Epoch

By Ryan Sandor Richards

Introduction

Epoch is a general purpose charting library for application developers and visualization designers. It focuses on two different aspects of visualization programming: basic charts for creating historical reports, and real-time charts for displaying frequently updating timeseries data.

Getting Started

To get started using Epoch, please refer to the Epoch Project Site. There you can find full documentation and guides to help you start using Epoch right away.

Requirements

Epoch has two external library requirements:

1. d3 - Used to generate the basic charts.
2. jQuery - Used for DOM manipulation, etc.

Developing Epoch

Developing Epoch is a reasonably straight forward process. In this section we'll cover the basic on how to develop Epoch by detailing common build task, exploring how the source is arranged, and finally show how to use rendering tests to aid development.

Basic Development Process

After cloning the repository, the best way to get started developing against Epoch is to follow the following steps:

1. Change to the source directory for the project
2. Run cake build to build the JavaScript and CSS from Source
3. In a web browser open the test/index.html and browse the rendering tests
4. Make changes in the CoffeeScript Source and use cake build or cake watch so that your changes are compiled
5. Use the rendering tests to see if your changes had the desired result

Keeping the rendering tests up-to-date is important! When developing use the following guidelines:

• When adding new features make sure to add new rendering tests
• When changing existing functionality, ensure that the appropriate rendering tests still pass
• If you want to make a new type of chart, add a whole new test suite for that chart!

Keeping the tests current makes it easier for others to review your code and spot issues. Also, pull requests without appropriate testing will not be merged... period.

Build Tasks

Epoch uses cake for its builds. The file defines the following tasks:

cake build                # Builds javascript from the coffeescript source (also packages).
cake package              # Packages the js and libraries into a single file.
cake compile              # Compiles the packaged source via the Google Closure Compiler
cake watch
cake sass                 # Compile sass source into css
cake release              # Releases a new version of the library

  -v, --version      Sets the version number for release

For the most part you'll only need to use the following tasks:

1. cake build / cake watch - These will compile the CoffeeScript into JavaScript and compile SCSS to css.
2. cake --version X.Y.Z release - This is used to create minified release versions of the library.

Source Structure

The directory structure for the Epoch project follows some basic guidelines, here's an overview of how it is structured:

coffee/                - Main source directory
  adapters/            - 3rd Party Library Adapters (currently only jQuery)
  basic/               - Basic Chart Classes
  time/                - Real-time Chart Classes
  adapters.coffee      - Options / Global Classes for Adapter Implementations
  basic.coffee         - Base Classes for Basic Charts
  epoch.coffee         - Main source file, defines name spaces, etc.
  time.coffee          - Base Classes for Real-Time Charts
doc/                   - Codo generated documentation
lib/                   - "Baked in" libraries
sass/                  - Scss source for the default epoch stylesheet
test/                  - Rendering tests
  basic/               - Basic chart rendering tests
  real-time/           - Real-time rendering tests

Copyright / Legal

The MIT License (MIT)

Copyright (c) 2014 Fastly, Inc.

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.