A little JavaScript class (without dependencies) to draw and animate SVG path strokes
JavaScript CSS HTML
Latest commit b7b11e6 Jun 20, 2016 lmgonzalves Update d3-ease in demo

README.md

Segment

A little JavaScript class (without dependencies) to draw and animate SVG path strokes.

See the DEMO.

Read this article to understand how it works.

Basic usage

HTML

Add the segment script, and define a path somewhere.

<script src="https://cdnjs.cloudflare.com/ajax/libs/segment-js/1.0.8/segment.js"></script>

<svg>
  <path id="my-path" ...>
</svg>

JavaScript

Initialize a new Segment with the path. Then draw a segment of stroke every time you want with: .draw(begin, end, duration, options).

var myPath = document.getElementById("my-path"),
    segment = new Segment(myPath);

segment.draw("25%", "75% - 10", 1);

Install with NPM

npm install segment-js

Constructor

The Segment constructor asks for 4 parameters:

  • path: DOM element to draw.
  • begin (optional, default 0): Length to start drawing the stroke.
  • end (optional, default 100%): Length to finish drawing the stroke.
  • circular (optional, default false): Allow begin and end values less than 0 and greater than 100%.

Method draw(begin, end, duration, options)

Name Type Default Description
begin string 0 Path length to start drawing.
end string 100% Path length to finish drawing.
duration float 0 Duration (in seconds) of the animation.
options object null Options for animation in object notation.

Note that begin and end can be negative values and can be written in any of these ways:

  • floatValue
  • percent
  • percent + floatValue
  • percent - floatValue

All possible options for draw method

Name Type Default Description
delay float 0 Waiting time (in seconds) to start drawing.
easing function linear Easing function (normalized). I highly recommend d3-ease.
circular boolean false If true, when the stroke reaches the end of the path it will resume at the beginning. The same applies in the opposite direction.
callback function null Function to call when the animation is done.

Example

function cubicIn(t) {
    return t * t * t;
}

function done() {
    alert("Done!");
}

segment.draw("-25%", "75% - 10", 1, {delay: 0.5, easing: cubicIn, circular: true, callback: done});

Animating with another library

It's possible to animate the path stroke using another JavaScript library, like GSAP. Segments offers a method called strokeDasharray that is useful for this issue. Here is an example using TweenLite (with CSSPlugin).

TweenLite.to(path, 1, { strokeDasharray: segment.strokeDasharray(begin, end) });