ui::OsThemeSnapshot¶

Header: winui/ui/themes/ThemeSource.hpp.

The system's theme settings, before any app override is applied.

The library reads one from the system's settings. A default-constructed snapshot is light, with Windows' default blue accent and no high contrast, which resolves to the colors Windows 11 shows out of the box.

Example:

// Preview both modes side by side, whatever the OS is set to.
const ui::Theme light = ui::resolve_theme(ui::ThemeRequest{}, ui::OsThemeSnapshot{.dark = false});
const ui::Theme dark  = ui::resolve_theme(ui::ThemeRequest{}, ui::OsThemeSnapshot{.dark = true});

ui::Window light_preview{{.title = "Light"}};
ui::Window dark_preview{{.title = "Dark"}};
light_preview.pin_theme(light);
dark_preview.pin_theme(dark);

Field	Type	Default
`dark`	`bool`	`false`	The system's app mode: true when "Choose your app mode" is set to Dark.
`accent`	`Color`	`Color::from_argb(0xFF0078D4)`	The user's accent color.
`accent_ramp`	`AccentRamp`		The system's lighter and darker shades of `accent`. The defaults are the shades of Windows' default blue.
`high_contrast`	`bool`	`false`	Whether a contrast theme is on. When true, resolve_theme() draws with `hc` whatever the ThemeRequest says.
`hc`	`HighContrastPalette`		The contrast theme's colors. Only read while `high_contrast` is true.
`menu_animation`	`bool`	`true`	The system's menu animation setting. With `menu_fade` and `combo_box_animation`, it sets how popups open in the Luna and Aero themes (`Theme::popup_motion`). All three are on by default. This one and `combo_box_animation` are off while the system turns UI effects off.
`menu_fade`	`bool`	`true`	See `menu_animation`: whether menus fade in (true) or slide in.
`combo_box_animation`	`bool`	`true`	See `menu_animation`: whether combo box drop-downs slide open.
`animations_enabled`	`bool`	`true`	The system's "Animation effects" setting. ThemeRequest::animations follows it by default.
`transparency_enabled`	`bool`	`true`	Whether the system draws transparency: "Transparency effects" is on in Settings, and neither Energy Saver nor a remote session turns it off. Fluent 2's in-app acrylic (Theme::overlay_material) follows it.
`system_variant`	`ThemeVariant`	`ThemeVariant::Fluent2`	What ThemeVariant::System draws: Fluent2 on Windows 11 (build 22000 and later), Fluent on any earlier Windows.