feat: add a title icon to every labelled card

Add card.ICON and a card.title helper that draws the glyph in the
highlight colour before the label, at the label's own size. The eight
labelled cards use it, in both the fit_unit width measurement and the
draw, so the icon cannot overrun a narrow cell. Clock (no label) and
weather (condition glyph already) are unchanged, and the no-data notice
titles stay text-only.

Codepoints were chosen against a rendered contact sheet, not fontconfig
alone, since a wrong codepoint draws a plausible neighbour.

1 files changed, 34 insertions, 0 deletions

diff --git a/lib/card.lua b/lib/card.lua
index 3c520b9..e3cb11e 100644
--- a/lib/card.lua
+++ b/lib/card.lua
@@ -118,6 +118,40 @@ function M.card(cr, rect, colors, pad)
            w = rect.w - pad * 2, h = rect.h - pad * 2 }
 end
 
+-- Card title glyphs, all present in FONT_MONO (Inconsolata Nerd Font).
+--
+-- Verified by rendering a contact sheet and looking at each one, not by
+-- fontconfig alone: a missing glyph draws as an invisible blank and a wrong
+-- codepoint as a plausible neighbour, so neither fails visibly.
+M.ICON = {
+  system     = '\u{F0EE0}',  -- cpu-64-bit
+  gpu        = '\u{F083E}',  -- video-4k-box (no GPU glyph exists)
+  disks      = '\u{F02CA}',  -- harddisk
+  cache      = '\u{F0ABA}',  -- folder-clock
+  network    = '\u{F0317}',  -- lan
+  slackware  = '\u{F318}',   -- linux-slackware
+  breaktimer = '\u{F13AB}',  -- timer
+  calendar   = '\u{F0E17}',  -- calendar-month
+}
+
+-- The gap between a title's icon and its text. One constant so the measured
+-- width and the drawn width cannot drift apart.
+local TITLE_GAP = '  '
+
+-- The full run a title occupies, for fit_unit to measure. Colour does not
+-- affect width, so measuring icon and text as one string is exact.
+function M.title_str(icon, text) return icon .. TITLE_GAP .. text end
+
+-- Draw a card title: the icon in `highlight`, the text in `label`, both at the
+-- caller's current font. x is the left edge, y the baseline.
+function M.title(cr, x, y, icon, text, colors)
+  M.rgba(cr, colors.highlight)
+  M.text(cr, x, y, icon)
+  x = x + M.advance(cr, icon .. TITLE_GAP)
+  M.rgba(cr, colors.label)
+  M.text(cr, x, y, text)
+end
+
 -- The no-data face: the card chrome with a named message in it.
 --
 -- Every cached card draws this when its sampler has not run, so the board keeps