feat: init dynamic wallpaper ($theme gen)

home/scripts.nix

@@ -14,7 +14,12 @@ in
     ++ lib.optionals hostConfig.isDarwin (builtins.attrValues customScripts.darwinPackages);
 
   home.activation.initializeThemeState = lib.hm.dag.entryAfter [ "writeBoundary" ] ''
-    mkdir -p "${customScripts.theme.paths.stateDir}" "${customScripts.theme.paths.fzfDir}" "${customScripts.theme.paths.ghosttyDir}" "${customScripts.theme.paths.tmuxDir}"
+    mkdir -p "${customScripts.theme.paths.stateDir}" \
+             "${customScripts.theme.paths.fzfDir}" \
+             "${customScripts.theme.paths.ghosttyDir}" \
+             "${customScripts.theme.paths.tmuxDir}" \
+             "${customScripts.theme.paths.lazygitDir}" \
+             "${customScripts.theme.wallpapers.dir}"
 
     if [[ -f "${customScripts.theme.paths.stateFile}" ]]; then
       mode=$(tr -d '[:space:]' < "${customScripts.theme.paths.stateFile}")
@@ -28,17 +33,43 @@ in
         fzf_target="${customScripts.theme.paths.fzfDir}/cozybox-light"
         ghostty_target="${customScripts.theme.paths.ghosttyDir}/cozybox-light"
         tmux_target="${customScripts.tmuxConfigs.light}"
+        lazygit_target="${customScripts.theme.paths.lazygitDir}/config-light.yml"
         ;;
       *)
         printf '%s\n' "${customScripts.theme.defaultMode}" > "${customScripts.theme.paths.stateFile}"
         fzf_target="${customScripts.theme.paths.fzfDir}/cozybox-dark"
         ghostty_target="${customScripts.theme.paths.ghosttyDir}/cozybox-dark"
         tmux_target="${customScripts.tmuxConfigs.dark}"
+        lazygit_target="${customScripts.theme.paths.lazygitDir}/config-dark.yml"
         ;;
     esac
 
     ln -sfn "$fzf_target" "${customScripts.theme.paths.fzfCurrentFile}"
     ln -sfn "$ghostty_target" "${customScripts.theme.paths.ghosttyCurrentFile}"
     ln -sfn "$tmux_target" "${customScripts.theme.paths.tmuxCurrentFile}"
+    ln -sfn "$lazygit_target" "${customScripts.theme.paths.lazygitCurrentFile}"
+    ${lib.optionalString hostConfig.isDarwin ''
+    lg_darwin="${config.home.homeDirectory}/Library/Application Support/lazygit"
+    mkdir -p "$lg_darwin"
+    case "$mode" in
+      light) ln -sfn "$lg_darwin/config-light.yml" "$lg_darwin/config.yml" ;;
+      *)     ln -sfn "$lg_darwin/config-dark.yml" "$lg_darwin/config.yml" ;;
+    esac
+    ''}
+
+    # seed wallpapers from static assets if no generated ones exist yet
+    if [[ ! -f "${customScripts.theme.wallpapers.dark}" ]]; then
+      cp "${customScripts.theme.wallpapers.staticDark}" "${customScripts.theme.wallpapers.dark}"
+    fi
+    if [[ ! -f "${customScripts.theme.wallpapers.light}" ]]; then
+      cp "${customScripts.theme.wallpapers.staticLight}" "${customScripts.theme.wallpapers.light}"
+    fi
+
+    # ensure wallpaper symlink points to active mode
+    case "$mode" in
+      light) wp_target="${customScripts.theme.wallpapers.light}" ;;
+      *)     wp_target="${customScripts.theme.wallpapers.dark}" ;;
+    esac
+    ln -sfn "$wp_target" "${customScripts.theme.wallpapers.current}"
   '';
 }

lib/theme.nix

@@ -14,8 +14,12 @@ let
     gray = "#928374";
   };
   wallpapers = {
-    dark = ../assets/wallpapers/topography-dark.jpg;
-    light = ../assets/wallpapers/topography-light.jpg;
+    dir = "${config.home.homeDirectory}/Pictures/Screensavers";
+    dark = "${config.home.homeDirectory}/Pictures/Screensavers/wallpaper-dark.jpg";
+    light = "${config.home.homeDirectory}/Pictures/Screensavers/wallpaper-light.jpg";
+    current = "${config.home.homeDirectory}/Pictures/Screensavers/wallpaper.jpg";
+    staticDark = ../assets/wallpapers/topography-dark.jpg;
+    staticLight = ../assets/wallpapers/topography-light.jpg;
   };
   paths = {
     stateDir = "${config.xdg.stateHome}/theme";

scripts/default.nix

@@ -76,6 +76,15 @@ let
       runtimeInputs = with pkgs; [ nix ];
     };
 
+    wallpaper-gen = mkScript {
+      name = "wallpaper-gen";
+      file = ./wallpaper-gen.sh;
+      runtimeInputs = with pkgs; [ uv ];
+      replacements = {
+        "@WALLPAPER_GEN_PY@" = "${./wallpaper-gen.py}";
+      };
+    };
+
     theme = mkScript {
       name = "theme";
       file = ./theme.sh;
@@ -110,8 +119,12 @@ let
         "@LAZYGIT_DARWIN_FILE@" = "${config.home.homeDirectory}/Library/Application Support/lazygit/config.yml";
         "@LAZYGIT_DARWIN_DARK_FILE@" = "${config.home.homeDirectory}/Library/Application Support/lazygit/config-dark.yml";
         "@LAZYGIT_DARWIN_LIGHT_FILE@" = "${config.home.homeDirectory}/Library/Application Support/lazygit/config-light.yml";
-        "@WALLPAPER_DARK_FILE@" = "${theme.wallpapers.dark}";
-        "@WALLPAPER_LIGHT_FILE@" = "${theme.wallpapers.light}";
+        "@WALLPAPER_DIR@" = theme.wallpapers.dir;
+        "@WALLPAPER_DARK_FILE@" = theme.wallpapers.dark;
+        "@WALLPAPER_LIGHT_FILE@" = theme.wallpapers.light;
+        "@WALLPAPER_CURRENT_FILE@" = theme.wallpapers.current;
+        "@WALLPAPER_STATIC_DARK@" = "${theme.wallpapers.staticDark}";
+        "@WALLPAPER_STATIC_LIGHT@" = "${theme.wallpapers.staticLight}";
       };
     };
   };

scripts/theme.sh

@@ -1,5 +1,5 @@
 usage() {
-  echo "usage: theme <dark|light|toggle|current>"
+  echo "usage: theme <dark|light|toggle|gen>"
 }
 
 read_mode() {
@@ -14,6 +14,21 @@ read_mode() {
   echo "@DEFAULT_MODE@"
 }
 
+set_wallpaper() {
+  if [[ "$(uname -s)" == "Darwin" ]] && command -v osascript >/dev/null 2>&1; then
+    if [[ -f "@WALLPAPER_CURRENT_FILE@" ]]; then
+      wp_resolved=$(readlink -f "@WALLPAPER_CURRENT_FILE@" 2>/dev/null || echo "@WALLPAPER_CURRENT_FILE@")
+      # macOS caches wallpaper data by file path - copy to a unique temp path
+      # so macOS is forced to read the new image data
+      wp_dir=$(dirname "$wp_resolved")
+      wp_tmp="${wp_dir}/.wallpaper-active-$$.jpg"
+      rm -f "${wp_dir}"/.wallpaper-active-*.jpg 2>/dev/null || true
+      cp "$wp_resolved" "$wp_tmp"
+      osascript -e "tell application \"System Events\" to tell every desktop to set picture to \"${wp_tmp}\"" >/dev/null 2>&1 || true
+    fi
+  fi
+}
+
 link_mode_assets() {
   local mode="$1"
   local fzf_target
@@ -44,13 +59,17 @@ link_mode_assets() {
       ;;
   esac
 
-  mkdir -p "@STATE_DIR@" "@FZF_DIR@" "@GHOSTTY_DIR@" "@TMUX_DIR@" "@LAZYGIT_DIR@"
+  mkdir -p "@STATE_DIR@" "@FZF_DIR@" "@GHOSTTY_DIR@" "@TMUX_DIR@" "@LAZYGIT_DIR@" "@WALLPAPER_DIR@"
   printf '%s\n' "$mode" > "@STATE_FILE@"
   ln -sfn "$fzf_target" "@FZF_CURRENT_FILE@"
   ln -sfn "$ghostty_target" "@GHOSTTY_CURRENT_FILE@"
   ln -sfn "$tmux_target" "@TMUX_CURRENT_FILE@"
   ln -sfn "$lazygit_target" "@LAZYGIT_CURRENT_FILE@"
 
+  if [[ -f "$wallpaper" ]]; then
+    ln -sfn "$wallpaper" "@WALLPAPER_CURRENT_FILE@"
+  fi
+
   if command -v tmux >/dev/null 2>&1 && tmux start-server >/dev/null 2>&1; then
     tmux source-file "@TMUX_CONFIG@" >/dev/null 2>&1 || true
   fi
@@ -65,7 +84,7 @@ link_mode_assets() {
 
     osascript -e "tell application \"System Events\" to tell appearance preferences to set dark mode to ${apple_dark_mode}" >/dev/null 2>&1 || true
 
-    osascript -e "tell application \"System Events\" to tell every desktop to set picture to \"${wallpaper}\"" >/dev/null 2>&1 || true
+    set_wallpaper
 
     osascript <<'EOF' >/dev/null 2>&1 || true
 tell application "System Events"
@@ -91,7 +110,7 @@ EOF
   )
 }
 
-mode="${1:-current}"
+mode="${1:-}"
 
 case "$mode" in
   dark|light)
@@ -103,8 +122,10 @@ case "$mode" in
       mode="dark"
     fi
     ;;
-  current)
-    read_mode
+  gen)
+    wallpaper-gen
+    set_wallpaper
+    printf 'generated new wallpaper\n'
     exit 0
     ;;
   *)

scripts/wallpaper-gen.py

@@ -0,0 +1,408 @@
+# /// script
+# dependencies = ["pillow"]
+# ///
+"""Generate topographic contour wallpapers from real-world elevation data."""
+from __future__ import annotations
+
+import json
+import math
+import os
+import random
+import subprocess
+import sys
+import urllib.request
+from datetime import datetime
+from io import BytesIO
+from typing import Iterator
+
+from PIL import Image, ImageChops, ImageDraw, ImageFilter, ImageFont
+
+Coord = tuple[float, float]
+Candidate = tuple[float, float, str]
+Rgb = tuple[int, int, int]
+
+HOME: str = os.environ["HOME"]
+DIR: str = os.path.join(HOME, "Pictures", "Screensavers")
+STATE: str = os.path.join(
+    os.environ.get("XDG_STATE_HOME", os.path.join(HOME, ".local", "state")),
+    "theme",
+    "current",
+)
+LOG_DIR: str = os.path.join(
+    os.environ.get("XDG_STATE_HOME", os.path.join(HOME, ".local", "state")),
+    "wallpaper",
+)
+LOG_FILE: str = os.path.join(LOG_DIR, "gen.log")
+HISTORY_FILE: str = os.path.join(LOG_DIR, "history.json")
+CACHE: str = os.path.join(
+    os.environ.get("XDG_CACHE_HOME", os.path.join(HOME, ".cache")),
+    "wallpaper",
+)
+
+os.makedirs(DIR, exist_ok=True)
+os.makedirs(LOG_DIR, exist_ok=True)
+os.makedirs(CACHE, exist_ok=True)
+
+TILE_URL: str = "https://s3.amazonaws.com/elevation-tiles-prod/terrarium/{z}/{x}/{y}.png"
+TILE_SIZE: int = 256
+ZOOM: int = 11
+CONTOUR_LEVELS: int = 20
+
+# cozybox palette - matches lib/theme.nix
+THEMES: dict[str, dict[str, Rgb]] = {
+    "dark": {
+        "bg": (0x18, 0x18, 0x18),
+        "line": (0x2d, 0x2d, 0x2d),
+        "label": (0xFF, 0xFF, 0xFF),
+    },
+    "light": {
+        "bg": (0xE7, 0xE7, 0xE7),
+        "line": (0xCE, 0xCE, 0xCE),
+        "label": (0x00, 0x00, 0x00),
+    },
+}
+
+# curated mountain/terrain locations with interesting topography
+LOCATIONS: list[Coord] = [
+    (46.56, 7.69),      # Swiss Alps - Bernese Oberland
+    (36.10, -112.09),    # Grand Canyon
+    (27.99, 86.93),      # Everest region
+    (61.22, 6.78),       # Norwegian fjords
+    (-50.94, -73.15),    # Patagonia
+    (36.25, 137.60),     # Japanese Alps
+    (39.11, -106.45),    # Colorado Rockies
+    (46.42, 11.84),      # Dolomites
+    (44.07, 6.87),       # French Alps
+    (-43.59, 170.14),    # New Zealand Alps
+    (64.07, -16.20),     # Iceland highlands
+    (28.60, 83.82),      # Annapurna
+    (42.50, 44.50),      # Caucasus
+    (47.07, 12.69),      # Austrian Alps
+    (45.83, 6.86),       # Mont Blanc
+]
+
+MIN_RELIEF: int = 400
+MAX_RETRIES: int = 20
+SEA_LEVEL: int = 32768
+MIN_LAND_FRACTION: float = 0.1
+PREVIEW_W: int = 384
+PREVIEW_H: int = 240
+GRID_COLS: int = 6
+GRID_ROWS: int = 4
+MIN_CONTOUR_COVERAGE: float = 0.15
+MIN_OCCUPIED_CELLS: int = 12
+MAX_CELL_SHARE: float = 0.15
+MAX_CACHED_CANDIDATES: int = 24
+HISTORY_SIZE: int = 10  # remember this many recent locations to avoid repeats
+RUN_ID: str = f"{datetime.now().strftime('%Y%m%dT%H%M%S')}-pid{os.getpid()}"
+
+
+def log(message: str) -> None:
+    line = f"{datetime.now().astimezone().isoformat(timespec='seconds')} [{RUN_ID}] {message}"
+    print(line, file=sys.stderr, flush=True)
+    with open(LOG_FILE, "a", encoding="utf-8") as f:
+        print(line, file=f)
+
+
+def load_history() -> list[Coord]:
+    try:
+        with open(HISTORY_FILE, encoding="utf-8") as f:
+            entries = json.load(f)
+        return [(e[0], e[1]) for e in entries if isinstance(e, list) and len(e) == 2]
+    except (FileNotFoundError, json.JSONDecodeError, KeyError):
+        return []
+
+
+def save_history(lat: float, lon: float) -> None:
+    history = load_history()
+    history.append((round(lat, 2), round(lon, 2)))
+    history = history[-HISTORY_SIZE:]
+    with open(HISTORY_FILE, "w", encoding="utf-8") as f:
+        json.dump(history, f)
+
+
+def random_location() -> Coord:
+    return random.uniform(-60, 70), random.uniform(-180, 180)
+
+
+def cached_locations(tiles_x: int, tiles_y: int) -> list[Coord]:
+    suffix = f"_z{ZOOM}_{tiles_x}x{tiles_y}.png"
+    locations: list[Coord] = []
+    for name in os.listdir(CACHE):
+        if not name.startswith("terrain_") or not name.endswith(suffix):
+            continue
+        coords = name[len("terrain_") : -len(suffix)]
+        try:
+            lat, lon = coords.split("_", 1)
+            locations.append((float(lat), float(lon)))
+        except ValueError:
+            continue
+    random.shuffle(locations)
+    return locations[:MAX_CACHED_CANDIDATES]
+
+
+def candidate_locations(tiles_x: int, tiles_y: int) -> Iterator[Candidate]:
+    seen: set[Coord] = set()
+    recent = {(round(lat, 2), round(lon, 2)) for lat, lon in load_history()}
+    cached: list[Coord] = cached_locations(tiles_x, tiles_y)
+    fallback: list[Coord] = list(LOCATIONS)
+    random.shuffle(fallback)
+    log(f"candidate_pools cached={len(cached)} curated={len(fallback)} random={MAX_RETRIES} recent_skip={len(recent)}")
+    for lat, lon in cached:
+        key = (round(lat, 2), round(lon, 2))
+        if key in seen or key in recent:
+            continue
+        seen.add(key)
+        yield lat, lon, "cached"
+    for lat, lon in fallback:
+        key = (round(lat, 2), round(lon, 2))
+        if key in seen or key in recent:
+            continue
+        seen.add(key)
+        yield lat, lon, "curated"
+    for _ in range(MAX_RETRIES):
+        lat, lon = random_location()
+        key = (round(lat, 2), round(lon, 2))
+        if key in seen or key in recent:
+            continue
+        seen.add(key)
+        yield lat, lon, "random"
+
+
+def reverse_geocode(lat: float, lon: float) -> str | None:
+    try:
+        url = f"https://nominatim.openstreetmap.org/reverse?lat={lat}&lon={lon}&format=json&zoom=6&accept-language=en"
+        req = urllib.request.Request(url, headers={"User-Agent": "wallpaper-gen/1.0"})
+        with urllib.request.urlopen(req, timeout=5) as resp:
+            data = json.loads(resp.read())
+        addr = data.get("address", {})
+        name = (
+            addr.get("region")
+            or addr.get("state_district")
+            or addr.get("state")
+            or addr.get("county")
+            or addr.get("country")
+        )
+        return name
+    except Exception:
+        return None
+
+
+def get_resolution() -> tuple[int, int]:
+    """Get primary display resolution on macOS."""
+    try:
+        out = subprocess.check_output(
+            ["system_profiler", "SPDisplaysDataType", "-json"],
+            timeout=5,
+        ).decode()
+        displays = json.loads(out)
+        for gpu in displays.get("SPDisplaysDataType", []):
+            for disp in gpu.get("spdisplays_ndrvs", []):
+                res = disp.get("_spdisplays_resolution", "")
+                if " x " in res:
+                    parts = res.split(" x ")
+                    w = int(parts[0].strip())
+                    h = int(parts[1].split()[0].strip())
+                    return w, h
+    except Exception:
+        pass
+    return 3024, 1964  # MacBook Pro 14" default
+
+
+def lat_lon_to_tile(lat: float, lon: float, zoom: int) -> tuple[int, int]:
+    n = 2**zoom
+    x = int(n * ((lon + 180) / 360))
+    lat_rad = math.radians(lat)
+    y = int(n * (1 - (math.log(math.tan(lat_rad) + 1 / math.cos(lat_rad)) / math.pi)) / 2)
+    return x, y
+
+
+def fetch_tile(z: int, x: int, y: int) -> Image.Image:
+    url = TILE_URL.format(z=z, x=x, y=y)
+    req = urllib.request.Request(url, headers={"User-Agent": "wallpaper-gen/1.0"})
+    with urllib.request.urlopen(req, timeout=15) as resp:
+        return Image.open(BytesIO(resp.read()))
+
+
+def fetch_terrain(
+    lat: float, lon: float, tiles_x: int, tiles_y: int, zoom: int
+) -> tuple[Image.Image, bool]:
+    tag = f"{lat:.2f}_{lon:.2f}_z{zoom}_{tiles_x}x{tiles_y}"
+    cache_file = os.path.join(CACHE, f"terrain_{tag}.png")
+    if os.path.exists(cache_file):
+        return Image.open(cache_file), True
+    cx, cy = lat_lon_to_tile(lat, lon, zoom)
+    sx, sy = cx - tiles_x // 2, cy - tiles_y // 2
+    full = Image.new("RGB", (tiles_x * TILE_SIZE, tiles_y * TILE_SIZE))
+    for ty in range(tiles_y):
+        for tx in range(tiles_x):
+            tile = fetch_tile(zoom, sx + tx, sy + ty)
+            full.paste(tile, (tx * TILE_SIZE, ty * TILE_SIZE))
+    full.save(cache_file)
+    return full, False
+
+
+def decode_terrarium(img: Image.Image) -> tuple[Image.Image, int, float]:
+    raw_bytes = img.tobytes()
+    px_count = len(raw_bytes) // 3
+    raw: list[int] = [0] * px_count
+    land: int = 0
+    for i in range(px_count):
+        off = i * 3
+        raw[i] = (raw_bytes[off] << 8) | raw_bytes[off + 1]
+        if raw[i] > SEA_LEVEL:
+            land += 1
+    lo, hi = min(raw), max(raw)
+    rng = hi - lo or 1
+    norm = bytearray((e - lo) * 255 // rng for e in raw)
+    return Image.frombytes("L", img.size, bytes(norm)), hi - lo, land / px_count
+
+
+def build_contour_mask(elevation: Image.Image, W: int, H: int) -> Image.Image:
+    S: int = 2
+    iW, iH = W * S, H * S
+    terrain = elevation.resize((iW, iH), Image.BICUBIC)
+    terrain = terrain.filter(ImageFilter.GaussianBlur(radius=15 * S))
+    step = max(1, 256 // CONTOUR_LEVELS)
+    terrain = terrain.point(lambda p: (p // step) * step)
+    eroded = terrain.filter(ImageFilter.MinFilter(3))
+    edges = ImageChops.subtract(terrain, eroded)
+    edges = edges.point(lambda p: 255 if p > 0 else 0)
+    edges = edges.filter(ImageFilter.MaxFilter(3))
+    edges = edges.filter(ImageFilter.GaussianBlur(radius=1.5 * S))
+    return edges.point(lambda p: 255 if p > 80 else 0)
+
+
+def contour_stats(elevation: Image.Image) -> tuple[float, int, float]:
+    mask = build_contour_mask(elevation, PREVIEW_W, PREVIEW_H).resize(
+        (PREVIEW_W, PREVIEW_H), Image.NEAREST
+    )
+    mask_bytes = mask.tobytes()
+    total: int = len(mask_bytes)
+    filled: int = 0
+    cell_counts: list[int] = [0] * (GRID_COLS * GRID_ROWS)
+    for y in range(PREVIEW_H):
+        row_off = y * PREVIEW_W
+        cy = y * GRID_ROWS // PREVIEW_H
+        for x in range(PREVIEW_W):
+            if mask_bytes[row_off + x]:
+                filled += 1
+                cx = x * GRID_COLS // PREVIEW_W
+                cell_counts[cy * GRID_COLS + cx] += 1
+    coverage = filled / total
+    occupied = sum(1 for count in cell_counts if count)
+    largest_share = max(cell_counts) / filled if filled else 1
+    return coverage, occupied, largest_share
+
+
+def candidate_summary(
+    elevation: Image.Image, relief: int, land_fraction: float
+) -> tuple[bool, str]:
+    if relief < MIN_RELIEF or land_fraction < MIN_LAND_FRACTION:
+        return False, (
+            f"relief={relief} land_fraction={land_fraction:.3f} "
+            f"thresholds=({MIN_RELIEF},{MIN_LAND_FRACTION:.3f})"
+        )
+    coverage, occupied, largest_share = contour_stats(elevation)
+    ok = (
+        coverage >= MIN_CONTOUR_COVERAGE
+        and occupied >= MIN_OCCUPIED_CELLS
+        and largest_share <= MAX_CELL_SHARE
+    )
+    return ok, (
+        f"relief={relief} land_fraction={land_fraction:.3f} "
+        f"coverage={coverage:.3f} occupied={occupied} largest_cell_share={largest_share:.3f} "
+        f"thresholds=({MIN_CONTOUR_COVERAGE:.3f},{MIN_OCCUPIED_CELLS},{MAX_CELL_SHARE:.3f})"
+    )
+
+
+def render_contours(
+    elevation: Image.Image, W: int, H: int, bg: Rgb, line_color: Rgb
+) -> Image.Image:
+    S: int = 2
+    iW, iH = W * S, H * S
+    edges = build_contour_mask(elevation, W, H)
+    bg_img = Image.new("RGB", (iW, iH), bg)
+    fg_img = Image.new("RGB", (iW, iH), line_color)
+    img = Image.composite(fg_img, bg_img, edges)
+    return img.resize((W, H), Image.LANCZOS)
+
+
+def find_font() -> str | None:
+    candidates = [
+        os.path.join(HOME, "Library/Fonts/BerkeleyMono-Regular.otf"),
+        os.path.join(HOME, "Library/Fonts/BerkeleyMono-Regular.ttf"),
+        os.path.join(HOME, ".local/share/fonts/berkeley-mono/BerkeleyMono-Regular.ttf"),
+        "/Library/Fonts/BerkeleyMono-Regular.otf",
+    ]
+    for path in candidates:
+        if os.path.exists(path):
+            return path
+    return None
+
+
+def gen() -> None:
+    W, H = get_resolution()
+    tiles_x = math.ceil(W / TILE_SIZE)
+    tiles_y = math.ceil(H / TILE_SIZE)
+
+    theme = "dark"
+    try:
+        with open(STATE) as f:
+            t = f.read().strip()
+            if t in THEMES:
+                theme = t
+    except FileNotFoundError:
+        pass
+
+    log(f"start theme={theme} resolution={W}x{H} tiles={tiles_x}x{tiles_y}")
+
+    for index, (lat, lon, source) in enumerate(candidate_locations(tiles_x, tiles_y), start=1):
+        log(f"candidate[{index}] source={source} lat={lat:.2f} lon={lon:.2f} begin")
+        try:
+            terrain_img, cache_hit = fetch_terrain(lat, lon, tiles_x, tiles_y, ZOOM)
+        except Exception as err:
+            log(f"candidate[{index}] source={source} lat={lat:.2f} lon={lon:.2f} fetch_error={err!r}")
+            continue
+        elevation, relief, land_fraction = decode_terrarium(terrain_img)
+        ok, summary = candidate_summary(elevation, relief, land_fraction)
+        status = "accept" if ok else "reject"
+        cache = "hit" if cache_hit else "miss"
+        log(f"candidate[{index}] source={source} lat={lat:.2f} lon={lon:.2f} cache={cache} {status} {summary}")
+        if ok:
+            break
+    else:
+        log("finish status=no_candidate")
+        return
+
+    elevation = elevation.crop((0, 0, min(elevation.width, W), min(elevation.height, H)))
+    save_history(lat, lon)
+    place = reverse_geocode(lat, lon)
+    log(f"selected lat={lat:.2f} lon={lon:.2f} place={place or '<none>'}")
+
+    coords = f"{lat:.2f}, {lon:.2f}"
+    label = f"{place} ({coords})" if place else coords
+    font_path = find_font()
+
+    for theme_name, colors in THEMES.items():
+        img = render_contours(elevation, W, H, colors["bg"], colors["line"])
+        draw = ImageDraw.Draw(img)
+        if font_path:
+            font = ImageFont.truetype(font_path, 14)
+        else:
+            font = ImageFont.load_default()
+        draw.text((24, H - 30), label, fill=colors["label"], font=font)
+        out_path = os.path.join(DIR, f"wallpaper-{theme_name}.jpg")
+        img.save(out_path, quality=95)
+        log(f"wrote theme={theme_name} path={out_path}")
+
+    link = os.path.join(DIR, "wallpaper.jpg")
+    if os.path.lexists(link):
+        os.unlink(link)
+    target = os.path.join(DIR, f"wallpaper-{theme}.jpg")
+    os.symlink(target, link)
+    log(f"finish status=ok target={target} link={link}")
+
+
+if __name__ == "__main__":
+    gen()

scripts/wallpaper-gen.sh

@@ -0,0 +1 @@
+uv run "@WALLPAPER_GEN_PY@"