test(vegas): cover the width cap still working when asked for

Defaulting the cap off must not quietly remove it. Asserts that an
explicit ratio is honoured and validates, alongside the existing check
that omitting it means uncapped.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Udr6MfaFLUPhX5Fgo67Jf5

config/config.template.json

@@ -149,7 +149,7 @@
             "min_plugin_width": 8,
             "lead_in_width": 0,
             "plugins_per_cycle": 6,
-            "max_plugin_width_ratio": 3.0,
+            "max_plugin_width_ratio": 0.0,
             "overflow_mode": "rotate",
             "dynamic_duration_enabled": true,
             "min_cycle_duration": 60,

docs/CONFIG_REFERENCE.md

@@ -127,7 +127,7 @@ Read by `src/vegas_mode/config.py` (`VegasScrollConfig.from_config`). See
 | `min_plugin_width` | int, `8` |
 | `lead_in_width` | int, `0` |
 | `plugins_per_cycle` | int, `6` |
-| `max_plugin_width_ratio` | float, `3.0` |
+| `max_plugin_width_ratio` | float, `0.0` |
 | `overflow_mode` | string, `"rotate"` |
 | `dynamic_duration_enabled` | bool, `true` |
 | `min_cycle_duration` | int, `60` |

src/vegas_mode/config.py

@@ -104,10 +104,22 @@ class VegasModeConfig:
     overflow_mode: str = "rotate"
 
     # Cap on one plugin's share of a cycle, as a multiple of display width.
-    # A single ticker returning 7,000px would otherwise hold the panel for over
-    # two minutes. Overflow is deferred to later cycles rather than discarded.
-    # 0 disables the cap.
-    max_plugin_width_ratio: float = 3.0
+    # 0 (the default) disables the cap, so every plugin contributes all of its
+    # content and is always entered at its beginning.
+    #
+    # Capping was the default until it proved to cost more than it bought.
+    # Measured over a 17-plugin fleet on a 512px panel, only four plugins were
+    # ever wide enough to hit a 3.0 cap; for those four it produced two visible
+    # faults. Content resumed mid-item on each appearance (a news ticker entered
+    # at column 6027 of its own strip), and the final window of a rotation was
+    # whatever happened to be left — 348px of a 1840px stocks ticker, seven
+    # seconds of panel time. Both read as the display being broken rather than
+    # as deferral working.
+    #
+    # A wide plugin does hold the panel for a long time uncapped: set the cap
+    # per plugin with vegas_max_width_screens where that matters, rather than
+    # globally where it mostly hurts plugins that were never the problem.
+    max_plugin_width_ratio: float = 0.0
 
     # Plugin management
     plugin_order: List[str] = field(default_factory=list)
@@ -159,7 +171,7 @@ class VegasModeConfig:
             lead_in_width=int(vegas_config.get('lead_in_width', 0)),
             plugins_per_cycle=int(vegas_config.get('plugins_per_cycle', 6)),
             max_plugin_width_ratio=float(
-                vegas_config.get('max_plugin_width_ratio', 3.0)),
+                vegas_config.get('max_plugin_width_ratio', 0.0)),
             overflow_mode=str(vegas_config.get('overflow_mode', 'rotate')),
             plugin_order=list(vegas_config.get('plugin_order', [])),
             excluded_plugins=set(vegas_config.get('excluded_plugins', [])),

test/test_vegas_density.py

@@ -781,6 +781,20 @@ class TestNewConfigKeys:
         assert cfg.render_width_pct == 100
         assert cfg.min_content_separation == 24
 
+    def test_width_cap_is_off_by_default(self):
+        # Capping made wide plugins resume mid-content on every appearance and
+        # emit runt final windows; it is now opt-in per plugin instead.
+        assert VegasModeConfig().max_plugin_width_ratio == 0.0
+        assert VegasModeConfig.from_config({}).max_plugin_width_ratio == 0.0
+
+    def test_width_cap_is_still_available_when_asked_for(self):
+        # Defaulting the cap off must not remove it: a user who sets a ratio
+        # still gets one, and 0 still means uncapped.
+        cfg = VegasModeConfig.from_config(
+            {'display': {'vegas_scroll': {'max_plugin_width_ratio': 3.0}}})
+        assert cfg.max_plugin_width_ratio == 3.0
+        assert cfg.validate() == []
+
     @pytest.mark.parametrize('overrides,bad_key', [
         ({'render_width_pct': 5}, 'render_width_pct'),
         ({'render_width_pct': 101}, 'render_width_pct'),

web_interface/templates/v3/partials/display.html

@@ -556,11 +556,11 @@
                         </div>
 
                         <div class="form-group" id="setting-display-vegas_max_plugin_width_ratio" data-setting-key="display.vegas_scroll.max_plugin_width_ratio">
-                            <label for="vegas_max_plugin_width_ratio" class="block text-sm font-medium text-gray-700">Max Plugin Width (screens){{ ui.help_tip('Caps how much of one cycle a single plugin may occupy, measured in screen widths (0–20).\nDefault: 3. A long ticker such as a news feed or leaderboard is trimmed to this and the remainder shown on later cycles, so one plugin cannot hold the display for minutes. Set 0 for no limit.', 'Max Plugin Width') }}</label>
+                            <label for="vegas_max_plugin_width_ratio" class="block text-sm font-medium text-gray-700">Max Plugin Width (screens){{ ui.help_tip('Caps how much of one cycle a single plugin may occupy, measured in screen widths (0–20).\nDefault: 0 (no limit) — every plugin shows all of its content and always starts at the beginning.\nSet a limit to stop one long ticker holding the display for minutes: it is cut to this width and the remainder shown on later cycles. The trade-off is that such a plugin then resumes mid-content on each appearance instead of starting fresh.', 'Max Plugin Width') }}</label>
                             <input type="number"
                                    id="vegas_max_plugin_width_ratio"
                                    name="vegas_max_plugin_width_ratio"
-                                   value="{{ main_config.display.get('vegas_scroll', {}).get('max_plugin_width_ratio', 3.0) }}"
+                                   value="{{ main_config.display.get('vegas_scroll', {}).get('max_plugin_width_ratio', 0.0) }}"
                                    min="0"
                                    max="20"
                                    step="0.5"