From 754c547d8745ca0037f04284e6d5330c25442336 Mon Sep 17 00:00:00 2001
From: Home Assistant Version Control <havc@local>
Date: Fri, 7 Aug 2026 14:47:25 +0000
Subject: [PATCH] opencode/printer-stats-z-chart-fix.md

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+# Printer Stats Dashboard — Z Position Chart Fix
+
+Date: 2026-08-07
+
+## Problem
+
+On the `/printer-stats` dashboard, the **Z Position (24h)** history chart showed large gaps.
+
+Root cause: `sensor.octoprint_current_z` only publishes when the printer moves (Z position changes). During idle periods there are no new state records, so the native `history-graph` card renders those stretches as a gap. An overnight OctoPrint outage (~19:50–21:33) also produced a long `unavailable` break in the line.
+
+The native `history-graph` card does **not** support `connect_spans` (it is silently ignored), so an initial attempt to bridge the gaps that way was a no-op.
+
+## Fix
+
+Replaced the "Z Position (24h)" card with `custom:apexcharts-card` (v2.2.3, already installed and in use on the dashboard — "Print Outcomes (30 days)").
+
+- `fill_raw: "last"` bridges null/`unavailable` values, so idle freezes and the outage render as a continuous flat line instead of a gap
+- ApexCharts connects consecutive history points directly, so periods with no new records draw as a straight line
+- Stroke width set to `1` (`apex_config.stroke`) so the line matches the dashboard's other charts
+- Card moved to directly below the "Print Activity" section header
+
+## Final Card Config
+
+Located at `/printer-stats` → History view → Print Activity section, `views[1].sections[1].cards[1]`.
+
+```yaml
+type: custom:apexcharts-card
+header:
+  show: true
+  title: Z Position (24h)
+  show_states: true
+  colorize_states: true
+graph_span: 24h
+series:
+  - entity: sensor.octoprint_current_z
+    name: Current Z
+    color: "#ab47bc"
+    type: line
+    curve: straight
+    fill_raw: "last"
+grid_options:
+  columns: full
+apex_config:
+  chart:
+    height: 300
+  stroke:
+    width: 1
+```
+
+## Config Hash History
+
+| Action | Config hash |
+|---|---|
+| Replaced card with apexcharts-card | `4c1f4ac4de6971e9` |
+| Thinned stroke to 1px | `deda8faff03c7b8b` |
+| Moved card below header | `df9fb734b0cb1562` |
+
+## Related Decisions
+
+See `decisions.yaml`:
+- `2026-08-07-octoprint-frozen-sensors-shown-via-idle-2` — why the sensor freezes during idle
+- `2026-08-07-octoprint-controls-are-mqtt-via` — print controls go through MQTT/input_boolean, not the old MQTT automation