feat: give the clock its own font

Installs Oswald (OFL-1.1, from googlefonts/OswaldFont) under
~/.fonts/o/Oswald with its license, and points the clock numerals at it
for the squared look the rounded Noto Sans Black did not have.

Per-widget fonts needed no new machinery: card.font() already takes any
family string, so FONT_* are shared defaults rather than a restriction.
FONT_CLOCK joins them, and the weather card keeps FONT_HEAVY, so the two
no longer have to agree.

Cairo still cannot ask for a weight above bold, so a heavier cut is
selected by family name as FONT_HEAVY already did. Worth knowing that
fontconfig substitutes a default for a family it does not recognise,
which is indistinguishable from the font not applying; fc-match tells
you which happened.

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

1 files changed, 12 insertions, 0 deletions

diff --git a/lib/card.lua b/lib/card.lua
index 4d94465..3352c4b 100644
--- a/lib/card.lua
+++ b/lib/card.lua
@@ -13,6 +13,18 @@ M.FONT_MONO  = 'Inconsolata Nerd Font'
 M.FONT_UI    = 'Noto Sans'
 M.FONT_HEAVY = 'Noto Sans Black'
 
+-- Shared defaults, not a restriction: card.font() takes any family string, so
+-- a widget wanting its own face just passes one. The clock does, for squared
+-- numerals (Oswald, OFL-1.1, installed under ~/.fonts/o/Oswald).
+--
+-- Cairo can only ask for Regular or Bold by weight, so a heavier cut is
+-- selected by the family name fontconfig registers for it, exactly as
+-- FONT_HEAVY does above: 'Oswald SemiBold' at NORMAL weight, not 'Oswald' at
+-- bold. Fontconfig silently substitutes a default for a family it does not
+-- know, which looks identical to the font "not applying", so check a new name
+-- with `fc-match` before trusting it.
+M.FONT_CLOCK = 'Oswald'
+
 function M.font(cr, family, size, bold)
   cairo_select_font_face(cr, family, CAIRO_FONT_SLANT_NORMAL,
     bold and CAIRO_FONT_WEIGHT_BOLD or CAIRO_FONT_WEIGHT_NORMAL)