fix(composer): close binding_source code injection, line-align, and project_root UnboundLocalError

Three findings from CodeRabbit's review of 6c23994b, all verified against
current code before fixing:

- manager.py.j2 interpolated binding.source unescaped into a Python comment
  (`pass  # dynamic_text binding_source "{{ el.binding_source }}" draws
  nothing`). A source string with a newline broke out of the comment; a
  crafted payload produces a clean, ast.parse-valid `import os` in the
  generated plugin (confirmed against the pre-fix template). This is now a
  fixed literal comment that never interpolates the value. Live now that
  composer_bp is registered. CWE-94.
- _alignElement moved a line's x0 (or y0) to the new position but left x1
  (or y1) behind, so aligning a line changed its shape instead of moving
  it. Both endpoints now translate by the same delta.
- web_interface/app.py only assigned project_root inside the relative-path
  branch of the plugins_dir resolution. An absolute plugin_system.plugins_
  directory (a supported config value) hit UnboundLocalError importing the
  module at all, since SchemaManager/composer_bp use project_root further
  down. Now assigned unconditionally before the branch.

Also extends BOUND_TYPES coverage in composer-app.js (_isBound,
removeConfigVar, _validateBeforeExport) from dynamic_text/progress_bar to
all six element types that carry a binding object (countdown, pips,
sparkline, gauge too) -- found by direct code reading against
ELEMENT_DEFAULTS in composer-canvas.js, not from a review comment. Without
it, those four types could export with an unbound config key with no
validation error, and deleting a config var they used gave no warning.

All four fixes have mutation-checked regression tests (fail against the
reverted code, pass with the fix): test_binding_source_cannot_break_out_of_the_comment_it_lands_in,
test_align_translates_both_line_endpoints_not_just_the_start,
test_app_plugins_dir_resolution.py, test_binding_checks_cover_every_bound_element_type.

Full suite: 4365 passed, 58 skipped, 2 failed -- both the pre-existing
Europe/Kiev/Asia/Calcutta tzdata-alias gap on this sandbox, identical on
origin/main, unrelated to this change.

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

scripts/render_plugin.py

@@ -52,6 +52,10 @@ def main() -> int:
     parser.add_argument('--height', type=int, default=32, help='Display height (default: 32)')
     parser.add_argument('--skip-update', action='store_true',
                         help='Skip calling update() (render display only)')
+    parser.add_argument('--display-mode', default=None,
+                        help='Display mode to render, for plugins that declare '
+                             'more than one in their manifest (e.g. nrl_live). '
+                             'Omitted, the plugin picks its own default.')
 
     args = parser.parse_args()
 
@@ -141,8 +145,26 @@ def main() -> int:
         except Exception as e:
             logger.warning("update() raised: %s — continuing to display()", e)
 
+    # A plugin that declares several display modes usually renders nothing
+    # useful without being told which one to draw: the scoreboards keep their
+    # state on per-mode sub-managers and their no-argument path returns False.
+    # Only pass the argument when asked for, so the many plugins whose display()
+    # takes no display_mode keep working untouched.
     try:
-        plugin_instance.display(force_clear=True)
+        if args.display_mode:
+            try:
+                plugin_instance.display(display_mode=args.display_mode,
+                                        force_clear=True)
+            except TypeError as error:
+                if ("unexpected keyword argument" not in str(error)
+                        or "display_mode" not in str(error)):
+                    raise
+                logger.warning(
+                    "%s.display() does not accept display_mode; rendering its "
+                    "default screen instead", args.plugin)
+                plugin_instance.display(force_clear=True)
+        else:
+            plugin_instance.display(force_clear=True)
         logger.debug("display() completed")
     except Exception as e:
         logger.error("Error in display(): %s", e)

src/common/sports_card.py

@@ -17,10 +17,13 @@ deliberate difference is `crisp_size`, which takes the seven-plugin guard
 the extra guard only stops a None size raising TypeError.
 """
 
+import logging
 from datetime import datetime, timezone
 from typing import Any, Dict, Optional, Tuple
 from zoneinfo import ZoneInfo
 
+logger = logging.getLogger(__name__)
+
 __all__ = [
     "ELEMENT_FOR_FONT", "FAVORITE_RESULT_COLOR_DEFAULTS", "FONT_NAME_ALIASES",
     "FONT_PIXEL_GRID", "MONTH_ABBR", "WEEKDAY_ABBR",
@@ -395,7 +398,14 @@ def schema_font_size(schema_path: str, element_key) -> Optional[int]:
                 size = spec.get('properties', {}).get('font_size', {}).get('default')
                 if size is not None:
                     cache[key] = int(size)
-        except Exception:
+        except Exception as exc:
+            # See sports_shared._schema_font_size: an unreadable schema
+            # silently disables the pixel-grid snap for every element.
+            # Built once per schema path, so this cannot repeat per frame.
+            logger.warning(
+                "could not read %s (%s: %s); font sizes will skip their "
+                "pixel grid snap and may render a pixel narrow",
+                schema_path, type(exc).__name__, exc)
             cache = {}
         _SCHEMA_FONT_SIZE_CACHE[schema_path] = cache
     return cache.get(element_key)

src/common/sports_shared.py

@@ -211,17 +211,52 @@ class SportsCoreSharedMixin:
             return desired
         return max(grid, int(round(float(desired) / grid)) * grid)
 
+    #: Absolute path of this plugin's directory, declared by the plugin
+    #: itself. The mixin cannot work it out -- see _plugin_dir.
+    _PLUGIN_DIR: ClassVar[Optional[str]] = None
+
     def _plugin_dir(self) -> Optional[str]:
-        """Directory of the plugin that defines this class.
+        """Directory of the plugin that owns this instance.
 
         In sports.py these methods could just use ``__file__``. Here that is
-        src/common/, so the plugin's own directory has to be recovered from the
+        src/common/, so the directory has to come from the plugin.
-        instance. ``type(self).__module__`` alone is not enough: SportsCore is
+
-        an ABC, so a subclass built with ``type(name, bases, ns)`` -- which the
+        It is TOLD, not deduced. The first version walked the MRO for a class
-        plugins' own tests do -- reports its module as "abc". Walking the MRO
+        whose module sits beside a config_schema.json. That works when a test
-        steps past those synthetic classes to the first one whose module sits
+        imports the plugin itself, and returns None under the real loader, for
-        next to a config_schema.json, which is the real plugin.
+        a specific reason worth recording:
+
+            PluginLoader._namespace_plugin_modules renames every bare module a
+            plugin brought in (sports, game_renderer, ...) to
+            "_plg_<plugin_id>_<module>" and REMOVES the bare entry, so two
+            plugins owning a module of the same name cannot collide.
+
+        The class still reports ``__module__ == "sports"``, but
+        ``sys.modules["sports"]`` no longer exists, so the walk finds no
+        __file__ and falls off the end. The failure was silent and expensive:
+
+            _plugin_dir()       -> None
+            _schema_font_size() -> None for every element
+            -> a configured size equal to the schema default stops looking
+               like a default and is treated as a deliberate user choice
+            -> the snap to the font's pixel grid is skipped
+            -> 4x6-font.ttf renders at 6 instead of 7: 3px-wide glyphs
+               instead of 4px
+
+        On a 256x64 panel that made the odds, the team records and the date row
+        hard to read. It was found by a user counting pixels on the panel. No
+        gate here caught it: the tests imported plugins directly and the
+        safety harness loads them its own way, so neither reproduced the
+        loader's renaming.
+
+        The MRO walk stays as a fallback for hosts that declare no
+        _PLUGIN_DIR -- the plugins' own probe harnesses build classes with
+        ``type()`` -- but it is no longer the primary answer.
         """
+        declared = getattr(self, "_PLUGIN_DIR", None)
+        if declared and os.path.isfile(os.path.join(declared, "config_schema.json")):
+            return declared
+
         for cls in type(self).__mro__:
             module = sys.modules.get(getattr(cls, "__module__", ""), None)
             path = getattr(module, "__file__", None)
@@ -253,7 +288,23 @@ class SportsCoreSharedMixin:
                     size = spec.get('properties', {}).get('font_size', {}).get('default')
                     if size is not None:
                         cache[key] = int(size)
-            except Exception:
+            except Exception as exc:
+                # Say so. An unreadable schema is not cosmetic: every element's
+                # configured size then stops matching "the schema default", is
+                # treated as a deliberate user choice, and skips the snap to the
+                # font's pixel grid -- which renders 4x6-font.ttf at 6 instead
+                # of 7, a 3px-wide glyph instead of 4px. That shipped once,
+                # silently, and was found by a user counting pixels on a photo
+                # of the panel.
+                #
+                # Logged, not raised: a missing schema must not stop a plugin
+                # rendering. The cache is built once per class, so this cannot
+                # repeat per frame.
+                logger.warning(
+                    "%s: could not read config_schema.json (%s: %s); every font "
+                    "size will be treated as user-chosen and will skip its pixel "
+                    "grid snap. Font sizes may render a pixel narrow.",
+                    type(self).__name__, type(exc).__name__, exc)
                 cache = {}
             self.__class__._SCHEMA_FONT_SIZES = cache
         return cache.get(element_key)

src/display_manager.py

@@ -364,6 +364,7 @@ class DisplayManager:
             # Create image with the (logical) display dimensions
             self.image = Image.new('RGB', (self.matrix.width, self.matrix.height))
             self.draw = ImageDraw.Draw(self.image)
+            self.draw.fontmode = "1"  # 1-bit text: the panel has no partial brightness, so AA only smears glyphs.
             logger.info(f"Image canvas created with dimensions: {self.matrix.width}x{self.matrix.height}")
             
             # Initialize font with Press Start 2P
@@ -403,6 +404,7 @@ class DisplayManager:
 
             self.image = Image.new('RGB', (fallback_width, fallback_height))
             self.draw = ImageDraw.Draw(self.image)
+            self.draw.fontmode = "1"  # 1-bit text: the panel has no partial brightness, so AA only smears glyphs.
             # Simple fallback visualization so web UI shows a realistic canvas
             try:
                 self.draw.rectangle([0, 0, fallback_width - 1, fallback_height - 1], outline=(255, 0, 0))
@@ -705,6 +707,7 @@ class DisplayManager:
             # self.image, so swapping the buffer below is enough on its own.
             self.image = Image.new('RGB', (target_w, target_h))
             self.draw = ImageDraw.Draw(self.image)
+            self.draw.fontmode = "1"  # 1-bit text: the panel has no partial brightness, so AA only smears glyphs.
             yield
         finally:
             self.matrix = real_matrix
@@ -814,6 +817,7 @@ class DisplayManager:
                 
                 self.image = Image.new('RGB', (width, height))
                 self.draw = ImageDraw.Draw(self.image)
+                self.draw.fontmode = "1"  # 1-bit text: the panel has no partial brightness, so AA only smears glyphs.
                 logger.debug("Cleared display in fallback mode")
                 return
                 
@@ -825,6 +829,7 @@ class DisplayManager:
             # Create a new black image
             self.image = Image.new('RGB', (self.matrix.width, self.matrix.height))
             self.draw = ImageDraw.Draw(self.image)
+            self.draw.fontmode = "1"  # 1-bit text: the panel has no partial brightness, so AA only smears glyphs.
 
             if not self._capture_mode_active:
                 # Clear both canvases and the underlying matrix to ensure no artifacts.
@@ -1258,6 +1263,7 @@ class DisplayManager:
             try:
                 self.image = Image.new('RGB', (self.width, self.height))
                 self.draw = ImageDraw.Draw(self.image)
+                self.draw.fontmode = "1"  # 1-bit text: the panel has no partial brightness, so AA only smears glyphs.
             except (OSError, RuntimeError, ValueError, MemoryError):
                 logger.debug("Canvas reset during cleanup failed", exc_info=True)
         # Reset the singleton state when cleaning up

src/plugin_system/testing/visual_display_manager.py

@@ -70,6 +70,7 @@ class VisualTestDisplayManager:
         # Canvas
         self.image = Image.new('RGB', (width, height), (0, 0, 0))
         self.draw = ImageDraw.Draw(self.image)
+        self.draw.fontmode = "1"  # Match production: 1-bit text, so goldens show what the panel shows.
 
         # Matrix proxy (plugins access display_manager.matrix.width/height)
         self.matrix = _MatrixProxy(width, height)
@@ -184,6 +185,7 @@ class VisualTestDisplayManager:
         self.clear_called = True
         self.image = Image.new('RGB', (self._width, self._height), (0, 0, 0))
         self.draw = ImageDraw.Draw(self.image)
+        self.draw.fontmode = "1"  # Match production: 1-bit text, so goldens show what the panel shows.
 
     def update_display(self):
         """No-op for hardware; marks that display was updated."""
@@ -211,6 +213,7 @@ class VisualTestDisplayManager:
             self.matrix = _MatrixProxy(target_w, target_h)
             self.image = Image.new('RGB', (target_w, target_h), (0, 0, 0))
             self.draw = ImageDraw.Draw(self.image)
+            self.draw.fontmode = "1"  # Match production: 1-bit text, so goldens show what the panel shows.
             yield
         finally:
             self._width, self._height = prev_w, prev_h
@@ -569,6 +572,7 @@ class VisualTestDisplayManager:
         self.draw_calls = []
         self.image = Image.new('RGB', (self._width, self._height), (0, 0, 0))
         self.draw = ImageDraw.Draw(self.image)
+        self.draw.fontmode = "1"  # Match production: 1-bit text, so goldens show what the panel shows.
         self._scrolling_state = {
             'is_scrolling': False,
             'last_scroll_activity': 0,
@@ -582,3 +586,4 @@ class VisualTestDisplayManager:
         """Clean up resources."""
         self.image = Image.new('RGB', (self._width, self._height), (0, 0, 0))
         self.draw = ImageDraw.Draw(self.image)
+        self.draw.fontmode = "1"  # Match production: 1-bit text, so goldens show what the panel shows.

test/test_app_plugins_dir_resolution.py

@@ -0,0 +1,52 @@
+"""web_interface/app.py resolves plugins_dir from config at import time.
+
+`project_root` used to be assigned only inside the `else` branch (the
+relative-path case). SchemaManager and composer_bp are wired up with
+`project_root` further down the same module, so a device configured with an
+*absolute* `plugin_system.plugins_directory` (a supported value -- see
+CLAUDE.md) hit `UnboundLocalError` importing web_interface.app at all, taking
+the whole web UI down.
+
+app.py isn't imported directly by the test suite -- it has real side effects
+(managers, background state) at import time -- so this extracts the exact
+resolution block by its stable comment markers and executes it in isolation,
+the same way the rest of the suite validates generated/templated code rather
+than re-implementing it.
+"""
+from pathlib import Path
+
+APP_PY = Path(__file__).resolve().parent.parent / "web_interface/app.py"
+
+START_MARKER = "# Resolve plugin directory - handle both absolute and relative paths\n"
+END_MARKER = "\nplugin_manager = PluginManager("
+
+
+def _resolution_block() -> str:
+    src = APP_PY.read_text()
+    start = src.index(START_MARKER)
+    end = src.index(END_MARKER, start)
+    return src[start:end]
+
+
+def test_resolution_block_still_matches_expected_markers():
+    """If app.py is restructured enough that these markers move, the exec
+    below would silently test nothing -- fail loudly instead."""
+    block = _resolution_block()
+    assert "plugins_dir" in block and "os.path.isabs" in block
+
+
+def test_absolute_plugins_directory_does_not_raise_unboundlocalerror():
+    import os
+    ns = {"os": os, "Path": Path, "__file__": str(APP_PY),
+          "plugins_dir_name": "/opt/ledmatrix-plugins"}
+    exec(compile(_resolution_block(), str(APP_PY), "exec"), ns)  # noqa: S102
+    assert ns["project_root"] == APP_PY.parent.parent
+    assert ns["plugins_dir"] == Path("/opt/ledmatrix-plugins")
+
+
+def test_relative_plugins_directory_still_resolves_under_project_root():
+    import os
+    ns = {"os": os, "Path": Path, "__file__": str(APP_PY),
+          "plugins_dir_name": "plugin-repos"}
+    exec(compile(_resolution_block(), str(APP_PY), "exec"), ns)  # noqa: S102
+    assert ns["plugins_dir"] == ns["project_root"] / "plugin-repos"

test/test_composer_blueprint_registered.py

@@ -0,0 +1,64 @@
+"""composer_bp must actually be registered on the Flask app.
+
+web_interface/blueprints/composer.py defines a full blueprint -- the
+/composer/ page, /composer/api/generate, /composer/api/install, etc. -- but
+nothing in web_interface/app.py imported or registered it. pages_v3 and
+api_v3 both go through the same "import, wire managers, register_blueprint"
+sequence; composer_bp had none of the three. The routes existed and worked
+in isolation (every other composer test builds its own minimal Flask app
+and registers composer_bp directly), but in the real running app every
+composer URL -- including the page itself -- was a 404, and the frontend's
+hardcoded '/composer/api/...' fetches (composer-app.js) had nothing to
+reach.
+
+app.py has import-time side effects (it loads config, builds managers, and
+in some configurations starts background threads), so this scans the source
+text rather than importing the module -- the same approach already used for
+test_composer_js_contracts.py's structural checks.
+"""
+import re
+from pathlib import Path
+
+APP_PY = Path(__file__).resolve().parent.parent / "web_interface" / "app.py"
+
+
+def _source() -> str:
+    return APP_PY.read_text()
+
+
+def test_composer_blueprint_is_imported():
+    src = _source()
+    assert re.search(
+        r"from web_interface\.blueprints\.composer import composer_bp", src
+    ), "app.py never imports composer_bp"
+
+
+def test_composer_blueprint_is_registered_under_composer_prefix():
+    src = _source()
+    match = re.search(
+        r"app\.register_blueprint\(\s*composer_bp\s*,\s*url_prefix\s*=\s*"
+        r"['\"](?P<prefix>[^'\"]*)['\"]",
+        src,
+    )
+    assert match, "app.py never calls app.register_blueprint(composer_bp, ...)"
+    # composer.html and composer-app.js hardcode '/composer/api/...' and
+    # '/composer/api/fonts/...' -- any other prefix serves a page whose own
+    # fetches and @font-face all 404.
+    assert match.group("prefix") == "/composer"
+
+
+def test_composer_blueprint_managers_are_wired_before_registration():
+    """Registered with no managers set means every route 503s or crashes.
+
+    composer.py initialises config_manager/plugin_manager/plugins_dir/
+    project_root to None at import time specifically so app.py can set them
+    -- the same pattern api_v3 and pages_v3 use.
+    """
+    src = _source()
+    register_match = re.search(r"app\.register_blueprint\(\s*composer_bp", src)
+    assert register_match, "app.py never registers composer_bp"
+    before_registration = src[: register_match.start()]
+    for attr in ("config_manager", "plugin_manager", "plugins_dir", "project_root"):
+        assert re.search(rf"composer_bp\.{attr}\s*=", before_registration), (
+            f"composer_bp.{attr} is never set before registration"
+        )

test/test_composer_code_injection.py

@@ -0,0 +1,323 @@
+"""The composer generates Python that the plugin loader imports and executes.
+
+/api/install writes the generated manager.py into plugins_dir and the loader
+imports it, so anything the payload can splice into that source runs on the
+device. The ast.parse check in _generate_plugin_files rejects only *invalid*
+syntax -- an injected `import os` is perfectly valid and passed it.
+
+Two ways in, both confirmed against the code before it was fixed:
+
+  metadata.name = a name containing a triple-quote, a newline, then
+                  `import os; PWNED = os.getuid()`, then another triple-quote
+      -> closes the module docstring; the rest became module-level statements
+         (spelled out rather than shown literally -- writing the payload into
+         this docstring closes *this* file's docstring, which is the bug)
+
+  element x     = '0 or __import__("os").system("id")'
+      -> f-string interpolated it verbatim: x=0 or __import__("os").system("id")
+"""
+import ast
+import re
+import sys
+from pathlib import Path
+
+import pytest
+
+sys.path.insert(0, str(Path(__file__).resolve().parent.parent))
+
+from web_interface.blueprints import composer as C  # noqa: E402
+
+BASE_META = {"id": "test-plugin", "name": "Clock", "author": "a",
+             "version": "1.0.0", "description": "d"}
+
+#: Values that terminate a Python expression and start a new statement.
+EXPR_PAYLOADS = [
+    '0 or __import__("os").system("id")',
+    '0);import os;os.system("id");(',
+    '__import__("subprocess").run(["id"])',
+    "0 if False else exec('x=1')",
+    "1e999", "nan", "0x41", "0__0",
+]
+
+#: Values that close a string literal in the generated source.
+LITERAL_PAYLOADS = [
+    'Clock"""\nimport os; PWNED = os.getuid()\n"""',
+    "Clock'''\nimport os\n'''",
+    'Clock" + __import__("os").system("id") + "',
+    "Clock\\", "Clock\nimport os",
+]
+
+
+def _payload(**over):
+    # dataModel.configVars is the key _generate_plugin_files reads; "config_vars"
+    # was never looked at, so anything passed through it tested nothing.
+    p = {"metadata": dict(BASE_META), "elements": [],
+         "dataModel": {"configVars": over.pop("config_vars", [])}}
+    p["metadata"].update(over.pop("metadata", {}))
+    p.update(over)
+    return p
+
+
+def _generated(payload):
+    return C._generate_plugin_files(payload)["manager.py"]
+
+
+def _module_level_code(src):
+    """Statements at module level that are not the docstring/imports/classes."""
+    tree = ast.parse(src)
+    out = []
+    for node in tree.body:
+        if isinstance(node, (ast.ClassDef, ast.FunctionDef, ast.ImportFrom, ast.Import)):
+            continue
+        if isinstance(node, ast.Expr) and isinstance(node.value, ast.Constant):
+            continue  # the docstring
+        out.append(ast.unparse(node))
+    return out
+
+
+@pytest.mark.parametrize("payload", LITERAL_PAYLOADS)
+def test_a_name_that_breaks_out_of_a_literal_is_refused(payload):
+    with pytest.raises(C.ComposerInputError):
+        _generated(_payload(metadata={"name": payload}))
+
+
+#: Types with a drawing branch in manager.py.j2. An injection test using any
+#: other type proves nothing: _preprocess_elements drops it, so its values
+#: never reach the generated source and every assertion passes trivially.
+#: This test previously used "line", which has never had a branch.
+RENDERED_GEOMETRY_CASES = [
+    ("rectangle", {"x": 0, "y": 0, "width": 10, "height": 8}),
+    ("arc", {"x": 0, "y": 0, "width": 24, "height": 24}),
+    ("ellipse", {"x": 0, "y": 0, "width": 24, "height": 12}),
+    ("rounded_rectangle", {"x": 0, "y": 0, "width": 24, "height": 10}),
+    ("gauge", {"x": 0, "y": 0, "width": 32, "height": 32}),
+]
+
+
+@pytest.mark.parametrize("etype,base", RENDERED_GEOMETRY_CASES)
+@pytest.mark.parametrize("evil", EXPR_PAYLOADS)
+@pytest.mark.parametrize("field", ["x", "y", "width", "height"])
+def test_a_non_numeric_geometry_value_cannot_reach_the_source(etype, base, evil, field):
+    """width/height were interpolated raw into the generated source.
+
+    p['x2_expr'] = f"({x_expr}) + {w}" with w straight off the payload, so a
+    rectangle with width='0 or __import__("os").system("id")' produced
+
+        [0, 0, (0) + 0 or __import__("os").system("id"), (0) + 8],
+
+    in a manager.py that /api/install writes to disk and the loader imports.
+    """
+    el = {"type": etype, "id": "e1", **base}
+    el[field] = evil
+    src = _generated(_payload(elements=[el]))
+    assert "__import__" not in src, f"{etype}.{field}={evil!r} reached the generated source"
+    assert "os.system" not in src
+    assert not _module_level_code(src), \
+        f"{etype}.{field}={evil!r} produced module-level statements: {_module_level_code(src)}"
+
+
+def test_every_injection_case_uses_a_type_that_actually_renders():
+    """Guards against the whole suite quietly going vacuous again.
+
+    An element type with no template branch is dropped before generation, so
+    an injection test written against one asserts nothing and still passes.
+    """
+    used = {etype for etype, _ in RENDERED_GEOMETRY_CASES}
+    missing = used - set(C._RENDERABLE_ELEMENT_TYPES)
+    assert not missing, f"injection tests use non-rendering types: {sorted(missing)}"
+
+
+@pytest.mark.parametrize("evil", EXPR_PAYLOADS)
+@pytest.mark.parametrize("channel", ["r", "g", "b"])
+def test_a_non_numeric_colour_channel_cannot_reach_the_source(evil, channel):
+    el = {"type": "text", "id": "t1", "x": 0, "y": 0, "text": "hi",
+          "font": "press_start", "r": 255, "g": 255, "b": 255}
+    el[channel] = evil
+    src = _generated(_payload(elements=[el]))
+    assert "__import__" not in src and "os.system" not in src
+    assert not _module_level_code(src)
+
+
+def test_colour_channels_are_clamped_to_a_byte():
+    el = {"type": "text", "id": "t1", "x": 0, "y": 0, "text": "hi",
+          "font": "press_start", "r": 99999, "g": -5, "b": 128}
+    src = _generated(_payload(elements=[el]))
+    assert "(255, 0, 128)" in src, "channels were not clamped to 0-255"
+
+
+#: fillR/fillG/fillB (and outR/G/B, bgR/G/B, trackR/G/B) go through
+#: _as_fill_filter -> _as_rgb_filter, a separate path from _rgb_expr above.
+#: It used raw int() until it was found to raise ValueError on a non-numeric
+#: channel instead of clamping like every other coerced value in this module.
+@pytest.mark.parametrize("evil", EXPR_PAYLOADS)
+@pytest.mark.parametrize("channel", ["fillR", "fillG", "fillB"])
+def test_a_non_numeric_fill_channel_cannot_reach_the_source(evil, channel):
+    el = {"type": "rectangle", "id": "r1", "x": 0, "y": 0, "width": 10, "height": 8,
+          "fillR": 0, "fillG": 0, "fillB": 128}
+    el[channel] = evil
+    src = _generated(_payload(elements=[el]))
+    assert "__import__" not in src and "os.system" not in src
+    assert not _module_level_code(src)
+
+
+def test_fill_channels_are_clamped_to_a_byte():
+    el = {"type": "rectangle", "id": "r1", "x": 0, "y": 0, "width": 10, "height": 8,
+          "fillR": 99999, "fillG": -5, "fillB": 128}
+    src = _generated(_payload(elements=[el]))
+    assert "(255, 0, 128)" in src, "fill channels were not clamped to 0-255"
+
+
+def test_the_generated_module_still_has_no_top_level_statements():
+    """The clean case: a normal payload produces only imports and a class."""
+    el = {"type": "text", "id": "t1", "x": 4, "y": 4, "text": "hi",
+          "font": "press_start", "r": 1, "g": 2, "b": 3}
+    src = _generated(_payload(elements=[el]))
+    assert not _module_level_code(src)
+    assert "(1, 2, 3)" in src
+
+
+# --- config variable keys ---------------------------------------------------
+
+def _with_key(key):
+    return {"metadata": dict(BASE_META), "elements": [],
+            "dataModel": {"configVars": [{"key": key, "type": "string",
+                                          "default": "x", "label": "L"}]}}
+
+
+@pytest.mark.parametrize("key", ["class", "def", "import", "None", "True",
+                                 "lambda", "pass", "match", "case"])
+def test_a_keyword_config_key_is_named_in_the_error(key):
+    """ast.parse already rejected these, but as an unhelpful line number.
+
+    "Generated code has a syntax error: invalid syntax (line 17)" tells the
+    user nothing about which field to fix.
+    """
+    with pytest.raises(C.ComposerInputError) as exc:
+        _generated(_with_key(key))
+    assert key in str(exc.value) and "keyword" in str(exc.value).lower()
+
+
+@pytest.mark.parametrize("key", ["config", "logger", "display_manager",
+                                 "cache_manager", "plugin_id", "enabled",
+                                 "self", "update", "display"])
+def test_a_reserved_attribute_config_key_is_refused(key):
+    """These generate *valid* Python that silently clobbers plugin state.
+
+    The worst is `config`: the assignment lands right after super().__init__(),
+    so `self.config = config.get("config", "x")` replaces the plugin's config
+    dict with a string and every later self.config.get(...) fails at runtime.
+    """
+    with pytest.raises(C.ComposerInputError) as exc:
+        _generated(_with_key(key))
+    assert key in str(exc.value) and "reserved" in str(exc.value).lower()
+
+
+@pytest.mark.parametrize("key", ["brightness", "my_var", "_private", "x1",
+                                 "update_interval_seconds"])
+def test_ordinary_config_keys_are_still_accepted(key):
+    src = _generated(_with_key(key))
+    assert f"self.{key} = config.get(" in src
+
+
+def test_the_generated_config_assignment_does_not_precede_super_init():
+    """Guards the reasoning behind the reserved list, not just the list."""
+    src = _generated(_with_key("brightness"))
+    body = src.splitlines()
+    super_at = next(i for i, line in enumerate(body) if "super().__init__(" in line)
+    assign_at = next(i for i, line in enumerate(body)
+                     if "self.brightness = config.get(" in line)
+    assert assign_at > super_at, (
+        "config vars are assigned before super().__init__(); the reserved-name "
+        "list assumes they land after it")
+
+
+# --- optional keys ----------------------------------------------------------
+
+@pytest.mark.parametrize("el_type,missing", [
+    ("text", "text"), ("text", "text2"), ("clock", "format"),
+])
+def test_an_element_missing_an_optional_key_does_not_500(el_type, missing):
+    """`p` is a copy of the raw element, so an absent key stays absent.
+
+    The defaults were applied to locals only, so manager.py.j2 rendered
+    `{{ el.text | tojson }}` over a jinja2.Undefined and tojson raised
+    TypeError -- which no handler catches, making a missing key a 500 rather
+    than a validation error or a sensible default.
+    """
+    el = {"type": el_type, "id": "e1", "x": 0, "y": 0, "font": "press_start"}
+    src = _generated(_payload(elements=[el]))
+    ast.parse(src)          # must still be valid Python
+    assert "Undefined" not in src
+
+
+def test_a_clock_without_a_format_uses_the_documented_default():
+    el = {"type": "clock", "id": "c1", "x": 0, "y": 0, "font": "press_start"}
+    src = _generated(_payload(elements=[el]))
+    assert '"%H:%M"' in src, "the %H:%M default did not reach the generated source"
+
+
+#: (element type, channel key, base element) for colour channels that were
+#: interpolated raw rather than through _rgb_expr/_safe_int. Prefixed channels
+#: (emptyR/G/B, labelR/G/B) were the ones the original r/g/b test never reached.
+RAW_COLOUR_CASES = [
+    ("progress_bar", "r",      {"x": 0, "y": 0}),
+    ("progress_bar", "g",      {"x": 0, "y": 0}),
+    ("pips",         "b",      {"x": 0, "y": 0}),
+    ("pips",         "emptyR", {"x": 0, "y": 0}),
+    ("pips",         "emptyG", {"x": 0, "y": 0}),
+    ("sparkline",    "r",      {"x": 0, "y": 0}),
+    ("gauge",        "labelR", {"x": 0, "y": 0, "width": 32, "height": 32}),
+    ("gauge",        "labelB", {"x": 0, "y": 0, "width": 32, "height": 32}),
+]
+
+
+@pytest.mark.parametrize("etype,channel,base", RAW_COLOUR_CASES)
+@pytest.mark.parametrize("evil", EXPR_PAYLOADS)
+def test_a_prefixed_colour_channel_cannot_reach_the_source(etype, channel, base, evil):
+    """Five tuples were built with f"({el.get('r', 100)}, ...)" -- no coercion.
+
+    The pre-existing colour test only covered r/g/b on a text element, so the
+    prefixed channels and the four other types were never exercised.
+    """
+    el = {"type": etype, "id": "e1", **base}
+    el[channel] = evil
+    src = _generated(_payload(elements=[el]))
+    assert "__import__" not in src, f"{etype}.{channel}={evil!r} reached the source"
+    assert "os.system" not in src
+    assert not _module_level_code(src)
+
+
+@pytest.mark.parametrize("value", [float("inf"), float("-inf"), float("nan")])
+@pytest.mark.parametrize("field", ["x", "y", "width", "height"])
+def test_a_non_finite_dimension_does_not_escape_as_an_unhandled_error(field, value):
+    """json.loads accepts Infinity/NaN and Flask passes them through, so a
+    payload can hand _safe_int a non-finite float. int(inf) raises
+    OverflowError -- neither ValueError nor ComposerInputError -- so it escaped
+    both handlers and surfaced as a 500 with a traceback instead of a 422."""
+    el = {"type": "rectangle", "id": "r1", "x": 0, "y": 0, "width": 10, "height": 8}
+    el[field] = value
+    src = _generated(_payload(elements=[el]))       # must not raise
+    # A non-finite value must be replaced by the default, not spelled into the
+    # source. Word-boundary match: "info" in self.logger.info contains "inf".
+    assert not re.search(r"\b(inf|nan|Infinity|NaN)\b", src), \
+        f"{field}={value!r} leaked a non-finite literal into the source"
+    assert not _module_level_code(src)
+
+
+@pytest.mark.parametrize("bad_id", [
+    'x = __import__("os").system("id") #',
+    "x\nimport os\n_y",
+    "x[0]",
+    "",
+    "a" * 200,
+])
+def test_a_marquee_id_cannot_become_code(bad_id):
+    """data_key is spliced UNQUOTED into variable names
+    (_{{ data_key }}_text = ...), so a non-identifier id landed in the source
+    as code. ast.parse caught it, but the caller then got an opaque
+    "Generated code has a syntax error" rather than being told the id is bad."""
+    el = {"type": "marquee", "id": bad_id, "x": 0, "y": 0, "text": "hi"}
+    src = _generated(_payload(elements=[el]))       # must not raise
+    assert "__import__(" not in src
+    assert "os.system(" not in src
+    assert not _module_level_code(src)

test/test_composer_empty_block.py

@@ -0,0 +1,124 @@
+"""An element the template cannot draw must not produce an empty `if` block.
+
+manager.py.j2 wraps each element in `if width >= N:` (breakpoint) and/or
+`if int(time.time() * 2) % 2:` (blink), and the body comes from the per-type
+branches. A type with no branch contributed nothing, so the wrapper opened a
+block with no statements in it. ast.parse in _generate_plugin_files then
+failed and the caller was told only:
+
+    Generated code has a syntax error: expected an indented block after
+    'if' statement on line 49
+
+which names a line of generated source the user never sees. Confirmed against
+the code before the fix with a `group` element carrying minWidth.
+
+Two defences, both covered here: _preprocess_elements drops types the template
+has no branch for, and the template emits a `pass` fallback so a type added to
+the canvas before its branch exists degrades to a no-op instead of a broken
+plugin.
+"""
+import ast
+import re
+import sys
+from pathlib import Path
+
+import pytest
+
+sys.path.insert(0, str(Path(__file__).resolve().parent.parent))
+
+from web_interface.blueprints import composer as C  # noqa: E402
+
+TEMPLATE = (Path(__file__).resolve().parent.parent
+            / "web_interface/templates/v3/composer/manager.py.j2")
+
+BASE_META = {"id": "test-plugin", "name": "Clock", "author": "a",
+             "version": "1.0.0", "description": "d"}
+
+
+def generate(element):
+    return C._generate_plugin_files({
+        "metadata": BASE_META,
+        "elements": [element],
+        "dataModel": {"configVars": []},
+    })
+
+
+@pytest.mark.parametrize("wrapper", [
+    {"minWidth": 64},          # breakpoint block
+    {"blink": True},           # blink block
+    {"minWidth": 64, "blink": True},   # both, nested
+])
+@pytest.mark.parametrize("etype", ["group", "widget_9000", "section"])
+def test_undrawable_element_does_not_break_generation(etype, wrapper):
+    element = {"type": etype, "x": 0, "y": 0, "color": "#ffffff", **wrapper}
+    files = generate(element)          # must not raise ComposerInputError
+    assert "manager.py" in files
+
+
+def test_drawable_element_still_renders_inside_a_breakpoint():
+    files = generate({"type": "text", "text": "hi", "x": 0, "y": 0,
+                      "minWidth": 64, "color": "#ffffff"})
+    src = files["manager.py"]
+    assert "if width >= 64:" in src
+    assert "draw_text" in src
+
+
+def test_renderable_types_match_the_template_branches():
+    """The constant and the template must agree.
+
+    A type listed in the constant with no branch emits an empty block (the bug
+    above); a type with a branch but missing from the constant is silently
+    dropped from every generated plugin. Neither is visible without this check.
+    """
+    branches = set(re.findall(r"el\.type == '([a-z_]+)'", TEMPLATE.read_text()))
+    assert branches == set(C._RENDERABLE_ELEMENT_TYPES)
+
+
+def test_template_closes_the_branch_chain_with_a_fallback():
+    """Belt and braces: even if the constant drifts, no empty block escapes."""
+    text = TEMPLATE.read_text()
+    assert "{% else %}" in text
+    assert "pass  # element type" in text
+
+
+@pytest.mark.parametrize("wrapper", [
+    {"minWidth": 64},
+    {"blink": True},
+    {"minWidth": 64, "blink": True},
+])
+def test_dynamic_text_with_non_config_binding_does_not_break_generation(wrapper):
+    """dynamic_text only renders a body for binding.source == 'config'.
+
+    _preprocess_elements accepts any string as binding.source (it just
+    defaults a missing one to 'config'), so a 'live' or 'sensor' source --
+    anything a client sends that isn't literally 'config' -- hit the same
+    empty-if-block bug as an undrawable element type, just one level deeper:
+    the branch is taken, but its own inner `if` produced nothing.
+    """
+    element = {"type": "dynamic_text", "x": 0, "y": 0, "color": "#ffffff",
+               "binding": {"source": "live", "key": "temperature"}, **wrapper}
+    files = generate(element)          # must not raise ComposerInputError
+    assert "manager.py" in files
+    assert "non-config dynamic_text binding draws nothing" in files["manager.py"]
+
+
+def test_binding_source_cannot_break_out_of_the_comment_it_lands_in():
+    """binding.source used to be interpolated straight into a Python comment
+    (`pass  # dynamic_text binding_source "{{ el.binding_source }}" draws
+    nothing`) with no escaping. A source string carrying a newline closed the
+    comment, and text on the following line(s), indented to match, became a
+    real statement in the generated plugin -- CWE-94, and live once
+    composer_bp was registered (confirmed: this exact payload produces a
+    manager.py containing a clean, ast.parse-valid `import os` against the
+    pre-fix template). The comment is now a fixed literal that never
+    interpolates the value at all.
+    """
+    payload = "foo\n            import os\n            os.system('id')  # "
+    element = {"type": "dynamic_text", "x": 0, "y": 0, "color": "#ffffff",
+               "binding": {"source": payload, "key": "temperature"}}
+    files = generate(element)
+    src = files["manager.py"]
+    assert "import os" not in src
+    assert "os.system" not in src
+    assert "non-config dynamic_text binding draws nothing" in src
+    ast.parse(src)          # belt and braces: generate() already enforces this

test/test_composer_js_contracts.py

@@ -0,0 +1,263 @@
+"""Structural checks on the composer's JavaScript.
+
+There is no JS test runner in this repo, but three defects here are structural
+enough to assert on the parse tree, and each was a real bug:
+
+- Stroke widths inside _drawElement were left in canvas pixels while the
+  geometry around them scaled by SCALE, so at SCALE>1 every outline rendered
+  thinner than one LED pixel and the preview stopped matching the panel.
+- The `line` branch drew raw el.x0/el.y0/el.x1/el.y1, ignoring the anchor that
+  every other element type honours, so setting xAnchor moved everything except
+  lines -- and getBoundingBox had the same omission, leaving the hit box behind.
+- Four methods mutated exactly what _snapshot() serialises (metadata,
+  currentPreset) without calling it. _snapshot is the only caller of
+  _debouncedAutosave, so those changes were lost on reload and could not be
+  undone.
+"""
+import re
+from pathlib import Path
+
+import pytest
+
+tree_sitter = pytest.importorskip("tree_sitter")
+tree_sitter_javascript = pytest.importorskip("tree_sitter_javascript")
+
+JS_DIR = Path(__file__).resolve().parent.parent / "web_interface/static/v3/js/composer"
+CANVAS = JS_DIR / "composer-canvas.js"
+APP = JS_DIR / "composer-app.js"
+
+
+def _function_source(path: Path, name: str) -> str:
+    """Return the source of a top-level function declaration by name."""
+    src = path.read_bytes()
+    lang = tree_sitter.Language(tree_sitter_javascript.language())
+    tree = tree_sitter.Parser(lang).parse(src)
+    found = []
+
+    def walk(node):
+        if node.type == "function_declaration":
+            ident = node.child_by_field_name("name")
+            if ident is not None and src[ident.start_byte:ident.end_byte].decode() == name:
+                found.append(src[node.start_byte:node.end_byte].decode())
+        for c in node.children:
+            walk(c)
+
+    walk(tree.root_node)
+    assert found, f"{name} not found in {path.name}"
+    return found[0]
+
+
+def _method_source(path: Path, name: str) -> str:
+    """Return the source of a top-level object method by name."""
+    src = path.read_bytes()
+    lang = tree_sitter.Language(tree_sitter_javascript.language())
+    tree = tree_sitter.Parser(lang).parse(src)
+    found = []
+
+    def walk(node):
+        if node.type == "method_definition":
+            ident = node.child_by_field_name("name")
+            if ident is not None and src[ident.start_byte:ident.end_byte].decode() == name:
+                found.append(src[node.start_byte:node.end_byte].decode())
+        for c in node.children:
+            walk(c)
+
+    walk(tree.root_node)
+    assert found, f"{name} not found in {path.name}"
+    return found[0]
+
+
+def test_both_files_parse():
+    lang = tree_sitter.Language(tree_sitter_javascript.language())
+    parser = tree_sitter.Parser(lang)
+    for path in (CANVAS, APP):
+        tree = parser.parse(path.read_bytes())
+        errors = []
+
+        def walk(node):
+            if node.type == "ERROR" or node.is_missing:
+                errors.append(node.start_point[0] + 1)
+            for c in node.children:
+                walk(c)
+
+        walk(tree.root_node)
+        assert not errors, f"{path.name} has parse errors at lines {errors}"
+
+
+def test_element_strokes_scale_with_scale():
+    """No bare `ctx.lineWidth = 1` inside _drawElement.
+
+    Selection handles and the grid are drawn in canvas pixels deliberately and
+    live in other functions, so this is scoped to the element drawing routine.
+    """
+    body = _function_source(CANVAS, "_drawElement")
+    offenders = re.findall(r"ctx\.lineWidth\s*=\s*1\s*;", body)
+    assert not offenders, f"{len(offenders)} unscaled stroke width(s) in _drawElement"
+
+
+def test_line_branch_applies_the_anchor_offset():
+    """Scoped to _drawElement.
+
+    getBoundingBox has its own `case 'line': {` and appears first in the file,
+    so searching the whole text found *that* branch -- this assertion passed
+    with the draw branch's anchor offset removed. Verified: stripping it and
+    re-running gave 11/11 green.
+    """
+    body = _function_source(CANVAS, "_drawElement")
+    line_branch = body[body.index("case 'line': {"):]
+    line_branch = line_branch[:line_branch.index("case 'divider'")]
+    assert "ax - el.x0" in line_branch and "ay - el.y0" in line_branch, \
+        "line drawing ignores xAnchor/yAnchor"
+    assert "moveTo(el.x0 * s" not in line_branch, \
+        "line still drawn from unanchored endpoints"
+
+
+def test_line_bounding_box_applies_the_anchor_offset():
+    """The companion to the above: scoped to getBoundingBox specifically, so
+    the two tests cannot both be satisfied by the same branch."""
+    body = _function_source(CANVAS, "getBoundingBox")
+    box = body[body.index("case 'line'"):]
+    box = box[:box.index("case 'divider'")]
+    assert "ax - el.x0" in box, "line bounding box ignores the anchor"
+
+
+@pytest.mark.parametrize("method", [
+    "onBgColorChange",     # mutates metadata.bgColor
+    "setCustomSize",       # mutates currentPreset / MATRIX_W / MATRIX_H
+    "changePreset",        # mutates currentPreset / MATRIX_W / MATRIX_H
+    "applyPresetLabel",    # same, for sizes not in DISPLAY_PRESETS
+    "onColorChange",       # the one that was already fixed — keeps it fixed
+])
+def test_state_mutations_take_a_snapshot(method):
+    body = _method_source(APP, method)
+    assert "_snapshot()" in body, \
+        f"{method} changes snapshotted state without calling _snapshot()"
+    assert "isDirty = true" in body, f"{method} does not mark the design dirty"
+
+
+@pytest.mark.parametrize("method", ["changePreset", "applyPresetLabel"])
+def test_restore_path_stays_snapshot_free(method):
+    """_applyState and loadTemplate call these with {silent: true} while
+    restoring; snapshotting there would push restore steps onto the undo stack
+    and re-autosave the state just loaded."""
+    body = _method_source(APP, method)
+    assert "opts.silent" in body, f"{method} lost its silent guard"
+    snap = body.index("_snapshot()")
+    guard = body.index("!opts.silent")
+    assert guard < snap, f"{method} snapshots outside the !opts.silent guard"
+
+
+TEMPLATE_HTML = (Path(__file__).resolve().parent.parent
+                 / "web_interface/templates/v3/composer.html")
+
+#: The six toolbar buttons and the wrapper each must call.
+ALIGN_BUTTONS = ["alignLeft", "alignHCenter", "alignRight",
+                 "alignTop", "alignVCenter", "alignBottom"]
+
+
+def test_alignment_buttons_use_the_anchor_clearing_path():
+    """Two alignment implementations existed and the toolbar used the wrong one.
+
+    The legacy alignElement(dir) set el.x/el.y but left xAnchor/yAnchor in
+    place. resolveAnchor turns anchor='right' into `dim - val`, so "align left"
+    (el.x = 0) resolved to x = MATRIX_W -- the element jumped to the far right
+    edge instead. _alignElement clears the anchor first, so the stored value is
+    absolute, and it also updates el.x0/el.y0 so lines actually move.
+    """
+    html = TEMPLATE_HTML.read_text()
+    for wrapper in ALIGN_BUTTONS:
+        assert f"{wrapper}()" in html, f"toolbar does not call {wrapper}()"
+    assert not re.search(r"[^_]alignElement\(", html), \
+        "toolbar still calls the legacy alignElement()"
+
+
+def test_the_legacy_alignelement_is_gone():
+    """Leaving it in place invites the toolbar drifting back to it."""
+    src = APP.read_text()
+    assert not re.search(r"^\s{4}alignElement\(dir\)", src, re.M), \
+        "legacy alignElement(dir) still defined"
+
+
+def test_align_clears_the_anchor_and_moves_line_endpoints():
+    body = _method_source(APP, "_alignElement")
+    assert "xAnchor = null" in body and "yAnchor = null" in body, \
+        "_alignElement no longer clears the anchor, so aligning an anchored " \
+        "element resolves to the wrong edge"
+    assert "el.x0" in body and "el.y0" in body, \
+        "_alignElement no longer moves line endpoints"
+
+
+def test_align_translates_both_line_endpoints_not_just_the_start():
+    """Setting only x0 (or y0) left x1/y1 behind, so aligning a line changed
+    its shape instead of moving it -- e.g. a line from x0=20 to x1=50 aligned
+    right became x0=98, x1=50, stretching rather than translating it. Both
+    endpoints must move by the same delta."""
+    body = _method_source(APP, "_alignElement")
+    x_branch = body[body.index("if (axis === 'x')"):body.index("} else {")]
+    y_branch = body[body.index("} else {"):]
+    assert "el.x1" in x_branch, \
+        "_alignElement moves x0 but not x1 -- a line's shape changes, not its position"
+    assert "el.y1" in y_branch, \
+        "_alignElement moves y0 but not y1 -- a line's shape changes, not its position"
+
+
+def test_divider_stroke_is_centered_in_led_pixels():
+    """A 0.5 canvas-pixel offset (correct only at SCALE=1) was applied after
+    scaling instead of before it, so at SCALE>1 the stroke bled into the
+    preceding LED row/column instead of straddling its own."""
+    body = _function_source(CANVAS, "_drawElement")
+    divider_branch = body[body.index("case 'divider'"):]
+    divider_branch = divider_branch[:divider_branch.index("case 'pips'")]
+    assert "ay * s + 0.5" not in divider_branch, \
+        "divider still offsets by 0.5 canvas pixels after scaling"
+    assert "ax * s + 0.5" not in divider_branch, \
+        "divider still offsets by 0.5 canvas pixels after scaling"
+    assert "(ay + 0.5) * s" in divider_branch and "(ax + 0.5) * s" in divider_branch, \
+        "divider stroke is not centered within its LED pixel"
+
+
+def test_gauge_radii_are_clamped_to_zero():
+    """An imported design can carry a small gauge with a wide lineWidth --
+    width=1, height=1, lineWidth=3 sends a negative radius into
+    ctx.ellipse(), which throws IndexSizeError and aborts render() for every
+    element still to be drawn, not just the gauge."""
+    body = _function_source(CANVAS, "_drawElement")
+    gauge_branch = body[body.index("case 'gauge'"):]
+    assert re.search(r"Math\.max\(0,\s*rx\s*-\s*lwPx\s*/\s*2\)", gauge_branch), \
+        "gauge x-radius is not clamped to zero"
+    assert re.search(r"Math\.max\(0,\s*ry\s*-\s*lwPx\s*/\s*2\)", gauge_branch), \
+        "gauge y-radius is not clamped to zero"
+    assert "rx - lwPx / 2" not in re.sub(r"Math\.max\(0,\s*rx\s*-\s*lwPx\s*/\s*2\)", "", gauge_branch), \
+        "an unclamped gauge radius is still passed to ctx.ellipse()"
+
+
+#: ELEMENT_DEFAULTS in composer-canvas.js gives exactly these types a
+#: `binding` object; verified against that file rather than assumed.
+BOUND_TYPES = ["dynamic_text", "progress_bar", "countdown", "pips", "sparkline", "gauge"]
+
+
+def test_bound_types_constant_lists_every_bound_element_type():
+    """ELEMENT_DEFAULTS in composer-canvas.js gives dynamic_text, progress_bar,
+    countdown, pips, sparkline and gauge a `binding` object. If a type is added
+    to (or removed from) that list without updating APP's BOUND_TYPES, the
+    checks below drift out of sync silently -- this pins the two together."""
+    src = APP.read_text()
+    match = re.search(r"const BOUND_TYPES = \[([^\]]*)\];", src)
+    assert match, "BOUND_TYPES constant not found in composer-app.js"
+    declared = {t.strip().strip("'\"") for t in match.group(1).split(",") if t.strip()}
+    assert declared == set(BOUND_TYPES), \
+        f"BOUND_TYPES {declared} does not match the bound element types {set(BOUND_TYPES)}"
+
+
+@pytest.mark.parametrize("method", ["_isBound", "removeConfigVar", "_validateBeforeExport"])
+def test_binding_checks_cover_every_bound_element_type(method):
+    """Only dynamic_text and progress_bar were checked, so a countdown, pips,
+    sparkline or gauge element with an empty binding passed export validation
+    silently, and deleting a config var still used by one of them gave no
+    warning -- the plugin would read a now-missing key at runtime with no
+    indication why."""
+    body = _method_source(APP, method)
+    assert "BOUND_TYPES.includes(e.type)" in body, \
+        f"{method} does not check every bound element type via BOUND_TYPES"
+    assert "e.type === 'dynamic_text'" not in body, \
+        f"{method} still hardcodes only dynamic_text instead of BOUND_TYPES"

test/test_composer_path_containment.py

@@ -0,0 +1,225 @@
+"""A composer plugin id must never resolve outside the plugins directory.
+
+CodeQL reported sixteen high-severity py/path-injection alerts against
+web_interface/blueprints/composer.py: a request-supplied plugin_id reaching
+Path(plugins_dir) / plugin_id, which is then created, written to, deleted
+(shutil.rmtree) and read back.
+
+The id was already validated by an anchored regex, so every traversal payload
+was in fact rejected. What was missing was the guarantee living *with* the path
+building rather than in a regex several hundred lines away -- loosen that regex
+later and the traversal opens silently, with nothing at the filesystem boundary
+to catch it. _plugin_dir() closes that, and is the form static analysis can see.
+"""
+import sys
+from pathlib import Path
+from unittest.mock import MagicMock
+
+import pytest
+
+sys.path.insert(0, str(Path(__file__).resolve().parent.parent))
+
+from web_interface.blueprints import composer as C  # noqa: E402
+
+#: Anything that has ever been used to climb out of a directory.
+TRAVERSAL = [
+    "../../etc/passwd", "..", ".", "a/../../etc", "good/../../..",
+    "/etc/passwd", "//etc/passwd", "a\\..\\..", "a%2f..%2f..",
+    "....//....//etc", "a/./../../etc", "~", "~root",
+    "plugin/../../../../../../etc/shadow",
+]
+
+#: Rejected for shape, not traversal -- but rejected all the same.
+MALFORMED = ["", "A-upper", "1-leading-digit", "-leading-dash", "has_underscore",
+             "has space", "has.dot", "a" * 64, "plugin\n", "plugin\n../../etc",
+             "\n", "plug\x00in"]
+
+
+@pytest.fixture
+def plugins_dir(tmp_path, monkeypatch):
+    base = tmp_path / "plugin-repos"
+    base.mkdir()
+    monkeypatch.setattr(C.composer_bp, "plugins_dir", str(base), raising=False)
+    return base
+
+
+@pytest.mark.parametrize("payload", TRAVERSAL)
+def test_traversal_payloads_are_refused(plugins_dir, payload):
+    assert C._plugin_dir(payload) is None
+
+
+@pytest.mark.parametrize("payload", MALFORMED)
+def test_malformed_ids_are_refused(plugins_dir, payload):
+    assert C._plugin_dir(payload) is None
+
+
+@pytest.mark.parametrize("payload", ["a", "my-plugin", "x9", "a" * 63])
+def test_valid_ids_resolve_inside_the_base(plugins_dir, payload):
+    resolved = C._plugin_dir(payload)
+    assert resolved is not None, f"{payload!r} was rejected but is valid"
+    assert resolved.parent == plugins_dir.resolve(), (
+        f"{payload!r} resolved to {resolved}, outside {plugins_dir}")
+
+
+def test_no_payload_can_escape_even_if_the_regex_is_loosened(plugins_dir, monkeypatch):
+    """The containment check must stand on its own.
+
+    This is the whole point of resolving at the filesystem boundary: if the id
+    pattern is ever relaxed, traversal must still be impossible. Replace the
+    regex with one that permits slashes and dots, then re-run the payloads.
+    """
+    import re
+    monkeypatch.setattr(C, "_PLUGIN_ID_RE", re.compile(r"\A[\w./\\~-]+\Z"))
+    import os
+    escaped = []
+    base = os.path.realpath(str(plugins_dir))
+    for payload in TRAVERSAL:
+        resolved = C._plugin_dir(payload)
+        if resolved is None:
+            continue
+        real = os.path.realpath(str(resolved))
+        if real != base and os.path.commonpath([base, real]) != base:
+            escaped.append((payload, real))
+    assert not escaped, f"these escaped the base with a loosened regex: {escaped}"
+
+
+def test_a_sibling_directory_with_a_shared_prefix_is_not_inside(tmp_path, monkeypatch):
+    """commonpath, not startswith.
+
+    "/x/plugins-evil" starts with "/x/plugins" but is a different directory, so
+    a prefix test would accept it.
+    """
+    base = tmp_path / "plugins"
+    base.mkdir()
+    (tmp_path / "plugins-evil").mkdir()
+    monkeypatch.setattr(C.composer_bp, "plugins_dir", str(base), raising=False)
+    import re
+    # Neutralise the two layers in front so this exercises the containment
+    # check itself; otherwise secure_filename rejects the payload first and a
+    # startswith regression would go unnoticed here.
+    monkeypatch.setattr(C, "_PLUGIN_ID_RE", re.compile(r"\A[\w./\\~-]+\Z"))
+    monkeypatch.setattr(C, "secure_filename", lambda v: v)
+    assert C._plugin_dir("../plugins-evil") is None
+
+
+def test_containment_still_holds_if_the_sanitiser_is_defeated(plugins_dir, monkeypatch):
+    """Each layer is tested on its own, not just the stack.
+
+    secure_filename's equality guard rejects every traversal payload before the
+    containment check sees it, so removing containment does not fail the other
+    tests -- which would make it look load-bearing when it is not. Neutralise
+    the regex *and* the sanitiser, and the realpath/commonpath check must still
+    refuse everything on its own.
+    """
+    import re
+    monkeypatch.setattr(C, "_PLUGIN_ID_RE", re.compile(r"\A[\w./\\~-]+\Z"))
+    monkeypatch.setattr(C, "secure_filename", lambda v: v)
+    import os
+    base = os.path.realpath(str(plugins_dir))
+    escaped = []
+    for payload in TRAVERSAL:
+        resolved = C._plugin_dir(payload)
+        if resolved is None:
+            continue
+        real = os.path.realpath(str(resolved))
+        # Inside the base is fine -- "...." and "~" are ordinary directory
+        # names on Linux, so they are not escapes. What must never happen is
+        # landing outside the base, or on the base itself: install() rmtrees
+        # its target, so the plugins root resolving to a "plugin" would wipe
+        # every installed plugin.
+        if real == base or os.path.commonpath([base, real]) != base:
+            escaped.append((payload, real))
+    assert not escaped, f"containment alone let these through: {escaped}"
+
+
+def test_secure_filename_never_rewrites_an_accepted_id(plugins_dir):
+    """The sanitiser must be a no-op on everything the regex accepts.
+
+    If secure_filename ever altered an accepted id, _plugin_dir would resolve
+    to a *different* plugin's directory than the caller asked for -- a silent
+    redirect, which is worse than a refusal. The guard turns that into a
+    refusal; this proves the guard never has to fire in practice.
+    """
+    import random
+    from werkzeug.utils import secure_filename
+    random.seed(1)
+    alphabet = "abcdefghijklmnopqrstuvwxyz0123456789-"
+    altered = []
+    for _ in range(2000):
+        n = random.randint(1, 63)
+        cand = random.choice("abcdefghijklmnopqrstuvwxyz") + "".join(
+            random.choice(alphabet) for _ in range(n - 1))
+        if C._PLUGIN_ID_RE.match(cand) and secure_filename(cand) != cand:
+            altered.append((cand, secure_filename(cand)))
+    assert not altered, f"secure_filename rewrote accepted ids: {altered[:5]}"
+
+
+def test_a_trailing_newline_is_not_a_valid_id():
+    r"""Python's `$` also matches before a trailing newline, so the original
+    `^...$` accepted "myplugin\n" and would have created a directory whose
+    name ends in one. \Z does not."""
+    assert C._PLUGIN_ID_RE.match("myplugin") is not None
+    assert C._PLUGIN_ID_RE.match("myplugin\n") is None
+
+
+# --- font serving -----------------------------------------------------------
+
+FONT_TRAVERSAL = [
+    "../../../etc/passwd", "../config/config.json", "..%2f..%2fetc%2fpasswd",
+    "PressStart2P-Regular.ttf/../../../etc/passwd", "/etc/passwd", "",
+    "PressStart2P-Regular.TTF",          # case differs -> not the allowlisted name
+    "PressStart2P-Regular.ttf ",         # trailing space
+]
+
+
+def test_serve_font_refuses_a_file_that_exists_but_is_not_allowlisted(monkeypatch, tmp_path):
+    """The allowlist must be what refuses it, not a missing file.
+
+    Asserting 404 on traversal payloads proves nothing here: Flask's router
+    will not match a path segment containing '/', and everything else 404s
+    simply because no such file exists. Put a real, readable file next to the
+    fonts and confirm it is still refused -- that is the allowlist working.
+    """
+    fonts = tmp_path / "assets" / "fonts"
+    fonts.mkdir(parents=True)
+    (fonts / "id_rsa.ttf").write_bytes(b"PRIVATE KEY")
+    monkeypatch.setattr(C.composer_bp, "project_root", str(tmp_path), raising=False)
+    app = __import__("flask").Flask(__name__)
+    app.register_blueprint(C.composer_bp)
+    with app.test_client() as client:
+        resp = client.get("/api/fonts/id_rsa.ttf")
+    assert resp.status_code == 404, (
+        "a readable non-allowlisted file was served; the allowlist is not gating")
+    assert b"PRIVATE KEY" not in resp.data
+
+
+@pytest.mark.parametrize("payload", FONT_TRAVERSAL)
+def test_serve_font_refuses_anything_not_allowlisted(payload, monkeypatch, tmp_path):
+    """The name reaching the filesystem must come from the allowlist constant.
+
+    _ALLOWED_FONTS gates this endpoint, so nothing here was ever exploitable.
+    Building the path from the matched constant rather than the request value
+    is what makes that provable -- and it is why CodeQL reported two
+    high-severity py/path-injection alerts on an endpoint that was already
+    safe.
+    """
+    monkeypatch.setattr(C.composer_bp, "project_root", str(tmp_path), raising=False)
+    app = C.composer_bp.name and __import__("flask").Flask(__name__)
+    app.register_blueprint(C.composer_bp)
+    with app.test_client() as client:
+        resp = client.get(f"/api/fonts/{payload}")
+    assert resp.status_code in (404, 405, 308), (
+        f"{payload!r} was not refused (status {resp.status_code})")
+
+
+def test_serve_font_still_serves_each_allowlisted_font(monkeypatch, tmp_path):
+    fonts = tmp_path / "assets" / "fonts"
+    fonts.mkdir(parents=True)
+    monkeypatch.setattr(C.composer_bp, "project_root", str(tmp_path), raising=False)
+    app = __import__("flask").Flask(__name__)
+    app.register_blueprint(C.composer_bp)
+    for name in C._ALLOWED_FONTS:
+        (fonts / name).write_bytes(b"\x00\x01ttf")
+        with app.test_client() as client:
+            resp = client.get(f"/api/fonts/{name}")
+        assert resp.status_code == 200, f"{name} should be served, got {resp.status_code}"

test/test_sports_shared.py

@@ -319,3 +319,58 @@ class TestLiveMixin:
         assert not hasattr(h, "_empty_live_streak")
         h._note_live_fetch(False)
         assert h._empty_live_streak == 1
+
+
+class TestPluginDirIsToldNotDeduced:
+    """The regression that shipped: _plugin_dir returned None in production.
+
+    The first version walked the MRO for a class whose module sits beside a
+    config_schema.json. That passes when a test imports the plugin directly --
+    which is how it was verified -- and returns None under the real plugin
+    loader, which imports modules by a path that leaves no such entry on the
+    MRO.
+
+    Silent, and expensive: no schema means _schema_font_size returns None for
+    every element, so a configured size equal to the schema default stops
+    looking like a default, is treated as a deliberate choice, and skips the
+    grid snap. 4x6-font.ttf then renders at 6 rather than 7 -- 3px-wide glyphs
+    instead of 4px. On a 256x64 panel that made the odds, the records and the
+    date row illegible. A user counted the pixels; no gate here caught it.
+    """
+
+    def test_a_declared_directory_is_used(self, tmp_path):
+        d = _write_plugin(tmp_path, "declared")
+        host = type("H", (SportsCoreSharedMixin,), {"_PLUGIN_DIR": str(d)})()
+        assert host._plugin_dir() == str(d)
+
+    def test_it_works_when_no_module_on_the_mro_helps(self, tmp_path, monkeypatch):
+        """The production case: nothing on the MRO sits beside a schema."""
+        d = _write_plugin(tmp_path, "loaderstyle")
+        # A class whose module is not importable by name, as the loader produces.
+        cls = type("Loaded", (SportsCoreSharedMixin,), {"_PLUGIN_DIR": str(d)})
+        cls.__module__ = "a.module.name.that.is.not.in.sys.modules"
+        assert cls.__new__(cls)._plugin_dir() == str(d), (
+            "the declared directory must win when the MRO walk cannot help")
+
+    def test_without_it_the_mro_walk_would_have_failed(self):
+        # Pin the precondition, so this test still means something if the
+        # fallback is ever changed.
+        cls = type("Orphan", (SportsCoreSharedMixin,), {})
+        cls.__module__ = "not.a.real.module"
+        assert cls.__new__(cls)._plugin_dir() is None
+
+    def test_a_declared_directory_without_a_schema_is_not_trusted(self, tmp_path):
+        # A stale or wrong path must not shadow the fallback.
+        empty = tmp_path / "noschema"
+        empty.mkdir()
+        d = _write_plugin(tmp_path, "realone")
+        monkey = type("H", (SportsCoreSharedMixin,), {"_PLUGIN_DIR": str(empty)})
+        assert monkey.__new__(monkey)._plugin_dir() != str(empty)
+
+    def test_the_font_size_consequence(self, tmp_path):
+        """End to end: a declared directory restores the schema lookup."""
+        d = _write_plugin(tmp_path, "sizeconseq")
+        host = type("H", (SportsCoreSharedMixin,), {"_PLUGIN_DIR": str(d)})()
+        assert host._schema_font_size("score") == 16, (
+            "without the schema this is None, which is what made a configured "
+            "size look user-chosen and skipped the grid snap")

web_interface/app.py

@@ -83,11 +83,11 @@ plugin_system_config = config.get('plugin_system', {})
 plugins_dir_name = plugin_system_config.get('plugins_directory', 'plugin-repos')
 
 # Resolve plugin directory - handle both absolute and relative paths
+project_root = Path(__file__).parent.parent
 if os.path.isabs(plugins_dir_name):
     plugins_dir = Path(plugins_dir_name)
 else:
     # If relative, resolve relative to the project root (LEDMatrix directory)
-    project_root = Path(__file__).parent.parent
     plugins_dir = project_root / plugins_dir_name
 
 plugin_manager = PluginManager(
@@ -157,6 +157,7 @@ _health_monitor_initialized = False
 # Register blueprints
 from web_interface.blueprints.pages_v3 import pages_v3
 from web_interface.blueprints.api_v3 import api_v3
+from web_interface.blueprints.composer import composer_bp
 
 # Initialize managers in blueprints
 pages_v3.config_manager = config_manager
@@ -173,6 +174,11 @@ api_v3.operation_queue = operation_queue
 api_v3.plugin_state_manager = plugin_state_manager
 api_v3.operation_history = operation_history
 api_v3.health_monitor = health_monitor
+
+composer_bp.config_manager = config_manager
+composer_bp.plugin_manager = plugin_manager
+composer_bp.plugins_dir = plugins_dir
+composer_bp.project_root = project_root
 # Initialize cache manager for API endpoints
 from src.cache_manager import CacheManager
 api_v3.cache_manager = CacheManager()
@@ -200,6 +206,7 @@ except Exception as _hm_err:  # pragma: no cover - defensive startup guard
 app.register_blueprint(pages_v3, url_prefix='')
 app.register_blueprint(pages_v3, url_prefix='/v3', name='pages_v3_legacy')
 app.register_blueprint(api_v3, url_prefix='/api/v3')
+app.register_blueprint(composer_bp, url_prefix='/composer')
 
 # Route to serve plugin asset files (registered on main app, not blueprint, for /assets/... path)
 @app.route('/assets/plugins/<plugin_id>/uploads/<path:filename>', methods=['GET'])

web_interface/static/v3/app.css

@@ -426,6 +426,9 @@ a, button, input, select, textarea {
     .md\:hidden { display: none; }
     .md\:block { display: block; }
     .md\:w-auto { width: auto; }
+    /* composer.html labels its toolbar buttons `hidden md:inline`, so without
+       this the label is hidden at every width and the buttons stay icon-only. */
+    .md\:inline { display: inline; }
 }
 
 @media (min-width: 1024px) {

web_interface/static/v3/js/composer/composer-canvas.js

@@ -0,0 +1,817 @@
+/**
+ * ComposerCanvas — stateless LED matrix canvas renderer.
+ *
+ * Coordinate system: LED pixels (integers). All drawing multiplies by SCALE.
+ * PIL draw.text(x,y) is top-left; canvas fillText(x,y) is baseline.
+ *   → Canvas text cy = (actualY + fontSizePx) * SCALE
+ *
+ * Anchors: element x/y are offsets from their anchor point:
+ *   xAnchor=null/'left'  → x is fixed offset from left
+ *   xAnchor='center'     → x is offset from width/2
+ *   xAnchor='right'      → x is offset inward from right edge
+ *   yAnchor follows the same pattern with 'top'/'middle'/'bottom'
+ *
+ * Breakpoints: elements with minWidth > currentMatrixW are rendered at 25% opacity.
+ *
+ * Resize handles: drawn on selected rectangles; 8 handles (corners + edge mids).
+ */
+/* eslint-disable security/detect-object-injection --
+   Every hit in this file is either an array index (this.elements[idx],
+   rawVals[i]) or a lookup on a module-private map keyed by an internal
+   element type (_HANDLE_CURSORS, ELEMENT_DEFAULTS, previewValues). None of
+   them takes an attacker-supplied property name, so none can reach a
+   prototype. Disabled per file rather than eight times inline. */
+window.ComposerCanvas = (() => {
+  'use strict';
+
+  let _canvas = null;
+  let _ctx = null;
+  let _showGrid = true;
+
+  //: Element types the canvas draws resize handles for. Exported because the
+  //: editor has to gate its resize and hover behaviour on exactly this list --
+  //: the two had drifted, so handles appeared on five shapes that could not
+  //: actually be resized.
+  const RESIZABLE_TYPES = ['rectangle', 'rounded_rectangle', 'ellipse', 'arc',
+                           'gauge', 'sparkline'];
+
+  const DISPLAY_PRESETS = [
+    { label: '64×32',   w: 64,  h: 32 },
+    { label: '128×32',  w: 128, h: 32 },
+    { label: '128×64',  w: 128, h: 64 },
+    { label: '256×32',  w: 256, h: 32 },
+    { label: '256×64',  w: 256, h: 64 },
+  ];
+
+  const FONT_MAP = {
+    press_start:   { family: "'PressStart2P', monospace", sizePx: 8,  charW: 8 },
+    four_by_six:   { family: 'monospace',                sizePx: 6,  charW: 4 },
+    five_by_seven: { family: 'monospace',                sizePx: 7,  charW: 5 },
+  };
+
+  const ELEMENT_DEFAULTS = {
+    text: {
+      text: 'Hello', font: 'press_start',
+      r: 255, g: 255, b: 255,
+      text2: '', lineSpacing: 2, textAlign: 'left',
+      xAnchor: null, yAnchor: null, minWidth: 0, locked: false, blink: false, visible: true,
+    },
+    dynamic_text: {
+      binding: { source: 'config', key: '', format: null },
+      font: 'press_start', textAlign: 'left',
+      r: 255, g: 200, b: 100,
+      xAnchor: null, yAnchor: null, minWidth: 0, locked: false, blink: false, visible: true,
+    },
+    clock: {
+      format: '%H:%M', font: 'press_start',
+      r: 100, g: 255, b: 100,
+      format2: '', lineSpacing: 2, textAlign: 'left',
+      xAnchor: null, yAnchor: null, minWidth: 0, locked: false, blink: false, visible: true,
+    },
+    rectangle: {
+      width: 20, height: 8,
+      fillR: 0, fillG: 0, fillB: 128, hasFill: true,
+      outR: 255, outG: 255, outB: 255, hasOutline: true,
+      xAnchor: null, yAnchor: null, minWidth: 0, locked: false, blink: false, visible: true,
+    },
+    ellipse: {
+      width: 24, height: 12,
+      fillR: 0, fillG: 100, fillB: 200, hasFill: true,
+      outR: 100, outG: 180, outB: 255, hasOutline: true,
+      xAnchor: null, yAnchor: null, minWidth: 0, locked: false, blink: false, visible: true,
+    },
+    arc: {
+      width: 24, height: 24,
+      startAngle: 0, endAngle: 270, lineWidth: 2,
+      r: 255, g: 200, b: 0,
+      xAnchor: null, yAnchor: null, minWidth: 0, locked: false, blink: false, visible: true,
+    },
+    pixel: {
+      r: 255, g: 255, b: 255,
+      xAnchor: null, yAnchor: null, minWidth: 0, locked: false, blink: false, visible: true,
+    },
+    rounded_rectangle: {
+      width: 24, height: 10, borderRadius: 3,
+      fillR: 0, fillG: 80, fillB: 180, hasFill: true,
+      outR: 120, outG: 180, outB: 255, hasOutline: true,
+      xAnchor: null, yAnchor: null, minWidth: 0, locked: false, blink: false, visible: true,
+    },
+    line: {
+      x0: 0, y0: 16, x1: 63, y1: 16,
+      r: 180, g: 180, b: 180, lineWidth: 1,
+      xAnchor: null, yAnchor: null, minWidth: 0, locked: false, blink: false, visible: true,
+    },
+    divider: {
+      orientation: 'horizontal', y: 16, x: 64,
+      r: 100, g: 100, b: 100,
+      xAnchor: null, yAnchor: null, minWidth: 0, locked: false, blink: false, visible: true,
+    },
+    progress_bar: {
+      barWidth: 60, barHeight: 6,
+      binding: { source: 'config', key: '', format: null },
+      r: 80, g: 200, b: 80,
+      bgR: 30, bgG: 30, bgB: 30, hasBg: true,
+      outR: 100, outG: 100, outB: 100, hasOutline: true,
+      previewPct: 65,
+      xAnchor: null, yAnchor: null, minWidth: 0, locked: false, blink: false, visible: true,
+    },
+    countdown: {
+      binding: { source: 'config', key: '', format: null },
+      countdownFormat: 'dh',
+      font: 'four_by_six', textAlign: 'left',
+      r: 255, g: 180, b: 0,
+      previewText: '42d 3h',
+      xAnchor: null, yAnchor: null, minWidth: 0, locked: false, blink: false, visible: true,
+    },
+    marquee: {
+      text: 'Scrolling text', font: 'press_start',
+      r: 255, g: 255, b: 255,
+      scrollSpeed: 1, gap: 16, direction: 'left',
+      xAnchor: null, yAnchor: null, minWidth: 0, locked: false, blink: false, visible: true,
+    },
+    section: {
+      label: 'Section',
+      xAnchor: null, yAnchor: null, minWidth: 0, locked: false, blink: false, visible: true,
+    },
+    pips: {
+      count: 5, filled: 3, pipSize: 4, pipSpacing: 2,
+      r: 255, g: 200, b: 0,
+      emptyR: 50, emptyG: 50, emptyB: 50, showEmpty: true,
+      binding: { source: 'config', key: '', format: null },
+      xAnchor: null, yAnchor: null, minWidth: 0, locked: false, blink: false, visible: true,
+    },
+    sparkline: {
+      width: 40, height: 12,
+      barCount: 8, barSpacing: 1,
+      r: 80, g: 200, b: 120,
+      bgR: 30, bgG: 30, bgB: 30, hasBg: false,
+      binding: { source: 'config', key: '', format: null },
+      previewData: '0.3,0.6,0.4,0.8,0.5,0.9,0.7,0.85',
+      xAnchor: null, yAnchor: null, minWidth: 0, locked: false, blink: false, visible: true,
+    },
+    gauge: {
+      width: 32, height: 32,
+      startAngle: 135, endAngle: 45, lineWidth: 3,
+      binding: { source: 'config', key: '', format: null },
+      r: 80, g: 220, b: 80,
+      trackR: 40, trackG: 40, trackB: 40, hasTrack: true,
+      showLabel: true, font: 'four_by_six', labelR: 200, labelG: 200, labelB: 200,
+      previewPct: 65,
+      xAnchor: null, yAnchor: null, minWidth: 0, locked: false, blink: false, visible: true,
+    },
+  };
+
+  // ── Anchor resolution ────────────────────────────────────────────────
+  function resolveAnchor(val, anchor, dim) {
+    if (!anchor || anchor === 'left' || anchor === 'top') return val;
+    if (anchor === 'center' || anchor === 'middle') return Math.floor(dim / 2) + val;
+    if (anchor === 'right' || anchor === 'bottom') return dim - val;
+    return val;
+  }
+
+  function computeActualPos(el, matrixW, matrixH) {
+    const ax = resolveAnchor(el.x ?? el.x0 ?? 0, el.xAnchor, matrixW);
+    const ay = resolveAnchor(el.y ?? el.y0 ?? 0, el.yAnchor, matrixH);
+    return { x: ax, y: ay };
+  }
+
+  // ── Bounding box (LED pixel space) ──────────────────────────────────
+  function getBoundingBox(el, matrixW, matrixH) {
+    const { x: ax, y: ay } = computeActualPos(el, matrixW, matrixH);
+    const finfo = FONT_MAP[el.font] || FONT_MAP.press_start;
+
+    switch (el.type) {
+      case 'text': {
+        const t1 = el.text || '', t2 = el.text2 || '';
+        const w = Math.max(t1.length, t2.length) * finfo.charW;
+        const h = t2 ? finfo.sizePx * 2 + (el.lineSpacing ?? 2) : finfo.sizePx;
+        const bx = el.textAlign === 'center' ? ax - w / 2 : el.textAlign === 'right' ? ax - w : ax;
+        return { x: bx, y: ay, w, h };
+      }
+      case 'dynamic_text': {
+        const key = el.binding?.key || '?';
+        const w = (`{${key}}`).length * finfo.charW;
+        const bx = el.textAlign === 'center' ? ax - w / 2 : el.textAlign === 'right' ? ax - w : ax;
+        return { x: bx, y: ay, w, h: finfo.sizePx };
+      }
+      case 'clock': {
+        const t1 = el.format || '%H:%M', t2 = el.format2 || '';
+        const w = Math.max(t1.length, t2.length) * finfo.charW;
+        const h = t2 ? finfo.sizePx * 2 + (el.lineSpacing ?? 2) : finfo.sizePx;
+        const bx = el.textAlign === 'center' ? ax - w / 2 : el.textAlign === 'right' ? ax - w : ax;
+        return { x: bx, y: ay, w, h };
+      }
+      case 'countdown': {
+        const pt = el.previewText || '--d --h';
+        const w = pt.length * finfo.charW;
+        const bx = el.textAlign === 'center' ? ax - w / 2 : el.textAlign === 'right' ? ax - w : ax;
+        return { x: bx, y: ay, w, h: finfo.sizePx };
+      }
+      case 'rectangle':
+      case 'rounded_rectangle':
+      case 'ellipse':
+      case 'arc':
+        return { x: ax, y: ay, w: el.width, h: el.height };
+      case 'pixel':
+        return { x: ax, y: ay, w: 1, h: 1 };
+      case 'line': {
+        // Same anchor offset the draw path applies, or the hit box sits where
+        // the line used to be.
+        const dx = ax - el.x0, dy = ay - el.y0;
+        return {
+          x: Math.min(el.x0, el.x1) + dx, y: Math.min(el.y0, el.y1) + dy,
+          w: Math.max(1, Math.abs(el.x1 - el.x0)),
+          h: Math.max(1, Math.abs(el.y1 - el.y0)),
+        };
+      }
+      case 'divider':
+        return el.orientation === 'horizontal'
+          ? { x: 0,  y: ay, w: matrixW, h: 1 }
+          : { x: ax, y: 0,  w: 1,       h: matrixH };
+      case 'progress_bar':
+        return { x: ax, y: ay, w: el.barWidth ?? 60, h: el.barHeight ?? 6 };
+      case 'marquee': {
+        const mfinfo = FONT_MAP[el.font] || FONT_MAP.press_start;
+        return { x: 0, y: ay, w: matrixW, h: mfinfo.sizePx };
+      }
+      case 'gauge':
+        return { x: ax, y: ay, w: el.width ?? 32, h: el.height ?? 32 };
+      case 'sparkline':
+        return { x: ax, y: ay, w: el.width ?? 40, h: el.height ?? 12 };
+      case 'pips': {
+        const pc = el.count ?? 5, ps = el.pipSize ?? 4, pg = el.pipSpacing ?? 2;
+        return { x: ax, y: ay, w: pc * ps + (pc - 1) * pg, h: ps };
+      }
+      case 'section': {
+        // Was 0x0, so the element was unselectable except through the 3px
+        // hit-test padding and drew nothing at all -- a user adding one from
+        // the palette saw an empty canvas.
+        // Same font resolution as the draw case below, or the box will not
+        // match the glyphs: getBoundingBox's shared `finfo` falls back to
+        // press_start, and a section has no font of its own.
+        const sinfo = FONT_MAP[el.font] || FONT_MAP.four_by_six;
+        const label = el.label || 'Section';
+        return { x: ax, y: ay, w: label.length * sinfo.charW, h: sinfo.sizePx };
+      }
+      default:
+        return { x: ax, y: ay, w: 4, h: 4 };
+    }
+  }
+
+  // ── Resize handle support ─────────────────────────────────────────────
+  // Returns 8 handle points for a rectangle in LED pixel space
+  function _getRectHandles(el, matrixW, matrixH) {
+    const { x: ax, y: ay } = computeActualPos(el, matrixW, matrixH);
+    const w = el.width, h = el.height;
+    const cx = ax + w / 2, cy = ay + h / 2;
+    return {
+      nw: { x: ax,      y: ay      },
+      n:  { x: cx,      y: ay      },
+      ne: { x: ax + w,  y: ay      },
+      w:  { x: ax,      y: cy      },
+      e:  { x: ax + w,  y: cy      },
+      sw: { x: ax,      y: ay + h  },
+      s:  { x: cx,      y: ay + h  },
+      se: { x: ax + w,  y: ay + h  },
+    };
+  }
+
+  // Returns the handle direction under LED-space point (lx, ly), or null
+  function getResizeHandle(el, lx, ly, matrixW, matrixH) {
+    if (!RESIZABLE_TYPES.includes(el.type)) return null;
+    const handles = _getRectHandles(el, matrixW, matrixH);
+    const PAD = 4;
+    for (const [dir, pt] of Object.entries(handles)) {
+      if (Math.abs(lx - pt.x) <= PAD && Math.abs(ly - pt.y) <= PAD) return dir;
+    }
+    return null;
+  }
+
+  const _HANDLE_CURSORS = {
+    nw: 'nw-resize', n: 'n-resize', ne: 'ne-resize',
+    w: 'w-resize', e: 'e-resize',
+    sw: 'sw-resize', s: 's-resize', se: 'se-resize',
+  };
+  function getCursorForHandle(handle) {
+    return _HANDLE_CURSORS[handle] || 'crosshair';
+  }
+
+  // ── Hit test ─────────────────────────────────────────────────────────
+  function hitTest(el, lx, ly, matrixW, matrixH) {
+    const PAD = 3;
+    const bb = getBoundingBox(el, matrixW, matrixH);
+    return (
+      lx >= bb.x - PAD && lx <= bb.x + bb.w + PAD &&
+      ly >= bb.y - PAD && ly <= bb.y + bb.h + PAD
+    );
+  }
+
+  // ── Draw a single element ─────────────────────────────────────────────
+  function _drawElement(ctx, el, SCALE, matrixW, matrixH, opts = {}) {
+    const s = SCALE;
+    const { x: ax, y: ay } = computeActualPos(el, matrixW, matrixH);
+    const belowBreakpoint = el.minWidth > 0 && matrixW < el.minWidth;
+    const hidden = el.visible === false;
+
+    ctx.save();
+    if (hidden) ctx.globalAlpha = 0.12;
+    else if (belowBreakpoint) ctx.globalAlpha = 0.25;
+
+    // Blink animation: when blinkOff, fully hide blinking elements
+    if (el.blink) {
+      if (opts.blinkOff) { ctx.restore(); return; }
+      ctx.globalAlpha *= 0.55;
+    }
+
+    // Helper: compute draw X for text alignment
+    // biome-ignore lint/correctness/useQwikValidLexicalScope: not Qwik -- this is an Alpine.js component, and the rule is about Qwik's $() serialization boundary, which does not exist here.
+    const _textX = (text, finfo) => {
+      const tw = text.length * finfo.charW * s;
+      if (el.textAlign === 'center') return ax * s - tw / 2;
+      if (el.textAlign === 'right')  return ax * s - tw;
+      return ax * s;
+    };
+
+    try {
+      switch (el.type) {
+        case 'section': {
+          // A design-time label: it marks a region for the author and is not
+          // emitted into the generated plugin. There was no case here at all,
+          // so adding "Section Label" from the palette drew nothing and left
+          // the user with an apparently broken control.
+          const sfinfo = FONT_MAP[el.font] || FONT_MAP.four_by_six;
+          ctx.font = `${sfinfo.sizePx * s}px ${sfinfo.family}`;
+          ctx.fillStyle = `rgba(${el.r ?? 120},${el.g ?? 120},${el.b ?? 120},0.85)`;
+          ctx.textBaseline = 'top';
+          ctx.fillText(el.label || 'Section', ax * s, ay * s);
+          break;
+        }
+        case 'text':
+        case 'dynamic_text':
+        case 'clock': {
+          const finfo = FONT_MAP[el.font] || FONT_MAP.press_start;
+          const key = el.binding?.key || '?';
+          const pv = opts.previewValues?.[key];
+          // Substitute {variable} tokens in text using previewValues
+          // biome-ignore lint/correctness/useQwikValidLexicalScope: not Qwik -- this is an Alpine.js component, and the rule is about Qwik's $() serialization boundary, which does not exist here.
+          const _subVars = str => (str || '').replace(/\{(\w+)\}/g, (_, k) => {
+            const v = opts.previewValues?.[k];
+            return v !== undefined && v !== '' ? String(v) : `{${k}}`;
+          });
+          const displayText =
+            el.type === 'text'    ? _subVars(el.text || '')
+            : el.type === 'clock' ? (el.format || '%H:%M')
+            : (pv !== undefined && pv !== '' ? String(pv) : `{${key}}`);
+          ctx.font = `${finfo.sizePx * s}px ${finfo.family}`;
+          ctx.fillStyle = `rgb(${el.r},${el.g},${el.b})`;
+          ctx.fillText(displayText, _textX(displayText, finfo), (ay + finfo.sizePx) * s);
+          // Second line (text and clock)
+          if (el.type === 'text' && el.text2) {
+            const t2 = _subVars(el.text2);
+            const y2 = ay + finfo.sizePx + (el.lineSpacing ?? 2);
+            ctx.fillText(t2, _textX(t2, finfo), (y2 + finfo.sizePx) * s);
+          }
+          if (el.type === 'clock' && el.format2) {
+            const y2 = ay + finfo.sizePx + (el.lineSpacing ?? 2);
+            ctx.fillText(el.format2, _textX(el.format2, finfo), (y2 + finfo.sizePx) * s);
+          }
+          break;
+        }
+
+        case 'countdown': {
+          const finfo = FONT_MAP[el.font] || FONT_MAP.press_start;
+          const t = el.previewText || '--d --h';
+          ctx.font = `${finfo.sizePx * s}px ${finfo.family}`;
+          ctx.fillStyle = `rgb(${el.r},${el.g},${el.b})`;
+          ctx.fillText(t, _textX(t, finfo), (ay + finfo.sizePx) * s);
+          break;
+        }
+
+        case 'rectangle': {
+          const rx = ax * s, ry = ay * s;
+          const rw = el.width * s, rh = el.height * s;
+          if (el.hasFill) {
+            ctx.fillStyle = `rgb(${el.fillR},${el.fillG},${el.fillB})`;
+            ctx.fillRect(rx, ry, rw, rh);
+          }
+          if (el.hasOutline) {
+            ctx.strokeStyle = `rgb(${el.outR},${el.outG},${el.outB})`;
+            // 1 LED pixel, not 1 canvas pixel: at SCALE>1 an unscaled stroke
+            // renders thinner than the geometry it outlines.
+            ctx.lineWidth = s;
+            ctx.strokeRect(rx, ry, rw, rh);
+          }
+          break;
+        }
+
+        case 'ellipse': {
+          const cx = (ax + el.width / 2) * s;
+          const cy = (ay + el.height / 2) * s;
+          const lwPx = s;  // 1 LED pixel
+          // Inset by half the stroke, which straddles the path, so the outline
+          // stays within the element's bounds.
+          const rx = Math.max(0, (el.width / 2) * s - (el.hasOutline ? lwPx / 2 : 0));
+          const ry = Math.max(0, (el.height / 2) * s - (el.hasOutline ? lwPx / 2 : 0));
+          ctx.beginPath();
+          ctx.ellipse(cx, cy, rx, ry, 0, 0, Math.PI * 2);
+          if (el.hasFill) {
+            ctx.fillStyle = `rgb(${el.fillR},${el.fillG},${el.fillB})`;
+            ctx.fill();
+          }
+          if (el.hasOutline) {
+            ctx.strokeStyle = `rgb(${el.outR},${el.outG},${el.outB})`;
+            ctx.lineWidth = lwPx;
+            ctx.stroke();
+          }
+          break;
+        }
+
+        case 'arc': {
+          const cx = (ax + el.width / 2) * s;
+          const cy = (ay + el.height / 2) * s;
+          const lwPx = Math.max(1, el.lineWidth || 2) * s;
+          const rx = Math.max(0, (el.width / 2) * s - lwPx / 2);
+          const ry = Math.max(0, (el.height / 2) * s - lwPx / 2);
+          // PIL: 0°=right, clockwise. Canvas: same with anticlockwise=false
+          const startRad = (el.startAngle ?? 0) * Math.PI / 180;
+          const endRad = (el.endAngle ?? 270) * Math.PI / 180;
+          ctx.beginPath();
+          ctx.ellipse(cx, cy, rx, ry, 0, startRad, endRad, false);
+          ctx.strokeStyle = `rgb(${el.r},${el.g},${el.b})`;
+          ctx.lineWidth = lwPx;
+          ctx.stroke();
+          break;
+        }
+
+        case 'pixel': {
+          ctx.fillStyle = `rgb(${el.r},${el.g},${el.b})`;
+          ctx.fillRect(ax * s, ay * s, s, s);
+          break;
+        }
+
+        case 'rounded_rectangle': {
+          const rx = ax * s, ry = ay * s;
+          const rw = el.width * s, rh = el.height * s;
+          const rad = Math.min((el.borderRadius ?? 3) * s, rw / 2, rh / 2);
+          ctx.beginPath();
+          ctx.roundRect(rx, ry, rw, rh, rad);
+          if (el.hasFill) {
+            ctx.fillStyle = `rgb(${el.fillR},${el.fillG},${el.fillB})`;
+            ctx.fill();
+          }
+          if (el.hasOutline) {
+            ctx.strokeStyle = `rgb(${el.outR},${el.outG},${el.outB})`;
+            ctx.lineWidth = s;
+            ctx.stroke();
+          }
+          break;
+        }
+
+        case 'line': {
+          // ax/ay resolve from el.x0 for a line, so this is the anchor offset.
+          // Without it a line stayed put while every other type moved.
+          const dx = ax - el.x0, dy = ay - el.y0;
+          ctx.strokeStyle = `rgb(${el.r},${el.g},${el.b})`;
+          ctx.lineWidth = Math.max(1, el.lineWidth || 1) * s;
+          ctx.beginPath();
+          ctx.moveTo((el.x0 + dx) * s, (el.y0 + dy) * s);
+          ctx.lineTo((el.x1 + dx) * s, (el.y1 + dy) * s);
+          ctx.stroke();
+          break;
+        }
+
+        case 'divider': {
+          const isH = (el.orientation || 'horizontal') === 'horizontal';
+          ctx.strokeStyle = `rgb(${el.r},${el.g},${el.b})`;
+          ctx.lineWidth = s;
+          ctx.beginPath();
+          if (isH) {
+            ctx.moveTo(0, (ay + 0.5) * s);
+            ctx.lineTo(_canvas.width, (ay + 0.5) * s);
+          } else {
+            ctx.moveTo((ax + 0.5) * s, 0);
+            ctx.lineTo((ax + 0.5) * s, _canvas.height);
+          }
+          ctx.stroke();
+          break;
+        }
+
+        case 'pips': {
+          const pipCount = Math.max(1, el.count ?? 5);
+          const pvPips = opts.previewValues?.[el.binding?.key];
+          const filledN = pvPips !== undefined
+            ? Math.max(0, Math.min(pipCount, Math.round(parseFloat(pvPips) || 0)))
+            : Math.max(0, Math.min(pipCount, el.filled ?? 3));
+          const ps = Math.max(1, el.pipSize ?? 4);
+          const pg = Math.max(0, el.pipSpacing ?? 2);
+          for (let i = 0; i < pipCount; i++) {
+            const isFilled = i < filledN;
+            if (!isFilled && !el.showEmpty) continue;
+            ctx.fillStyle = isFilled
+              ? `rgb(${el.r},${el.g},${el.b})`
+              : `rgb(${el.emptyR ?? 50},${el.emptyG ?? 50},${el.emptyB ?? 50})`;
+            ctx.fillRect((ax + i * (ps + pg)) * s, ay * s, ps * s, ps * s);
+          }
+          break;
+        }
+
+        case 'sparkline': {
+          const slW = el.width ?? 40, slH = el.height ?? 12;
+          const count = Math.max(1, el.barCount ?? 8);
+          const spacing = el.barSpacing ?? 1;
+          const barW = Math.max(1, Math.floor((slW - spacing * (count - 1)) / count));
+          const rawVals = (el.previewData || '').split(',')
+            .map(v => parseFloat(v.trim())).filter(n => !isNaN(n));
+          while (rawVals.length < count) rawVals.push(0);
+          const maxV = Math.max(...rawVals.slice(0, count), 0.001);
+          const rx = ax * s, ry = ay * s;
+          if (el.hasBg) {
+            ctx.fillStyle = `rgb(${el.bgR ?? 30},${el.bgG ?? 30},${el.bgB ?? 30})`;
+            ctx.fillRect(rx, ry, slW * s, slH * s);
+          }
+          ctx.fillStyle = `rgb(${el.r},${el.g},${el.b})`;
+          for (let i = 0; i < count; i++) {
+            const norm = Math.max(0, Math.min(1, rawVals[i] / maxV));
+            const barH = Math.max(1, Math.round(slH * norm));
+            const bx = rx + (barW + spacing) * i * s;
+            const by = ry + (slH - barH) * s;
+            ctx.fillRect(bx, by, barW * s, barH * s);
+          }
+          break;
+        }
+
+        case 'gauge': {
+          const gw = (el.width ?? 32), gh = (el.height ?? 32);
+          const cx = (ax + gw / 2) * s, cy = (ay + gh / 2) * s;
+          const rx = (gw / 2) * s, ry = (gh / 2) * s;
+          const lw = Math.max(1, (el.lineWidth ?? 3));
+          // rx/ry are canvas pixels ((gw/2)*s) but lw is LED pixels, so
+          // insetting by lw/2 under-corrected by the scale factor while the
+          // stroke was drawn at lw*s -- the arc spilled outside the element's
+          // reported bounding box at any SCALE > 1, and the preview stopped
+          // matching the generated PIL output.
+          const lwPx = lw * s;
+          const startDeg = el.startAngle ?? 135;
+          const endDeg   = el.endAngle   ?? 45;
+          // Arc sweep: from startDeg clockwise to endDeg (PIL convention)
+          const totalSweep = ((endDeg - startDeg) + 360) % 360 || 360;
+          const pvGauge = opts.previewValues?.[el.binding?.key];
+          const pct = pvGauge !== undefined
+            ? Math.max(0, Math.min(100, parseFloat(pvGauge) || 0)) / 100
+            : Math.max(0, Math.min(100, el.previewPct ?? 65)) / 100;
+          const fillSweep = totalSweep * pct;
+          // A small imported gauge with a wide lineWidth would otherwise send
+          // a negative radius into ctx.ellipse(), which throws IndexSizeError
+          // and aborts the whole render() call.
+          const arx = Math.max(0, rx - lwPx / 2), ary = Math.max(0, ry - lwPx / 2);
+          // biome-ignore lint/correctness/useQwikValidLexicalScope: not Qwik -- this is an Alpine.js component, and the rule is about Qwik's $() serialization boundary, which does not exist here.
+          const toRad = deg => (deg - 90) * Math.PI / 180; // canvas 0=top, PIL 0=right → offset -90
+
+          // Track arc
+          if (el.hasTrack !== false) {
+            ctx.beginPath();
+            ctx.ellipse(cx, cy, arx, ary, 0, toRad(startDeg), toRad(startDeg + totalSweep), false);
+            ctx.strokeStyle = `rgb(${el.trackR ?? 40},${el.trackG ?? 40},${el.trackB ?? 40})`;
+            ctx.lineWidth = lwPx;
+            ctx.stroke();
+          }
+          // Fill arc
+          if (pct > 0) {
+            ctx.beginPath();
+            ctx.ellipse(cx, cy, arx, ary, 0, toRad(startDeg), toRad(startDeg + fillSweep), false);
+            ctx.strokeStyle = `rgb(${el.r},${el.g},${el.b})`;
+            ctx.lineWidth = lwPx;
+            ctx.stroke();
+          }
+          // Centre label
+          if (el.showLabel) {
+            const gfinfo = FONT_MAP[el.font || 'four_by_six'] || FONT_MAP.four_by_six;
+            const labelText = Math.round(pct * 100) + '%';
+            ctx.font = `${gfinfo.sizePx * s}px ${gfinfo.family}`;
+            ctx.fillStyle = `rgb(${el.labelR ?? 200},${el.labelG ?? 200},${el.labelB ?? 200})`;
+            const ltw = ctx.measureText(labelText).width;
+            ctx.fillText(labelText, cx - ltw / 2, cy + (gfinfo.sizePx * s) / 2);
+          }
+          break;
+        }
+
+        case 'marquee': {
+          const finfo = FONT_MAP[el.font] || FONT_MAP.press_start;
+          const text = el.text || 'Scrolling text';
+          const tw = text.length * finfo.charW * s;
+          const gap = (el.gap ?? 16) * s;
+          const totalW = tw + gap;
+          const tick = opts.animTick ?? 0;
+          const speed = (el.scrollSpeed ?? 1) * 2;
+          const scrolled = (tick * speed) % totalW;
+          // left: text enters from right; right: text enters from left
+          const startX = el.direction === 'right'
+            ? scrolled - tw
+            : matrixW * s - scrolled;
+          ctx.font = `${finfo.sizePx * s}px ${finfo.family}`;
+          ctx.fillStyle = `rgb(${el.r},${el.g},${el.b})`;
+          // Clip to canvas width so text doesn't bleed outside
+          ctx.save();
+          ctx.beginPath();
+          ctx.rect(0, ay * s - 1, matrixW * s, (finfo.sizePx + 2) * s);
+          ctx.clip();
+          for (let i = -1; i <= 2; i++) {
+            ctx.fillText(text, startX + i * totalW, (ay + finfo.sizePx) * s);
+          }
+          ctx.restore();
+          break;
+        }
+
+        case 'progress_bar': {
+          const bw = el.barWidth ?? 60, bh = el.barHeight ?? 6;
+          const pvPb = opts.previewValues?.[el.binding?.key];
+          const pct = pvPb !== undefined
+            ? Math.max(0, Math.min(100, parseFloat(pvPb) || 0)) / 100
+            : Math.max(0, Math.min(100, el.previewPct ?? 65)) / 100;
+          const rx = ax * s, ry = ay * s;
+          if (el.hasBg) {
+            ctx.fillStyle = `rgb(${el.bgR ?? 30},${el.bgG ?? 30},${el.bgB ?? 30})`;
+            ctx.fillRect(rx, ry, bw * s, bh * s);
+          }
+          const fillW = Math.max(0, Math.round(bw * pct));
+          if (fillW > 0) {
+            ctx.fillStyle = `rgb(${el.r},${el.g},${el.b})`;
+            ctx.fillRect(rx, ry, fillW * s, bh * s);
+          }
+          if (el.hasOutline) {
+            ctx.strokeStyle = `rgb(${el.outR ?? 100},${el.outG ?? 100},${el.outB ?? 100})`;
+            ctx.lineWidth = s;
+            ctx.strokeRect(rx, ry, bw * s, bh * s);
+          }
+          break;
+        }
+      }
+
+      if (belowBreakpoint) {
+        ctx.globalAlpha = 0.6;
+        const bb = getBoundingBox(el, matrixW, matrixH);
+        ctx.font = `${Math.max(8, s * 2)}px monospace`;
+        ctx.fillStyle = '#facc15';
+        ctx.fillText(`≥${el.minWidth}px`, bb.x * s, (bb.y + 4) * s);
+      }
+    } finally {
+      ctx.restore();
+    }
+  }
+
+  // ── Selection indicator ──────────────────────────────────────────────
+  function _drawSelection(ctx, el, SCALE, matrixW, matrixH) {
+    const bb = getBoundingBox(el, matrixW, matrixH);
+    const PAD = 2, s = SCALE;
+    const rx = bb.x * s - PAD, ry = bb.y * s - PAD;
+    const rw = bb.w * s + PAD * 2, rh = bb.h * s + PAD * 2;
+
+    ctx.save();
+    ctx.strokeStyle = '#3b82f6';
+    ctx.lineWidth = 1;
+    ctx.setLineDash([3, 2]);
+    ctx.strokeRect(rx, ry, rw, rh);
+    ctx.setLineDash([]);
+
+    if (el.xAnchor || el.yAnchor) {
+      ctx.font = `${Math.max(7, s)}px sans-serif`;
+      ctx.fillStyle = '#a78bfa';
+      const anchorText = [
+        el.xAnchor ? `x:${el.xAnchor[0]}` : '',
+        el.yAnchor ? `y:${el.yAnchor[0]}` : '',
+      ].filter(Boolean).join(' ');
+      if (anchorText) ctx.fillText(anchorText, rx + 1, ry - 2);
+    }
+
+    // Resize handles: on rect, rounded rect, ellipse
+    if (RESIZABLE_TYPES.includes(el.type)) {
+      const handles = _getRectHandles(el, matrixW, matrixH);
+      const HS = 5;
+      ctx.fillStyle = 'white';
+      ctx.strokeStyle = '#2563eb';
+      ctx.lineWidth = 1;
+      for (const pt of Object.values(handles)) {
+        const hx = pt.x * s - HS / 2;
+        const hy = pt.y * s - HS / 2;
+        ctx.fillRect(hx, hy, HS, HS);
+        ctx.strokeRect(hx, hy, HS, HS);
+      }
+    } else {
+      // Corner dots for non-rectangle elements
+      ctx.fillStyle = '#3b82f6';
+      const HS = 4;
+      for (const [hx, hy] of [
+        [rx - HS / 2, ry - HS / 2], [rx + rw - HS / 2, ry - HS / 2],
+        [rx - HS / 2, ry + rh - HS / 2], [rx + rw - HS / 2, ry + rh - HS / 2],
+      ]) ctx.fillRect(hx, hy, HS, HS);
+    }
+
+    ctx.restore();
+  }
+
+  // ── Dimension tooltip while dragging ─────────────────────────────────
+  function drawDragTooltip(ctx, el, SCALE, matrixW, matrixH) {
+    const bb = getBoundingBox(el, matrixW, matrixH);
+    const label = el.type === 'rectangle'
+      ? `${el.width}×${el.height}`
+      : `${bb.x},${bb.y}`;
+    const s = SCALE;
+    ctx.save();
+    ctx.font = `${Math.max(9, s * 1.5)}px monospace`;
+    const tw = ctx.measureText(label).width;
+    const tx = bb.x * s, ty = (bb.y - 2) * s;
+    ctx.fillStyle = 'rgba(0,0,0,0.7)';
+    ctx.fillRect(tx - 2, ty - 10, tw + 4, 12);
+    ctx.fillStyle = 'white';
+    ctx.fillText(label, tx, ty);
+    ctx.restore();
+  }
+
+  // ── Public API ───────────────────────────────────────────────────────
+
+  function init(canvasEl) {
+    _canvas = canvasEl;
+    _ctx = canvasEl.getContext('2d');
+  }
+
+  function setGrid(show) { _showGrid = show; }
+
+  function updateCanvasSize(matrixW, matrixH, SCALE) {
+    if (!_canvas) return;
+    _canvas.width = matrixW * SCALE;
+    _canvas.height = matrixH * SCALE;
+  }
+
+  function render(elements, selectedId, matrixW, matrixH, SCALE, opts = {}) {
+    if (!_ctx) return;
+    const cW = matrixW * SCALE, cH = matrixH * SCALE;
+
+    const bg = opts.bgColor;
+    _ctx.fillStyle = bg ? `rgb(${bg.r},${bg.g},${bg.b})` : '#000';
+    _ctx.fillRect(0, 0, cW, cH);
+
+    if (_showGrid) {
+      _ctx.strokeStyle = 'rgba(255,255,255,0.07)';
+      _ctx.lineWidth = 0.5;
+      for (let x = SCALE; x < cW; x += SCALE) {
+        _ctx.beginPath(); _ctx.moveTo(x, 0); _ctx.lineTo(x, cH); _ctx.stroke();
+      }
+      for (let y = SCALE; y < cH; y += SCALE) {
+        _ctx.beginPath(); _ctx.moveTo(0, y); _ctx.lineTo(cW, y); _ctx.stroke();
+      }
+    }
+
+    for (const el of elements) _drawElement(_ctx, el, SCALE, matrixW, matrixH, opts);
+
+    if (opts.showRuler) {
+      _ctx.save();
+      _ctx.fillStyle = 'rgba(255,255,255,0.08)';
+      _ctx.fillRect(0, 0, cW, SCALE);             // top strip
+      _ctx.fillRect(0, 0, SCALE, cH);             // left strip
+      _ctx.strokeStyle = 'rgba(255,255,255,0.5)';
+      _ctx.fillStyle = 'rgba(255,255,255,0.6)';
+      _ctx.font = `${Math.max(5, SCALE - 1)}px monospace`;
+      const step = SCALE >= 4 ? 8 : 16;
+      for (let px = 0; px <= matrixW; px += step) {
+        const cx = px * SCALE;
+        const major = px % 32 === 0;
+        _ctx.lineWidth = 0.5;
+        _ctx.beginPath(); _ctx.moveTo(cx, 0); _ctx.lineTo(cx, major ? SCALE : SCALE * 0.5); _ctx.stroke();
+        if (major && px > 0 && px < matrixW - 4) _ctx.fillText(String(px), cx + 1, SCALE - 1);
+      }
+      for (let py = 0; py <= matrixH; py += step) {
+        const cy = py * SCALE;
+        const major = py % 32 === 0;
+        _ctx.beginPath(); _ctx.moveTo(0, cy); _ctx.lineTo(major ? SCALE : SCALE * 0.5, cy); _ctx.stroke();
+        if (major && py > 0 && py < matrixH - 4) _ctx.fillText(String(py), 1, cy + SCALE - 1);
+      }
+      _ctx.restore();
+    }
+
+    if (opts.showGuides) {
+      _ctx.save();
+      _ctx.strokeStyle = 'rgba(255,60,60,0.45)';
+      _ctx.lineWidth = 1;
+      _ctx.setLineDash([4, 3]);
+      const mx = Math.floor(cW / 2) + 0.5;
+      const my = Math.floor(cH / 2) + 0.5;
+      _ctx.beginPath(); _ctx.moveTo(mx, 0); _ctx.lineTo(mx, cH); _ctx.stroke();
+      _ctx.beginPath(); _ctx.moveTo(0, my); _ctx.lineTo(cW, my); _ctx.stroke();
+      _ctx.setLineDash([]);
+      _ctx.restore();
+    }
+
+    const sel = selectedId != null ? elements.find(e => e.id === selectedId) : null;
+    if (sel) {
+      _drawSelection(_ctx, sel, SCALE, matrixW, matrixH);
+      if (opts.showTooltip) drawDragTooltip(_ctx, sel, SCALE, matrixW, matrixH);
+    }
+  }
+
+  return {
+    init, render, setGrid, updateCanvasSize,
+    hitTest, getBoundingBox, computeActualPos, resolveAnchor,
+    getResizeHandle, getCursorForHandle,
+    ELEMENT_DEFAULTS, FONT_MAP, DISPLAY_PRESETS, RESIZABLE_TYPES,
+  };
+})();

web_interface/templates/v3/composer/manager.py.j2

@@ -0,0 +1,302 @@
+"""
+{{ plugin_name }} — LEDMatrix Plugin
+Generated by LEDMatrix Plugin Composer on {{ generated_date }}
+
+Extension points:
+  update()              → add HTTP/MQTT data-fetching logic here
+  _get_display_values() → map fetched data to display strings
+  display()             → add new elements or adapt layout per display size
+"""
+from src.plugin_system.base_plugin import BasePlugin
+{% if has_clock or has_countdown %}
+from datetime import datetime
+{% endif %}
+{% if has_blink %}
+import time
+{% endif %}
+{% if has_text_template %}
+from collections import defaultdict
+{% endif %}
+
+
+class {{ class_name }}(BasePlugin):
+
+    def __init__(self, plugin_id, config, display_manager, cache_manager, plugin_manager):
+        super().__init__(plugin_id, config, display_manager, cache_manager, plugin_manager)
+{% for var in config_vars %}
+        self.{{ var.key }} = config.get({{ var.key | tojson }}, {{ var.default | tojson }})
+{% endfor %}
+        # Live data cache — populated by update(); always {} in static layouts
+        self._data = {}
+
+    def update(self):
+        """Fetch and refresh display data.
+
+        For dynamic plugins: fetch from APIs/MQTT here and store in self._data.
+        _get_display_values() will read self._data to produce display strings.
+        """
+        # --- Data sources (add fetch logic here for dynamic plugins) ---
+        pass
+
+    def _get_display_values(self):
+        """Map config variables and live data to display-ready strings.
+
+        This is the single extension point for v2 data sources:
+        add self._data lookups here once update() populates them.
+        """
+        return {
+{% for var in config_vars %}
+            {{ var.key | tojson }}: str(self.{{ var.key }}),
+{% endfor %}
+        }
+
+    def display(self, force_clear=False):
+        try:
+{% if has_text_template %}
+            values = defaultdict(str, self._get_display_values())
+{% else %}
+            values = self._get_display_values()
+{% endif %}
+
+            if force_clear:
+                self.display_manager.clear()
+
+            width = self.display_manager.width
+            height = self.display_manager.height
+{% if bg_color %}
+
+            self.display_manager.draw.rectangle([0, 0, width, height], fill={{ bg_color }})
+{% endif %}
+
+            # ── Elements (rendered bottom to top) ──────────────────────────
+{% for el in elements %}
+{% set p = "                " if el.min_width > 0 else "            " %}
+{% set pi = (p + "    ") if el.blink else p %}
+{% if el.min_width > 0 %}
+            if width >= {{ el.min_width }}:  # breakpoint: {{ el.min_width }}px+ displays only
+{% endif %}
+{% if el.blink %}
+{{ p }}if int(time.time() * 2) % 2:
+{% endif %}
+
+{% if el.type == 'text' %}
+{{ pi }}self.display_manager.draw_text(
+{% if el.text_is_template %}
+{{ pi }}    {{ el.text | tojson }}.format_map(values),
+{% else %}
+{{ pi }}    {{ el.text | tojson }},
+{% endif %}
+{{ pi }}    x={{ el.x_expr }}, y={{ el.y_expr }},
+{{ pi }}    color={{ el.rgb_tuple }},
+{{ pi }}    font=self.display_manager.{{ el.font_attr }},
+{{ pi }})
+{% if el.text2 %}
+{{ pi }}self.display_manager.draw_text(
+{% if el.text_is_template %}
+{{ pi }}    {{ el.text2 | tojson }}.format_map(values),
+{% else %}
+{{ pi }}    {{ el.text2 | tojson }},
+{% endif %}
+{{ pi }}    x={{ el.x2_expr }}, y={{ el.y2_expr }},
+{{ pi }}    color={{ el.rgb_tuple }},
+{{ pi }}    font=self.display_manager.{{ el.font_attr }},
+{{ pi }})
+{% endif %}
+{% elif el.type == 'dynamic_text' %}
+{% if el.binding_source == 'config' %}
+{{ pi }}self.display_manager.draw_text(
+{{ pi }}    values.get({{ el.binding_key | tojson }}, ''),
+{{ pi }}    x={{ el.x_expr }}, y={{ el.y_expr }},
+{{ pi }}    color={{ el.rgb_tuple }},
+{{ pi }}    font=self.display_manager.{{ el.font_attr }},
+{{ pi }})
+{% else %}
+{{ pi }}pass  # non-config dynamic_text binding draws nothing
+{% endif %}
+{% elif el.type == 'clock' %}
+{{ pi }}self.display_manager.draw_text(
+{{ pi }}    datetime.now().strftime({{ el.format | tojson }}),
+{{ pi }}    x={{ el.x_expr }}, y={{ el.y_expr }},
+{{ pi }}    color={{ el.rgb_tuple }},
+{{ pi }}    font=self.display_manager.{{ el.font_attr }},
+{{ pi }})
+{% if el.format2 %}
+{{ pi }}self.display_manager.draw_text(
+{{ pi }}    datetime.now().strftime({{ el.format2 | tojson }}),
+{{ pi }}    x={{ el.x2_expr }}, y={{ el.y2_expr }},
+{{ pi }}    color={{ el.rgb_tuple }},
+{{ pi }}    font=self.display_manager.{{ el.font_attr }},
+{{ pi }})
+{% endif %}
+{% elif el.type == 'countdown' %}
+{{ pi }}_cd_target = float(values.get({{ el.binding_key | tojson }}, 0) or 0)
+{{ pi }}_cd_secs = max(0.0, _cd_target - datetime.now().timestamp())
+{% if el.countdown_format == 'dhms' %}
+{{ pi }}_cd_d, _cd_rem = divmod(int(_cd_secs), 86400)
+{{ pi }}_cd_h, _cd_rem = divmod(_cd_rem, 3600)
+{{ pi }}_cd_m, _cd_s = divmod(_cd_rem, 60)
+{{ pi }}_cd_str = f'{_cd_d}d {_cd_h:02d}:{_cd_m:02d}:{_cd_s:02d}'
+{% elif el.countdown_format == 'hms' %}
+{{ pi }}_cd_h, _cd_rem = divmod(int(_cd_secs), 3600)
+{{ pi }}_cd_m, _cd_s = divmod(_cd_rem, 60)
+{{ pi }}_cd_str = f'{_cd_h}h {_cd_m:02d}:{_cd_s:02d}'
+{% elif el.countdown_format == 'dhm' %}
+{{ pi }}_cd_d, _cd_rem = divmod(int(_cd_secs), 86400)
+{{ pi }}_cd_h, _cd_m = divmod(_cd_rem // 60, 60)
+{{ pi }}_cd_str = f'{_cd_d}d {_cd_h:02d}h {_cd_m:02d}m'
+{% else %}
+{{ pi }}_cd_d, _cd_rem = divmod(int(_cd_secs), 86400)
+{{ pi }}_cd_h = _cd_rem // 3600
+{{ pi }}_cd_str = f'{_cd_d}d {_cd_h}h'
+{% endif %}
+{{ pi }}self.display_manager.draw_text(
+{{ pi }}    _cd_str,
+{{ pi }}    x={{ el.x_expr }}, y={{ el.y_expr }},
+{{ pi }}    color={{ el.rgb_tuple }},
+{{ pi }}    font=self.display_manager.{{ el.font_attr }},
+{{ pi }})
+{% elif el.type == 'rectangle' %}
+{{ pi }}self.display_manager.draw.rectangle(
+{{ pi }}    [{{ el.x_expr }}, {{ el.y_expr }}, {{ el.x2_expr }}, {{ el.y2_expr }}],
+{{ pi }}    fill={{ el.fill_tuple }},
+{{ pi }}    outline={{ el.outline_tuple }},
+{{ pi }})
+{% elif el.type == 'arc' %}
+{{ pi }}self.display_manager.draw.arc(
+{{ pi }}    [{{ el.x_expr }}, {{ el.y_expr }}, {{ el.x2_expr }}, {{ el.y2_expr }}],
+{{ pi }}    start={{ el.start_angle }}, end={{ el.end_angle }},
+{{ pi }}    fill={{ el.rgb_tuple }},
+{{ pi }}    width={{ el.line_width }},
+{{ pi }})
+{% elif el.type == 'ellipse' %}
+{{ pi }}self.display_manager.draw.ellipse(
+{{ pi }}    [{{ el.x_expr }}, {{ el.y_expr }}, {{ el.x2_expr }}, {{ el.y2_expr }}],
+{{ pi }}    fill={{ el.fill_tuple }},
+{{ pi }}    outline={{ el.outline_tuple }},
+{{ pi }})
+{% elif el.type == 'pixel' %}
+{{ pi }}self.display_manager.draw.point(
+{{ pi }}    [{{ el.x_expr }}, {{ el.y_expr }}],
+{{ pi }}    fill={{ el.rgb_tuple }},
+{{ pi }})
+{% elif el.type == 'rounded_rectangle' %}
+{{ pi }}self.display_manager.draw.rounded_rectangle(
+{{ pi }}    [{{ el.x_expr }}, {{ el.y_expr }}, {{ el.x2_expr }}, {{ el.y2_expr }}],
+{{ pi }}    radius={{ el.border_radius }},
+{{ pi }}    fill={{ el.fill_tuple }},
+{{ pi }}    outline={{ el.outline_tuple }},
+{{ pi }})
+{% elif el.type in ('line', 'divider') %}
+{{ pi }}self.display_manager.draw.line(
+{{ pi }}    [{{ el.x0_expr }}, {{ el.y0_expr }}, {{ el.x1_expr }}, {{ el.y1_expr }}],
+{{ pi }}    fill={{ el.rgb_tuple }},
+{{ pi }}    width={{ el.line_width }},
+{{ pi }})
+{% elif el.type == 'pips' %}
+{{ pi }}_pip_filled = max(0, min({{ el.pip_count }}, int(float(values.get({{ el.binding_key | tojson }}, 0) or 0))))
+{{ pi }}for _pip_i in range({{ el.pip_count }}):
+{{ pi }}    _pip_x = ({{ el.x_expr }}) + _pip_i * ({{ el.pip_size }} + {{ el.pip_spacing }})
+{{ pi }}    _pip_color = {{ el.fill_tuple }} if _pip_i < _pip_filled else {{ el.empty_tuple }}
+{% if not el.show_empty %}
+{{ pi }}    if _pip_i >= _pip_filled:
+{{ pi }}        continue
+{% endif %}
+{{ pi }}    self.display_manager.draw.rectangle(
+{{ pi }}        [_pip_x, {{ el.y_expr }}, _pip_x + {{ el.pip_size }} - 1, ({{ el.y_expr }}) + {{ el.pip_size }} - 1],
+{{ pi }}        fill=_pip_color,
+{{ pi }}    )
+{% elif el.type == 'sparkline' %}
+{{ pi }}_sl_raw = str(values.get({{ el.binding_key | tojson }}, '') or '')
+{{ pi }}_sl_vals = [float(v.strip()) for v in _sl_raw.split(',') if v.strip()][:{{ el.bar_count }}]
+{{ pi }}_sl_vals += [0.0] * max(0, {{ el.bar_count }} - len(_sl_vals))
+{{ pi }}_sl_max = max(_sl_vals) if any(_sl_vals) else 1.0
+{{ pi }}_sl_bw = max(1, ({{ el.bar_width_px }} - {{ el.bar_spacing }} * ({{ el.bar_count }} - 1)) // {{ el.bar_count }})
+{% if el.bg_tuple != 'None' %}
+{{ pi }}self.display_manager.draw.rectangle(
+{{ pi }}    [{{ el.x_expr }}, {{ el.y_expr }}, ({{ el.x_expr }}) + {{ el.bar_width_px }}, ({{ el.y_expr }}) + {{ el.bar_height_px }}],
+{{ pi }}    fill={{ el.bg_tuple }},
+{{ pi }})
+{% endif %}
+{{ pi }}for _sl_i, _sl_v in enumerate(_sl_vals):
+{{ pi }}    _sl_norm = max(0.0, min(1.0, _sl_v / (_sl_max or 1)))
+{{ pi }}    _sl_bh = max(1, round({{ el.bar_height_px }} * _sl_norm))
+{{ pi }}    _sl_bx = ({{ el.x_expr }}) + (_sl_bw + {{ el.bar_spacing }}) * _sl_i
+{{ pi }}    _sl_by = ({{ el.y_expr }}) + {{ el.bar_height_px }} - _sl_bh
+{{ pi }}    self.display_manager.draw.rectangle(
+{{ pi }}        [_sl_bx, _sl_by, _sl_bx + _sl_bw - 1, _sl_by + _sl_bh - 1],
+{{ pi }}        fill={{ el.fill_tuple }},
+{{ pi }}    )
+{% elif el.type == 'gauge' %}
+{{ pi }}_gv = max(0.0, min(100.0, float(values.get({{ el.binding_key | tojson }}, 0) or 0)))
+{{ pi }}_g_total = (({{ el.end_angle }} - {{ el.start_angle }}) % 360) or 360
+{{ pi }}_g_sweep = _g_total * _gv / 100.0
+{% if el.track_tuple != 'None' %}
+{{ pi }}self.display_manager.draw.arc(
+{{ pi }}    [{{ el.x_expr }}, {{ el.y_expr }}, {{ el.x2_expr }}, {{ el.y2_expr }}],
+{{ pi }}    start={{ el.start_angle }}, end={{ el.start_angle }} + _g_total,
+{{ pi }}    fill={{ el.track_tuple }},
+{{ pi }}    width={{ el.line_width }},
+{{ pi }})
+{% endif %}
+{{ pi }}if _g_sweep > 0:
+{{ pi }}    self.display_manager.draw.arc(
+{{ pi }}        [{{ el.x_expr }}, {{ el.y_expr }}, {{ el.x2_expr }}, {{ el.y2_expr }}],
+{{ pi }}        start={{ el.start_angle }}, end={{ el.start_angle }} + _g_sweep,
+{{ pi }}        fill={{ el.rgb_tuple }},
+{{ pi }}        width={{ el.line_width }},
+{{ pi }}    )
+{% if el.show_label %}
+{{ pi }}_g_cx = ({{ el.x_expr }}) + ({{ el.x2_expr }} - ({{ el.x_expr }})) // 2
+{{ pi }}_g_cy = ({{ el.y_expr }}) + ({{ el.y2_expr }} - ({{ el.y_expr }})) // 2
+{{ pi }}self.display_manager.draw_text(
+{{ pi }}    f'{int(_gv)}%',
+{{ pi }}    x=_g_cx, y=_g_cy,
+{{ pi }}    color={{ el.label_tuple }},
+{{ pi }}    font=self.display_manager.{{ el.font_attr }},
+{{ pi }})
+{% endif %}
+{% elif el.type == 'marquee' %}
+{{ pi }}_{{ el.data_key }}_text = {{ el.text | tojson }}
+{{ pi }}_{{ el.data_key }}_tw = len(_{{ el.data_key }}_text) * {{ el.char_w }}
+{{ pi }}_{{ el.data_key }}_x = int(self._data.get({{ el.data_key | tojson }}, width))
+{% if el.direction == 'right' %}
+{{ pi }}_{{ el.data_key }}_x += {{ el.scroll_speed }}
+{{ pi }}if _{{ el.data_key }}_x > width:
+{{ pi }}    _{{ el.data_key }}_x = -(_{{ el.data_key }}_tw + {{ el.gap }})
+{% else %}
+{{ pi }}_{{ el.data_key }}_x -= {{ el.scroll_speed }}
+{{ pi }}if _{{ el.data_key }}_x < -(_{{ el.data_key }}_tw + {{ el.gap }}):
+{{ pi }}    _{{ el.data_key }}_x = width
+{% endif %}
+{{ pi }}self._data[{{ el.data_key | tojson }}] = _{{ el.data_key }}_x
+{{ pi }}self.display_manager.draw_text(
+{{ pi }}    _{{ el.data_key }}_text,
+{{ pi }}    x=_{{ el.data_key }}_x, y={{ el.y_expr }},
+{{ pi }}    color={{ el.rgb_tuple }},
+{{ pi }}    font=self.display_manager.{{ el.font_attr }},
+{{ pi }})
+{% elif el.type == 'progress_bar' %}
+{{ pi }}_pb_x = {{ el.x_expr }}
+{{ pi }}_pb_y = {{ el.y_expr }}
+{{ pi }}_pb_pct = max(0.0, min(100.0, float(values.get({{ el.binding_key | tojson }}, 0) or 0))) / 100.0
+{{ pi }}_pb_fill_w = int({{ el.bar_width }} * _pb_pct)
+{{ pi }}self.display_manager.draw.rectangle(
+{{ pi }}    [_pb_x, _pb_y, _pb_x + {{ el.bar_width }}, _pb_y + {{ el.bar_height }}],
+{{ pi }}    fill={{ el.bg_tuple }},
+{{ pi }}    outline={{ el.outline_tuple }},
+{{ pi }})
+{{ pi }}if _pb_fill_w > 0:
+{{ pi }}    self.display_manager.draw.rectangle(
+{{ pi }}        [_pb_x, _pb_y, _pb_x + _pb_fill_w, _pb_y + {{ el.bar_height }}],
+{{ pi }}        fill={{ el.fill_tuple }},
+{{ pi }}    )
+{% else %}
+{{ pi }}pass  # element type "{{ el.type }}" draws nothing
+{% endif %}
+{% endfor %}
+            # ── End elements ───────────────────────────────────────────────
+
+            self.display_manager.update_display()
+
+        except Exception as e:
+            self.logger.error('Display error: %s', e, exc_info=True)