Doodle: Compositional Graphics

Copyright 2015 Underscore.

A Scala library for compositional vector graphics, with a native back-end via Swing and Java2D, and an HTML canvas backend via Scala.js.

Distributed under the Apache 2.0 license.

Creative Scala

Doodle is featured in Creative Scala, our free introductory Scala ebook. Follow the link to download your copy from our web site.

Getting Started

1. Start SBT:

   bash$ sbt
   
   > # This is the SBT prompt. Press Ctrl+D to quit to the OS.

2. Start the console:

   > console
   
   scala> # This is the Scala prompt. Press Ctrl+D to quit to SBT.

3. Use Scala commands to draw a shape in a native window:

   scala> (Circle(10) fillColor Color.red).draw

   A window should appear containing a red circle.

Drawing in the Browser

You can also draw Doodle pictures in the browser. The process is slightly different.

1. Write your code in js/src/main/scala/Main.scala

2. Start SBT:

   bash$ sbt
   
   > # This is the SBT prompt. Press Ctrl+D to quit to the OS.

3. Compile the JS version:

   > fastOptJS

4. Open your browser and point to http://localhost:12345/index.html to see an HTML 5 canvas version of the code.

Viewing the Examples

Doodle ships with a set of examples for each of the exercises in Creative Scala. See the shared/src/main/scala/doodle/examples directory for a complete list.

To view an example, simply run the sbt console, and draw the examples from there. For example:

bash$ sbt console

When the console is running, type

scala> Sierpinski.image.draw

Directory Structure

Source code is in the following directories:

 - shared / src / {main,test} / scala
 - jvm    / src / {main,test} / scala
 - js     / src / {main,test} / scala

SBT Commands

We provide three quick aliases for common commands:

> console   runs the console using the JVM codebase
> fastOptJS compiles the JS codebase
> test      runs the unit tests for both codebases

Using Doodle as a Library

You can grab Doodle from our training repository on Bintray. See the releases tab for a list of releases. Once you know which release you want, add the following to your build.sbt:

scalaVersion := "2.11.2" // Doodle is compatible with Scala 2.11 only

resolvers += "Underscore Training" at "https://dl.bintray.com/underscoreio/training"

libraryDependencies += "underscoreio" %% "doodle" % <<RELEASE_VERSION>>

If you are considering using Doodle on the Scala console, you may also want to add the following to your build:

initialCommands in console := """
  |import doodle.core._
  |import doodle.syntax._
  |import doodle.jvm._
  |import doodle.examples._
""".trim.stripMargin

Note that, if you are using the older 0.1.0 release, the syntax for using the draw function is different. Drawing the same red circle that we did in the 'Getting Started' section above can be accomplished with the following:

scala> draw(Circle(10).fillColor(Color.red))

Acknowledgements

Doodle was written by Noel Welsh and Dave Gurnell with contributions from Jono Ferguson, Richard Dallaway, and Mat Moore.