feat(icons): read the icon theme from gsettings

The icon theme name was hardcoded in three places (bin/wb-icon,
modules/extras/taskbar.jsonc and install.sh), so switching themes in the
appearance drawer was silently reverted as far as this bar was concerned.

wb-icon now reads org.gnome.desktop.interface icon-theme and gains two modes
for install.sh: --path NAME prints one icon's absolute path, --theme prints
the resolved theme name.

Icons are resolved per name rather than by substituting a directory prefix,
because themes disagree about both subdirectory and file extension: the Suru
themes keep web-browser at categories/22/*.svg, elementary-xfce at
apps/22/*.png. Only a real GTK lookup knows the path.

styles/modules.css therefore carries @ICON:name@ placeholders and
modules/extras/taskbar.jsonc carries @ICON_THEME@, both filled at install
time. taskbar.jsonc is generated rather than symlinked for that reason, and
install.sh removes the old symlink first so the redirect cannot overwrite the
committed source.

A theme missing one of the twenty names fails the install at the --selftest
step rather than drawing empty pills.

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

1 files changed, 33 insertions, 6 deletions

diff --git a/install.sh b/install.sh
index 42bc50a..775e318 100755
--- a/install.sh
+++ b/install.sh
@@ -15,7 +15,6 @@ set -euo pipefail
 repo="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 target="$HOME/.config/waybar-udt"
 udt="$(cd "$repo/../unified-desktop-theme" 2>/dev/null && pwd || true)"
-icons="$HOME/.local/share/icons/Material-Black-Plum-Suru"
 
 mkdir -p "$target/modules/hyprland" "$target/modules/custom" \
          "$target/modules/extras" "$target/modules/image" \
@@ -96,7 +95,7 @@ for f in modules/clock.jsonc \
          modules/custom/vmdot.jsonc modules/custom/privacy_dots.jsonc \
          modules/custom/presentation.jsonc modules/custom/mail.jsonc \
          modules/custom/launcher.jsonc \
-         modules/extras/taskbar.jsonc modules/extras/tray.jsonc \
+         modules/extras/tray.jsonc \
          modules/image/volume.jsonc modules/image/language.jsonc; do
     ln -sfn "$repo/$f" "$target/$f"
 done
@@ -105,11 +104,37 @@ for f in style.css fonts.css global.css pills.css; do
     ln -sfn "$repo/styles/$f" "$target/styles/$f"
 done
 
-# modules.css is generated rather than linked: it carries the icon theme's
-# absolute path, which cannot be committed, and the accent-tinted launcher.
-sed -e "s|@ICONS@|$icons|g" -e "s|@CONFIG@|$target|g" \
+# modules.css is generated rather than linked: it carries absolute icon paths,
+# which cannot be committed, and the accent-tinted launcher.
+#
+# Each @ICON:name@ is resolved by wb-icon, which reads the desktop's icon theme
+# from gsettings. Resolving per name rather than substituting one directory is
+# what makes a theme switch work at all: themes disagree about both the
+# subdirectory and the file extension (Suru keeps web-browser at
+# categories/22/*.svg, elementary-xfce at apps/22/*.png), so only a real icon
+# lookup knows the path. An unresolved name is left as-is and reported; the
+# selftest below is what turns that into a failed install.
+sed -e "s|@CONFIG@|$target|g" \
     "$repo/styles/modules.css" > "$target/styles/modules.css"
 
+for name in $(grep -o '@ICON:[a-z0-9-]*@' "$target/styles/modules.css" \
+              | sed 's/@ICON:\(.*\)@/\1/' | sort -u); do
+    if path="$("$repo/bin/wb-icon" --path "$name")"; then
+        sed -i "s|@ICON:$name@|$path|g" "$target/styles/modules.css"
+    else
+        echo "warning: no icon named '$name' in the current icon theme" >&2
+    fi
+done
+
+# taskbar.jsonc names the icon theme, which is gsettings' to say, so it is
+# generated for the same reason modules.css is. Every other module is a symlink.
+# An earlier install symlinked this file into the repo. Writing through that
+# link would overwrite the committed source with a generated copy, so the link
+# is removed first; the redirect below then creates a real file.
+rm -f "$target/modules/extras/taskbar.jsonc"
+sed "s|@ICON_THEME@|$("$repo/bin/wb-icon" --theme)|g" \
+    "$repo/modules/extras/taskbar.jsonc" > "$target/modules/extras/taskbar.jsonc"
+
 # The launcher module carries no generated path any more: its mark is a CSS
 # background, so modules.css owns the paths and the module file is a plain
 # symlink like every other.
@@ -149,7 +174,9 @@ ln -sfn "$repo/bin/wb-lang" "$HOME/bin/wb-lang"
 
 # ----------------------------------------------------------------- checks --
 # A missing icon renders as an empty pill and nothing says why, so the names
-# are checked here, while someone is watching.
+# are checked here, while someone is watching. The theme is whatever gsettings
+# says, so this also catches a switch to a theme that lacks one of these names.
+echo "icon theme: $("$repo/bin/wb-icon" --theme)"
 "$repo/bin/wb-icon" --selftest
 
 echo