From cf5c60da38657aa3abd7db50726429296eea702a Mon Sep 17 00:00:00 2001
From: Martin Fuchs <public@deffekt.ch>
Date: Sun, 16 Aug 2026 16:31:48 +0200
Subject: [PATCH] stop fix

---
 lib/README.md      |  2 +-
 lib/WallPlotter.js | 24 ++++++++----------------
 2 files changed, 9 insertions(+), 17 deletions(-)

diff --git a/lib/README.md b/lib/README.md
index ebfa4a0..3ba74f6 100644
--- a/lib/README.md
+++ b/lib/README.md
@@ -152,7 +152,7 @@ Returns estimated duration in **milliseconds** for the current path buffer, or f
 
 `stopPath()` aborts the current `runPath` and unblocks any wait for Marlin `ok`.
 
-`stopPlot()` first press is the same as **Pause**: finish the current stroke, then **Resume** continues. Second press is an emergency `M410` quick-stop. That leaves belt length unknown on a polargraph, so **home is cleared** — jog to origin and press **H** before plotting again. An `ok` timeout pauses the same way (no `M410`); that segment is skipped.
+`stopPlot()` first press is the same as **Pause**: finish the current stroke, then **Resume** continues. Second press stops the browser from sending more moves. The **in-flight** `G1` still runs — this firmware does not have `EMERGENCY_PARSER`, so `M410` cannot interrupt motion (and on a polargraph it desyncs belts). Unplug power for a hard stop.
 
 ### `pausePlot()` / `resumePlot()`
 
diff --git a/lib/WallPlotter.js b/lib/WallPlotter.js
index d14e435..ce8c6c3 100644
--- a/lib/WallPlotter.js
+++ b/lib/WallPlotter.js
@@ -354,27 +354,19 @@ class WallPlotter {
 
   /**
    * First press: pause after the current stroke (safe to Resume).
-   * Second press: emergency M410 — home is cleared, do not resume.
+   * Second press: stop sending more moves. The in-flight G1 still finishes
+   * (Marlin has no emergency parser). Do not send M410 — it cannot interrupt
+   * a running move, and on a polargraph it desyncs belt lengths.
    */
   async stopPlot() {
     const hadWait = this._okResolvers.length > 0;
 
     if (this.isPlotting && this.isPaused) {
       this.stopPath();
-      if (this.connected && !this._plotTestOnly) {
-        try {
-          await this.send('M410', { waitOk: false, allowWithoutHome: true });
-        } catch (_) {
-          /* port may be busy */
-        }
-        this.homeSet = false;
-        this._okIgnoreUntil = performance.now() + 1500;
-        this._homeWarning = 'Re-home (H) after emergency stop — position is unknown';
-        this.statusText = this._homeWarning;
-      } else {
-        this.statusText = 'Stopped';
-      }
-      this.onLog('plot aborted — set home before plotting again');
+      this.statusText = 'Stopped — current stroke may still finish';
+      this.onLog(
+        'plot aborted — motors finish the in-flight move (unplug power for a hard stop)'
+      );
       return;
     }
 
@@ -1517,7 +1509,7 @@ class WallPlotter {
         'H           set current pos as home (G92) — required first',
         '0           go to origin (0, 0)',
         'P           toggle pen (test up/down angles)',
-        'S           stop after current stroke (S again = e-stop, re-home)',
+        'S           stop sending (in-flight stroke still finishes)',
         'C           connect / disconnect',
       ];
       for (let i = 0; i < help.length; i++) {