Calendar · Months: a month view, a year view, event chips and cards

CalendarMonthView lays a month in week rows. An event across days lies
over them as a bar in the first free lane, cut at the week's edge;
the rest sit by the hour as chips, and a crowded day keeps the rest
behind "N more". Arrows move a day, Page keys turn the month, and
Enter or a double press opens the day; the cursor holds through the
owner's echo of a turn. Days sit at sevenths of their row, as the bars
do, so text never widens a column.

YearView shows twelve small months; a day with something on it wears a
dot in its first event's hue. EventChip is an event in a line and
EventCard a block with its hours and place. MiniCalendar points to
forms::Calendar. Palette::hue is now the one home for a chart color by
index, for mail labels and events alike.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/theme/calendar.rs

@@ -0,0 +1,24 @@
+use gpui::Rems;
+
+use super::{Theme, tokens::px_to_rems};
+
+/// Calendar's measures.
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub struct CalendarSizes {
+    /// An event's chip in a day, tall.
+    pub chip: Rems,
+    /// Rows of events a month's day holds under its number.
+    pub day_rows: usize,
+    /// A day in a year's small months, square.
+    pub mini_day: Rems,
+}
+
+impl Theme {
+    pub fn calendar(&self) -> CalendarSizes {
+        CalendarSizes {
+            chip: px_to_rems(20.0),
+            day_rows: 3,
+            mini_day: px_to_rems(28.0),
+        }
+    }
+}

src/theme/mod.rs

@@ -1,3 +1,4 @@
+mod calendar;
 mod chart;
 mod files;
 mod generative;
@@ -11,6 +12,7 @@ use std::time::{Duration, Instant};
 use gpui::{App, Global, SharedString, WindowAppearance};
 
 use crate::motion;
+pub use calendar::CalendarSizes;
 pub use chart::ChartSizes;
 pub use files::FileSizes;
 pub use generative::GenerativeSizes;

src/theme/palette.rs

@@ -118,6 +118,14 @@ fn c8<const N: usize>(hex: [u32; N]) -> [Hsla; N] {
 }
 
 impl Palette {
+    /// The chart color at `hue`; a hue past the chart fails, naming `owner`.
+    pub fn hue(&self, hue: usize, owner: impl std::fmt::Display) -> Hsla {
+        *self
+            .chart
+            .get(hue)
+            .unwrap_or_else(|| panic!("{owner}: no chart hue {hue}"))
+    }
+
     pub fn light(high_contrast: bool) -> Self {
         let mut palette = Self {
             bg: c(0xfcfaf7),