Centralize accent foreground contrast across Ferese UI

Cargo.lock

@@ -1709,6 +1709,7 @@ name = "ferese-lock"
 version = "0.1.0"
 dependencies = [
  "ferese-config",
+ "ferese-theme",
  "image",
  "jiff",
  "libc",
@@ -1737,6 +1738,7 @@ version = "0.1.0"
 dependencies = [
  "ferese-config",
  "ferese-ipc",
+ "ferese-theme",
  "image",
  "libcosmic",
  "notify",
@@ -1753,6 +1755,7 @@ dependencies = [
  "ferese-config",
  "ferese-core",
  "ferese-protocols",
+ "ferese-theme",
  "iced_accessibility",
  "jiff",
  "libcosmic",
@@ -1764,6 +1767,13 @@ dependencies = [
  "zbus",
 ]
 
+[[package]]
+name = "ferese-theme"
+version = "0.1.0"
+dependencies = [
+ "libcosmic",
+]
+
 [[package]]
 name = "feresectl"
 version = "0.1.0"
@@ -7371,6 +7381,7 @@ version = "0.1.0"
 dependencies = [
  "dirs",
  "ferese-config",
+ "ferese-theme",
  "futures-util",
  "gstreamer",
  "jiff",

Cargo.toml

@@ -5,6 +5,7 @@ members = [
     "crates/ferese-animation",
     "crates/ferese-core",
     "crates/ferese-config",
+    "crates/ferese-theme",
     "crates/ferese-ipc",
     "crates/ferese-layout",
     "crates/ferese-protocols",

crates/ferese-theme/Cargo.toml

@@ -0,0 +1,9 @@
+[package]
+name = "ferese-theme"
+version.workspace = true
+edition.workspace = true
+license.workspace = true
+rust-version = "1.95"
+
+[dependencies]
+libcosmic.workspace = true

crates/ferese-theme/src/lib.rs

@@ -0,0 +1,226 @@
+//! Ferese owns foreground contrast; toolkit defaults must not choose it separately.
+use cosmic::{
+    iced::{Background, Color},
+    theme,
+    widget::button,
+};
+
+pub fn luminance(color: Color) -> f32 {
+    let linear = |v: f32| {
+        if v <= 0.04045 {
+            v / 12.92
+        } else {
+            ((v + 0.055) / 1.055).powf(2.4)
+        }
+    };
+    0.2126 * linear(color.r) + 0.7152 * linear(color.g) + 0.0722 * linear(color.b)
+}
+
+pub fn contrast(a: Color, b: Color) -> f32 {
+    let (a, b) = (luminance(a), luminance(b));
+    (a.max(b) + 0.05) / (a.min(b) + 0.05)
+}
+
+/// Resolve a control fill against its surface before selecting its foreground.
+/// The returned fill is opaque, so wallpaper and translucent panels cannot change
+/// the contrast of a small, filled control.
+pub fn composite(fill: Color, surface: Color) -> Color {
+    let a = fill.a.clamp(0., 1.);
+    Color::from_rgb(
+        fill.r * a + surface.r * (1. - a),
+        fill.g * a + surface.g * (1. - a),
+        fill.b * a + surface.b * (1. - a),
+    )
+}
+
+/// Preserve the user's preferred color when it passes normal-text contrast.
+/// Otherwise black or white always provides at least 4.5:1 on an opaque sRGB fill.
+pub fn foreground(background: Color, preferred: Color) -> Color {
+    let preferred = composite(preferred, background);
+    if contrast(background, preferred) >= 4.5 {
+        return preferred;
+    }
+    if contrast(background, Color::BLACK) >= contrast(background, Color::WHITE) {
+        Color::BLACK
+    } else {
+        Color::WHITE
+    }
+}
+
+/// Resolve configured accent transparency before passing an opaque color to a toolkit.
+pub fn accent_color(accent: Color, surface: Color) -> cosmic::cosmic_theme::palette::Srgb {
+    rgba(composite(accent, surface)).color
+}
+
+/// Supply the same semantic on-accent colors to native toolkit controls.
+pub fn apply(native: &mut cosmic::cosmic_theme::Theme, preferred: Color) {
+    let surface: Color = native.primary(false).base.into();
+    for component in [&mut native.accent, &mut native.accent_button] {
+        let base = composite(component.base.into(), surface);
+        let on = foreground(base, preferred);
+        component.hover = rgba(readable_fill(
+            composite(component.hover.into(), surface),
+            base,
+            on,
+        ));
+        component.pressed = rgba(readable_fill(
+            composite(component.pressed.into(), surface),
+            base,
+            on,
+        ));
+        component.selected = rgba(composite(component.selected.into(), surface));
+        component.base = rgba(base);
+        component.on = rgba(on);
+        component.selected_text = rgba(foreground(
+            composite(component.selected.into(), surface),
+            on,
+        ));
+        component.disabled = rgba(composite(Color { a: 0.5, ..base }, surface));
+        component.on_disabled = rgba(foreground(composite(Color { a: 0.5, ..base }, surface), on));
+    }
+}
+
+// Native controls reuse one foreground for normal/hover/pressed. Keep their
+// hover feedback, but pull an unreadable fill toward the readable normal fill.
+fn readable_fill(candidate: Color, base: Color, on: Color) -> Color {
+    for step in 0..=20 {
+        let t = step as f32 / 20.;
+        let fill = Color::from_rgb(
+            candidate.r + (base.r - candidate.r) * t,
+            candidate.g + (base.g - candidate.g) * t,
+            candidate.b + (base.b - candidate.b) * t,
+        );
+        if contrast(fill, on) >= 4.5 {
+            return fill;
+        }
+    }
+    base
+}
+
+fn rgba(c: Color) -> cosmic::cosmic_theme::palette::Srgba {
+    cosmic::cosmic_theme::palette::Srgba::new(c.r, c.g, c.b, c.a)
+}
+
+#[derive(Clone, Copy)]
+enum State {
+    Active,
+    Hovered,
+    Pressed,
+    Disabled,
+}
+
+fn style(theme: &cosmic::Theme, state: State, focused: bool) -> button::Style {
+    let native = theme.cosmic();
+    let component = &native.accent_button;
+    let fill: Color = match state {
+        State::Active => component.base.into(),
+        State::Hovered => component.hover.into(),
+        State::Pressed => component.pressed.into(),
+        State::Disabled => Color {
+            a: 0.5,
+            ..component.base.into()
+        },
+    };
+    let background = composite(fill, native.primary(false).base.into());
+    let foreground = foreground(background, component.on.into());
+    button::Style {
+        background: Some(Background::Color(background)),
+        text_color: Some(foreground),
+        icon_color: Some(foreground),
+        border_radius: native.corner_radii.radius_xl.into(),
+        outline_width: if focused { 1. } else { 0. },
+        outline_color: foreground,
+        ..Default::default()
+    }
+}
+
+/// Filled accent buttons and selected rows share this per-state contrast policy.
+pub fn accent_button() -> theme::Button {
+    theme::Button::Custom {
+        active: Box::new(|focused, theme| style(theme, State::Active, focused)),
+        hovered: Box::new(|focused, theme| style(theme, State::Hovered, focused)),
+        pressed: Box::new(|focused, theme| style(theme, State::Pressed, focused)),
+        disabled: Box::new(|theme| style(theme, State::Disabled, false)),
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    #[test]
+    fn reference_contrast_values_use_linear_srgb() {
+        assert!((contrast(Color::BLACK, Color::WHITE) - 21.).abs() < 0.00001);
+        assert!((contrast(Color::from_rgb8(128, 128, 128), Color::BLACK) - 5.31721).abs() < 0.0001);
+    }
+    #[test]
+    fn foreground_preserves_readable_theme_text_and_rejects_low_contrast() {
+        let preferred = Color::from_rgb8(240, 242, 246);
+        assert_eq!(foreground(Color::BLACK, preferred), preferred);
+        assert_eq!(foreground(Color::WHITE, preferred), Color::BLACK);
+        assert_eq!(
+            foreground(Color::from_rgb8(61, 123, 230), preferred),
+            Color::BLACK
+        );
+    }
+    #[test]
+    fn all_accent_hues_and_opacities_have_readable_text() {
+        for r in (0..=255).step_by(17) {
+            for g in (0..=255).step_by(17) {
+                for b in (0..=255).step_by(17) {
+                    for surface in [Color::BLACK, Color::WHITE] {
+                        for alpha in [0., 0.2, 0.5, 1.] {
+                            let fill = composite(Color::from_rgba8(r, g, b, alpha), surface);
+                            let on = foreground(fill, Color::from_rgb8(120, 130, 140));
+                            assert!(contrast(fill, on) >= 4.5, "{fill:?}: {on:?}");
+                        }
+                    }
+                }
+            }
+        }
+    }
+    #[test]
+    fn native_button_states_keep_text_and_icons_readable() {
+        for accent in [
+            Color::BLACK,
+            Color::WHITE,
+            Color::from_rgb8(61, 123, 230),
+            Color::from_rgb8(255, 220, 0),
+        ] {
+            for mut native in [
+                cosmic::cosmic_theme::ThemeBuilder::dark()
+                    .accent(rgba(accent).color)
+                    .build(),
+                cosmic::cosmic_theme::ThemeBuilder::light()
+                    .accent(rgba(accent).color)
+                    .build(),
+            ] {
+                apply(&mut native, Color::from_rgb8(244, 247, 251));
+                for component in [&native.accent, &native.accent_button] {
+                    for fill in [component.base, component.hover, component.pressed] {
+                        assert!(contrast(fill.into(), component.on.into()) >= 4.5);
+                    }
+                    assert!(
+                        contrast(component.selected.into(), component.selected_text.into()) >= 4.5
+                    );
+                    assert!(
+                        contrast(component.disabled.into(), component.on_disabled.into()) >= 4.5
+                    );
+                }
+                let theme = cosmic::Theme::custom(std::sync::Arc::new(native));
+                for state in [
+                    State::Active,
+                    State::Hovered,
+                    State::Pressed,
+                    State::Disabled,
+                ] {
+                    let style = style(&theme, state, false);
+                    let Some(Background::Color(fill)) = style.background else {
+                        panic!("No fill")
+                    };
+                    assert_eq!(style.text_color, style.icon_color);
+                    assert!(contrast(fill, style.text_color.unwrap()) >= 4.5);
+                }
+            }
+        }
+    }
+}

docs/configuration.md

@@ -145,6 +145,15 @@ these six visually distinct.
 | `border` | `"#FFFFFF18"` | Unfocused window border |
 | `shadow` | `"#00000055"` | Window shadow color |
 
+Ferese derives the text and icon color for filled accent controls from the
+configured theme. It keeps the configured text color when it reaches a 4.5:1
+contrast ratio; otherwise it chooses black or white. The same rule is shared by
+native dialogs, settings selections, and notification badges. Hover, pressed,
+and disabled accent-button states use the same policy. Small filled controls
+resolve accent transparency against their theme surface so wallpaper cannot
+make their labels unreadable. No separate per-application color setting is needed.
+The target follows [normal-text contrast guidance](https://www.w3.org/WAI/WCAG22/Understanding/contrast-minimum.html).
+
 | `theme.geometry` key | Type | Default | Meaning |
 | --- | --- | --- | --- |
 | `border_width` | number ≥ 0 | `1` | Window border thickness |

portal/Cargo.toml

@@ -14,6 +14,7 @@ name = "ferese-record"
 path = "src/record_main.rs"
 
 [dependencies]
+ferese-theme = { path = "../crates/ferese-theme" }
 gstreamer = "0.24"
 futures-util = "0.3"
 dirs = "6"

portal/src/picker.rs

@@ -174,7 +174,7 @@ impl cosmic::Application for Picker {
                 sources = sources.push(
                     button::custom(entry)
                         .class(if selected {
-                            cosmic::theme::Button::Suggested
+                            ferese_theme::accent_button()
                         } else {
                             cosmic::theme::Button::Standard
                         })
@@ -215,7 +215,7 @@ impl cosmic::Application for Picker {
                 .spacing(8)
                 .align_y(Alignment::Center),
             )
-            .class(cosmic::theme::Button::Suggested)
+            .class(ferese_theme::accent_button())
             .padding([6, 16]);
             if !self.selected.is_empty() {
                 share = share.on_press(Message::Share);
@@ -288,15 +288,15 @@ fn appearance() -> (cosmic::Theme, cosmic::font::Font) {
     } else {
         cosmic::cosmic_theme::ThemeBuilder::dark()
     };
-    let theme = cosmic::Theme::custom(std::sync::Arc::new(
+    let mut native = builder
-        builder
         .bg_color(background)
         .primary_container_bg(background)
         .text_tint(foreground.color)
-            .accent(accent.color)
+        .accent(ferese_theme::accent_color(accent.into(), background.into()))
         .corner_radii(corners)
-            .build(),
+        .build();
-    ));
+    ferese_theme::apply(&mut native, foreground.into());
+    let theme = cosmic::Theme::custom(std::sync::Arc::new(native));
     let family: &'static str =
         Box::leak(string("theme.typography.font_family", "Inter").into_boxed_str());
 

shell/ferese-lock/Cargo.toml

@@ -6,6 +6,7 @@ license.workspace = true
 rust-version = "1.95"
 
 [dependencies]
+ferese-theme = { path = "../../crates/ferese-theme" }
 ferese-config = { path = "../../crates/ferese-config" }
 libcosmic.workspace = true
 jiff.workspace = true

shell/ferese-lock/src/appearance.rs

@@ -115,15 +115,15 @@ impl Appearance {
         corners.radius_m = [self.radius; 4];
         corners.radius_l = [self.radius; 4];
         corners.radius_xl = [self.radius; 4];
-        cosmic::Theme::custom(std::sync::Arc::new(
+        let mut native = builder
-            builder
             .corner_radii(corners)
             .bg_color(color(self.panel))
             .primary_container_bg(color(self.panel))
             .text_tint(color(self.text).color)
-                .accent(color(self.accent).color)
+            .accent(ferese_theme::accent_color(self.accent, self.panel))
-                .build(),
+            .build();
-        ))
+        ferese_theme::apply(&mut native, self.text);
+        cosmic::Theme::custom(std::sync::Arc::new(native))
     }
 }
 

shell/ferese-lock/src/main.rs

@@ -362,9 +362,12 @@ impl Locker {
             .center_x(avatar_size)
             .center_y(avatar_size)
             .class(theme::Container::custom(move |_| {
+                let fill = ferese_theme::composite(a.accent.scale_alpha(0.18), a.panel);
+                let on = ferese_theme::foreground(fill, a.accent);
                 widget::container::Style {
-                    background: Some(iced::Background::Color(a.accent.scale_alpha(0.18))),
+                    background: Some(iced::Background::Color(fill)),
-                    text_color: Some(a.accent),
+                    text_color: Some(on),
+                    icon_color: Some(on),
                     border: iced::Border {
                         radius: (avatar_size / 2.).into(),
                         width: 1.,

shell/ferese-settings/Cargo.toml

@@ -6,6 +6,7 @@ license.workspace = true
 rust-version = "1.93"
 
 [dependencies]
+ferese-theme = { path = "../../crates/ferese-theme" }
 ferese-config = { path = "../../crates/ferese-config" }
 libcosmic = { workspace = true, features = ["wgpu", "a11y", "xdg-portal"] }
 ferese-ipc = { path = "../../crates/ferese-ipc" }

shell/ferese-settings/src/visuals.rs

@@ -62,16 +62,7 @@ impl Palette {
     }
 }
 
-fn luminance(color: Color) -> f32 {
+use ferese_theme::luminance;
-    let channel = |value: f32| {
-        if value <= 0.04045 {
-            value / 12.92
-        } else {
-            ((value + 0.055) / 1.055).powf(2.4)
-        }
-    };
-    0.2126 * channel(color.r) + 0.7152 * channel(color.g) + 0.0722 * channel(color.b)
-}
 
 fn surface_shade(base: Color) -> Color {
     if luminance(base) > 0.5 {
@@ -145,8 +136,8 @@ pub fn input_style(p: Palette) -> theme::TextInput {
 }
 
 fn styled_button(p: Palette, selected: bool, navigation: bool) -> theme::Button {
-    let style = move |hover: bool| button::Style {
+    let style = move |hover: bool| {
-        background: Some(Background::Color(if selected {
+        let background = if selected {
             mix(p.sidebar, p.accent, if hover { 0.24 } else { 0.17 })
         } else if hover {
             mix(p.card, surface_shade(p.sidebar), 0.06)
@@ -154,9 +145,16 @@ fn styled_button(p: Palette, selected: bool, navigation: bool) -> theme::Button
             p.sidebar
         } else {
             p.card
-        })),
+        };
-        text_color: Some(p.text),
+        let on = if selected {
-        icon_color: None,
+            ferese_theme::foreground(background, p.text)
+        } else {
+            p.text
+        };
+        button::Style {
+            background: Some(Background::Color(background)),
+            text_color: Some(on),
+            icon_color: Some(on),
             border_radius: 9.into(),
             border_width: if selected { 1. } else { 0. },
             border_color: if selected {
@@ -168,6 +166,7 @@ fn styled_button(p: Palette, selected: bool, navigation: bool) -> theme::Button
             outline_color: Color::TRANSPARENT,
             overlay: None,
             shadow_offset: Vector::ZERO,
+        }
     };
 
     theme::Button::Custom {
@@ -180,7 +179,10 @@ fn styled_button(p: Palette, selected: bool, navigation: bool) -> theme::Button
 
 pub fn native_theme(snapshot: Option<&Snapshot>) -> cosmic::Theme {
     let Some(snapshot) = snapshot else {
-        return cosmic::Theme::custom(std::sync::Arc::new(cosmic::theme::COSMIC_DARK.clone()));
+        let mut native = cosmic::theme::COSMIC_DARK.clone();
+        let preferred = native.background(false).on.into();
+        ferese_theme::apply(&mut native, preferred);
+        return cosmic::Theme::custom(std::sync::Arc::new(native));
     };
     let palette = Palette::from(snapshot);
     let builder = if luminance(palette.sidebar) > 0.5 {
@@ -188,12 +190,13 @@ pub fn native_theme(snapshot: Option<&Snapshot>) -> cosmic::Theme {
     } else {
         cosmic::cosmic_theme::ThemeBuilder::dark()
     };
-    let theme = builder
+    let mut theme = builder
         .bg_color(cosmic_color(palette.background))
         .primary_container_bg(cosmic_color(palette.card))
         .text_tint(cosmic_color(palette.text).color)
-        .accent(cosmic_color(palette.accent).color)
+        .accent(ferese_theme::accent_color(palette.accent, palette.card))
         .build();
+    ferese_theme::apply(&mut theme, palette.text);
     cosmic::Theme::custom(std::sync::Arc::new(theme))
 }
 

shell/ferese-shell/Cargo.toml

@@ -6,6 +6,7 @@ license.workspace = true
 rust-version = "1.93"
 
 [dependencies]
+ferese-theme = { path = "../../crates/ferese-theme" }
 ferese-config = { path = "../../crates/ferese-config" }
 ferese-core = { path = "../../crates/ferese-core" }
 ferese-protocols = { path = "../../crates/ferese-protocols", default-features = false, features = ["client"] }

shell/ferese-shell/src/notification_ui.rs

@@ -65,18 +65,6 @@ fn blend(base: Color, foreground: Color, amount: f32) -> Color {
     }
 }
 
-fn contrast_text(background: Color, opacity: f32) -> Color {
-    let level = background.r * 0.2126 + background.g * 0.7152 + background.b * 0.0722;
-    Color {
-        a: opacity,
-        ..if level > 0.6 {
-            Color::BLACK
-        } else {
-            Color::WHITE
-        }
-    }
-}
-
 fn age_label(age: Duration) -> String {
     match age.as_secs() {
         0..60 => "now".into(),
@@ -345,16 +333,25 @@ impl FereseShell {
                     ..Default::default()
                 }));
         let icon: Element<'_, cosmic::Action<Message>> = if count > 1 {
+            let badge_fill = ferese_theme::composite(
+                color(palette.accent),
+                color(if history {
+                    palette.surface_base
+                } else {
+                    palette.surface_popover
+                }),
+            );
+            let badge_text = ferese_theme::foreground(badge_fill, color(palette.text_primary));
             let badge = container(
                 text(count.to_string())
                     .size(10)
                     .font(bold)
-                    .class(theme::Text::Color(contrast_text(accent, opacity))),
+                    .class(theme::Text::Color(badge_text.scale_alpha(opacity))),
             )
             .center_x(16)
             .center_y(16)
             .class(theme::Container::custom(move |_| container::Style {
-                background: Some(Background::Color(accent)),
+                background: Some(Background::Color(badge_fill.scale_alpha(opacity))),
                 border: Border {
                     radius: motion::radius(8.0).into(),
                     ..Default::default()