feat: centre the clock numerals

Horizontally centred in the card; the weekday and date stay against the
left edge at the bottom.

Each line is centred on its own ink width via measure(), not advance():
ink is what centring wants, and Oswald is proportional, so 10 and 05 are
not the same width and a shared measurement would leave one of them
visibly off-centre.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

1 files changed, 9 insertions, 2 deletions

diff --git a/widgets/clock.lua b/widgets/clock.lua
index b7c80d9..01f6012 100644
--- a/widgets/clock.lua
+++ b/widgets/clock.lua
@@ -43,8 +43,15 @@ function M.draw(cr, rect, colors)
   -- Tight leading, as in the mockup: the numerals nearly touch.
   local y2 = y1 + size * 0.92
 
-  card.text(cr, x, y1, os.date('%H'))
-  card.text(cr, x, y2, os.date('%M'))
+  -- Centred horizontally: measure(), not advance(), because ink width is what
+  -- centring wants. Oswald is condensed, so '10' and '03' differ in width and
+  -- each line is centred on its own measurement rather than a shared one.
+  local function centred(s, baseline)
+    local w = card.measure(cr, s)
+    card.text(cr, inner.x + (inner.w - w) / 2, baseline, s)
+  end
+  centred(os.date('%H'), y1)
+  centred(os.date('%M'), y2)
 
   -- Weekday and date sit against the bottom edge, not at a fixed drop from the
   -- numerals. That is what puts the slack of a tall cell in the middle of the