[feat] remember remote display resolutions across connections

apps/desktop/src/gui/features/devices/session_device_manager.cpp

@@ -253,6 +253,8 @@ int SessionDeviceManager::InitializeScreenCapturer() {
         uint64_t send_errors = 0;
         for (const std::string &remote_id : connected_remote_ids) {
           if (owner_.managed_host_frontend_ && remote_id.rfind("lan/", 0) != 0) continue;
+          // Warm/shared capture may already be running for another controller.
+          if (!owner_.DisplayResolutionsReadyForCapture(remote_id)) continue;
           if (!owner_.preview_subscriptions_.ShouldSend(remote_id, now_time,
                                                         stream_id)) continue;
           if (owner_.WithController(
@@ -693,6 +695,9 @@ void SessionDeviceManager::PushAudio(const std::string& remote_id,
 }
 
 void SessionDeviceManager::UpdateInteractions() {
+  // Restore the previous session's modes and apply the new controller's saved
+  // selections before starting capture or allowing an early input return.
+  owner_.HandleDisplayResolutionChanges();
   // Release even when pending remote-input cleanup makes this tick return early.
   UpdateScreenSharingPower();
 #ifdef _WIN32
@@ -720,7 +725,8 @@ void SessionDeviceManager::UpdateInteractions() {
 
   if (owner_.start_screen_capturer_ && !owner_.screen_capturer_is_started_) {
     const auto now = std::chrono::steady_clock::now();
-    if (now >= next_capture_start_retry_) {
+    if (now >= next_capture_start_retry_ &&
+        owner_.DisplayResolutionsReadyForCapture()) {
       next_capture_start_retry_ = now + std::chrono::seconds(1);
       if (StartScreenCapturer() == 0) {
         owner_.screen_capturer_is_started_ = true;
@@ -799,7 +805,6 @@ void SessionDeviceManager::UpdateInteractions() {
   }
 
   owner_.keyboard_.CheckRemoteTimeouts();
-  owner_.HandleDisplayResolutionChanges();
 }
 
 void SessionDeviceManager::DrainCapturedKeyboardInput() {

apps/desktop/src/gui/features/settings/remote_resolution_store.cpp

@@ -0,0 +1,77 @@
+#include "remote_resolution_store.h"
+
+#include <fstream>
+
+#include <display_resolution_preferences.h>
+
+#include "common/private_file.h"
+
+namespace crossdesk {
+namespace {
+constexpr std::uintmax_t kMaxStoreBytes = 8 * 1024 * 1024;
+}
+
+bool RemoteResolutionStore::Load(const std::filesystem::path &path) {
+  std::lock_guard lock(mutex_);
+  path_ = path;
+  devices_.clear();
+  try {
+    if (!std::filesystem::exists(path_)) return true;
+    if (std::filesystem::file_size(path_) > kMaxStoreBytes) return false;
+    std::ifstream input(path_, std::ios::binary);
+    const auto json = nlohmann::json::parse(input);
+    if (json.at("version") != 1 || !json.at("devices").is_object())
+      return false;
+    for (const auto &[device, values] : json.at("devices").items()) {
+      std::vector<DisplayResolutionPreference> preferences;
+      if (!device.empty() && ReadDisplayResolutionPreferences(values, preferences))
+        devices_.emplace(device, std::move(preferences));
+    }
+    return true;
+  } catch (const std::exception &) {
+    return false;
+  }
+}
+
+std::vector<DisplayResolutionPreference>
+RemoteResolutionStore::Get(const std::string &device) const {
+  std::lock_guard lock(mutex_);
+  const auto found = devices_.find(device);
+  return found == devices_.end() ? std::vector<DisplayResolutionPreference>{}
+                                : found->second;
+}
+
+bool RemoteResolutionStore::Remember(
+    const std::string &device, const DisplayResolutionPreference &preference) {
+  if (device.empty() || !ValidDisplayResolutionPreference(preference))
+    return false;
+  std::lock_guard lock(mutex_);
+  if (path_.empty()) return false;
+  auto updated = devices_;
+  auto &preferences = updated[device];
+  const auto found = std::find_if(preferences.begin(), preferences.end(),
+      [&](const auto &saved) { return saved.display_key == preference.display_key; });
+  if (found != preferences.end()) {
+    if (found->resolution == preference.resolution) return true;
+    *found = preference;
+  } else {
+    if (preferences.size() >= kMaxResolutionDisplays)
+      preferences.erase(preferences.begin());
+    preferences.push_back(preference);
+  }
+  try {
+    nlohmann::json json{{"version", 1}, {"devices", nlohmann::json::object()}};
+    for (const auto &[id, saved] : updated)
+      json["devices"][id] = DisplayResolutionPreferencesJson(saved);
+    const auto text = json.dump(2);
+    if (text.size() > kMaxStoreBytes) return false;
+    private_file::EnsureDirectory(path_.parent_path());
+    private_file::Write(path_, text);
+    devices_ = std::move(updated);
+    return true;
+  } catch (const std::exception &) {
+    return false;
+  }
+}
+
+} // namespace crossdesk

apps/desktop/src/gui/features/settings/remote_resolution_store.h

@@ -0,0 +1,33 @@
+/*
+ * @Author: DI JUNKUN
+ * @Date: 2026-11-11
+ * Copyright (c) 2026 by DI JUNKUN, All Rights Reserved.
+ */
+
+#ifndef _REMOTE_RESOLUTION_STORE_H_
+#define _REMOTE_RESOLUTION_STORE_H_
+
+#include <filesystem>
+#include <map>
+#include <mutex>
+
+#include <display_resolution.h>
+
+namespace crossdesk {
+
+class RemoteResolutionStore {
+public:
+  bool Load(const std::filesystem::path &path);
+  std::vector<DisplayResolutionPreference> Get(const std::string &device) const;
+  bool Remember(const std::string &device,
+                const DisplayResolutionPreference &preference);
+
+private:
+  mutable std::mutex mutex_;
+  std::filesystem::path path_;
+  std::map<std::string, std::vector<DisplayResolutionPreference>> devices_;
+};
+
+} // namespace crossdesk
+
+#endif