Feature Flags

Opaline uses Cargo feature flags to keep the dependency tree lean. Enable only what you need.

Default Features

These are enabled by default with opaline = "0.4":

Feature	Description	Dependencies
builtin-themes	39 embedded TOML themes via include_str!	None
gradients	Multi-stop gradient support (Gradient type)	unicode-segmentation 1.12
ratatui	From impls, inherent span()/line()/text()/gradient_text() on Theme	ratatui-core 0.1

Optional Features

These must be explicitly enabled:

Feature	Description	Dependencies
cli	colored crate adapter: ThemeCliExt, ColoredExt, gradient_string	colored 3
crossterm	Direct crossterm adapter: Color, ContentStyle, gradient helpers	crossterm 0.29
owo-colors	Zero-allocation terminal coloring: Style conversion, OwoThemeExt	owo-colors 4
css	CSS custom properties + classes generation from tokens/styles/gradients	None
syntect	Syntax highlighting theme generation: Color, StyleModifier, Theme	syntect 5
egui	Immediate-mode GUI adapter: Color32, Visuals from theme tokens	egui 0.33
global-state	Process-wide theme singleton: current(), set_theme()	parking_lot 0.12
discovery	User theme directory scanning: app_theme_dirs(), theme_dirs()	dirs 6
widgets	Theme selector widget with live preview	ratatui 0.30, crossterm 0.29, unicode-width 0.2 (enables global-state + builtin-themes)

Configuration Examples

# Default: builtins + gradients + ratatui
[dependencies]
opaline = "0.4"

# Minimal: just the core engine, no builtins or adapters
[dependencies]
opaline = { version = "0.4", default-features = false }

# Core + gradients only (for non-Ratatui use)
[dependencies]
opaline = { version = "0.4", default-features = false, features = ["gradients"] }

# CLI tool (colored output, no TUI)
[dependencies]
opaline = { version = "0.4", features = ["cli"] }

# Direct crossterm styling
[dependencies]
opaline = { version = "0.4", features = ["crossterm"] }

# Zero-allocation terminal coloring
[dependencies]
opaline = { version = "0.4", features = ["owo-colors"] }

# CSS generation for web frameworks (Leptos, Yew, Dioxus, Tauri)
[dependencies]
opaline = { version = "0.4", features = ["css"] }

# Syntax highlighting theme generation
[dependencies]
opaline = { version = "0.4", features = ["syntect"] }

# egui GUI theming
[dependencies]
opaline = { version = "0.4", features = ["egui"] }

# Full TUI app with global state
[dependencies]
opaline = { version = "0.4", features = ["global-state"] }

# User-configurable themes
[dependencies]
opaline = { version = "0.4", features = ["discovery"] }

# TUI app with theme picker widget
[dependencies]
opaline = { version = "0.4", features = ["widgets"] }

# Everything
[dependencies]
opaline = { version = "0.4", features = [
    "builtin-themes", "gradients", "ratatui",
    "cli", "crossterm", "owo-colors", "css",
    "syntect", "egui",
    "global-state", "discovery", "widgets"
] }

Feature Interactions

Some features gate additional API when combined:

Combination	Unlocks
ratatui + gradients	theme.gradient_text(), gradient_spans(), gradient_line(), gradient_bar(), gradient_text_line()
cli + gradients	gradient_string() (colored crate)
crossterm + gradients	gradient_styled(), gradient_bar()
owo-colors + gradients	gradient_string() (owo-colors)
css + gradients	Gradient CSS custom properties as linear-gradient()
global-state + builtin-themes	load_theme_by_name(), load_theme_by_name_with()
builtin-themes + discovery	list_available_themes_for_app(), list_available_themes_in_dirs()
global-state + builtin-themes + discovery	load_theme_by_name_for_app(), load_theme_by_name_for_app_with(), load_theme_by_name_in_dirs()

Without Default Features

With default-features = false, you get:

• OpalineColor, OpalineStyle, OpalineError
• Theme, ThemeBuilder
• load_from_str(toml, None), load_from_file(path)
• Schema types (ThemeFile, ThemeMeta, StyleDef)
• Resolver pipeline

You lose:

• No builtin themes (must provide your own TOML)
• No gradient support
• No Ratatui type conversions