egui Adapter

The egui feature maps Opaline themes onto egui's Visuals system, bringing token-based theming to immediate-mode GUI applications.

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

Color Conversion

OpalineColor converts to egui::Color32:

use opaline::OpalineColor;
use egui::Color32;

let color = OpalineColor::new(225, 53, 255);
let egui_color: Color32 = color.into();
// → Color32::from_rgb(225, 53, 255)

Visuals Generation

Convert a full Opaline theme to egui Visuals:

use opaline::adapters::egui::to_egui_visuals;

let theme = opaline::Theme::default();
let visuals = to_egui_visuals(&theme);

// Apply in your egui app
ctx.set_visuals(visuals);

The function starts from Visuals::dark() or Visuals::light() based on the theme variant, then overrides the main color properties. Text cursor, shadow, and text-edit colors keep egui's defaults, as do non-color properties (corner radii, shadows, spacing).

Token → Visuals Mapping

Opaline Token	Visuals Field
bg.base	panel_fill, widgets.noninteractive.bg_fill
bg.panel	window_fill, widgets.inactive.bg_fill
bg.highlight	faint_bg_color, widgets.hovered.bg_fill
bg.code	code_bg_color
bg.selection	selection.bg_fill, widgets.active.bg_fill
text.primary	widgets.open.fg_stroke
bg.base ±0.5	extreme_bg_color (darkened for dark themes, lightened for light)
text.secondary	widgets.inactive.fg_stroke
text.muted	widgets.noninteractive.fg_stroke
accent.primary	hyperlink_color, selection.stroke, widgets.hovered.fg_stroke
accent.secondary	widgets.open.bg_stroke
border.focused	widgets.hovered.bg_stroke
border.unfocused	window_stroke, widgets.noninteractive.bg_stroke
warning	warn_fg_color
error	error_fg_color

Widget States

Each widget state uses a different layer of the theme:

Widget State	Background	Foreground	Border
Noninteractive	bg.base	text.muted	border.unfocused
Inactive	bg.panel	text.secondary	border.unfocused
Hovered	bg.highlight	accent.primary	border.focused
Active	bg.selection	accent.primary	accent.primary
Open	bg.highlight	text.primary	accent.secondary

Runtime Theme Switching

use opaline::adapters::egui::to_egui_visuals;

fn switch_theme(ctx: &egui::Context, theme_name: &str) {
    let theme = opaline::load_by_name(theme_name).expect("valid theme");
    ctx.set_visuals(to_egui_visuals(&theme));
}

All 39 builtin themes work with egui. Dark themes start from Visuals::dark(), light themes from Visuals::light().