Hallucination

A library for working with images in Scala

Images are commonplace in many programming environments, so they ought to be as easy to work with as text. Hallucination aspires to make this possible.

Features

• simple immutable API for reading and writing image files
• supports standard Java ImageIO formats: GIF, JPEG, BMP and PNG
• read directly from any Turbulence source
• access image metadata and individual pixel colors

Availability Plan

Hallucination has not yet been published. The medium-term plan is to build Hallucination with Fury and to publish it as a source build on Vent. This will enable ordinary users to write and build software which depends on Hallucination.

Subsequently, Hallucination will also be made available as a binary in the Maven Central repository. This will enable users of other build tools to use it.

For the overeager, curious and impatient, see building.

Getting Started

All terms and types are define in the hallucination package, and can be used with:

import hallucination.*

Reading images

To read an image of a known type, the read method of its codec object should be used. Currently, four codecs are defined:

• Png
• Gif
• Jpeg, and
• Bmp

The source of the image may be any source that can be read as Bytes by Turbulence, for example:

import galilei.*

val image = Png.read(% / p"home" / p"work" / p"image.png")

The resultant value will be an instance of Image[Png], that is, an Image parameterized with the erased phantom type Png.

It's possible to use Turbulence's readAs method to read an Image[?] from a source of Bytes, for example:

import turbulence.*
import hellenism.*

val icon = (Classpath / p"icon.bmp").readAs[Image[Bmp]]

Accessing Image data

The width and height of the image are available through the width and height methods of Image[?].

The color of the pixel at given coordinates within the image can be accessed, as an Rgb24 value, using Image's apply method, i.e. image(x, y).

Status

Hallucination is classified as embryotic. For reference, Scala One projects are categorized into one of the following five stability levels:

• embryonic: for experimental or demonstrative purposes only, without any guarantees of longevity
• fledgling: of proven utility, seeking contributions, but liable to significant redesigns
• maturescent: major design decisions broady settled, seeking probatory adoption and refinement
• dependable: production-ready, subject to controlled ongoing maintenance and enhancement; tagged as version 1.0.0 or later
• adamantine: proven, reliable and production-ready, with no further breaking changes ever anticipated

Projects at any stability level, even embryonic projects, can still be used, as long as caution is taken to avoid a mismatch between the project's stability level and the required stability and maintainability of your own project.

Hallucination is designed to be small. Its entire source code currently consists of 60 lines of code.

Building

Hallucination will ultimately be built by Fury, when it is published. In the meantime, two possibilities are offered, however they are acknowledged to be fragile, inadequately tested, and unsuitable for anything more than experimentation. They are provided only for the necessity of providing some answer to the question, "how can I try Hallucination?".

1. Copy the sources into your own project

   Read the fury file in the repository root to understand Hallucination's build structure, dependencies and source location; the file format should be short and quite intuitive. Copy the sources into a source directory in your own project, then repeat (recursively) for each of the dependencies.

   The sources are compiled against the latest nightly release of Scala 3. There should be no problem to compile the project together with all of its dependencies in a single compilation.

2. Build with Wrath

   Wrath is a bootstrapping script for building Hallucination and other projects in the absence of a fully-featured build tool. It is designed to read the fury file in the project directory, and produce a collection of JAR files which can be added to a classpath, by compiling the project and all of its dependencies, including the Scala compiler itself.

   Download the latest version of wrath, make it executable, and add it to your path, for example by copying it to /usr/local/bin/.

   Clone this repository inside an empty directory, so that the build can safely make clones of repositories it depends on as peers of hallucination. Run wrath -F in the repository root. This will download and compile the latest version of Scala, as well as all of Hallucination's dependencies.

   If the build was successful, the compiled JAR files can be found in the .wrath/dist directory.

Contributing

Contributors to Hallucination are welcome and encouraged. New contributors may like to look for issues marked beginner.

We suggest that all contributors read the Contributing Guide to make the process of contributing to Hallucination easier.

Please do not contact project maintainers privately with questions unless there is a good reason to keep them private. While it can be tempting to repsond to such questions, private answers cannot be shared with a wider audience, and it can result in duplication of effort.

Author

Hallucination was designed and developed by Jon Pretty, and commercial support and training on all aspects of Scala 3 is available from Propensive OÜ.

Name

An hallucination is a sensation of something appearing real, but existing only in ones mind. An image is a visual hallucination.

In general, Scala One project names are always chosen with some rationale, however it is usually frivolous. Each name is chosen for more for its uniqueness and intrigue than its concision or catchiness, and there is no bias towards names with positive or "nice" meanings—since many of the libraries perform some quite unpleasant tasks.

Names should be English words, though many are obscure or archaic, and it should be noted how willingly English adopts foreign words. Names are generally of Greek or Latin origin, and have often arrived in English via a romance language.

Logo

Hallucination's logo is a simplistic eye, the organ that is stimulated by images.

License

Hallucination is copyright © 2024 Jon Pretty & Propensive OÜ, and is made available under the Apache 2.0 License.