1 files changed, 51 insertions, 2 deletions
diff --git a/bin/udt-accent b/bin/udt-accent
index 2dfc9a0..17a225d 100755
--- a/bin/udt-accent
+++ b/bin/udt-accent
@@ -99,6 +99,11 @@ POWER_ICONS = {
 # The sddm user reaches it through the 0711 home, so it has to stay 0644.
 AVATAR = Path.home() / ".user-icon.jpg"
 
+# wallp's config and state: which output each logical screen (H, V) is, and
+# the wallpaper on it. Read so the greeter can show each monitor its own
+# wallpaper, as the desktop does.
+WALLP = Path.home() / ".config" / "wallp"
+
 
 def write_atomic(path, content, mode=None, dir_mode=None):
     """Write a file atomically, so no reader ever sees it half-written.
@@ -502,7 +507,32 @@ def power_icons():
     return {key: find_icon(theme, names) for key, names in POWER_ICONS.items()}
 
 
-def sddm_conf(palette, name, image, icons=None, avatar=""):
+def screen_wallpapers(conf=WALLP):
+    """Each output's wallpaper, {output: path}, from wallp's conf and state.
+
+    Empty when wallp is not set up; a screen with no saved wallpaper is left
+    out. Either way the greeter falls back to `background` for that screen.
+    """
+    outputs = {}
+    try:
+        for line in (conf / "wallp.conf").read_text().splitlines():
+            key, _, val = line.partition("=")
+            if key in ("OUTPUT_H", "OUTPUT_V") and val:
+                outputs[key[-1]] = val
+    except OSError:
+        return {}
+    walls = {}
+    for side, output in outputs.items():
+        try:
+            path = (conf / f"wall_{side.lower()}").read_text().strip()
+        except OSError:
+            continue
+        if path:
+            walls[output] = os.path.realpath(path)
+    return walls
+
+
+def sddm_conf(palette, name, image, icons=None, avatar="", walls=None):
     """The SDDM theme config, as an INI fragment.
 
     theme.conf.user overrides theme.conf and is exposed to the theme as the
@@ -516,6 +546,9 @@ def sddm_conf(palette, name, image, icons=None, avatar=""):
         f"background={os.path.realpath(image)}",
         f"accent={ACCENTS[name]}",
     ]
+    # Per-screen wallpapers, keyed by output name. The greeter prefers these
+    # over `background` on the screen they name.
+    lines += [f"background_{out}={path}" for out, path in (walls or {}).items()]
     lines += [f"{key}={palette.get(key, '#000000')}" for key in SDDM_KEYS]
     icons = icons or {}
     lines += [f"{key}={icons.get(key, '')}" for key in POWER_ICONS]
@@ -539,7 +572,8 @@ def write_sddm(name, image):
               file=sys.stderr)
         return
     write_atomic(SDDM_OUTPUT, sddm_conf(palette, name, image, power_icons(),
-                           str(AVATAR) if AVATAR.is_file() else ""),
+                           str(AVATAR) if AVATAR.is_file() else "",
+                           screen_wallpapers()),
                  mode=0o644, dir_mode=0o755)
 
 
@@ -780,6 +814,21 @@ def selftest():
         assert "\navatar=/tmp/me.jpg\n" in "\n" + text
         assert f"\navatarUser={getpass.getuser()}\n" in "\n" + text
 
+    # Per-screen wallpapers come from wallp's output names and saved state; a
+    # screen with no saved wallpaper is left out, and no wallp at all gives none.
+    with tempfile.TemporaryDirectory() as tmpdir:
+        conf = Path(tmpdir)
+        assert screen_wallpapers(conf) == {}
+        (conf / "wallp.conf").write_text("# c\nOUTPUT_H=DP-1\nOUTPUT_V=DP-3\nDEFAULT_H=~/x\n")
+        (conf / "wall_h").write_text("/tmp/h.jpg\n")
+        assert screen_wallpapers(conf) == {"DP-1": "/tmp/h.jpg"}
+        (conf / "wall_v").write_text("/tmp/v.png\n")
+        walls = screen_wallpapers(conf)
+        assert walls == {"DP-1": "/tmp/h.jpg", "DP-3": "/tmp/v.png"}, walls
+        text = sddm_conf({}, FALLBACK, "/tmp/h.jpg", walls=walls)
+        assert "\nbackground_DP-1=/tmp/h.jpg\n" in text
+        assert "\nbackground_DP-3=/tmp/v.png\n" in text
+
     got = power_icons()
     assert set(got) == {"powerIcon", "rebootIcon", "suspendIcon", "hibernateIcon"}