O1Library Docs
Fall 2026
Docs API

# Introduction to O1Library

O1Library is a toolkit designed for the course Programming 1 (a.k.a. O1) at Aalto University. It contains an assortment of tools; most prominently, it provides a framework for simple graphical programming and utilities for playing sound.

## Using O1Library as a Student

This is the “front page” of O1Library’s documentation. However, this is probably not the best place to start learning about O1Library as a student. That’s because the library’s most relevant content is introduced bit by bit in the chapters of O1’s custom ebook alongside the associated programming concepts and assignments.

You may nevertheless find this documentation useful as a reference. You can also find some optional content here that you may wish to try.

O1Library’s main package is called simply `o1`. The contents of that package are available with the simple command `import o1.*` in your Scala programs. Some of them you’ll use a lot; some of them you won’t necessarily need at all. For a list of what is available there, see the docs for that package.

## Subpackages

The tools available in the top-level package `o1` are actually implemented in a number of subpackages (`o1.gui`, `o1.sound`, etc.). The top-level package contains “shortcut aliases” to those actual implementations. The aliases are there to enable the convenient `import o1.*` command.

The key subpackages are listed below. They contain some additional tools beyond what is available via `import o1.*`.

- o1.gui contains tools for building simple GUIs. The toolkit is particularly well suited to constructing GUIs that display information as 2D images and/or geometric shapes. It is not designed for demanding graphical needs that call for high efficiency. Some of these tools are built on the Swing GUI library, and the two libraries can be used in combination.

- `o1.sound` consists of two subpackages. One, o1.sound.midi, handles MIDI sound described in terms of notes, instruments, and other directives. Another, o1.sound.sampled, is for working with recorded sound samples.

- o1.world contains tools for locations and movement in two-dimensional space. The subpackage o1.world.objects contains additional tools for representing entities that reside within two-dimensional spaces.

- o1.grid contains tools for working with grid-like two-dimensional structures.

- o1.util contains miscellaneous tools for added convenience. They are used internally by some given programs in O1. The package is not directly relevant to O1 students. Not all of its contents are listed in this documentation.