Windows client: support the Linux host

LinuxHost/README.md

@@ -1,6 +1,6 @@
 # iframe-linux-host
 
-Streams a Linux (X11) desktop to iFrame clients: the iPad app and the Linux client. It's a
+Streams a Linux (X11) desktop to iFrame clients: the iPad app, the Linux client and the Windows client. It's a
 **separate host** from the Mac's `iframe-host` (`Host/`, Swift). They share only the wire protocol,
 so either kind of client connects to either kind of host. The C protocol helpers (framing, JSON,
 key table) come from `Linux/src/`.
@@ -76,10 +76,11 @@ one decision is what ⌘ becomes:
 
 - **iPad (and any client that doesn't say otherwise): ⌘ → Ctrl**, so ⌘C copies, ⌘V pastes and
   ⌘T opens a tab, as a Mac user expects. ⌃ is also Ctrl, so Ctrl+C in a terminal still works.
-- **Linux client: ⌘ → Super.** The Linux client tells the host it's a Linux machine
-  (`"os":"linux"` in its hello), and the host tells the client it's Linux (`"os":"linux"` in its
-  welcome). The client then sends Ctrl, Alt and Super as themselves, so every key lands exactly
-  where it is on your keyboard.
+- **Linux and Windows clients: ⌘ → Super.** These clients say what they are (`"os":"linux"` or
+  `"os":"windows"` in their hello), and the host tells the client it's Linux (`"os":"linux"` in its
+  welcome). The client then sends Ctrl, Alt and Super (the Windows key) as themselves, so every
+  key lands exactly where it is on your keyboard. On Windows the Windows key reaches the host
+  only while the stream is fullscreen; otherwise Windows keeps it for the Start menu.
 
 `--cmd-key ctrl|super` overrides this. Text from the iPad's on-screen keyboard is typed as
 Unicode; characters with no key on the layout are typed through a temporarily remapped spare

LinuxHost/src/main.c

@@ -65,7 +65,7 @@ typedef struct Session {
     pthread_mutex_t send_lock;
     char name[192];
     bool authenticated;
-    bool linux_client;
+    bool pc_client;  // Linux or Windows: its Ctrl, Alt and Super keys map one-to-one
     Capture *cap;
     Encoder *enc;
     Streamer *streamer;
@@ -132,13 +132,13 @@ static bool start_stream(Session *s, bool supports_hevc, int max_fps, bool local
     capture_monitor_origin(s->cap, &ox, &oy);
     pthread_mutex_lock(&input_lock);
     input_set_region(input, ox, oy, w, h);
-    input_set_cmd(input, cfg.cmd != CMD_AUTO ? cfg.cmd : s->linux_client ? CMD_SUPER : CMD_CTRL);
+    input_set_cmd(input, cfg.cmd != CMD_AUTO ? cfg.cmd : s->pc_client ? CMD_SUPER : CMD_CTRL);
     input_keep_awake(input);
     pthread_mutex_unlock(&input_lock);
 
     char name[256], json[512];
     json_escape(host_name, name, sizeof name);
-    // "os" is an addition the iPad app ignores; the Linux client uses it to map keys 1:1.
+    // "os" is an addition the iPad app ignores; the Linux and Windows clients use it to map keys 1:1.
     int n = snprintf(json, sizeof json,
                      "{\"width\":%d,\"height\":%d,\"pointWidth\":%d,\"pointHeight\":%d,\"codec\":%d,\"fps\":%d,"
                      "\"hostName\":\"%s\",\"isVirtual\":false,\"os\":\"linux\"}",
@@ -156,7 +156,7 @@ static bool start_stream(Session *s, bool supports_hevc, int max_fps, bool local
     };
     s->streamer = streamer_start(s->cap, s->enc, sc, session_send, s);
     host_log("streaming %dx%d @ %d fps, %s, start %.0f Mbps, ⌘ → %s, cursor %s", w, h, fps, encoder_name(s->enc), mbps,
-             (cfg.cmd != CMD_AUTO ? cfg.cmd : s->linux_client ? CMD_SUPER : CMD_CTRL) == CMD_CTRL ? "Ctrl" : "Super",
+             (cfg.cmd != CMD_AUTO ? cfg.cmd : s->pc_client ? CMD_SUPER : CMD_CTRL) == CMD_CTRL ? "Ctrl" : "Super",
              local_cursor ? "drawn by the client" : "in the video");
     return true;
 }
@@ -175,7 +175,7 @@ static bool handle_hello(Session *s, const char *j, size_t len) {
     char peer[INET6_ADDRSTRLEN + 8];
     snprintf(peer, sizeof peer, "%.*s", (int)sizeof peer - 1, s->name);  // still just the address
     snprintf(s->name, sizeof s->name, "%s (%s)", name, peer);
-    s->linux_client = strcmp(os, "linux") == 0;
+    s->pc_client = strcmp(os, "linux") == 0 || strcmp(os, "windows") == 0;
 
     pthread_mutex_lock(&server_lock);
     bool ok = (int)version == IFRAME_PROTOCOL_VERSION && constant_time_equals(pin, cfg.pin);

Windows/README.md

@@ -1,17 +1,17 @@
 # iFrame for Windows
 
-A Windows 10/11 x64 client for the existing `iframe-host` on your Mac. The portable app includes its runtime; users do not need Node, Python, FFmpeg, or a separate codec installation.
+A Windows 10/11 x64 client for `iframe-host` on a Mac or `iframe-linux-host` on a Linux PC ([LinuxHost](../LinuxHost/README.md)). The portable app includes its runtime; users do not need Node, Python, FFmpeg, or a separate codec installation.
 
 ## Connect
 
-1. Start the Mac host using the instructions in the repository README. Grant its Screen Recording and Accessibility permissions.
+1. Start the host. On a Mac, follow the repository README and grant Screen Recording and Accessibility permissions; on Linux, see [LinuxHost](../LinuxHost/README.md).
 2. Open `iFrame-0.1.0-Windows-x64.exe` from `Windows/dist`.
-3. Choose a nearby Mac, or enter its IP address, Tailscale address, or hostname. The default TCP port is **7878**. Discovery uses mDNS on the local network; manual addresses also work when discovery is unavailable. Select **☆ Save** next to the port to keep an address under **Saved Macs**; select a saved Mac to fill in its address and port.
-4. Enter the host PIN, choose the display size/density, and click **Connect to Mac**.
+3. Choose a nearby computer (marked Mac or Linux), or enter its IP address, Tailscale address, or hostname. The default TCP port is **7878**. Discovery uses mDNS on the local network; manual addresses also work when discovery is unavailable. Select **☆ Save** next to the port to keep an address under **Saved computers**; select a saved computer to fill in its address and port.
+4. Enter the host PIN, choose the display size/density, and click **Connect**.
 
 The app remembers saved Macs, the last address and display settings, but never saves the PIN. Preferences are stored in Electron's per-user app data directory. Windows may ask to allow local network access for discovery. The distributed executable is unsigned.
 
-**Retina** requests a virtual Mac display at the selected pixel size with two pixels per Mac point. **Native** gives more desktop space. **Mirror** uses the Mac's existing display. Display size is chosen at connection time; resizing the app scales the picture without restarting the Mac display. Reconnect to change resolution or density.
+**Retina** requests a virtual Mac display at the selected pixel size with two pixels per Mac point. **Native** gives more desktop space. **Mirror** uses the Mac's existing display. Display size is chosen at connection time; resizing the app scales the picture without restarting the Mac display. Reconnect to change resolution or density. A Linux host streams its monitor as it is, so these settings apply only to Macs.
 
 ## Controls
 
@@ -23,13 +23,14 @@ The app remembers saved Macs, the last address and display settings, but never s
 | Alt | Mac Option |
 | Windows key, fullscreen | Mac Command; the Start menu and Windows+ shortcuts are captured while the stream is fullscreen and focused |
 | Windows key, windowed (default mapping) | Mac Control, when Windows does not intercept it |
+| Linux host | Keys map one-to-one: Ctrl → Ctrl, Alt → Alt, Windows key → Super (fullscreen), so Super opens the desktop's menu; the Ctrl/Command option is ignored |
 | Ctrl+Alt+F | Toggle fullscreen |
 | Ctrl+Alt+R | Release keyboard focus to the toolbar |
 | Ctrl+Alt+Q | Disconnect |
 | Send text | Send pasted or typed Unicode text to the focused Mac field |
 | Refresh | Request a new keyframe |
 
-Disable **Use Ctrl for Mac Command shortcuts** for literal Ctrl → Control and Windows → Command mapping. Windows reserves shortcuts such as Alt+Tab, Windows+L, and Ctrl+Alt+Delete; these stay local. Held keys and mouse buttons are released when focus leaves the desktop. The host also releases input when the connection ends.
+Disable **On a Mac, use Ctrl for Command shortcuts** for literal Ctrl → Control and Windows → Command mapping. Windows reserves shortcuts such as Alt+Tab, Windows+L, and Ctrl+Alt+Delete; these stay local. Held keys and mouse buttons are released when focus leaves the desktop. The host also releases input when the connection ends.
 
 ## Build and test
 

Windows/src/main.cjs

@@ -41,16 +41,16 @@ listen('ack', (id, micros) => session.ack(id, micros));
 listen('keyframe', () => session.keyframe());
 function startDiscovery() {
   try {
-    discovery = new Bonjour({}, () => emit('discovery-warning', 'Discovery is unavailable. Enter the Mac address below.'));
+    discovery = new Bonjour({}, () => emit('discovery-warning', 'Discovery is unavailable. Enter the host address below.'));
     browser = discovery.find({ type: 'iframe', protocol: 'tcp' });
     browser.on('up', service => {
       const host = service.addresses?.find(a => /^\d+\.\d+\.\d+\.\d+$/.test(a)) ?? service.host;
       if (!host) return;
-      hosts.set(service.fqdn, { id: service.fqdn, name: service.name, host, port: service.port });
+      hosts.set(service.fqdn, { id: service.fqdn, name: service.name, host, port: service.port, os: service.txt?.os === 'linux' ? 'linux' : 'mac' });
       emit('hosts', [...hosts.values()]);
     });
     browser.on('down', service => { hosts.delete(service.fqdn); emit('hosts', [...hosts.values()]); });
-  } catch { emit('discovery-warning', 'Discovery is unavailable. Enter the Mac address below.'); }
+  } catch { emit('discovery-warning', 'Discovery is unavailable. Enter the host address below.'); }
 }
 app.whenReady().then(async () => {
   window = new BrowserWindow({ width: 1180, height: 820, minWidth: 760, minHeight: 620, show: !smoke,

Windows/src/protocol.cjs

@@ -66,7 +66,7 @@ function inputPacket(input) {
 
 function validateOptions(o) {
   if (!o || typeof o.host !== 'string' || !o.host.trim() || o.host.length > 253 || /[\s/\\]/.test(o.host.trim()))
-    throw new Error('Enter a Mac IP address or hostname, without a URL prefix.');
+    throw new Error('Enter the host IP address or hostname, without a URL prefix.');
   if (!Number.isInteger(o.port) || o.port < 1 || o.port > 65535) throw new Error('Port must be between 1 and 65535.');
   if (typeof o.pin !== 'string' || o.pin.length > 256) throw new Error('Invalid PIN.');
   if (![30, 60, 120].includes(o.fps) || ![0, 1, 1.5, 2].includes(o.scale)) throw new Error('Invalid stream settings.');

Windows/src/session.cjs

@@ -14,7 +14,7 @@ class Session extends EventEmitter {
     const fail = message => { if (this.socket !== socket) return; this.close(); this.emit('state', { phase: 'failed', message }); };
     const parser = new Parser((type, data) => {
       if (this.socket !== socket) return;
-      if (type === T.authFailed) return fail('Wrong PIN or incompatible host protocol. Check the PIN on your Mac.');
+      if (type === T.authFailed) return fail('Wrong PIN or incompatible host protocol. Check the PIN on the host.');
       if (type === T.welcome) {
         const w = JSON.parse(data.toString());
         if (w.codec !== 0) return fail('The host is forcing HEVC. Restart it with H.264 or automatic codec selection.');
@@ -41,12 +41,12 @@ class Session extends EventEmitter {
       }
     });
     socket.setNoDelay(true); socket.setKeepAlive(true, 5000); socket.setTimeout(15000);
-    socket.on('timeout', () => fail('The Mac stopped responding. Check the network and reconnect.'));
+    socket.on('timeout', () => fail('The host stopped responding. Check the network and reconnect.'));
     socket.on('data', chunk => { try { parser.push(chunk); } catch (e) { fail(`Stream error: ${e.message}`); } });
     socket.on('error', e => fail(`Cannot connect to ${o.host}:${o.port} (${e.code ?? e.message}).`));
-    socket.on('close', () => fail('The Mac closed the connection. Check its screen recording permission and host log.'));
+    socket.on('close', () => fail('The host closed the connection. Check the host log (on a Mac, also its screen recording permission).'));
     socket.on('connect', () => {
-      this.send(T.hello, Buffer.from(JSON.stringify({ version: 1, pin: o.pin, name: os.hostname(), supportsHEVC: false,
+      this.send(T.hello, Buffer.from(JSON.stringify({ version: 1, pin: o.pin, name: os.hostname(), os: 'windows', supportsHEVC: false,
         // localCursor: the Mac sends its cursor shape and leaves the pointer out of the video.
         localCursor: true, maxFPS: o.fps, display: { width: o.width, height: o.height, uiScale: o.scale } })));
       this.timer = setInterval(() => {

Windows/ui/app.mjs

@@ -9,6 +9,7 @@ try {
   for (const id of settings) if (saved[id] !== undefined) $(id).value = saved[id];
   $('swap').checked = saved.swap !== false;
 } catch { /* Ignore an unreadable preference file. The PIN is never persisted. */ }
+const linuxHost = () => welcome?.os === 'linux';
 const status = message => { $('status').textContent = message; };
 function saveSettings() {
   try { localStorage.setItem('iframe-settings', JSON.stringify(Object.fromEntries([...settings.map(id => [id, $(id).value]), ['swap', $('swap').checked]]))); } catch {}
@@ -19,7 +20,8 @@ const video = new Video($('video'), api, fail, ms => { frames++; decodeTotal +=
 const macCursor = new MacCursor($('video'));
 window.addEventListener('resize', () => macCursor.apply());
 const releaseInput = attachInput($('video'), api, {
-  active: () => active, swap: () => $('swap').checked,
+  // A Linux host maps keys one-to-one (Ctrl → Ctrl, Windows → Super); the Ctrl/Command swap is for Macs.
+  active: () => active, swap: () => $('swap').checked && !linuxHost(),
   shortcut: code => { if (code === 'KeyF') toggleFullscreen(); else if (code === 'KeyQ') disconnect(); else $('fullscreen').focus(); }
 });
 function disconnect() { releaseInput(); return api.disconnect(); }
@@ -62,13 +64,13 @@ api.onState(state => {
     $('waiting').textContent = 'Waiting for the first frame…';
     $('host-name').textContent = welcome.hostName;
     $('stream-info').textContent = `${welcome.width} × ${welcome.height} · H.264 · ${welcome.fps} fps`;
-    $('keyboard-mode').textContent = $('swap').checked ? 'Ctrl → ⌘ Command' : 'Windows → ⌘ Command';
+    $('keyboard-mode').textContent = linuxHost() ? 'Ctrl → Ctrl · Windows → Super' : $('swap').checked ? 'Ctrl → ⌘ Command' : 'Windows → ⌘ Command';
     $('pin').value = ''; $('video').focus(); macCursor.setWelcome(welcome);
   } else if (!connecting) {
     releaseInput(); active = false; video.close(); macCursor.reset(); welcome = null; frames = 0; decodeTotal = 0; hostStats = {}; rtt = 0;
     $('text-dialog').close('cancel'); $('connect-page').hidden = false; $('stream-page').hidden = true;
     status(state.phase === 'failed' ? state.message : ''); $('connect').focus();
-  } else status('Connecting to your Mac…');
+  } else status('Connecting…');
 });
 api.onMessage(({type, data}) => {
   try {
@@ -86,8 +88,8 @@ api.onRtt(value => { rtt = value; });
 let knownHosts = [];
 function showHosts(hosts) {
   knownHosts = hosts; const selected = $('discovered').value;
-  $('discovered').replaceChildren(new Option(hosts.length ? 'Choose a Mac…' : 'No Macs found yet · enter an address below', ''));
-  for (const host of hosts) $('discovered').add(new Option(`${host.name} · ${host.host}`, host.id));
+  $('discovered').replaceChildren(new Option(hosts.length ? 'Choose a computer…' : 'No computers found yet · enter an address below', ''));
+  for (const host of hosts) $('discovered').add(new Option(`${host.name} · ${host.os === 'linux' ? 'Linux' : 'Mac'} · ${host.host}`, host.id));
   $('discovered').value = selected;
 }
 api.onHosts(showHosts); api.hosts().then(showHosts);
@@ -122,7 +124,7 @@ function updateBookmarkButton() {
   $('bookmark').disabled = !a.host || !Number.isInteger(a.port) || a.port < 1 || a.port > 65535;
   $('bookmark').textContent = saved ? '★ Saved' : '☆ Save';
   $('bookmark').setAttribute('aria-pressed', String(saved));
-  $('bookmark').title = saved ? 'Remove this Mac from saved Macs' : 'Save this address';
+  $('bookmark').title = saved ? 'Remove from saved computers' : 'Save this address';
 }
 $('bookmark').onclick = () => {
   const a = address(), i = bookmarkIndex(a);
@@ -135,7 +137,7 @@ showBookmarks();
 setInterval(() => {
   if (active) {
     const n = v => Number.isFinite(v) ? v.toFixed(1) : '—';
-    $('stats').textContent = `${welcome?.isVirtual ? 'Virtual display' : 'Mac display'} · H.264\nReceived    ${frames} fps\nDecode      ${n(frames ? decodeTotal/frames : 0)} ms\nRound trip  ${n(rtt)} ms\nBitrate     ${n(hostStats.mbps)} Mbps\nHost encode ${n(hostStats.encodeMs)} ms\nHost drops  ${hostStats.dropped ?? '—'}`;
+    $('stats').textContent = `${welcome?.isVirtual ? 'Virtual display' : linuxHost() ? 'Linux display' : 'Mac display'} · H.264\nReceived    ${frames} fps\nDecode      ${n(frames ? decodeTotal/frames : 0)} ms\nRound trip  ${n(rtt)} ms\nBitrate     ${n(hostStats.mbps)} Mbps\nHost encode ${n(hostStats.encodeMs)} ms\nHost drops  ${hostStats.dropped ?? '—'}`;
   }
   frames = 0; decodeTotal = 0;
 }, 1000);