refactor: unify card no-data face and fluid sizing

Extract card.notice so every cached card's no-data state is one fluid,
theme-consistent face instead of a copy per widget, and delete the
fixed-size card.label it replaces.

Derive weather's arc geometry from its band (pad, curve room, sun dot,
time labels) instead of fixed pixels, and cap the arc at a proportion of
the card's width rather than 240px.

Derive disks' bar-fallback height and its address type from the card's
own label scale.

Standardise the big-value factor to 1.0 across the fit_unit cards and
document the big-value colour rule and the disks headline exception.

1 files changed, 22 insertions, 24 deletions

diff --git a/widgets/weather.lua b/widgets/weather.lua
index f50c6f1..a0c7b3a 100644
--- a/widgets/weather.lua
+++ b/widgets/weather.lua
@@ -12,34 +12,28 @@ local M = {}
 local CACHE = (os.getenv('XDG_CACHE_HOME') or (os.getenv('HOME') .. '/.cache'))
   .. '/udt/weather.json'
 
--- Draw the card chrome with a message in it. Used for every no-data state, so
--- the dashboard keeps its shape instead of showing an empty cell, which is
--- indistinguishable from a crashed widget.
-local function draw_notice(cr, inner, colors, line1, line2)
-  card.font(cr, card.FONT_UI, 15, true)
-  card.rgba(cr, colors.label)
-  card.text(cr, inner.x, inner.y + 24, line1)
-  card.font(cr, card.FONT_MONO, 12, false)
-  card.text(cr, inner.x, inner.y + 48, line2)
-end
-
 -- The daylight arc: a curve, its baseline, the sun, and the two times.
 --
 -- The dot is placed by evaluating the curve at t rather than by computing a
 -- point on a circle: the curve IS the path, so evaluating it keeps the dot on
 -- the arc if the control points are ever adjusted.
 local function draw_arc(cr, x, y, w, h, colors, w_data, now)
-  local pad = 4
+  -- Every dimension derives from the band, not fixed pixels: the time labels
+  -- take a fraction of the height, the curve's room is what they leave, and the
+  -- dot and edge pad follow the same proportions so the arc composes at any
+  -- size the cell gives it.
+  local label_h = math.max(10, math.min(16, h * 0.16))
+  local pad = math.max(4, w * 0.012)
   local x0, x1 = x + pad, x + w - pad
   -- Room under the curve for the time labels.
-  local base = y + h - 20
-  local top = y + 6
+  local base = y + h - label_h * 1.5
+  local top = y + h * 0.08
 
   -- Cubic Bezier control points, chosen so the curve peaks near the middle at
   -- about two thirds of the band height.
   local p0 = { x0, base }
-  local c1 = { x0 + (x1 - x0) * 0.22, top - 10 }
-  local c2 = { x1 - (x1 - x0) * 0.22, top - 10 }
+  local c1 = { x0 + (x1 - x0) * 0.22, top - h * 0.14 }
+  local c2 = { x1 - (x1 - x0) * 0.22, top - h * 0.14 }
   local p3 = { x1, base }
 
   -- The baseline: the horizon the sun rises from and sets into.
@@ -70,13 +64,13 @@ local function draw_arc(cr, x, y, w, h, colors, w_data, now)
   -- At night the dot is parked at an end, so it takes the dim colour: a bright
   -- dot sitting on the horizon would read as a sun that is still up.
   card.rgba(cr, day and colors.body or colors.label, 1)
-  cairo_arc(cr, sx, sy, 5, 0, math.pi * 2)
+  cairo_arc(cr, sx, sy, math.max(3, math.min(9, h * 0.045)), 0, math.pi * 2)
   cairo_fill(cr)
 
   -- The times, each behind its own glyph, at the ends of the arc.
-  card.font(cr, card.FONT_MONO, 12, false)
+  card.font(cr, card.FONT_MONO, label_h, false)
   card.rgba(cr, colors.label)
-  local ty = y + h - 2
+  local ty = y + h - label_h * 0.15
   card.text(cr, x0, ty,
     weather.ICON.sunrise .. ' ' .. os.date('%H:%M', w_data.sunrise))
   card.text_right(cr, x1, ty,
@@ -97,12 +91,13 @@ function M.draw(cr, rect, colors)
     -- draw (every update_interval), since this whole branch reruns each
     -- frame until a fetch succeeds.
     local envf = io.open(os.getenv('HOME') .. '/.config/udt/weather.env', 'r')
-    if envf then
-      envf:close()
-      draw_notice(cr, inner, colors, 'no weather data', 'waiting for first fetch')
+    local hint = 'waiting for first fetch'
+    if not envf then
+      hint = 'set ~/.config/udt/weather.env'
     else
-      draw_notice(cr, inner, colors, 'no weather data', 'set ~/.config/udt/weather.env')
+      envf:close()
     end
+    card.notice(cr, inner, colors, 'WEATHER', 'no weather data', hint)
     return
   end
 
@@ -194,7 +189,10 @@ function M.draw(cr, rect, colors)
   -- This is what lets one widget sit in a 2x2 or a 2x3 cell unchanged.
   local bottom = inner.y + inner.h
   local arc_y = sy + row_step * 0.6
-  local arc_h = math.min(bottom - arc_y, inner.h * 0.34, 240)
+  -- The cap is a proportion of the card's width, not a fixed 240px: an arch
+  -- taller than about 0.6 of its own width reads as a cathedral door rather
+  -- than a day's arc, and the ceiling has to follow a card that is resized.
+  local arc_h = math.min(bottom - arc_y, inner.h * 0.34, inner.w * 0.6)
   if arc_h >= 70 then
     draw_arc(cr, inner.x, arc_y, inner.w, arc_h, colors, w, now)
   end