Paper.js - The Swiss Army Knife of Vector Graphics Scripting

If you want to work with Paper.js, simply download the latest "stable" version
from http://paperjs.org/download/

• Website: http://paperjs.org/
• Questions: https://stackoverflow.com/questions/tagged/paperjs
• Discussion forum: https://groups.google.com/group/paperjs
• Mainline source code: https://github.com/paperjs/paper.js
• Twitter: @paperjs
• Latest releases: http://paperjs.org/download/
• Pre-built development versions:
  prebuilt/module
  and prebuilt/dist
  branches.

Installing Paper.js

The recommended way to install and maintain Paper.js as a dependency in your
project is through the Node.js Package Manager (NPM)
for browsers, Node.js or Electron.

If NPM is already installed, simply type one of these commands in your project
folder:

npm install paper

Upon execution, you will find a paper folder inside the project's
node_modules folder.

For more information on how to install Node.js and NPM, read the chapter
Installing Node.js and NPM.

Which Version to Use

The various distributions come with two different pre-build versions of
Paper.js, in minified and normal variants:

• paper-full.js – The full version for the browser, including PaperScript
  support and Acorn.js
• paper-core.js – The core version for the browser, without PaperScript
  support nor Acorn.js. You can use this to shave off some bytes and compilation
  time when working with JavaScript directly.

Installing Node.js and NPM

Node.js comes with the Node Package Manager (NPM). There are many tutorials
explaining the different ways to install Node.js on different platforms. It is
generally not recommended to install Node.js through OS-supplied package
managers, as the its development cycles move fast and these versions are often
out-of-date.

On macOS, Homebrew is a good option if one version of
Node.js that is kept up to date with brew upgrade is enough:
https://treehouse.github.io/installation-guides/mac/node-mac.html

NVM can be used instead to install and
maintain multiple versions of Node.js on the same platform, as often required by
different projects:
https://nodesource.com/blog/installing-node-js-tutorial-using-nvm-on-mac-os-x-and-ubuntu/

Homebrew is recommended on macOS also if you intend to install Paper.js with
rendering to the Canvas on Node.js, as described in the next paragraph.

For Linux, see https://nodejs.org/download/ to locate 32-bit and 64-bit Node.js
binaries as well as sources, or use NVM, as described in the paragraph above.

Installing Paper.js Using NPM

Paper.js comes in three different versions on NPM: paper, paper-jsdom and
paper-jsdom-canvas. Depending on your use case, you need to required a
different one:

• paper is the main library, and can be used directly in a browser
  context, e.g. a web browser or worker.
• paper-jsdom is a shim module for Node.js, offering headless use with SVG
  importing and exporting through jsdom.
• paper-jsdom-canvas is a shim module for Node.js, offering canvas rendering
  through Node-Canvas as well as
  SVG importing and exporting through jsdom.

In order to install paper-jsdom-canvas, you need the Cairo Graphics
library installed in your system:

Installing Native Dependencies

Paper.js relies on Node-Canvas for
rendering, which in turn relies on the native libraries
Cairo and Pango.

Installing Native Dependencies on macOS

Paper.js relies on Node-Canvas for rendering, which in turn relies on Cairo and
Pango. The easiest way to install Cairo is through
Homebrew, by issuing the command:

brew install cairo pango

Note that currently there is an issue on macOS with Cairo. If the above causes
errors, the following will most likely fix it:

PKG_CONFIG_PATH=/opt/X11/lib/pkgconfig/ npm install paper

Also, whenever you would like to update the modules, you will need to execute:

PKG_CONFIG_PATH=/opt/X11/lib/pkgconfig/ npm update

If you keep forgetting about this requirement, or would like to be able to type
simple and clean commands, add this to your .bash_profile file:

# PKG Config for Pango / Cairo
export PKG_CONFIG_PATH=/usr/local/lib/pkgconfig:/opt/X11/lib/pkgconfig

After adding this line, your commands should work in the expected way:

npm install paper
npm update

Installing Native Dependencies on Debian/Ubuntu Linux

sudo apt-get install pkg-config libcairo2-dev libpango1.0-dev libssl-dev libjpeg62-dev libgif-dev

You might also need to install the build-essential package if you don't usually
build from c++ sources:

sudo apt-get install build-essential

Installing Native Dependencies for Electron

In order to build Node-Canvas for use of paper-jsdom-canvas in Electron, which
is likely to use a different version of V8 than the Node binary installed in
your system, you need to manually specify the location of Electron’s headers.
Follow these steps to do so:

Electron — Using Native Node
Modules

After Native Dependencies have been installed

You should now be able to install the Paper.js module with jsdom and Canvas
rendering from NPM:

npm install paper-jsdom-canvas

Development

The main Paper.js source tree is hosted on
GitHub. git is required to create a
clone of the repository, and can be easily installed through your preferred
package manager on your platform.

Get the Source

git clone --recursive git://github.com/paperjs/paper.js.git
cd paper.js

To refresh your clone and fetch changes from origin, run:

git fetch origin

To update the jsdoc-toolkit submodule, used to generate the documentation,
run:

git submodule update  --init --recursive

Setting Up For Building

As of 2016, Paper.js uses Gulp.js for building, and has a
couple of dependencies as NPM modules. Read the chapter Installing
Node.js and NPM if you still need to
install these.

In order to be able to build Paper.js, after checking out the repository, paper
has dependencies that need to be installed. Install them by issuing the
following commands from the Paper.js directory:

npm install

It is also recommended to install Gulp.js globally, so you can easier execute
the build commands from anywhere in the command line:

npm install -g gulp

Building the Library

The Paper.js sources are distributed across many separate files, organised in
subfolders inside the src folder. To compile them all into distributable
files, you can run the build task:

gulp build

You will then find the built library files inside the dist folder, named
paper-full.js and paper-core.js, along with their minified versions. Read
more about this in Which Version to Use?.

Running Directly from Separate Source Files

As a handy alternative to building the library after each change to try it out
in your scripts, there is the load task, that replaces the built libraries
with symbolic links to the scrc/load.js script. This script then load the
library directly from all the separate source files in the src folder, through
the Prepro.js JavaScript preprocessing
library.

This means you can switch between loading from sources and loading a built
library simply by running.

gulp load

And to go back to a built library

gulp build

Note that your PaperScripts examples do not need to change, they can keep
loading dist/paper-full.js, which will always do the right thing. Note also
that src/load.js handles both browsers and Node.js, as supported by Prepro.js.

Other Build Tasks

Create a final zipped distribution file inside the dist folder:

gulp dist

And since dist is the default task, this is the same:

gulp

Branch structure

Since the release of version 0.9.22, Paper.js has adopted aspects of the Git-
Flow workflow. All development is taking place in the
develop branch, which is
only merged into master
when a new release occurs.

As of version 0.9.26, the dist folder is excluded on all branches, and the
building is now part of the npm publish process by way of the prepublish
script.

We also offer prebuilt versions of the latest state of the develop branch on
prebuilt/module
and prebuilt/dist.

Building the Documentation

Similarly to building the library, you can run the docs task to build the
documentation:

gulp docs

Your docs will then be located at dist/docs.

Testing

Paper.js was developed and tested from day 1 using proper unit testing through
jQuery's Qunit. To run the tests after any
change to the library's source, simply open index.html inside the test
folder in your web browser. There should be a green bar at the top, meaning all
tests have passed. If the bar is red, some tests have not passed. These will be
highlighted and become visible when scrolling down.

If you are testing on Chrome, some of the tests will fail due to the browser's
CORS restrictions. In order to run the browser based tests on Chrome, you need
to run a local web-server through Gulp.js. The following command will handle it
for you, and will also open the browser at the right address straight away:

gulp test:browser

You can also run the unit tests through PhantomJS in Gulp directly on the
command line:

gulp test:phantom

To test the Node.js version of Paper.js, use this command:

gulp test:node

And to test both the PhantomJS and Node.js environments together, simply run:

gulp test

Contributing

The main Paper.js source tree is hosted on GitHub, thus you should create a fork
of the repository in which you perform development. See
https://help.github.com/articles/fork-a-repo/.

We prefer that you send a
pull request on GitHub
which will then be merged into the official main line repository.
You need to sign the Paper.js CLA to be able to contribute (see below).

Also, in your first contribution, add yourself to the end of AUTHORS.md (which
of course is optional).

In addition to contributing code you can also triage issues which may include
reproducing bug reports or asking for vital information, such as version numbers
or reproduction instructions. If you would like to start triaging issues, one
easy way to get started is to
subscribe to paper.js on CodeTriage.

Get the source (for contributing):

If you want to contribute to the project you will have to make a
fork. Then do this:

git clone --recursive git@github.com:yourusername/paper.js.git
cd paper.js
git remote add upstream git://github.com/paperjs/paper.js.git

To then fetch changes from upstream, run

git fetch upstream

Creating and Submitting a Patch

As mentioned above, we prefer that you send a
pull request on GitHub:

1. Create a fork of the upstream repository by visiting
   https://github.com/paperjs/paper.js/fork. If you feel insecure, here's a
   great guide: https://help.github.com/articles/fork-a-repo/

2. Clone of your repository: git clone https://yourusername@github.com/yourusername/paper.js.git

3. This is important: Create a so-called topic branch based on the develop
   branch: git checkout -tb name-of-my-patch develop where name-of-my-patch
   is a short but descriptive name of the patch you're about to create. Don't
   worry about the perfect name though -- you can change this name at any time
   later on.

4. Hack! Make your changes, additions, etc., commit them then push them to your
   GitHub fork: git push origin name-of-my-patch

5. Send a pull request to the upstream repository's owner by visiting your
   repository's site at GitHub (i.e. https://github.com/yourusername/paper.js)
   and press the "Pull Request" button. Make sure you are creating the pull
   request to the develop branch, not the master branch. Here's a good guide
   on pull requests: https://help.github.com/articles/about-pull-requests/

Use one topic branch per feature:

Don't mix different kinds of patches in the same branch. Instead, merge them all
together into your develop branch (or develop everything in your develop
branch and then cherry-pick-and-merge into the different topic branches). Git
provides for an extremely flexible workflow, which in many ways causes more
confusion than it helps you when new to collaborative software development. The
guides provided by GitHub at https://help.github.com/ are a really good
starting point and reference. If you are fixing an issue, a convenient way to
name the branch is to use the issue number as a prefix, like this: git checkout -tb issue-937-feature-add-text-styling.

Contributor License Agreement

Before we can accept any contributions to Paper.js, you need to sign this
CLA:

Contributor License Agreement

The purpose of this agreement is to clearly define the terms under which
intellectual property has been contributed to Paper.js and thereby allow us to
defend the project should there be a legal dispute regarding the software at
some future time.

For a list of authors and contributors, please see
AUTHORS.

License

Distributed under the MIT license. See
LICENSE
fo details.