egui_styled

A styling layer for egui that adds per-widget hover/focus/active styling, semantic design tokens, and composable style functions. Tailwind-style utility styling for an immediate-mode toolkit, with Flutter-shaped widgets.

Build UI thinking about what things look like, rather than how egui's internals work.

Why?

egui's styling lives on ui.visuals_mut(), which is global to the current Ui. Applying a custom hover color to one button means cloning the visuals, mutating three WidgetVisuals states, and wrapping in ui.scope every time on every widget. The pattern is correct but is tricky to scale.

egui_styled wraps egui's widgets with builder APIs that handle the visuals dance for you, and adds a small theme system so colors/spacing/radii live in one place.

Before / After

A card with two themed text inputs and two buttons.

With egui_styled

use egui_styled::prelude::*;

// One line fetches both. `WebPalette` is the opt-in starter color set;
// swap for your own struct (game palette, IDE syntax theme, etc).
let (t, c) = ui.ctx().design::<WebPalette>();

Styled::frame()
    .bg(c.bg_surface)
    .corner_radius(t.rounding_lg)
    .padding(t.spacing_lg)
    .border(1.0, c.border)
    .show(ui, |ui| {
        Styled::text_edit(&mut username)
            .hint("Username")
            .full_width()
            .bg(c.bg_secondary)
            .corner_radius(t.rounding_md)
            .border(1.0, c.border)
            .focus_border(1.0, c.border_focus)
            .show(ui);
        Styled::text_edit(&mut email)
            .hint("Email")
            .full_width()
            .bg(c.bg_secondary)
            .corner_radius(t.rounding_md)
            .border(1.0, c.border)
            .focus_border(1.0, c.border_focus)
            .show(ui);
        Styled::row().gap(t.spacing_sm).show(ui, |ui| {
            Styled::button("Cancel")
                .bg(Color32::TRANSPARENT)
                .hover_bg(c.bg_elevated)
                .show(ui);
            Styled::button("Save")
                .bg(c.accent)
                .hover_bg(c.accent_hover)
                .text_color(c.fg_on_accent)
                .show(ui);
        });
    });

ui.scope(|ui| {
    egui::Frame::none()
        .fill(rgb(30, 30, 30))
        .rounding(Rounding::same(8.0))
        .inner_margin(Margin::same(16.0))
        .stroke(Stroke::new(1.0, rgb(60, 60, 60)))
        .show(ui, |ui| {
            // Username copy 1 of 2
            ui.scope(|ui| {
                let v = ui.visuals_mut();
                v.widgets.inactive.rounding  = Rounding::same(4.0);
                v.widgets.active.rounding    = Rounding::same(4.0);
                v.widgets.hovered.rounding   = Rounding::same(4.0);
                v.widgets.inactive.bg_fill   = rgb(20, 20, 20);
                v.widgets.active.bg_fill     = rgb(20, 20, 20);
                v.widgets.hovered.bg_fill    = rgb(25, 25, 25);
                v.widgets.inactive.bg_stroke = Stroke::new(1.0, rgb(60, 60, 60));
                v.widgets.active.bg_stroke   = Stroke::new(1.0, rgb(100, 100, 255));
                v.widgets.hovered.bg_stroke  = Stroke::new(1.0, rgb(80, 80, 80));
                ui.add(TextEdit::singleline(&mut username)
                    .hint_text("Username")
                    .desired_width(f32::INFINITY));
            });
            // Email copy 2 of 2
            ui.scope(|ui| {
                let v = ui.visuals_mut();
                v.widgets.inactive.rounding  = Rounding::same(4.0);
                v.widgets.active.rounding    = Rounding::same(4.0);
                v.widgets.hovered.rounding   = Rounding::same(4.0);
                v.widgets.inactive.bg_fill   = rgb(20, 20, 20);
                v.widgets.active.bg_fill     = rgb(20, 20, 20);
                v.widgets.hovered.bg_fill    = rgb(25, 25, 25);
                v.widgets.inactive.bg_stroke = Stroke::new(1.0, rgb(60, 60, 60));
                v.widgets.active.bg_stroke   = Stroke::new(1.0, rgb(100, 100, 255));
                v.widgets.hovered.bg_stroke  = Stroke::new(1.0, rgb(80, 80, 80));
                ui.add(TextEdit::singleline(&mut email)
                    .hint_text("Email")
                    .desired_width(f32::INFINITY));
            });
            // Buttons with custom hover - another scope+visuals_mut each
            ui.horizontal(|ui| {
                ui.scope(|ui| {
                    let v = ui.visuals_mut();
                    v.widgets.inactive.bg_fill = Color32::TRANSPARENT;
                    v.widgets.hovered.bg_fill  = rgb(40, 40, 40);
                    ui.button("Cancel");
                });
                ui.scope(|ui| {
                    let v = ui.visuals_mut();
                    v.widgets.inactive.bg_fill = rgb(60, 60, 255);
                    v.widgets.hovered.bg_fill  = rgb(80, 80, 255);
                    v.widgets.active.bg_fill   = rgb(40, 40, 200);
                    v.widgets.inactive.fg_stroke = Stroke::new(1.0, Color32::WHITE);
                    ui.button("Save");
                });
            });
        });
});

Same UI, ~50 lines vs ~30 and the raw-egui side is mostly visuals_mut copy-paste. Per-widget hover/focus colors. Once you start composing styles, the duplication on the After side collapses too.

Fair comparison: you can also factor the raw-egui side into helper functions, which closes most of the line gap (~25 vs ~20). The bigger remaining win is what kind of helper you can write: in raw egui, your helper has to take &mut Ui and render immediately. In egui_styled a style helper returns impl Fn(W) -> W, a pure value you can store, compose with other helpers, or tweak per call site (.apply(primary_button(&t)).margin_top(8.0)). Uniformity matters too: every helper in egui_styled has the same shape regardless of whether it styles a button, frame, or input.

Features

Installation

[dependencies]
egui_styled = "0.1"
egui = "0.34"

Design tokens

egui_styled ships geometry/typography tokens in [StyledTheme] (universally useful - spacing, radii, font sizes, font families) and an optional starter color palette in [WebPalette] (semantic web-style color names). Colors are inherently domain-specific, so the library doesn't force its vocabulary on you - for games, IDEs, or anything else, define your own struct and store it via the generic DesignSlots mechanism.

Geometry (StyledTheme)

use egui::{CornerRadius, FontFamily};
use egui_styled::prelude::*;

pub fn geometry() -> StyledTheme {
    StyledTheme {
        rounding_sm: CornerRadius::same(2),
        rounding_md: CornerRadius::same(4),
        rounding_lg: CornerRadius::same(8),
        rounding_full: CornerRadius::same(u8::MAX),
        spacing_xs: 2.0, spacing_sm: 4.0, spacing_md: 8.0, spacing_lg: 16.0, spacing_xl: 32.0,
        font_size_sm: 12.0, font_size_md: 14.0, font_size_lg: 18.0, font_size_xl: 24.0,
        // Swap for `FontFamily::Name("YourFont".into())` after registering
        // the font with egui at startup.
        font_family_display: FontFamily::Proportional,
        font_family_body:    FontFamily::Proportional,
        font_family_mono:    FontFamily::Monospace,
    }
}

Pair the family tokens with the size scale at the call site via the helper methods:

Styled::label("Score")
    .font(theme.font_display(theme.font_size_xl))
    .show(ui);

Colors - Option A: use the starter palette

If your app fits a web/dashboard vocabulary (accent, error, warning, success, fg_on_accent, etc.), use [WebPalette]:

use egui::Color32;
use egui_styled::prelude::*;

pub fn dark_palette() -> WebPalette {
    WebPalette {
        bg_primary:    Color32::from_rgb(15, 15, 15),
        bg_secondary:  Color32::from_rgb(20, 20, 20),
        bg_surface:    Color32::from_rgb(30, 30, 30),
        bg_elevated:   Color32::from_rgb(40, 40, 40),
        fg_primary:    Color32::from_gray(240),
        fg_secondary:  Color32::from_gray(180),
        fg_muted:      Color32::from_gray(120),
        fg_on_accent:  Color32::WHITE,
        accent:        Color32::from_rgb(60, 60, 255),
        accent_hover:  Color32::from_rgb(80, 80, 255),
        accent_active: Color32::from_rgb(40, 40, 200),
        error:         Color32::from_rgb(255, 80, 80),
        warning:       Color32::from_rgb(255, 180, 60),
        success:       Color32::from_rgb(80, 200, 120),
        border:        Color32::from_rgb(60, 60, 60),
        border_focus:  Color32::from_rgb(100, 100, 255),
    }
}

Colors - Option B: define your own

If your app has domain-specific colors that don't fit web semantics (game HUDs, IDE syntax, etc.), define your own struct and store it the same way:

use egui::{Color32, FontFamily};
use egui_styled::prelude::*;

#[derive(Clone, Default)]
struct ArcadeColors {
    pub hud_glow:      Color32,
    pub enemy_red:     Color32,
    pub powerup_yellow: Color32,
    pub score_bg:      Color32,
}

Storing and reading

Both StyledTheme and any user-defined type are stored on egui::Context via the same primitive:

// Once at startup
ctx.set_styled_theme(geometry());
ctx.set_design_data(dark_palette());     // or ArcadeColors { ... }

// Anywhere in your UI
let t = ui.ctx().styled_theme();
let p = ui.ctx().design_data::<WebPalette>();   // or ::<ArcadeColors>()

DesignSlots is the underlying typed-storage trait - one slot per TypeId. ThemeExt::set_styled_theme / styled_theme are convenience wrappers over it. If you need two slots of the same underlying type (two Vec<Color32> palettes, etc.), newtype them.

See examples/theme_demo.rs for two themes (midnight, parchment) you can use as starting points.

Composing styles

Reuse styling across call sites with the Apply trait. Since colors and geometry are separate, helpers typically close over both:

fn primary_button(t: &StyledTheme, p: &WebPalette)
    -> impl Fn(StyledButton) -> StyledButton + 'static
{
    let (t, p) = (t.clone(), p.clone());
    move |b| {
        b.bg(p.accent)
         .hover_bg(p.accent_hover)
         .active_bg(p.accent_active)
         .text_color(p.fg_on_accent)
         .corner_radius(t.rounding_md)
    }
}

Styled::button("Save").apply(primary_button(&t, &p)).show(ui);

Apply is implemented for every styled type and is in the prelude.

The library doesn't ship preset helpers like primary_button - what's "primary" is a product decision, not a library one. Define them in your app the way above, alongside whatever color type you've chosen.

Examples

cargo run --example basic              # buttons + frame
cargo run --example containers         # row / column / nesting
cargo run --example text_edit          # focus state styling
cargo run --example theme_demo         # live theme switching with swatches
cargo run --example composable_styles  # Apply + reusable style functions
cargo run --example all_widgets        # every widget in one screen
cargo run --example game_over          # full game-over screen - Area + Column + custom palette

Performance

Per styled widget the overhead vs raw egui is approximately:

• 1 ui.scope (which egui itself uses constantly internally)
• 2 egui::Memory lookups (pseudo-state load/store)
• 1 SharedStyle::resolve (a branch chain over Options)

Mostly stack work, plus a few small heap allocations per widget: a Visuals clone, the scope's child Ui state, occasional short strings when a font override round-trips through RichText on text widgets.

Status

Pre-1.0. The API surface is functional but not used in anger. Expect rough edges, especially around slider and combo box styling. Feedback and bug reports welcome.

License

MIT or Apache-2.0, at your option.