-less").append
                ('<a style="cursor:pointer" class="adjust">' + moreText + '</a>');
        }
    });
    $(".adjust").click(function() {
        if ($(this).prev().css('overflow') == 'hidden')
        {
            $(this).prev().css('height', 'auto').css('overflow', 'visible');
            $(this).text(lessText);
        }
        else {
            $(this).prev().css('height', adjustheight).css('overflow', 'hidden');
            $(this).text(moreText);
        }
    });
});

Based on this, but updated: http://shakenandstirredweb.com/240/jquery-moreless-text