Theming and localization

Themes are Rust values. Theme supplies dark, light and high-contrast presets, and public fields for customization. The token layer defines spacing, sizing and semantic colours used by the chart and application components.

Apply a theme

use egui_charts::{ChartBuilder, theme::{self, Theme}};

let context = egui::Context::default();
let theme = Theme::dark();
theme::apply_to_egui(&context, &theme);
let mut chart = ChartBuilder::new().with_theme(theme).build();

Apply the theme at startup to propagate tokens into egui. Chart::set_theme updates an existing chart and the context. Use set_theme_override for a local chart theme when multiple charts need different appearances. Enable serde to serialize Theme in host settings.

Fonts and images

apply_to_egui installs the bundled Roboto face ahead of the application’s proportional fonts. To replace it, call Context::set_fonts afterwards. The host supplies additional glyph coverage. The chart installs SVG image loading; applications displaying other image formats install their own loaders.

Translate the interface

Install a host text lookup with localization::set_translator before drawing. Missing entries keep English text. Replacing or clearing the lookup takes effect on the next frame; translations and fonts belong to the host. UI labels and accessibility names use that lookup, while dates and numbers use the chart’s formatters and locale. Chart::set_locale controls localized calendar labels; locales enables the locale tables.