r3bl_ansi_color

Why R3BL?

R3BL TUI library & suite of apps focused on developer productivity

We are working on building command line apps in Rust which have rich text user interfaces (TUI). We want to lean into the terminal as a place of productivity, and build all kinds of awesome apps for it.

1. 🔮 Instead of just building one app, we are building a library to enable any kind of rich TUI development w/ a twist: taking concepts that work really well for the frontend mobile and web development world and re-imagining them for TUI & Rust.

   • Taking inspiration from things like React, SolidJS, Elm, iced-rs, Jetpack Compose, JSX, CSS, but making everything async (so they can be run in parallel & concurrent via Tokio).
   • Even the thread running the main event loop doesn't block since it is async.
   • Using proc macros to create DSLs to implement something inspired by CSS & JSX.

2. 🌎 We are building apps to enhance developer productivity & workflows.

   • The idea here is not to rebuild tmux in Rust (separate processes mux'd onto a single terminal window). Rather it is to build a set of integrated "apps" (or "tasks") that run in the same process that renders to one terminal window.
   • Inside of this terminal window, we can implement things like "app" switching, routing, tiling layout, stacking layout, etc. so that we can manage a lot of TUI apps (which are tightly integrated) that are running in the same process, in the same window. So you can imagine that all these "app"s have shared application state. Each "app" may also have its own local application state.
   • Here are some examples of the types of "app"s we plan to build (for which this infrastructure acts as the open source engine):
     1. Multi user text editors w/ syntax highlighting.
     2. Integrations w/ github issues.
     3. Integrations w/ calendar, email, contacts APIs.

All the crates in the r3bl-open-core repo provide lots of useful functionality to help you build TUI (text user interface) apps, along w/ general niceties & ergonomics that all Rustaceans 🦀 can enjoy 🎉.

Table of contents

• Introduction
• Changelog
• Learn how these crates are built, provide feedback
• How to use it
• Build, run, test tasks
  • Prerequisites
  • Nushell commands
• References
• Why make a new crate for this?

Introduction

Rust crate to generate formatted ANSI 256 (8-bit) and truecolor (24-bit) color output to stdout. On macOS, the default Terminal.app does not support truecolor, so ANSI 256 colors are used instead.

This crate performs its own detection of terminal color capability heuristically. And does not use other crates to perform this function.

Here's a screenshot of running the main example on various operating systems:

Running on Linux Tilix

Running on Windows Terminal

Running on macOS terminal app (note ANSI 256 runtime detection)

Running on macOS iTerm app (note Truecolor runtime detection)

Changelog

Please check out the changelog to see how the library has evolved over time.

Learn how these crates are built, provide feedback

To learn how we built this crate, please take a look at the following resources.

• If you like consuming video content, here's our YT channel. Please consider subscribing.
• If you like consuming written content, here's our developer site. Please consider subscribing to our newsletter.
• If you have questions, please join our discord server.

How to use it

The main struct that we have to consider is AnsiStyledText. It has two fields:

• text - the text to print.
• style - a list of styles to apply to the text.

Here's an example.

use r3bl_ansi_color::{AnsiStyledText, Style, Color};

AnsiStyledText {
    text: "Print a formatted (bold, italic, underline) string w/ ANSI color codes.",
    style: &[
        Style::Bold,
        Style::Italic,
        Style::Underline,
        Style::Foreground(Color::Rgb(50, 50, 50)),
        Style::Background(Color::Rgb(100, 200, 1)),
    ],
}
.println();

Please a look at the main example to get a better idea of how to use this crate.

Build, run, test tasks

Prerequisites

🌠 In order for these to work you have to install the Rust toolchain and nu and cargo-watch:

1. Install the Rust toolchain using rustup by following the instructions here.
2. Install cargo-watch using cargo install cargo-watch.
3. Install flamegraph using cargo install flamegraph.
4. Install nu on your system using cargo install nu. It is available for Linux, macOS, and Windows. And it is written in Rust.

Nushell commands

The following commands will watch for changes in the source folder and re-run:

References

• ANSI Escape Codes
• ASCII Table
• Xterm 256color Chart
• 256 Colors Cheat Sheet
• List of ANSI Color Escape Sequences
• Color Metric

Why make a new crate for this?

• There are a few crates on crates.io that do similar things but they don't amenable licenses.
• Other crates simply ignore ANSI 256 colors and only support truecolor, even when they claim that they support it.
• And there are other crates which don't correctly report that macOS Terminal.app does not support truecolor and only supports ANSI 256 color.

Here are some relevant links:

1. Issue 47: concolor
2. anstream documentation
3. colorchoice documentation
4. colorchoice-clap documentation
5. term_supports_ansi_color function
6. anstyle-query crate
7. supports-color documentation
8. r3bl_ansi_color crate (the source in ansi_color folder is this crate)
9. colored crate

License: Apache-2.0