html2pdf

html2pdf converts any webpage or element into a printable PDF entirely client-side using html2canvas and jsPDF.

Getting started

HTML

The simplest way to use html2pdf is to download dist/html2pdf.bundle.min.js to your project folder and include it in your HTML with:

<script src="html2pdf.bundle.min.js"></script>

Note: Click here for more information about using the unbundled version dist/html2canvas.min.js.

NPM

Install html2pdf and its dependencies using NPM with npm install --save html2pdf.js (make sure to include .js in the package name).

Note: You can use NPM to create your project, but html2pdf will not run in Node.js, it must be run in a browser.

Bower

Install html2pdf and its dependencies using Bower with bower install --save html2pdf.js (make sure to include .js in the package name).

Usage

Once installed, html2pdf is ready to use. The following command will generate a PDF of #element-to-print and prompt the user to save the result:

var element = document.getElementById('element-to-print');
html2pdf(element);

Advanced usage

Every step of html2pdf is configurable, using its new Promise-based API. If html2pdf is called without arguments, it will return a Worker object:

var worker = html2pdf();  // Or:  var worker = new html2pdf.Worker;

This worker has methods that can be chained sequentially, as each Promise resolves, and allows insertion of your own intermediate functions between steps. A prerequisite system allows you to skip over mandatory steps (like canvas creation) without any trouble:

// This will implicitly create the canvas and PDF objects before saving.
var worker = html2pdf().from(element).save();

Workflow

The basic workflow of html2pdf tasks (enforced by the prereq system) is:

.from() -> .toContainer() -> .toCanvas() -> .toImg() -> .toPdf() -> .save()

Worker API

Method	Arguments	Description
from	src, type	Sets the source (HTML string or element) for the PDF. Optional `type` specifies other sources: `'string'`, `'element'`, `'canvas'`, or `'img'`.
to	target	Converts the source to the specified target (`'container'`, `'canvas'`, `'img'`, or `'pdf'`). Each target also has its own `toX` method that can be called directly: `toContainer()`, `toCanvas()`, `toImg()`, and `toPdf()`.
output	type, options, src	Routes to the appropriate `outputPdf` or `outputImg` method based on specified `src` (`'pdf'` (default) or `'img'`).
outputPdf	type, options	Sends `type` and `options` to the jsPDF object's `output` method, and returns the result as a Promise (use `.then` to access). See the jsPDF source code for more info.
outputImg	type, options	Returns the specified data type for the image as a Promise (use `.then` to access). Supported types: `'img'`, `'datauristring'`/`'dataurlstring'`, and `'datauri'`/`'dataurl'`.
save	filename	Saves the PDF object with the optional filename (creates user download prompt).
set	opt	Sets the specified properties. See Options below for more details.
get	key, cbk	Returns the property specified in `key`, either as a Promise (use `.then` to access), or by calling `cbk` if provided.
then	onFulfilled, onRejected	Standard Promise method, with `this` re-bound to the Worker, and with added progress-tracking (see Progress below). Note that `.then` returns a `Worker`, which is a subclass of Promise.
thenCore	onFulFilled, onRejected	Standard Promise method, with `this` re-bound to the Worker (no progress-tracking). Note that `.thenCore` returns a `Worker`, which is a subclass of Promise.
thenExternal	onFulfilled, onRejected	True Promise method. Using this 'exits' the Worker chain - you will not be able to continue chaining Worker methods after `.thenExternal`.
catch, catchExternal	onRejected	Standard Promise method. `catchExternal` exits the Worker chain - you will not be able to continue chaining Worker methods after `.catchExternal`.
error	msg	Throws an error in the Worker's Promise chain.

A few aliases are also provided for convenience:

Method	Alias
save	saveAs
set	using
output	export
then	run

Options

html2pdf can be configured using an optional opt parameter:

var element = document.getElementById('element-to-print');
var opt = {
  margin:       1,
  filename:     'myfile.pdf',
  image:        { type: 'jpeg', quality: 0.98 },
  html2canvas:  { scale: 2 },
  jsPDF:        { unit: 'in', format: 'letter', orientation: 'portrait' }
};

// New Promise-based usage:
html2pdf().from(element).set(opt).save();

// Old monolithic-style usage:
html2pdf(element, opt);

The opt parameter has the following optional fields:

Name	Type	Default	Description
margin	number or array	0	PDF margin (in jsPDF units). Can be a single number, `[vMargin, hMargin]`, or `[top, left, bottom, right]`.
filename	string	'file.pdf'	The default filename of the exported PDF.
image	object	{type: 'jpeg', quality: 0.95}	The image type and quality used to generate the PDF. See the Extra Features section below.
enableLinks	boolean	true	If enabled, PDF hyperlinks are automatically added ontop of all anchor tags.
html2canvas	object	{ }	Configuration options sent directly to `html2canvas` (see here for usage).
jsPDF	object	{ }	Configuration options sent directly to `jsPDF` (see here for usage).

Page-breaks

You may add html2pdf-specific page-breaks to your document by adding the CSS class html2pdf__page-break to any element (normally an empty div). For React elements, use className=html2pdf__page-break. During PDF creation, these elements will be given a height calculated to fill the remainder of the PDF page that they are on. Example usage:

<div id="element-to-print">
  <span>I'm on page 1!</span>
  <div class="html2pdf__page-break"></div>
  <span>I'm on page 2!</span>
</div>

Image type and quality

You may customize the image type and quality exported from the canvas by setting the image option. This must be an object with the following fields:

Name	Type	Default	Description
type	string	'jpeg'	The image type. HTMLCanvasElement only supports 'png', 'jpeg', and 'webp' (on Chrome).
quality	number	0.95	The image quality, from 0 to 1. This setting is only used for jpeg/webp (not png).

These options are limited to the available settings for HTMLCanvasElement.toDataURL(), which ignores quality settings for 'png' images. To enable png image compression, try using the canvas-png-compression shim, which should be an in-place solution to enable png compression via the quality option.

Progress

The Worker object returned by html2pdf() has a built-in progress-tracking mechanism. It will be updated to allow a progress callback that will be called with each update, however it is currently a work-in-progress.

Dependencies

html2pdf depends on the external packages html2canvas, jsPDF, and es6-promise. These dependencies are automatically loaded when using NPM or the bundled package.

If using the unbundled dist/html2pdf.min.js (or its un-minified version), you must also include each dependency. Order is important, otherwise html2canvas will be overridden by jsPDF's own internal implementation:

<script src="es6-promise.auto.min.js"></script>
<script src="jspdf.min.js"></script>
<script src="html2canvas.min.js"></script>
<script src="html2pdf.min.js"></script>

Contributing

Issues

When submitting an issue, please provide reproducible code that highlights the issue, preferably by creating a fork of this template jsFiddle (which has html2pdf already loaded). Remember that html2pdf uses html2canvas and jsPDF as dependencies, so it's a good idea to check each of those repositories' issue trackers to see if your problem has already been addressed.

Pull requests

If you want to create a new feature or bugfix, please feel free to fork and submit a pull request! Use the develop branch, which features the latest development, and make changes to /src/ rather than directly to /dist/. You can test your changes by rebuilding with npm run build.

Credits

Erik Koopmans

License

The MIT License

wayhe-penghao / html2pdf Goto Github PK

html2pdf's Introduction