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/wire.rs

@@ -0,0 +1,73 @@
+//! A theme in message words, as the display hands it to a window
+//! (`types::display::window::THEME`). Its name stays behind.
+
+use crate::{Rgba, Theme};
+
+pub const WORDS: usize = types::display::window::THEME_WORDS;
+
+fn colours(t: &Theme) -> [Rgba; 12] {
+    [
+        t.background,
+        t.surface,
+        t.surface_raised,
+        t.accent,
+        t.on_accent,
+        t.text_primary,
+        t.text_secondary,
+        t.destructive,
+        t.on_destructive,
+        t.focus,
+        t.orbs[0],
+        t.orbs[1],
+    ]
+}
+
+pub fn encode(t: &Theme) -> [usize; WORDS] {
+    let c = colours(t);
+    let mut w = [0usize; WORDS];
+    for i in 0..6 {
+        w[i] = c[2 * i].to_rgb() as usize | (c[2 * i + 1].to_rgb() as usize) << 32;
+    }
+    w[6] = t.corner_radius as usize
+        | (t.spacing_base as usize) << 8
+        | (t.blur_radius as usize) << 16
+        | (t.panel_opacity as usize) << 24
+        | (t.highlight as usize) << 32
+        | (t.duration_fast as usize) << 40;
+    w[7] = t.duration_normal as usize
+        | (t.spring_stiffness as usize) << 16
+        | (t.spring_damping as usize & 0xff) << 32
+        | (t.orbs[2].to_rgb() as usize & 0xff_ffff) << 40;
+    w
+}
+
+pub fn decode(w: [usize; WORDS]) -> Theme {
+    let c = |i: usize| Rgba::rgb((w[i / 2] >> (32 * (i % 2))) as u32 & 0xff_ffff);
+    let byte = |word: usize, at: u32| (w[word] >> at) as u8;
+    let half = |word: usize, at: u32| (w[word] >> at) as u16;
+    Theme {
+        name: [0; crate::NAME_BYTES],
+        name_len: 0,
+        background: c(0),
+        surface: c(1),
+        surface_raised: c(2),
+        accent: c(3),
+        on_accent: c(4),
+        text_primary: c(5),
+        text_secondary: c(6),
+        destructive: c(7),
+        on_destructive: c(8),
+        focus: c(9),
+        orbs: [c(10), c(11), Rgba::rgb((w[7] >> 40) as u32 & 0xff_ffff)],
+        corner_radius: byte(6, 0) as f32,
+        spacing_base: byte(6, 8) as f32,
+        blur_radius: byte(6, 16),
+        panel_opacity: byte(6, 24),
+        highlight: byte(6, 32),
+        duration_fast: half(6, 40),
+        duration_normal: half(7, 0),
+        spring_stiffness: half(7, 16),
+        // At most 200 (see `parse`): a byte.
+        spring_damping: byte(7, 32) as u16,
+    }
+}