feat(theme): themes as files (theme crate: toml subset + ints, contrast check, wire); whimsy dark + light; display reads themes/, serves THEME/THEME_NAME, init SET_THEME -> THEME_CHANGED to all windows, bar themed; k-ui follows; settings appearance; init keeps choice in sealed users/<id>/settings/, reapplies at sign-in + display restart

crates/theme/src/lib.rs

@@ -0,0 +1,202 @@
+//! A theme's tokens and the words apps describe their UI in (see the
+//! vision's K-UI note): apps say what a thing is (a primary button, a
+//! heading), never its colour or size. Themes are files (`themes/*.toml`
+//! on the system image), read strictly (`parse`) and refused unless every
+//! pairing text is drawn in has enough contrast (`check`). The display
+//! holds the one in use and hands it to every window (`wire`). Pure.
+
+#![no_std]
+#![forbid(unsafe_code)]
+
+mod contrast;
+mod parse;
+pub mod wire;
+
+#[cfg(test)]
+mod tests;
+
+pub use contrast::{check, ratio};
+pub use parse::{Error, parse};
+
+/// A colour as the theme names it: straight (not premultiplied) RGBA.
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub struct Rgba(pub u8, pub u8, pub u8, pub u8);
+
+impl Rgba {
+    pub const fn opaque(r: u8, g: u8, b: u8) -> Self {
+        Self(r, g, b, 255)
+    }
+
+    /// From `0xrrggbb`.
+    pub const fn rgb(v: u32) -> Self {
+        Self::opaque((v >> 16) as u8, (v >> 8) as u8, v as u8)
+    }
+
+    pub const fn to_rgb(self) -> u32 {
+        (self.0 as u32) << 16 | (self.1 as u32) << 8 | self.2 as u32
+    }
+}
+
+/// Steps of the spacing scale.
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum Spacing {
+    None,
+    Xs,
+    Sm,
+    Md,
+    Lg,
+    Xl,
+}
+
+/// Steps of the type scale.
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum TextStyle {
+    Heading,
+    Subheading,
+    Body,
+    Caption,
+    Label,
+}
+
+/// What a text is, for its colour.
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum TextColour {
+    Primary,
+    Secondary,
+    Accent,
+    OnAccent,
+}
+
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum ButtonVariant {
+    Primary,
+    Secondary,
+    Ghost,
+    Destructive,
+}
+
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum Weight {
+    Regular,
+    SemiBold,
+}
+
+/// A theme's name: what Settings lists and a user's choice records.
+pub const NAME_BYTES: usize = types::name::BYTES;
+
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub struct Theme {
+    pub name: [u8; NAME_BYTES],
+    pub name_len: usize,
+    pub background: Rgba,
+    pub surface: Rgba,
+    pub surface_raised: Rgba,
+    pub accent: Rgba,
+    pub on_accent: Rgba,
+    pub text_primary: Rgba,
+    pub text_secondary: Rgba,
+    pub destructive: Rgba,
+    pub on_destructive: Rgba,
+    pub focus: Rgba,
+    /// Soft colours the wallpaper glows with, behind the glass.
+    pub orbs: [Rgba; 3],
+    pub corner_radius: f32,
+    /// The spacing scale's unit, in pixels.
+    pub spacing_base: f32,
+    /// Milliseconds; zero turns motion off.
+    pub duration_fast: u16,
+    pub duration_normal: u16,
+    pub spring_stiffness: u16,
+    pub spring_damping: u16,
+    /// Pixels.
+    pub blur_radius: u8,
+    /// Percent.
+    pub panel_opacity: u8,
+    pub highlight: u8,
+}
+
+pub(crate) const fn name_bytes(s: &[u8]) -> ([u8; NAME_BYTES], usize) {
+    let mut out = [0u8; NAME_BYTES];
+    let mut i = 0;
+    while i < s.len() && i < NAME_BYTES {
+        out[i] = s[i];
+        i += 1;
+    }
+    (out, i)
+}
+
+impl Theme {
+    /// What a window shows before the display has said, and what the
+    /// display uses when no theme file loads; `disk/themes/whimsy-dark.toml`
+    /// says the same (a test keeps them so).
+    pub const WHIMSY_DARK: Theme = Theme {
+        name: name_bytes(b"Whimsy Dark").0,
+        name_len: name_bytes(b"Whimsy Dark").1,
+        background: Rgba::rgb(0x0f0e17),
+        surface: Rgba::rgb(0x1a1a2e),
+        surface_raised: Rgba::rgb(0x2a2a44),
+        accent: Rgba::rgb(0x4fc3f7),
+        on_accent: Rgba::rgb(0x0f0e17),
+        text_primary: Rgba::rgb(0xe0e0e0),
+        text_secondary: Rgba::rgb(0x9e9eb8),
+        destructive: Rgba::rgb(0xef5350),
+        on_destructive: Rgba::rgb(0x1a0a0a),
+        focus: Rgba::rgb(0xffffff),
+        orbs: [Rgba::rgb(0x3a1c71), Rgba::rgb(0x0f4c5c), Rgba::rgb(0x5b1a4a)],
+        corner_radius: 16.0,
+        spacing_base: 4.0,
+        duration_fast: 150,
+        duration_normal: 280,
+        spring_stiffness: 300,
+        spring_damping: 30,
+        blur_radius: 12,
+        panel_opacity: 72,
+        highlight: 18,
+    };
+
+    pub fn name(&self) -> &[u8] {
+        &self.name[..self.name_len]
+    }
+
+    pub fn space(&self, s: Spacing) -> f32 {
+        self.spacing_base
+            * match s {
+                Spacing::None => 0.0,
+                Spacing::Xs => 1.0,
+                Spacing::Sm => 2.0,
+                Spacing::Md => 4.0,
+                Spacing::Lg => 6.0,
+                Spacing::Xl => 8.0,
+            }
+    }
+
+    /// A text style's size in pixels and its weight.
+    pub fn text(&self, s: TextStyle) -> (f32, Weight) {
+        match s {
+            TextStyle::Heading => (32.0, Weight::SemiBold),
+            TextStyle::Subheading => (22.0, Weight::SemiBold),
+            TextStyle::Body => (17.0, Weight::Regular),
+            TextStyle::Caption => (13.0, Weight::Regular),
+            TextStyle::Label => (17.0, Weight::SemiBold),
+        }
+    }
+
+    pub fn text_colour(&self, c: TextColour) -> Rgba {
+        match c {
+            TextColour::Primary => self.text_primary,
+            TextColour::Secondary => self.text_secondary,
+            TextColour::Accent => self.accent,
+            TextColour::OnAccent => self.on_accent,
+        }
+    }
+
+    /// A button's fill (none for a ghost) and its label's colour.
+    pub fn button(&self, v: ButtonVariant) -> (Option<Rgba>, Rgba) {
+        match v {
+            ButtonVariant::Primary => (Some(self.accent), self.on_accent),
+            ButtonVariant::Secondary => (Some(self.surface_raised), self.text_primary),
+            ButtonVariant::Ghost => (None, self.accent),
+            ButtonVariant::Destructive => (Some(self.destructive), self.on_destructive),
+        }
+    }
+}