[verified] merge experimental into nested AT-SPI fix

session/fix-panels.py

@@ -0,0 +1,143 @@
+#!/usr/bin/env python3
+"""Bring back a taskbar that Plasma saved against a screen this desktop doesn't have.
+
+Plasma 6.2.5 ties each panel to a screen number (lastScreen in its containment), and the
+numbers rank the enabled outputs by priority: 0 is the primary screen. A panel whose
+number is past the screen count gets no view and stays hidden; Plasma never moves it,
+even on a later start (sanitizeScreenLayout() only remaps a panel whose number has no
+desktop, and the Frametop desktop keeps a desktop for every spare output it has seen).
+So a taskbar saved on a spare output (issue #18), or on a screen that a smaller layout
+dropped, was lost until the config was deleted.
+
+The session runs this before Plasma starts, so nothing races Plasma for the file. Each
+panel numbered at or past the screen count moves to screen 0, with its system tray's
+containment, and keeps its widgets and settings. A panel is left where it is when screen
+0 already has a panel on that edge: it comes back by itself if the screens do. The file
+is backed up once per repair (<file>.ft-bak), and the changes go through kwriteconfig6.
+
+  fix-panels.py [--screens N] [--file APPLETSRC] [--check]
+    --screens  the desktop's screen count (default: the configured layout's)
+    --file     default: $XDG_CONFIG_HOME/plasma-org.kde.plasma.desktop-appletsrc, with
+               XDG_CONFIG_HOME defaulting to the Frametop desktop's ~/.config/frametop
+    --check    change nothing; list the panels, and exit 1 if one is lost
+"""
+import argparse
+import os
+import re
+import shutil
+import subprocess
+import sys
+
+EDGES = {3: "top", 4: "bottom", 5: "left", 6: "right"}  # Plasma::Types::Location
+SYSTRAY = "org.kde.plasma.private.systemtray"
+GROUP = re.compile(r"\[([^\]]*)\]")
+
+
+def parse(text):
+    """KConfig text -> {(group, subgroup, ...): {key: value}}."""
+    groups, cur = {}, None
+    for line in text.splitlines():
+        line = line.strip()
+        if line.startswith("["):
+            cur = tuple(GROUP.findall(line))
+            groups.setdefault(cur, {})
+        elif cur is not None and "=" in line and not line.startswith("#"):
+            k, v = line.split("=", 1)
+            groups[cur][re.sub(r"\[\$.*\]$", "", k.strip())] = v.strip()
+    return groups
+
+
+def number(v, default=-1):
+    try:
+        return int(v)
+    except (TypeError, ValueError):
+        return default
+
+
+def panels(groups):
+    """The panels, by containment id: location, lastScreen, and the ids of their system
+    trays' own containments (which sit on the same edge and screen as the panel)."""
+    trays, found = {}, {}
+    for g, keys in groups.items():
+        if len(g) == 5 and g[0] == "Containments" and g[2] == "Applets" and g[4] == "Configuration":
+            tray = keys.get("SystrayContainmentId")
+            if tray:
+                trays.setdefault(g[1], []).append(tray)
+    owned = {t for ts in trays.values() for t in ts}
+    for g, keys in groups.items():
+        if len(g) != 2 or g[0] != "Containments" or number(g[1]) <= 0 or g[1] in owned:
+            continue
+        loc = number(keys.get("location"), 0)
+        if loc in EDGES and keys.get("plugin") != SYSTRAY:
+            found[g[1]] = {"location": loc, "screen": number(keys.get("lastScreen")),
+                           "plugin": keys.get("plugin", "?"), "trays": trays.get(g[1], [])}
+    return dict(sorted(found.items(), key=lambda kv: number(kv[0])))
+
+
+def plan(groups, screens):
+    """(moves, kept): moves are (panel id, from screen, containment ids to put on screen 0);
+    kept are (panel id, from screen, why) for lost panels left alone."""
+    found = panels(groups)
+    taken = {(p["screen"], p["location"]) for p in found.values() if 0 <= p["screen"] < screens}
+    moves, kept = [], []
+    for pid, p in found.items():
+        if p["screen"] < screens:
+            continue  # on a screen this desktop has (Plasma puts -1 on the first one itself)
+        if (0, p["location"]) in taken:
+            kept.append((pid, p["screen"], f"the first screen already has a {EDGES[p['location']]} panel"))
+            continue
+        taken.add((0, p["location"]))
+        moves.append((pid, p["screen"], [pid, *p["trays"]]))
+    return moves, kept
+
+
+def default_screens():
+    sys.path.insert(0, os.path.join(os.path.dirname(os.path.realpath(__file__)), "..", "layout"))
+    import ft_layout
+    return ft_layout.screen_count()
+
+
+def main(argv):
+    ap = argparse.ArgumentParser(description=__doc__.split("\n\n")[0])
+    ap.add_argument("--screens", type=int)
+    ap.add_argument("--file")
+    ap.add_argument("--check", action="store_true")
+    a = ap.parse_args(argv)
+    config = os.environ.get("XDG_CONFIG_HOME") or os.path.expanduser("~/.config/frametop")
+    path = a.file or os.path.join(config, "plasma-org.kde.plasma.desktop-appletsrc")
+    screens = a.screens if a.screens else default_screens()
+    try:
+        with open(path) as f:
+            groups = parse(f.read())
+    except FileNotFoundError:
+        if a.check:
+            print("no Plasma config yet (Plasma makes the default taskbar)")
+        return 0
+    moves, kept = plan(groups, screens)
+
+    if a.check:
+        found = panels(groups)
+        for pid, p in found.items():
+            lost = " (lost: no such screen)" if p["screen"] >= screens else ""
+            print(f"panel {pid}: screen {p['screen']}, {EDGES[p['location']]}{lost}")
+        if not found:
+            print("no panels")
+        print(f"{screens} screen(s)")
+        return 1 if moves or kept else 0
+
+    if moves:
+        shutil.copy2(path, path + ".ft-bak")
+    for pid, was, ids in moves:
+        for cid in ids:
+            subprocess.run(["kwriteconfig6", "--file", os.path.abspath(path), "--group", "Containments",
+                            "--group", cid, "--key", "lastScreen", "0"], check=True)
+        print(f"frametop: panel {pid} was saved on screen {was}, which this desktop doesn't have "
+              f"({screens} screen(s)); moved it to the first screen (backup: {path}.ft-bak)", file=sys.stderr)
+    for pid, was, why in kept:
+        print(f"frametop: panel {pid} is saved on screen {was}, which this desktop doesn't have; "
+              f"left there: {why}", file=sys.stderr)
+    return 0
+
+
+if __name__ == "__main__":
+    sys.exit(main(sys.argv[1:]))

session/frametop-session.sh

@@ -249,8 +249,47 @@ elif [ "$(kreadconfig6 --file "$kwinrc" --group org.kde.kdecoration2 --key theme
   kwriteconfig6 --file "$kwinrc" --group org.kde.kdecoration2 --key theme --delete
 fi
 
+# KWin draws through zink on the headset's GPU, which vrcompositor needs, so the blur and
+# background contrast behind panels and menus and the window animations cost frames for
+# little. They're off by default in this desktop. Each is written once, before KWin first
+# reads it, and only if this desktop's config doesn't have it yet; the marker keeps it
+# from coming back, since System Settings deletes a setting put back to KDE's default.
+# docs/reference.md says how to turn them on again.
+default() {  # file group key value
+  [ -n "$(kreadconfig6 --file "$1" --group "$2" --key "$3")" ] || kwriteconfig6 --file "$1" --group "$2" --key "$3" "$4"
+}
+frametoprc=$XDG_CONFIG_HOME/frametoprc
+if [ "$(kreadconfig6 --file "$frametoprc" --group Defaults --key effects)" != 1 ]; then
+  default "$kwinrc" Plugins blurEnabled false
+  default "$kwinrc" Plugins contrastEnabled false
+  default "$XDG_CONFIG_HOME/kdeglobals" KDE AnimationDurationFactor 0
+  kwriteconfig6 --file "$frametoprc" --group Defaults --key effects 1
+fi
+
+# System autostart entries this desktop doesn't need, hidden for it alone by a copy with
+# Hidden=true in its own autostart folder, once and unless there's a file of that name
+# already. Discover's update notifier starts Discover itself to check for updates (about
+# 600 MB and a share of a core, with Flatpak's helper and AppStream behind it); updates
+# come with SteamOS and from Discover in the stock desktop. IBus can't reach the
+# desktop's apps: KWin's input method is ft-textinput, and the session drops the
+# variables that point apps at IBus or XIM. Deleting the copy brings an entry back.
+if [ "$(kreadconfig6 --file "$frametoprc" --group Defaults --key autostart)" != 1 ]; then
+  for entry in org.kde.discover.notifier ibus; do
+    src=/etc/xdg/autostart/$entry.desktop dst=$XDG_CONFIG_HOME/autostart/$entry.desktop
+    [ -r "$src" ] && [ ! -e "$dst" ] || continue
+    mkdir -p "$(dirname "$dst")"
+    sed '/^\[Desktop Entry\]$/a Hidden=true' "$src" > "$dst"
+  done
+  kwriteconfig6 --file "$frametoprc" --group Defaults --key autostart 1
+fi
+
 # Profiles reopen apps (docs/profiles.md), so Plasma's own session restore stays off here;
 # with both, apps would open twice.
 kwriteconfig6 --file "$XDG_CONFIG_HOME/ksmserverrc" --group General --key loginMode emptySession
 
+# Plasma keeps a panel on a screen number, and never moves one whose screen this desktop
+# doesn't have, like a spare output or a screen a smaller layout dropped. Put such a panel
+# back on the first (primary) screen before Plasma reads the file (session/fix-panels.py).
+python3 "$here/fix-panels.py" --screens "$screens" || true
+
 dbus-run-session startplasma-wayland

session/frametop.conf.example

@@ -38,7 +38,7 @@ POINTER_GAZE_SHOW=1        # gaze mode, with POINTER_GAZE_DOT=moving: the dot sh
 POINTER_GAZE_MOUSE=precision # gaze mode: the left button holds back its press, the mouse steers, the release clicks (precision) | clicks right away (direct)
 POINTER_HEAD_DEADZONE=0.5  # keyboard clicks at the gaze (Meta+J, Meta+K): degrees the head turns before the held dot moves with it
 POINTER_KEY_TAP=0.25       # keyboard clicks: let go within this (s) and it clicks where the dot was at the press, and tells the gaze tracker it was right
-GAZE_TRACKER=steam         # gaze service: steam = SteamVR's eye tracker | own = our own (gaze/tracker: its frame grabber needs gaze/tracker/install.sh; calibrated with Calibrate on Frametop Input Settings' Gaze page)
+GAZE_TRACKER=auto          # gaze service: auto = our own eye tracker when it's installed (gaze/tracker/install.sh, which install.sh offers), else SteamVR's | own = ours | steam = SteamVR's. Each keeps its own calibration (Calibrate on Frametop Input Settings' Gaze page)
 GAZE_EYE=auto              # gaze service: eye bias. auto = each eye weighted by how far off it was at your recent nudges | left | right = that eye counts twice
 HANDS_SWAP_SIDES=0         # hand tracking (hands/run.sh install): 1 = the side cameras' names are swapped, which some SteamVR restarts cause (hands/tools/check_sides.py --ring tells)
 HANDS_CPUS=5,6,7           # hand tracking: the CPUs its model threads run on
@@ -54,7 +54,6 @@ POINTER_PINCH_DEADZONE=1.5 # hands: degrees the pinching hand moves before the p
 POINTER_GRIP_GAIN=1        # hands: the pointer moves this times the gripping hand's angle
 POINTER_GRIP_BELOW=0.35    # hands: grips beginning more than this (m) below the eyes are ignored (hands on a desk)
 POINTER_PINCH_TYPING=1     # hands: no pinch within this many seconds of a key (typing touches thumb to index)
-META_DASHBOARD=0   # 1 = a Meta tap on a pass-through keyboard toggles the SteamVR dashboard (pointer mode only)
 SHARE_KEYS=0       # 1 = keys of keyboards grabbed for the desktop also go to @frametop_keys, for hotkey tools (any local process can listen)
 DISPLAY_OFF_MIN=0  # minutes without use before frametop-power turns the displays off, even if the headset seems worn (0 = never)
 DISPLAY_MOVE_MM=5  # displays off: the headset or a controller moving this far (mm) within 10 s counts as use

session/tests/test_fix_panels.py

@@ -0,0 +1,162 @@
+#!/usr/bin/env python3
+"""Tests for session/fix-panels.py: issue #18's config (the taskbar saved on spare output 8
+of a 3-screen desktop), panels that are fine, an edge that's taken, and a real run of
+kwriteconfig6 on a copy. Nothing here touches the running desktop or its config.
+
+  python3 session/tests/test_fix_panels.py
+"""
+import importlib.util
+import os
+import subprocess
+import sys
+import tempfile
+import unittest
+
+HERE = os.path.dirname(os.path.realpath(__file__))
+SCRIPT = os.path.join(HERE, "..", "fix-panels.py")
+spec = importlib.util.spec_from_file_location("fix_panels", SCRIPT)
+fp = importlib.util.module_from_spec(spec)
+spec.loader.exec_module(fp)
+
+
+def desktop(cid, screen):
+    return f"""[Containments][{cid}]
+activityId=7e1d1a3c-0000-4000-8000-000000000000
+formfactor=0
+immutability=1
+lastScreen={screen}
+location=0
+plugin=org.kde.plasma.folder
+wallpaperplugin=org.kde.image
+"""
+
+
+def panel(cid, screen, location=4, tray=None):
+    text = f"""[Containments][{cid}]
+activityId=
+formfactor=2
+immutability=1
+lastScreen={screen}
+location={location}
+plugin=org.kde.panel
+wallpaperplugin=org.kde.image
+
+[Containments][{cid}][Applets][{cid}1]
+immutability=1
+plugin=org.kde.plasma.kickoff
+"""
+    if tray:
+        text += f"""
+[Containments][{cid}][Applets][{cid}2]
+immutability=1
+plugin=org.kde.plasma.systemtray
+
+[Containments][{cid}][Applets][{cid}2][Configuration]
+PreloadWeight=90
+SystrayContainmentId={tray}
+
+[Containments][{tray}]
+activityId=
+formfactor=2
+immutability=1
+lastScreen={screen}
+location={location}
+plugin=org.kde.plasma.private.systemtray
+popupHeight=432
+"""
+    return text
+
+
+ISSUE_18 = "\n".join([desktop(1, 0), desktop(18, 1), desktop(19, 2)] + [desktop(20 + i, 3 + i) for i in range(8)]
+                     + [panel(10, 8, tray=11), "[ScreenMapping]\nitemsOnDisabledScreens=\n"])
+
+
+class Plan(unittest.TestCase):
+    def test_issue_18(self):
+        moves, kept = fp.plan(fp.parse(ISSUE_18), 3)
+        self.assertEqual(moves, [("10", 8, ["10", "11"])])
+        self.assertEqual(kept, [])
+
+    def test_panel_on_a_screen_stays(self):
+        for screen in (0, 2, -1):
+            moves, kept = fp.plan(fp.parse(desktop(1, 0) + panel(2, screen, tray=8)), 3)
+            self.assertEqual((moves, kept), ([], []), screen)
+
+    def test_tray_is_not_a_panel(self):
+        found = fp.panels(fp.parse(panel(2, 0, tray=8)))
+        self.assertEqual(list(found), ["2"])
+        self.assertEqual(found["2"]["trays"], ["8"])
+
+    def test_desktops_never_move(self):
+        moves, _ = fp.plan(fp.parse(ISSUE_18), 1)
+        self.assertEqual([m[0] for m in moves], ["10"])
+
+    def test_edge_taken_on_first_screen(self):
+        text = panel(2, 0, tray=8) + panel(10, 8, tray=11)
+        moves, kept = fp.plan(fp.parse(text), 3)
+        self.assertEqual(moves, [])
+        self.assertEqual([k[:2] for k in kept], [("10", 8)])
+
+    def test_other_edge_is_free(self):
+        moves, kept = fp.plan(fp.parse(panel(2, 0) + panel(10, 4, location=3)), 3)
+        self.assertEqual(moves, [("10", 4, ["10"])])
+        self.assertEqual(kept, [])
+
+    def test_two_lost_on_one_edge(self):
+        moves, kept = fp.plan(fp.parse(panel(10, 5) + panel(12, 8)), 3)
+        self.assertEqual([m[0] for m in moves], ["10"])
+        self.assertEqual([k[0] for k in kept], ["12"])
+
+    def test_screen_count_went_down(self):
+        moves, _ = fp.plan(fp.parse(panel(2, 1, location=3)), 1)
+        self.assertEqual(moves, [("2", 1, ["2"])])
+
+
+class Run(unittest.TestCase):
+    def setUp(self):
+        self.dir = tempfile.TemporaryDirectory()
+        self.path = os.path.join(self.dir.name, "plasma-org.kde.plasma.desktop-appletsrc")
+        with open(self.path, "w") as f:
+            f.write(ISSUE_18)
+
+    def tearDown(self):
+        self.dir.cleanup()
+
+    def run_script(self, *args):
+        return subprocess.run([sys.executable, SCRIPT, "--file", self.path, "--screens", "3", *args],
+                              capture_output=True, text=True)
+
+    def test_check_reports_and_changes_nothing(self):
+        r = self.run_script("--check")
+        self.assertEqual(r.returncode, 1)
+        self.assertIn("panel 10: screen 8, bottom (lost", r.stdout)
+        with open(self.path) as f:
+            self.assertEqual(f.read(), ISSUE_18)
+
+    def test_repair(self):
+        r = self.run_script()
+        self.assertEqual(r.returncode, 0, r.stderr)
+        self.assertIn("moved it to the first screen", r.stderr)
+        with open(self.path) as f:
+            groups = fp.parse(f.read())
+        self.assertEqual(groups[("Containments", "10")]["lastScreen"], "0")
+        self.assertEqual(groups[("Containments", "11")]["lastScreen"], "0")
+        self.assertEqual(groups[("Containments", "10", "Applets", "101")]["plugin"], "org.kde.plasma.kickoff")
+        self.assertEqual(groups[("Containments", "25")]["lastScreen"], "8")  # a spare's desktop
+        with open(self.path + ".ft-bak") as f:
+            self.assertEqual(f.read(), ISSUE_18)
+        # A second run finds nothing to do and leaves the backup alone.
+        os.remove(self.path + ".ft-bak")
+        r = self.run_script()
+        self.assertEqual((r.returncode, r.stderr), (0, ""))
+        self.assertFalse(os.path.exists(self.path + ".ft-bak"))
+        self.assertEqual(self.run_script("--check").returncode, 0)
+
+    def test_no_config_yet(self):
+        os.remove(self.path)
+        self.assertEqual(self.run_script().returncode, 0)
+        self.assertEqual(self.run_script("--check").returncode, 0)
+
+
+if __name__ == "__main__":
+    unittest.main()

session/vnc-bridge.sh

@@ -11,6 +11,16 @@
 # screen placed lower or further right. Instead the VNC screen is the primary's size, and
 # the workspace-sized RDP window inside it is shifted so the primary fills it. The pointer
 # maps 1:1. When the layout changes, the VNC screen resizes and the RDP client reconnects.
+#
+# The RDP client runs only while someone watches. While connected, krdp captures and
+# H.264-encodes every redraw in software, about 60% of a core, with FreeRDP and Xvnc adding
+# about 30% more, even with no VNC viewer. krdp starts its capture per RDP connection and
+# stops it when the connection closes, so it idles without one. So FreeRDP starts when a
+# VNC client connects (the screen is black for the few seconds that takes) and stops
+# VNC_IDLE_SEC (45) seconds after the last one leaves. Xvnc has no hook for clients, so ss
+# counts them: whenever Xvnc writes to its log (it logs each connection), every second
+# while FreeRDP runs, and every 5 seconds otherwise. The log only wakes this script up;
+# what it says doesn't matter.
 set -eu
 
 here=$(dirname "$(readlink -f "$0")")
@@ -57,16 +67,51 @@ stop_rdp() { pkill -f "[x]freerdp /v:127.0.0.1:$rdp_port " 2>/dev/null || true;
 trap 'stop_rdp; pkill -f "[X]vnc $display " 2>/dev/null || true' EXIT
 
 box bash -c 'vncpasswd -f < "$1/vnc-password" > "$1/vnc-passwd.bin" && chmod 600 "$1/vnc-passwd.bin"' - "$creds"
-box Xvnc "$display" -geometry "${w}x${h}" -depth 24 \
+exec {xlog}< <(box Xvnc "$display" -geometry "${w}x${h}" -depth 24 \
   -interface "$addr" -rfbport "$vnc_port" \
   -SecurityTypes VncAuth -PasswordFile "$creds/vnc-passwd.bin" \
-  -AlwaysShared -desktop "Steam Frame (Frametop)" &
+  -AlwaysShared -desktop "Steam Frame (Frametop)" 2>&1)
 xvnc=$!
-sleep 2
 
-# Keep an RDP connection open inside the VNC screen. Reconnect if it drops or the layout changes.
+# Wait up to $1 seconds, less if Xvnc logs something; its lines go on to this log.
+nap() {
+  local line rc=0
+  IFS= read -rt "$1" -u "$xlog" line || rc=$?
+  if [ $rc -eq 0 ]; then
+    printf '%s\n' "$line"
+    while IFS= read -rt 0.1 -u "$xlog" line; do printf '%s\n' "$line"; done
+  elif [ $rc -le 128 ]; then
+    sleep 1  # Xvnc's output closed: it's exiting
+  fi
+  return 0
+}
+nap 2
+
+# A connected VNC client: an established TCP connection to Xvnc's port. Any connection
+# counts, authenticated or not; it's on the tailnet only.
+clients() { [ -n "$(ss -Htn state established "( sport = :$vnc_port )" 2>/dev/null)" ]; }
+
+# ft-screens drops screens you aren't looking at to a low frame rate, and krdp would
+# stream that. "watch SECONDS" asks it for full rate on every screen for that long: sent
+# when a client connects and renewed every few seconds while one stays, so it lapses by
+# itself if this script dies. An older ft-screens just answers that it doesn't know it.
+watch() {
+  if command -v socat >/dev/null; then
+    printf 'watch 15' | socat -u - ABSTRACT-SENDTO:ft_screens 2>/dev/null
+  else
+    python3 -c 'import socket; socket.socket(socket.AF_UNIX, socket.SOCK_DGRAM).sendto(b"watch 15", "\0ft_screens")' 2>/dev/null
+  fi || true
+}
+
+# What remote-view depends on: KWin's saved outputs (positions, scales, primary) and
+# Frametop's layout (screen sizes). It's read again only after one of these changes, and
+# once a minute in case a change didn't touch them, and only while FreeRDP runs.
+layout_files=("$HOME/.config/frametop/kwinoutputconfig.json" "$HOME/.config/frametop-layout.json")
+stamp() { stat -c %y "${layout_files[@]}" 2>/dev/null || true; }
+
+# Start FreeRDP inside the VNC screen, sized and shifted for $v.
 # /cert:ignore is fine here: the connection never leaves this host.
-while kill -0 $xvnc 2>/dev/null; do
+start_rdp() {
   read -r x y w h ww wh <<< "$v"
   box env DISPLAY=$display bash -c '
     size=$1 x=$2 y=$3 ww=$4 wh=$5 creds=$6 rdp_port=$7
@@ -80,6 +125,7 @@ while kill -0 $xvnc 2>/dev/null; do
     rdp=$!
     # FreeRDP takes no negative position, so move its window once it is up.
     for _ in $(seq 60); do
+      kill -0 $rdp 2>/dev/null || break
       win=$(xdotool search --class xfreerdp 2>/dev/null | tail -1)
       [ -n "$win" ] && break
       sleep 0.5
@@ -88,14 +134,58 @@ while kill -0 $xvnc 2>/dev/null; do
     wait $rdp
   ' vnc-rdp "${w}x$h" "$x" "$y" "$ww" "$wh" "$creds" "$rdp_port" || true &
   rdp=$!
-  while kill -0 $rdp 2>/dev/null; do
-    sleep 5
-    now=$(view) || continue
-    [ -n "$now" ] && [ "$now" != "$v" ] || continue
-    echo "layout changed: $v -> $now"
-    v=$now
-    stop_rdp
-  done
-  wait $rdp 2>/dev/null || true
-  sleep 2
+}
+
+idle_sec=${VNC_IDLE_SEC:-45}
+rdp=           # FreeRDP's job while it runs
+seen=0         # when a client was last seen ($SECONDS)
+watched=-99    # when "watch" was last sent
+stamp_v=       # stamp() when $v was read
+recheck=0      # read the layout every 2 seconds until then
+next_view=0    # next time to read it
+while kill -0 $xvnc 2>/dev/null; do
+  if clients; then
+    if [ $((SECONDS - watched)) -ge 5 ]; then watch; watched=$SECONDS; fi
+    seen=$SECONDS
+    if [ -z "$rdp" ]; then
+      echo "VNC client connected, starting the RDP client"
+      now=$(view) && [ -n "$now" ] && v=$now
+      stamp_v=$(stamp) recheck=0 next_view=$((SECONDS + 60))
+      start_rdp
+    fi
+  elif [ "$seen" -ne 0 ]; then
+    watched=-99
+    if [ $((SECONDS - seen)) -ge "$idle_sec" ]; then
+      seen=0
+      if [ -n "$rdp" ]; then
+        echo "no VNC client for ${idle_sec}s, stopping the RDP client"
+        stop_rdp
+        wait "$rdp" 2>/dev/null || true
+        rdp=
+      fi
+    fi
+  fi
+  if [ -n "$rdp" ] && ! kill -0 "$rdp" 2>/dev/null; then
+    # It dropped, or the layout changed: reconnect next round if a client is still there.
+    wait "$rdp" 2>/dev/null || true
+    rdp=
+    nap 2
+    continue
+  fi
+  if [ -n "$rdp" ]; then
+    # A layout change shows up in KWin's outputs a few seconds after the files change.
+    s=$(stamp)
+    [ "$s" = "$stamp_v" ] || { stamp_v=$s; recheck=$((SECONDS + 10)) next_view=$SECONDS; }
+    if [ "$SECONDS" -ge "$next_view" ]; then
+      next_view=$((SECONDS + 60))
+      [ "$SECONDS" -ge "$recheck" ] || next_view=$((SECONDS + 2))
+      now=$(view) || now=
+      if [ -n "$now" ] && [ "$now" != "$v" ]; then
+        echo "layout changed: $v -> $now"
+        v=$now
+        stop_rdp
+      fi
+    fi
+  fi
+  if [ -n "$rdp" ] || [ "$seen" -ne 0 ]; then nap 1; else nap 5; fi
 done