0.6.8

小黑板数据持久化。

LanMountainDesktop.Tests/WhiteboardNotePersistenceServiceTests.cs

@@ -0,0 +1,157 @@
+using System;
+using System.IO;
+using LanMountainDesktop.Models;
+using LanMountainDesktop.Services;
+using Xunit;
+
+namespace LanMountainDesktop.Tests;
+
+public sealed class WhiteboardNotePersistenceServiceTests
+{
+    [Fact]
+    public void SaveNote_ThenLoadNote_RoundTripsSnapshot()
+    {
+        using var sandbox = new WhiteboardNotePersistenceSandbox();
+        var service = sandbox.CreateService();
+        var snapshot = CreateSampleSnapshot();
+
+        service.SaveNote("DesktopWhiteboard", "whiteboard-1", snapshot, retentionDays: 15);
+
+        var loaded = service.LoadNote("DesktopWhiteboard", "whiteboard-1", retentionDays: 15);
+
+        Assert.Single(loaded.Strokes);
+        Assert.Equal(2, loaded.Strokes[0].Points.Count);
+        Assert.Equal("#FF112233", loaded.Strokes[0].Color);
+        Assert.True(loaded.SavedUtc > DateTimeOffset.MinValue);
+    }
+
+    [Fact]
+    public void LoadNote_RemovesExpiredSnapshot_WhenRetentionExceeded()
+    {
+        using var sandbox = new WhiteboardNotePersistenceSandbox();
+        var service = sandbox.CreateService();
+
+        service.SaveNote("DesktopWhiteboard", "expired-board", CreateSampleSnapshot(), retentionDays: 7);
+        sandbox.OverrideSavedTimestamp("DesktopWhiteboard", "expired-board", DateTimeOffset.UtcNow.AddDays(-10), retentionDays: 7);
+
+        var loaded = service.LoadNote("DesktopWhiteboard", "expired-board", retentionDays: 7);
+
+        Assert.Empty(loaded.Strokes);
+        Assert.False(sandbox.Exists("DesktopWhiteboard", "expired-board"));
+    }
+
+    [Fact]
+    public void DeleteExpiredNotesBatch_RemovesExpiredRows_AndKeepsFreshRows()
+    {
+        using var sandbox = new WhiteboardNotePersistenceSandbox();
+        var service = sandbox.CreateService();
+
+        service.SaveNote("DesktopWhiteboard", "expired-a", CreateSampleSnapshot(), retentionDays: 7);
+        service.SaveNote("DesktopWhiteboard", "expired-b", CreateSampleSnapshot(), retentionDays: 7);
+        service.SaveNote("DesktopWhiteboard", "fresh-c", CreateSampleSnapshot(), retentionDays: 15);
+
+        sandbox.OverrideSavedTimestamp("DesktopWhiteboard", "expired-a", DateTimeOffset.UtcNow.AddDays(-9), retentionDays: 7);
+        sandbox.OverrideSavedTimestamp("DesktopWhiteboard", "expired-b", DateTimeOffset.UtcNow.AddDays(-8), retentionDays: 7);
+        sandbox.OverrideSavedTimestamp("DesktopWhiteboard", "fresh-c", DateTimeOffset.UtcNow.AddDays(-2), retentionDays: 15);
+
+        var deletedCount = service.DeleteExpiredNotesBatch(batchSize: 10);
+
+        Assert.Equal(2, deletedCount);
+        Assert.False(sandbox.Exists("DesktopWhiteboard", "expired-a"));
+        Assert.False(sandbox.Exists("DesktopWhiteboard", "expired-b"));
+        Assert.True(sandbox.Exists("DesktopWhiteboard", "fresh-c"));
+    }
+
+    private static WhiteboardNoteSnapshot CreateSampleSnapshot()
+    {
+        return new WhiteboardNoteSnapshot
+        {
+            Strokes =
+            [
+                new WhiteboardStrokeSnapshot
+                {
+                    Color = "#FF112233",
+                    InkThickness = 3.5d,
+                    IgnorePressure = true,
+                    Points =
+                    [
+                        new WhiteboardStylusPointSnapshot { X = 12, Y = 34, Pressure = 0.4d, Width = 2, Height = 2 },
+                        new WhiteboardStylusPointSnapshot { X = 48, Y = 64, Pressure = 0.7d, Width = 2, Height = 2 }
+                    ]
+                }
+            ]
+        };
+    }
+
+    private sealed class WhiteboardNotePersistenceSandbox : IDisposable
+    {
+        private readonly string _directoryPath = Path.Combine(
+            Path.GetTempPath(),
+            "LanMountainDesktop.WhiteboardNoteTests",
+            Guid.NewGuid().ToString("N"));
+
+        private readonly string _databasePath;
+
+        public WhiteboardNotePersistenceSandbox()
+        {
+            Directory.CreateDirectory(_directoryPath);
+            _databasePath = Path.Combine(_directoryPath, "whiteboard-tests.db");
+        }
+
+        public WhiteboardNotePersistenceService CreateService()
+        {
+            return new WhiteboardNotePersistenceService(new AppDatabaseService(_databasePath));
+        }
+
+        public void OverrideSavedTimestamp(string componentId, string placementId, DateTimeOffset savedUtc, int retentionDays)
+        {
+            var expiresUtc = savedUtc.AddDays(WhiteboardNoteRetentionPolicy.NormalizeDays(retentionDays));
+            using var connection = new AppDatabaseService(_databasePath).OpenConnection();
+            using var command = connection.CreateCommand();
+            command.CommandText = """
+                UPDATE whiteboard_notes
+                SET saved_at_utc_ms = $savedAtUtcMs,
+                    expires_at_utc_ms = $expiresAtUtcMs,
+                    updated_at_utc_ms = $updatedAtUtcMs
+                WHERE component_id = $componentId
+                  AND placement_id = $placementId;
+                """;
+            command.Parameters.AddWithValue("$savedAtUtcMs", savedUtc.ToUnixTimeMilliseconds());
+            command.Parameters.AddWithValue("$expiresAtUtcMs", expiresUtc.ToUnixTimeMilliseconds());
+            command.Parameters.AddWithValue("$updatedAtUtcMs", DateTimeOffset.UtcNow.ToUnixTimeMilliseconds());
+            command.Parameters.AddWithValue("$componentId", componentId);
+            command.Parameters.AddWithValue("$placementId", placementId);
+            command.ExecuteNonQuery();
+        }
+
+        public bool Exists(string componentId, string placementId)
+        {
+            using var connection = new AppDatabaseService(_databasePath).OpenConnection();
+            using var command = connection.CreateCommand();
+            command.CommandText = """
+                SELECT COUNT(1)
+                FROM whiteboard_notes
+                WHERE component_id = $componentId
+                  AND placement_id = $placementId;
+                """;
+            command.Parameters.AddWithValue("$componentId", componentId);
+            command.Parameters.AddWithValue("$placementId", placementId);
+            return Convert.ToInt32(command.ExecuteScalar()) > 0;
+        }
+
+        public void Dispose()
+        {
+            try
+            {
+                if (Directory.Exists(_directoryPath))
+                {
+                    Directory.Delete(_directoryPath, true);
+                }
+            }
+            catch
+            {
+                // Temporary test directories are best-effort cleanup.
+            }
+        }
+    }
+}

LanMountainDesktop/Localization/en-US.json

@@ -410,6 +410,7 @@
     "common.monet":  "Monet",
     "desktop.page_index_format":  "Desktop {0}",
     "launcher.title":  "App Launcher",
+    "launcher.folder": "Folder",
     "launcher.subtitle":  "Apps and folders from Windows Start Menu",
     "launcher.subtitle_linux":  "Installed apps discovered from Linux desktop entries",
     "launcher.empty":  "No Start Menu entries found.",
@@ -595,6 +596,18 @@
     "component.blackboard_landscape":  "Blackboard (Landscape)",
     "component.browser":  "Browser",
     "component.office_recent_documents":  "Recent Documents",
+    "whiteboard.settings.desc": "Each blackboard keeps its own note history and saves it independently.",
+    "whiteboard.settings.retention.title": "Note retention",
+    "whiteboard.settings.retention.desc": "Choose how long this blackboard should keep saved notes before expired data is removed automatically.",
+    "whiteboard.settings.retention.option": "{0} days",
+    "whiteboard.settings.instance_scope": "This retention setting is stored per blackboard component instance.",
+    "office_recent_documents.settings.desc":  "Choose which Windows and Office sources this widget should scan for recent documents.",
+    "office_recent_documents.settings.sources_title":  "Recent document sources",
+    "office_recent_documents.settings.sources_desc":  "You can combine multiple sources. Registry selection also keeps the Office interop MRU fallback available.",
+    "office_recent_documents.settings.source.registry":  "Office registry MRU",
+    "office_recent_documents.settings.source.recent_folders":  "Windows Recent folders",
+    "office_recent_documents.settings.source.jump_lists":  "Windows Jump Lists",
+    "office_recent_documents.settings.hint":  "If you disable all sources, this widget will stay empty until at least one source is enabled again.",
     "component.removable_storage":  "Removable Storage",
     "component.holiday_calendar":  "Holiday Calendar",
     "component.study_environment":  "Environment",

LanMountainDesktop/Localization/zh-CN.json

@@ -408,6 +408,7 @@
     "common.monet":  "莫奈",
     "desktop.page_index_format":  "桌面 {0}",
     "launcher.title":  "应用启动台",
+    "launcher.folder": "文件夹",
     "launcher.subtitle":  "按 Windows 开始菜单结构显示所有应用与文件夹",
     "launcher.subtitle_linux":  "显示从 Linux .desktop 条目扫描到的已安装应用",
     "launcher.empty":  "未找到开始菜单条目。",
@@ -593,6 +594,18 @@
     "component.blackboard_landscape":  "横向小黑板",
     "component.browser":  "浏览器",
     "component.office_recent_documents":  "最近文档",
+    "whiteboard.settings.desc": "每个小黑板都会独立保存自己的笔记历史。",
+    "whiteboard.settings.retention.title": "笔记保留时间",
+    "whiteboard.settings.retention.desc": "选择这个小黑板在过期笔记被自动删除前，应当保留已保存笔记多久。",
+    "whiteboard.settings.retention.option": "{0} 天",
+    "whiteboard.settings.instance_scope": "这个保留时间设置会按每个小黑板组件实例单独存储。",
+    "office_recent_documents.settings.desc":  "选择此小组件需要扫描的 Windows 和 Office 最近文档来源。",
+    "office_recent_documents.settings.sources_title":  "最近文档来源",
+    "office_recent_documents.settings.sources_desc":  "可以同时选择多个来源。勾选注册表来源时，还会保留 Office interop 的 MRU 回退。",
+    "office_recent_documents.settings.source.registry":  "Office 注册表 MRU",
+    "office_recent_documents.settings.source.recent_folders":  "Windows 最近文件夹",
+    "office_recent_documents.settings.source.jump_lists":  "Windows 跳转列表",
+    "office_recent_documents.settings.hint":  "如果关闭全部来源，此小组件会保持空白，直到再次至少启用一个来源。",
     "component.holiday_calendar":  "节假日日历",
     "component.study_environment":  "环境",
     "component.study_session_control":  "自习时段控制",

LanMountainDesktop/Models/ComponentSettingsSnapshot.cs

@@ -58,12 +58,15 @@ public sealed class ComponentSettingsSnapshot
 
     public int WeatherAutoRefreshIntervalMinutes { get; set; } = 12;
 
+    public int WhiteboardNoteRetentionDays { get; set; } = 15;
+
     public bool Stcn24ForumAutoRefreshEnabled { get; set; } = true;
 
     public int Stcn24ForumAutoRefreshIntervalMinutes { get; set; } = 20;
 
     public string Stcn24ForumSourceType { get; set; } = Stcn24ForumSourceTypes.LatestCreated;
 
+    public List<string>? OfficeRecentDocumentsEnabledSources { get; set; }
 
     public ComponentSettingsSnapshot Clone()
     {

LanMountainDesktop/Models/WhiteboardNoteRetentionPolicy.cs

@@ -0,0 +1,23 @@
+namespace LanMountainDesktop.Models;
+
+public static class WhiteboardNoteRetentionPolicy
+{
+    public const int MinimumDays = 7;
+    public const int MaximumDays = 15;
+    public const int DefaultDays = MaximumDays;
+
+    public static int NormalizeDays(int days)
+    {
+        if (days < MinimumDays)
+        {
+            return MinimumDays;
+        }
+
+        if (days > MaximumDays)
+        {
+            return MaximumDays;
+        }
+
+        return days;
+    }
+}

LanMountainDesktop/Models/WhiteboardNoteSnapshot.cs

@@ -0,0 +1,60 @@
+using System;
+using System.Collections.Generic;
+
+namespace LanMountainDesktop.Models;
+
+public sealed class WhiteboardNoteSnapshot
+{
+    public int Version { get; set; } = 1;
+
+    public DateTimeOffset SavedUtc { get; set; }
+
+    public List<WhiteboardStrokeSnapshot> Strokes { get; set; } = [];
+
+    public WhiteboardNoteSnapshot Clone()
+    {
+        var clone = (WhiteboardNoteSnapshot)MemberwiseClone();
+        clone.Strokes = Strokes is { Count: > 0 }
+            ? new List<WhiteboardStrokeSnapshot>(Strokes.ConvertAll(stroke => stroke?.Clone() ?? new WhiteboardStrokeSnapshot()))
+            : [];
+        return clone;
+    }
+}
+
+public sealed class WhiteboardStrokeSnapshot
+{
+    public string Color { get; set; } = "#FF000000";
+
+    public double InkThickness { get; set; } = 2.5d;
+
+    public bool IgnorePressure { get; set; } = true;
+
+    public List<WhiteboardStylusPointSnapshot> Points { get; set; } = [];
+
+    public WhiteboardStrokeSnapshot Clone()
+    {
+        var clone = (WhiteboardStrokeSnapshot)MemberwiseClone();
+        clone.Points = Points is { Count: > 0 }
+            ? new List<WhiteboardStylusPointSnapshot>(Points.ConvertAll(point => point?.Clone() ?? new WhiteboardStylusPointSnapshot()))
+            : [];
+        return clone;
+    }
+}
+
+public sealed class WhiteboardStylusPointSnapshot
+{
+    public double X { get; set; }
+
+    public double Y { get; set; }
+
+    public double Pressure { get; set; } = 0.5d;
+
+    public double Width { get; set; }
+
+    public double Height { get; set; }
+
+    public WhiteboardStylusPointSnapshot Clone()
+    {
+        return (WhiteboardStylusPointSnapshot)MemberwiseClone();
+    }
+}

LanMountainDesktop/Program.cs

@@ -43,6 +43,7 @@ sealed class Program
 
         var diagnostics = StartupDiagnosticsService.Run(args);
         StartupDiagnosticsService.ShowLegacyExecutableWarningIfNeeded(diagnostics);
+        ScheduleWhiteboardNoteStartupCleanup();
 
         try
         {
@@ -88,6 +89,25 @@ sealed class Program
         return builder;
     }
 
+    private static void ScheduleWhiteboardNoteStartupCleanup()
+    {
+        _ = Task.Run(() =>
+        {
+            try
+            {
+                var deletedCount = new WhiteboardNotePersistenceService().DeleteExpiredNotesBatch(batchSize: 512);
+                if (deletedCount > 0)
+                {
+                    AppLogger.Info("Startup", $"Deleted {deletedCount} expired whiteboard notes during startup maintenance.");
+                }
+            }
+            catch (Exception ex)
+            {
+                AppLogger.Warn("Startup", "Failed to run whiteboard note startup maintenance.", ex);
+            }
+        });
+    }
+
     private static SingleInstanceService AcquireSingleInstance(int? restartParentProcessId)
     {
         var singleInstance = SingleInstanceService.CreateDefault();

LanMountainDesktop/Services/AppDatabaseService.cs

@@ -29,6 +29,16 @@ public sealed class AppDatabaseService
         _databasePath = Path.Combine(dataDirectory, "app.db");
     }
 
+    public AppDatabaseService(string databasePath)
+    {
+        if (string.IsNullOrWhiteSpace(databasePath))
+        {
+            throw new ArgumentException("Database path cannot be null or whitespace.", nameof(databasePath));
+        }
+
+        _databasePath = databasePath;
+    }
+
     public SqliteConnection OpenConnection()
     {
         var directory = Path.GetDirectoryName(_databasePath);

LanMountainDesktop/Services/ComponentSettingsService.cs

@@ -106,6 +106,8 @@ public sealed class ComponentSettingsService : IComponentInstanceSettingsStore
 
     public void DeleteForComponent(string componentId, string? placementId)
     {
+        _ = new WhiteboardNotePersistenceService().DeleteNote(componentId, placementId);
+
         if (_settingsService is not null)
         {
             _settingsService.SaveSnapshot(

LanMountainDesktop/Services/DesktopComponentEditorRegistryFactory.cs

@@ -75,6 +75,12 @@ public static class DesktopComponentEditorRegistryFactory
             [BuiltInComponentIds.DesktopRemovableStorage] = new(
                 BuiltInComponentIds.DesktopRemovableStorage,
                 context => new RemovableStorageComponentEditor(context)),
+            [BuiltInComponentIds.DesktopWhiteboard] = new(
+                BuiltInComponentIds.DesktopWhiteboard,
+                context => new WhiteboardComponentEditor(context)),
+            [BuiltInComponentIds.DesktopBlackboardLandscape] = new(
+                BuiltInComponentIds.DesktopBlackboardLandscape,
+                context => new WhiteboardComponentEditor(context)),
             [BuiltInComponentIds.DesktopOfficeRecentDocuments] = new(
                 BuiltInComponentIds.DesktopOfficeRecentDocuments,
                 context => new OfficeRecentDocumentsComponentEditor(context)),

LanMountainDesktop/Services/IWhiteboardNotePersistenceService.cs

@@ -0,0 +1,19 @@
+using System;
+using LanMountainDesktop.Models;
+
+namespace LanMountainDesktop.Services;
+
+public interface IWhiteboardNotePersistenceService
+{
+    WhiteboardNoteSnapshot LoadNote(string componentId, string? placementId, int retentionDays);
+
+    void SaveNote(string componentId, string? placementId, WhiteboardNoteSnapshot snapshot, int retentionDays);
+
+    bool DeleteNote(string componentId, string? placementId);
+
+    bool TryDeleteExpiredNote(string componentId, string? placementId, int retentionDays);
+
+    bool IsExpired(WhiteboardNoteSnapshot snapshot, int retentionDays, DateTimeOffset? now = null);
+
+    DateTimeOffset? GetExpirationUtc(WhiteboardNoteSnapshot snapshot, int retentionDays);
+}

LanMountainDesktop/Services/WhiteboardNotePersistenceService.cs

@@ -0,0 +1,338 @@
+using System;
+using System.Text.Json;
+using LanMountainDesktop.Models;
+using Microsoft.Data.Sqlite;
+
+namespace LanMountainDesktop.Services;
+
+public sealed class WhiteboardNotePersistenceService : IWhiteboardNotePersistenceService
+{
+    private const int DefaultCleanupBatchSize = 256;
+    private static readonly JsonSerializerOptions JsonOptions = new()
+    {
+        PropertyNameCaseInsensitive = true
+    };
+
+    private readonly object _schemaSyncRoot = new();
+    private readonly AppDatabaseService _databaseService;
+    private bool _schemaInitialized;
+
+    public WhiteboardNotePersistenceService(AppDatabaseService? databaseService = null)
+    {
+        _databaseService = databaseService ?? AppDatabaseServiceFactory.CreateDefault();
+    }
+
+    public WhiteboardNoteSnapshot LoadNote(string componentId, string? placementId, int retentionDays)
+    {
+        if (!TryNormalizeKeys(componentId, placementId, out var normalizedComponentId, out var normalizedPlacementId))
+        {
+            return new WhiteboardNoteSnapshot();
+        }
+
+        try
+        {
+            using var connection = OpenConnection();
+            DeleteExpiredInternal(
+                connection,
+                normalizedComponentId,
+                normalizedPlacementId,
+                WhiteboardNoteRetentionPolicy.NormalizeDays(retentionDays),
+                DateTimeOffset.UtcNow);
+
+            using var command = connection.CreateCommand();
+            command.CommandText = """
+                SELECT note_json, saved_at_utc_ms
+                FROM whiteboard_notes
+                WHERE component_id = $componentId
+                  AND placement_id = $placementId
+                LIMIT 1;
+                """;
+            command.Parameters.AddWithValue("$componentId", normalizedComponentId);
+            command.Parameters.AddWithValue("$placementId", normalizedPlacementId);
+
+            using var reader = command.ExecuteReader();
+            if (!reader.Read() || reader.IsDBNull(0))
+            {
+                return new WhiteboardNoteSnapshot();
+            }
+
+            var json = reader.GetString(0);
+            if (string.IsNullOrWhiteSpace(json))
+            {
+                return new WhiteboardNoteSnapshot();
+            }
+
+            var snapshot = JsonSerializer.Deserialize<WhiteboardNoteSnapshot>(json, JsonOptions) ?? new WhiteboardNoteSnapshot();
+            if (!reader.IsDBNull(1))
+            {
+                snapshot.SavedUtc = DateTimeOffset.FromUnixTimeMilliseconds(reader.GetInt64(1));
+            }
+
+            if (IsExpired(snapshot, retentionDays))
+            {
+                DeleteNote(normalizedComponentId, normalizedPlacementId);
+                return new WhiteboardNoteSnapshot();
+            }
+
+            return snapshot.Clone();
+        }
+        catch
+        {
+            return new WhiteboardNoteSnapshot();
+        }
+    }
+
+    public void SaveNote(string componentId, string? placementId, WhiteboardNoteSnapshot snapshot, int retentionDays)
+    {
+        if (!TryNormalizeKeys(componentId, placementId, out var normalizedComponentId, out var normalizedPlacementId))
+        {
+            return;
+        }
+
+        try
+        {
+            var nowUtc = DateTimeOffset.UtcNow;
+            var persistedSnapshot = snapshot?.Clone() ?? new WhiteboardNoteSnapshot();
+            persistedSnapshot.SavedUtc = nowUtc;
+            var expiresUtc = GetExpirationUtc(persistedSnapshot, retentionDays) ?? nowUtc.AddDays(WhiteboardNoteRetentionPolicy.DefaultDays);
+            var json = JsonSerializer.Serialize(persistedSnapshot, JsonOptions);
+
+            using var connection = OpenConnection();
+            using var command = connection.CreateCommand();
+            command.CommandText = """
+                INSERT INTO whiteboard_notes(
+                    component_id,
+                    placement_id,
+                    note_json,
+                    saved_at_utc_ms,
+                    expires_at_utc_ms,
+                    updated_at_utc_ms)
+                VALUES(
+                    $componentId,
+                    $placementId,
+                    $noteJson,
+                    $savedAtUtcMs,
+                    $expiresAtUtcMs,
+                    $updatedAtUtcMs)
+                ON CONFLICT(component_id, placement_id) DO UPDATE SET
+                    note_json = excluded.note_json,
+                    saved_at_utc_ms = excluded.saved_at_utc_ms,
+                    expires_at_utc_ms = excluded.expires_at_utc_ms,
+                    updated_at_utc_ms = excluded.updated_at_utc_ms;
+                """;
+            command.Parameters.AddWithValue("$componentId", normalizedComponentId);
+            command.Parameters.AddWithValue("$placementId", normalizedPlacementId);
+            command.Parameters.AddWithValue("$noteJson", json);
+            command.Parameters.AddWithValue("$savedAtUtcMs", persistedSnapshot.SavedUtc.ToUnixTimeMilliseconds());
+            command.Parameters.AddWithValue("$expiresAtUtcMs", expiresUtc.ToUnixTimeMilliseconds());
+            command.Parameters.AddWithValue("$updatedAtUtcMs", nowUtc.ToUnixTimeMilliseconds());
+            command.ExecuteNonQuery();
+        }
+        catch
+        {
+            // Keep whiteboard usable even when persistence is unavailable.
+        }
+    }
+
+    public bool DeleteNote(string componentId, string? placementId)
+    {
+        if (!TryNormalizeKeys(componentId, placementId, out var normalizedComponentId, out var normalizedPlacementId))
+        {
+            return false;
+        }
+
+        try
+        {
+            using var connection = OpenConnection();
+            using var command = connection.CreateCommand();
+            command.CommandText = """
+                DELETE FROM whiteboard_notes
+                WHERE component_id = $componentId
+                  AND placement_id = $placementId;
+                """;
+            command.Parameters.AddWithValue("$componentId", normalizedComponentId);
+            command.Parameters.AddWithValue("$placementId", normalizedPlacementId);
+            return command.ExecuteNonQuery() > 0;
+        }
+        catch
+        {
+            return false;
+        }
+    }
+
+    public bool TryDeleteExpiredNote(string componentId, string? placementId, int retentionDays)
+    {
+        if (!TryNormalizeKeys(componentId, placementId, out var normalizedComponentId, out var normalizedPlacementId))
+        {
+            return false;
+        }
+
+        try
+        {
+            using var connection = OpenConnection();
+            return DeleteExpiredInternal(
+                connection,
+                normalizedComponentId,
+                normalizedPlacementId,
+                WhiteboardNoteRetentionPolicy.NormalizeDays(retentionDays),
+                DateTimeOffset.UtcNow);
+        }
+        catch
+        {
+            return false;
+        }
+    }
+
+    public int DeleteExpiredNotesBatch(int batchSize = DefaultCleanupBatchSize, DateTimeOffset? now = null)
+    {
+        try
+        {
+            using var connection = OpenConnection();
+            using var command = connection.CreateCommand();
+            command.CommandText = """
+                DELETE FROM whiteboard_notes
+                WHERE rowid IN (
+                    SELECT rowid
+                    FROM whiteboard_notes
+                    WHERE expires_at_utc_ms <= $nowUtcMs
+                    ORDER BY expires_at_utc_ms ASC
+                    LIMIT $batchSize
+                );
+                """;
+            command.Parameters.AddWithValue("$nowUtcMs", (now ?? DateTimeOffset.UtcNow).ToUnixTimeMilliseconds());
+            command.Parameters.AddWithValue("$batchSize", NormalizeBatchSize(batchSize));
+            return command.ExecuteNonQuery();
+        }
+        catch
+        {
+            return 0;
+        }
+    }
+
+    public bool IsExpired(WhiteboardNoteSnapshot snapshot, int retentionDays, DateTimeOffset? now = null)
+    {
+        if (snapshot is null)
+        {
+            return false;
+        }
+
+        var expirationUtc = GetExpirationUtc(snapshot, retentionDays);
+        if (!expirationUtc.HasValue)
+        {
+            return false;
+        }
+
+        return expirationUtc.Value <= (now ?? DateTimeOffset.UtcNow);
+    }
+
+    public DateTimeOffset? GetExpirationUtc(WhiteboardNoteSnapshot snapshot, int retentionDays)
+    {
+        if (snapshot is null || snapshot.SavedUtc == default)
+        {
+            return null;
+        }
+
+        return snapshot.SavedUtc.AddDays(WhiteboardNoteRetentionPolicy.NormalizeDays(retentionDays));
+    }
+
+    private SqliteConnection OpenConnection()
+    {
+        var connection = _databaseService.OpenConnection();
+        EnsureSchema(connection);
+        return connection;
+    }
+
+    private void EnsureSchema(SqliteConnection connection)
+    {
+        if (_schemaInitialized)
+        {
+            return;
+        }
+
+        lock (_schemaSyncRoot)
+        {
+            if (_schemaInitialized)
+            {
+                return;
+            }
+
+            using var command = connection.CreateCommand();
+            command.CommandText = """
+                CREATE TABLE IF NOT EXISTS whiteboard_notes (
+                    component_id TEXT NOT NULL,
+                    placement_id TEXT NOT NULL,
+                    note_json TEXT NOT NULL,
+                    saved_at_utc_ms INTEGER NOT NULL,
+                    expires_at_utc_ms INTEGER NOT NULL,
+                    updated_at_utc_ms INTEGER NOT NULL,
+                    PRIMARY KEY (component_id, placement_id)
+                );
+
+                CREATE INDEX IF NOT EXISTS idx_whiteboard_notes_expires_at
+                    ON whiteboard_notes(expires_at_utc_ms);
+                """;
+            command.ExecuteNonQuery();
+            _schemaInitialized = true;
+        }
+    }
+
+    private static bool DeleteExpiredInternal(
+        SqliteConnection connection,
+        string componentId,
+        string placementId,
+        int retentionDays,
+        DateTimeOffset nowUtc)
+    {
+        using var selectCommand = connection.CreateCommand();
+        selectCommand.CommandText = """
+            SELECT saved_at_utc_ms
+            FROM whiteboard_notes
+            WHERE component_id = $componentId
+              AND placement_id = $placementId
+            LIMIT 1;
+            """;
+        selectCommand.Parameters.AddWithValue("$componentId", componentId);
+        selectCommand.Parameters.AddWithValue("$placementId", placementId);
+
+        var scalar = selectCommand.ExecuteScalar();
+        if (scalar is not long savedAtUtcMs)
+        {
+            return false;
+        }
+
+        var savedUtc = DateTimeOffset.FromUnixTimeMilliseconds(savedAtUtcMs);
+        var expiresUtc = savedUtc.AddDays(WhiteboardNoteRetentionPolicy.NormalizeDays(retentionDays));
+        if (expiresUtc > nowUtc)
+        {
+            return false;
+        }
+
+        using var deleteCommand = connection.CreateCommand();
+        deleteCommand.CommandText = """
+            DELETE FROM whiteboard_notes
+            WHERE component_id = $componentId
+              AND placement_id = $placementId;
+            """;
+        deleteCommand.Parameters.AddWithValue("$componentId", componentId);
+        deleteCommand.Parameters.AddWithValue("$placementId", placementId);
+        return deleteCommand.ExecuteNonQuery() > 0;
+    }
+
+    private static bool TryNormalizeKeys(
+        string componentId,
+        string? placementId,
+        out string normalizedComponentId,
+        out string normalizedPlacementId)
+    {
+        normalizedComponentId = componentId?.Trim() ?? string.Empty;
+        normalizedPlacementId = placementId?.Trim() ?? string.Empty;
+        return !string.IsNullOrWhiteSpace(normalizedComponentId);
+    }
+
+    private static int NormalizeBatchSize(int batchSize)
+    {
+        return batchSize <= 0
+            ? DefaultCleanupBatchSize
+            : Math.Clamp(batchSize, 1, 4096);
+    }
+}

LanMountainDesktop/Styles/GlassModule.axaml

@@ -165,7 +165,13 @@
         <Setter Property="RenderTransform" Value="scale(1.05)" />
     </Style>
 
-    <Style Selector="Border.glass-panel">
+    <!--
+        半透明表面样式类
+        注意：这些样式使用纯色半透明画刷模拟玻璃效果，并非真正的 Mica/Acrylic 模糊材质。
+        真正的 Mica/Acrylic 效果仅通过 WindowTransparencyLevel 在独立窗口上应用。
+    -->
+
+    <Style Selector="Border.surface-translucent-panel">
         <Setter Property="Background" Value="{DynamicResource AdaptiveGlassPanelBackgroundBrush}" />
         <Setter Property="BorderBrush" Value="{DynamicResource AdaptiveGlassPanelBorderBrush}" />
         <Setter Property="BorderThickness" Value="1.2" />
@@ -174,7 +180,7 @@
         <Setter Property="BoxShadow" Value="0 4 12 #1A000000" />
     </Style>
 
-    <Style Selector="Border.glass-strong">
+    <Style Selector="Border.surface-translucent-strong">
         <Setter Property="Background" Value="{DynamicResource AdaptiveGlassStrongBackgroundBrush}" />
         <Setter Property="BorderBrush" Value="{DynamicResource AdaptiveGlassStrongBorderBrush}" />
         <Setter Property="BorderThickness" Value="1.5" />
@@ -183,7 +189,7 @@
         <Setter Property="BoxShadow" Value="0 8 24 #26000000" />
     </Style>
 
-    <Style Selector="Border.glass-island">
+    <Style Selector="Border.surface-translucent-island">
         <Setter Property="Background" Value="{DynamicResource AdaptiveDockGlassBackgroundBrush}" />
         <Setter Property="BorderBrush" Value="{DynamicResource AdaptiveDockGlassBorderBrush}" />
         <Setter Property="BorderThickness" Value="1.5" />
@@ -197,7 +203,7 @@
         </Setter>
     </Style>
 
-    <Style Selector="Border.mica-strong">
+    <Style Selector="Border.surface-solid-strong">
         <Setter Property="Background" Value="{DynamicResource AdaptiveGlassStrongBackgroundBrush}" />
         <Setter Property="BorderThickness" Value="0" />
         <Setter Property="CornerRadius" Value="36" />
@@ -205,11 +211,18 @@
         <Setter Property="BoxShadow" Value="0 8 22 #2A000000" />
     </Style>
 
-    <Style Selector="Border.glass-overlay">
+    <Style Selector="Border.surface-translucent-overlay">
         <Setter Property="Background" Value="{DynamicResource AdaptiveGlassOverlayBackgroundBrush}" />
         <Setter Property="BorderThickness" Value="0" />
         <Setter Property="CornerRadius" Value="0" />
         <Setter Property="Opacity" Value="{DynamicResource AdaptiveGlassOverlayOpacity}" />
     </Style>
 
+    <!-- 向后兼容的旧样式类（已弃用） -->
+    <Style Selector="Border.glass-panel" />
+    <Style Selector="Border.glass-strong" />
+    <Style Selector="Border.glass-island" />
+    <Style Selector="Border.mica-strong" />
+    <Style Selector="Border.glass-overlay" />
+
 </Styles>

LanMountainDesktop/Views/ComponentEditors/OfficeRecentDocumentsComponentEditor.axaml.cs

@@ -29,7 +29,9 @@ public partial class OfficeRecentDocumentsComponentEditor : ComponentEditorViewB
             snapshot.OfficeRecentDocumentsEnabledSources,
             useDefaultWhenEmpty: snapshot.OfficeRecentDocumentsEnabledSources is null);
 
-        HeadlineTextBlock.Text = Context?.Definition.DisplayName ?? "Office Recent Documents";
+        HeadlineTextBlock.Text = Context?.Definition.DisplayName ?? L(
+            "component.office_recent_documents",
+            "Recent Documents");
         DescriptionTextBlock.Text = L(
             "office_recent_documents.settings.desc",
             "Choose which Windows and Office sources this widget should scan for recent documents.");

LanMountainDesktop/Views/ComponentEditors/WhiteboardComponentEditor.axaml

@@ -0,0 +1,40 @@
+<UserControl xmlns="https://github.com/avaloniaui"
+             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+             xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+             mc:Ignorable="d"
+             x:Class="LanMountainDesktop.Views.ComponentEditors.WhiteboardComponentEditor">
+    <StackPanel Spacing="16">
+        <Border Classes="component-editor-hero-card"
+                Padding="24">
+            <StackPanel Spacing="8">
+                <TextBlock x:Name="HeadlineTextBlock"
+                           Classes="component-editor-headline"
+                           TextWrapping="Wrap" />
+                <TextBlock x:Name="DescriptionTextBlock"
+                           Classes="component-editor-secondary-text"
+                           TextWrapping="Wrap" />
+            </StackPanel>
+        </Border>
+
+        <Border Classes="component-editor-card"
+                Padding="20">
+            <StackPanel Spacing="12">
+                <TextBlock x:Name="RetentionHeaderTextBlock"
+                           Classes="component-editor-section-title" />
+                <TextBlock x:Name="RetentionDescriptionTextBlock"
+                           Classes="component-editor-secondary-text"
+                           TextWrapping="Wrap" />
+                <ComboBox x:Name="RetentionComboBox"
+                          Classes="component-editor-select"
+                          HorizontalAlignment="Stretch"
+                          SelectionChanged="OnRetentionSelectionChanged" />
+            </StackPanel>
+        </Border>
+
+        <TextBlock x:Name="InstanceHintTextBlock"
+                   Classes="component-editor-secondary-text"
+                   Margin="12,0"
+                   TextWrapping="Wrap" />
+    </StackPanel>
+</UserControl>

LanMountainDesktop/Views/ComponentEditors/WhiteboardComponentEditor.axaml.cs

@@ -0,0 +1,106 @@
+using System;
+using System.Linq;
+using Avalonia.Controls;
+using Avalonia.Interactivity;
+using LanMountainDesktop.ComponentSystem;
+using LanMountainDesktop.Models;
+
+namespace LanMountainDesktop.Views.ComponentEditors;
+
+public partial class WhiteboardComponentEditor : ComponentEditorViewBase
+{
+    private bool _suppressEvents;
+
+    public WhiteboardComponentEditor()
+        : this(null)
+    {
+    }
+
+    public WhiteboardComponentEditor(DesktopComponentEditorContext? context)
+        : base(context)
+    {
+        InitializeComponent();
+        BuildRetentionOptions();
+        ApplyState();
+    }
+
+    private void BuildRetentionOptions()
+    {
+        RetentionComboBox.Items.Clear();
+        for (var days = WhiteboardNoteRetentionPolicy.MinimumDays; days <= WhiteboardNoteRetentionPolicy.MaximumDays; days++)
+        {
+            var item = new ComboBoxItem
+            {
+                Tag = days.ToString(),
+                Content = L(
+                    "whiteboard.settings.retention.option",
+                    "{0} days").Replace("{0}", days.ToString())
+            };
+            item.Classes.Add("component-editor-select-item");
+            RetentionComboBox.Items.Add(item);
+        }
+    }
+
+    private void ApplyState()
+    {
+        var snapshot = LoadSnapshot();
+        var retentionDays = NormalizeRetentionDays(snapshot.WhiteboardNoteRetentionDays);
+
+        HeadlineTextBlock.Text = Context?.Definition.DisplayName ?? "Blackboard";
+        DescriptionTextBlock.Text = L(
+            "whiteboard.settings.desc",
+            "Each blackboard keeps its own note history and saves it independently.");
+        RetentionHeaderTextBlock.Text = L(
+            "whiteboard.settings.retention.title",
+            "Note retention");
+        RetentionDescriptionTextBlock.Text = L(
+            "whiteboard.settings.retention.desc",
+            "Choose how long this blackboard should keep saved notes before expired data is removed automatically.");
+        InstanceHintTextBlock.Text = L(
+            "whiteboard.settings.instance_scope",
+            "This retention setting is stored per blackboard component instance.");
+
+        _suppressEvents = true;
+        RetentionComboBox.SelectedItem = RetentionComboBox.Items
+            .OfType<ComboBoxItem>()
+            .FirstOrDefault(item =>
+                item.Tag is string tag &&
+                int.TryParse(tag, out var days) &&
+                days == retentionDays);
+        _suppressEvents = false;
+    }
+
+    private void OnRetentionSelectionChanged(object? sender, SelectionChangedEventArgs e)
+    {
+        _ = sender;
+        _ = e;
+        if (_suppressEvents)
+        {
+            return;
+        }
+
+        var snapshot = LoadSnapshot();
+        snapshot.WhiteboardNoteRetentionDays = GetSelectedRetentionDays();
+        SaveSnapshot(snapshot, nameof(ComponentSettingsSnapshot.WhiteboardNoteRetentionDays));
+    }
+
+    private int GetSelectedRetentionDays()
+    {
+        if (RetentionComboBox.SelectedItem is ComboBoxItem item &&
+            item.Tag is string tag &&
+            int.TryParse(tag, out var days))
+        {
+            return NormalizeRetentionDays(days);
+        }
+
+        return WhiteboardNoteRetentionPolicy.DefaultDays;
+    }
+
+    private static int NormalizeRetentionDays(int days)
+    {
+        return WhiteboardNoteRetentionPolicy.NormalizeDays(
+            days <= 0
+                ? WhiteboardNoteRetentionPolicy.DefaultDays
+                : days);
+    }
+}

LanMountainDesktop/Views/ComponentLibraryWindow.axaml

@@ -38,7 +38,7 @@
         <Grid Grid.Row="1"
               ColumnDefinitions="240,*"
               ColumnSpacing="12">
-            <Border Classes="glass-panel"
+            <Border Classes="surface-translucent-panel"
                     CornerRadius="24"
                     Padding="10">
                 <ListBox x:Name="CategoryListBox"
@@ -70,7 +70,7 @@
             </Border>
 
             <Border Grid.Column="1"
-                    Classes="glass-strong"
+                    Classes="surface-translucent-strong"
                     CornerRadius="24"
                     Padding="10">
                 <ScrollViewer VerticalScrollBarVisibility="Auto"

LanMountainDesktop/Views/Components/ClockWidget.axaml

@@ -1,4 +1,4 @@
-<UserControl xmlns="https://github.com/avaloniaui"
+<UserControl xmlns="https://github.com/avaloniaui"
              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
              xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
              xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
@@ -8,7 +8,7 @@
              x:Class="LanMountainDesktop.Views.Components.ClockWidget">
 
     <Border x:Name="RootBorder"
-            Classes="glass-panel"
+            Classes="surface-translucent-panel"
             Padding="0"
             CornerRadius="24">
         <StackPanel Orientation="Horizontal"

LanMountainDesktop/Views/Components/StudyDeductionReasonsWidget.axaml

@@ -7,7 +7,7 @@
              d:DesignHeight="220"
              x:Class="LanMountainDesktop.Views.Components.StudyDeductionReasonsWidget">
     <Border x:Name="RootBorder"
-            Classes="glass-strong"
+            Classes="surface-translucent-strong"
             CornerRadius="22"
             Padding="12,10"
             ClipToBounds="True">

LanMountainDesktop/Views/Components/StudyInterruptDensityWidget.axaml

@@ -7,7 +7,7 @@
              d:DesignHeight="220"
              x:Class="LanMountainDesktop.Views.Components.StudyInterruptDensityWidget">
     <Border x:Name="RootBorder"
-            Classes="glass-strong"
+            Classes="surface-translucent-strong"
             CornerRadius="22"
             Padding="14,10"
             ClipToBounds="True">

LanMountainDesktop/Views/Components/StudyNoiseCurveWidget.axaml

@@ -1,4 +1,4 @@
-<UserControl xmlns="https://github.com/avaloniaui"
+<UserControl xmlns="https://github.com/avaloniaui"
              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
              xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
              xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
@@ -8,7 +8,7 @@
              d:DesignHeight="320"
              x:Class="LanMountainDesktop.Views.Components.StudyNoiseCurveWidget">
     <Border x:Name="RootBorder"
-            Classes="glass-strong"
+            Classes="surface-translucent-strong"
             CornerRadius="24"
             Padding="14,10"
             ClipToBounds="True">

LanMountainDesktop/Views/Components/StudyNoiseDistributionWidget.axaml

@@ -8,7 +8,7 @@
              d:DesignHeight="320"
              x:Class="LanMountainDesktop.Views.Components.StudyNoiseDistributionWidget">
     <Border x:Name="RootBorder"
-            Classes="glass-strong"
+            Classes="surface-translucent-strong"
             CornerRadius="24"
             Padding="14,10"
             ClipToBounds="True">

LanMountainDesktop/Views/Components/StudyScoreOverviewWidget.axaml

@@ -7,7 +7,7 @@
              d:DesignHeight="360"
              x:Class="LanMountainDesktop.Views.Components.StudyScoreOverviewWidget">
     <Border x:Name="RootBorder"
-            Classes="glass-strong"
+            Classes="surface-translucent-strong"
             CornerRadius="24"
             Padding="16,14"
             ClipToBounds="True">

LanMountainDesktop/Views/Components/StudySessionControlWidget.axaml

@@ -8,7 +8,7 @@
              d:DesignHeight="150"
              x:Class="LanMountainDesktop.Views.Components.StudySessionControlWidget">
     <Border x:Name="RootBorder"
-            Classes="glass-strong"
+            Classes="surface-translucent-strong"
             CornerRadius="18"
             Padding="14,10"
             ClipToBounds="True">

LanMountainDesktop/Views/Components/StudySessionHistoryWidget.axaml

@@ -7,7 +7,7 @@
              d:DesignHeight="220"
              x:Class="LanMountainDesktop.Views.Components.StudySessionHistoryWidget">
     <Border x:Name="RootBorder"
-            Classes="glass-strong"
+            Classes="surface-translucent-strong"
             CornerRadius="22"
             Padding="12,10"
             ClipToBounds="True">

LanMountainDesktop/Views/Components/WhiteboardWidget.axaml.cs

@@ -1,4 +1,5 @@
-using System;
+using System;
+using System.Collections.Generic;
 using System.IO;
 using System.Linq;
 using System.Reflection;
@@ -9,13 +10,18 @@ using Avalonia.Interactivity;
 using Avalonia.Media;
 using Avalonia.Platform.Storage;
 using Avalonia.Styling;
+using Avalonia.Threading;
 using DotNetCampus.Inking;
+using DotNetCampus.Inking.Primitive;
 using FluentIcons.Avalonia;
+using LanMountainDesktop.ComponentSystem;
+using LanMountainDesktop.Models;
+using LanMountainDesktop.Services;
 using SkiaSharp;
 
 namespace LanMountainDesktop.Views.Components;
 
-public partial class WhiteboardWidget : UserControl, IDesktopComponentWidget
+public partial class WhiteboardWidget : UserControl, IDesktopComponentWidget, IComponentPlacementContextAware, IDisposable
 {
     private enum WhiteboardToolMode
     {
@@ -24,11 +30,22 @@ public partial class WhiteboardWidget : UserControl, IDesktopComponentWidget
     }
 
     private static readonly PropertyInfo? StrokeColorProperty = typeof(SkiaStroke).GetProperty(nameof(SkiaStroke.Color));
+    private static readonly PropertyInfo? StrokePointListProperty = typeof(SkiaStroke).GetProperty("PointList");
     private readonly int _baseWidthCells;
+    private readonly IComponentInstanceSettingsStore _componentSettingsStore = HostComponentSettingsStoreProvider.GetOrCreate();
+    private readonly IWhiteboardNotePersistenceService _notePersistenceService = new WhiteboardNotePersistenceService();
+    private readonly DispatcherTimer _noteSaveTimer = new() { Interval = TimeSpan.FromMinutes(5) };
     private double _currentCellSize = 48;
     private WhiteboardToolMode _toolMode = WhiteboardToolMode.Pen;
     private bool? _isNightModeApplied;
     private SKColor _currentInkColor = SKColors.Black;
+    private string _componentId = BuiltInComponentIds.DesktopWhiteboard;
+    private string _placementId = string.Empty;
+    private int _noteRetentionDays = WhiteboardNoteRetentionPolicy.DefaultDays;
+    private bool _isApplyingPersistedSnapshot;
+    private bool _noteDirty;
+    private int _noteLoadRevision;
+    private bool _disposed;
 
     public WhiteboardWidget()
         : this(baseWidthCells: 2)
@@ -43,21 +60,26 @@ public partial class WhiteboardWidget : UserControl, IDesktopComponentWidget
         DetachedFromVisualTree += OnDetachedFromVisualTree;
         SizeChanged += OnSizeChanged;
         ActualThemeVariantChanged += OnActualThemeVariantChanged;
+        _noteSaveTimer.Tick += OnNoteSaveTimerTick;
 
         ConfigureInkCanvas();
         ApplyCellSize(_currentCellSize);
+        RefreshFromSettings();
         ApplyThemeVisual(force: true);
         SetToolMode(WhiteboardToolMode.Pen);
     }
 
+    public int NoteRetentionDays => _noteRetentionDays;
+
     private void OnAttachedToVisualTree(object? sender, VisualTreeAttachmentEventArgs e)
     {
         ApplyThemeVisual(force: true);
+        SchedulePersistedNoteLoad();
     }
 
     private void OnDetachedFromVisualTree(object? sender, VisualTreeAttachmentEventArgs e)
     {
-        // Keep all state in-memory for lightweight re-attach scenarios.
+        PersistNoteImmediately();
     }
 
     private void OnSizeChanged(object? sender, SizeChangedEventArgs e)
@@ -79,6 +101,9 @@ public partial class WhiteboardWidget : UserControl, IDesktopComponentWidget
         settings.EraserSize = new Size(20, 20);
         settings.IsBitmapCacheEnabled = true;
         settings.MaxBitmapCacheSize = 2048;
+        InkCanvas.StrokeCollected += OnInkCanvasStrokeCollected;
+        InkCanvas.PointerReleased += OnInkCanvasPointerReleased;
+        InkCanvas.PointerCaptureLost += OnInkCanvasPointerCaptureLost;
     }
 
     public void ApplyCellSize(double cellSize)
@@ -134,6 +159,63 @@ public partial class WhiteboardWidget : UserControl, IDesktopComponentWidget
         RefreshToolButtonVisuals();
     }
 
+    public void SetComponentPlacementContext(string componentId, string? placementId)
+    {
+        var nextComponentId = string.IsNullOrWhiteSpace(componentId)
+            ? BuiltInComponentIds.DesktopWhiteboard
+            : componentId.Trim();
+        var nextPlacementId = placementId?.Trim() ?? string.Empty;
+
+        if (_noteDirty &&
+            HasValidPersistenceContext() &&
+            (string.Compare(_componentId, nextComponentId, StringComparison.OrdinalIgnoreCase) != 0 ||
+             string.Compare(_placementId, nextPlacementId, StringComparison.OrdinalIgnoreCase) != 0))
+        {
+            PersistNoteImmediately();
+        }
+
+        _componentId = nextComponentId;
+        _placementId = nextPlacementId;
+        RefreshFromSettings();
+        ClearAllStrokes();
+        SchedulePersistedNoteLoad();
+    }
+
+    public void RefreshFromSettings()
+    {
+        try
+        {
+            if (!HasValidPersistenceContext())
+            {
+                _noteRetentionDays = WhiteboardNoteRetentionPolicy.DefaultDays;
+                return;
+            }
+
+            var snapshot = _componentSettingsStore.LoadForComponent(_componentId, _placementId);
+            _noteRetentionDays = NormalizeRetentionDays(snapshot.WhiteboardNoteRetentionDays);
+            _notePersistenceService.TryDeleteExpiredNote(_componentId, _placementId, _noteRetentionDays);
+        }
+        catch
+        {
+            _noteRetentionDays = WhiteboardNoteRetentionPolicy.DefaultDays;
+        }
+    }
+
+    public void Dispose()
+    {
+        if (_disposed)
+        {
+            return;
+        }
+
+        _disposed = true;
+        _noteSaveTimer.Stop();
+        _noteSaveTimer.Tick -= OnNoteSaveTimerTick;
+        InkCanvas.StrokeCollected -= OnInkCanvasStrokeCollected;
+        InkCanvas.PointerReleased -= OnInkCanvasPointerReleased;
+        InkCanvas.PointerCaptureLost -= OnInkCanvasPointerCaptureLost;
+    }
+
     private void RecolorAllStrokes(SKColor targetColor)
     {
         for (var i = 0; i < InkCanvas.Strokes.Count; i++)
@@ -183,6 +265,14 @@ public partial class WhiteboardWidget : UserControl, IDesktopComponentWidget
         return false;
     }
 
+    private static int NormalizeRetentionDays(int days)
+    {
+        return WhiteboardNoteRetentionPolicy.NormalizeDays(
+            days <= 0
+                ? WhiteboardNoteRetentionPolicy.DefaultDays
+                : days);
+    }
+
     private static double CalculateRelativeLuminance(Color color)
     {
         static double ToLinear(double channel)
@@ -267,25 +357,8 @@ public partial class WhiteboardWidget : UserControl, IDesktopComponentWidget
 
     private void OnClearButtonClick(object? sender, RoutedEventArgs e)
     {
-        var strokeList = InkCanvas.Strokes.ToList();
-        foreach (var stroke in strokeList)
-        {
-            try
-            {
-                if (ReferenceEquals(stroke.InkCanvas, InkCanvas.AvaloniaSkiaInkCanvas))
-                {
-                    InkCanvas.AvaloniaSkiaInkCanvas.RemoveStaticStroke(stroke);
-                }
-            }
-            catch
-            {
-                // Keep the widget alive even if one stroke removal fails.
-            }
-        }
-
-        InkCanvas.AvaloniaSkiaInkCanvas.UseBitmapCache(false);
-        InkCanvas.AvaloniaSkiaInkCanvas.InvalidateBitmapCache();
-        InkCanvas.InvalidateVisual();
+        ClearAllStrokes();
+        QueueNoteSave();
     }
 
     private async void OnExportButtonClick(object? sender, RoutedEventArgs e)
@@ -358,4 +431,273 @@ public partial class WhiteboardWidget : UserControl, IDesktopComponentWidget
 
         svgCanvas.Flush();
     }
+
+    private void OnInkCanvasStrokeCollected(object? sender, DotNetCampus.Inking.Contexts.AvaloniaSkiaInkCanvasStrokeCollectedEventArgs e)
+    {
+        _ = sender;
+        _ = e;
+        QueueNoteSave();
+    }
+
+    private void OnInkCanvasPointerReleased(object? sender, Avalonia.Input.PointerReleasedEventArgs e)
+    {
+        _ = sender;
+        _ = e;
+        QueueNoteSave();
+    }
+
+    private void OnInkCanvasPointerCaptureLost(object? sender, Avalonia.Input.PointerCaptureLostEventArgs e)
+    {
+        _ = sender;
+        _ = e;
+        QueueNoteSave();
+    }
+
+    private void OnNoteSaveTimerTick(object? sender, EventArgs e)
+    {
+        _ = sender;
+        if (_disposed || _isApplyingPersistedSnapshot || !HasValidPersistenceContext())
+        {
+            _noteSaveTimer.Stop();
+            return;
+        }
+
+        if (!_noteDirty)
+        {
+            _noteSaveTimer.Stop();
+            return;
+        }
+
+        var noteSnapshot = BuildNoteSnapshot();
+        var componentId = _componentId;
+        var placementId = _placementId;
+        var retentionDays = _noteRetentionDays;
+        _noteDirty = false;
+        _noteSaveTimer.Stop();
+        _ = Task.Run(() => _notePersistenceService.SaveNote(componentId, placementId, noteSnapshot, retentionDays));
+    }
+
+    private void QueueNoteSave()
+    {
+        if (_disposed || _isApplyingPersistedSnapshot || !HasValidPersistenceContext())
+        {
+            return;
+        }
+
+        _noteDirty = true;
+        if (!_noteSaveTimer.IsEnabled)
+        {
+            _noteSaveTimer.Start();
+        }
+    }
+
+    private void PersistNoteImmediately()
+    {
+        if (_disposed || _isApplyingPersistedSnapshot || !HasValidPersistenceContext())
+        {
+            return;
+        }
+
+        if (!_noteDirty)
+        {
+            return;
+        }
+
+        _noteDirty = false;
+        _noteSaveTimer.Stop();
+        var noteSnapshot = BuildNoteSnapshot();
+        var componentId = _componentId;
+        var placementId = _placementId;
+        var retentionDays = _noteRetentionDays;
+        _ = Task.Run(() => _notePersistenceService.SaveNote(
+            componentId,
+            placementId,
+            noteSnapshot,
+            retentionDays));
+    }
+
+    private async void SchedulePersistedNoteLoad()
+    {
+        if (!HasValidPersistenceContext())
+        {
+            return;
+        }
+
+        var revision = ++_noteLoadRevision;
+        var componentId = _componentId;
+        var placementId = _placementId;
+        var retentionDays = _noteRetentionDays;
+
+        try
+        {
+            var noteSnapshot = await Task.Run(() => _notePersistenceService.LoadNote(componentId, placementId, retentionDays));
+            if (_disposed || revision != _noteLoadRevision ||
+                !string.Equals(_componentId, componentId, StringComparison.OrdinalIgnoreCase) ||
+                !string.Equals(_placementId, placementId, StringComparison.OrdinalIgnoreCase))
+            {
+                return;
+            }
+
+            Dispatcher.UIThread.Post(() =>
+            {
+                if (_disposed || revision != _noteLoadRevision)
+                {
+                    return;
+                }
+
+                _isApplyingPersistedSnapshot = true;
+                try
+                {
+                    ClearAllStrokes();
+                    ApplyNoteSnapshot(noteSnapshot);
+                    RecolorAllStrokes(_currentInkColor);
+                }
+                finally
+                {
+                    _isApplyingPersistedSnapshot = false;
+                }
+            });
+        }
+        catch
+        {
+            // Best effort only. Whiteboard should stay usable if persistence is unavailable.
+        }
+    }
+
+    private WhiteboardNoteSnapshot BuildNoteSnapshot()
+    {
+        return new WhiteboardNoteSnapshot
+        {
+            Strokes = InkCanvas.Strokes
+                .Select(BuildStrokeSnapshot)
+                .Where(static stroke => stroke.Points.Count > 0)
+                .ToList()
+        };
+    }
+
+    private static WhiteboardStrokeSnapshot BuildStrokeSnapshot(SkiaStroke stroke)
+    {
+        var pointList = TryGetStrokePoints(stroke);
+        return new WhiteboardStrokeSnapshot
+        {
+            Color = ToHexColor(stroke.Color),
+            InkThickness = stroke.InkThickness,
+            IgnorePressure = stroke.IgnorePressure,
+            Points = pointList
+                .Select(static point => new WhiteboardStylusPointSnapshot
+                {
+                    X = point.X,
+                    Y = point.Y,
+                    Pressure = point.Pressure,
+                    Width = point.Width ?? 0,
+                    Height = point.Height ?? 0
+                })
+                .ToList()
+        };
+    }
+
+    private void ApplyNoteSnapshot(WhiteboardNoteSnapshot snapshot)
+    {
+        if (snapshot.Strokes.Count == 0)
+        {
+            return;
+        }
+
+        var renderer = InkCanvas.AvaloniaSkiaInkCanvas.Settings.InkStrokeRenderer;
+        foreach (var strokeSnapshot in snapshot.Strokes)
+        {
+            var stylusPoints = strokeSnapshot.Points
+                .Select(ConvertStylusPoint)
+                .ToList();
+            if (stylusPoints.Count == 0)
+            {
+                continue;
+            }
+
+            var path = renderer.RenderInkToPath(stylusPoints, strokeSnapshot.InkThickness);
+            var staticStroke = SkiaStroke.CreateStaticStroke(
+                InkId.NewId(),
+                path,
+                new StylusPointListSpan(stylusPoints, 0, stylusPoints.Count),
+                ParseStrokeColor(strokeSnapshot.Color),
+                (float)strokeSnapshot.InkThickness,
+                strokeSnapshot.IgnorePressure,
+                renderer);
+            InkCanvas.AvaloniaSkiaInkCanvas.AddStaticStroke(staticStroke);
+        }
+
+        InkCanvas.AvaloniaSkiaInkCanvas.UpdateBitmapCache();
+        InkCanvas.InvalidateVisual();
+    }
+
+    private static InkStylusPoint ConvertStylusPoint(WhiteboardStylusPointSnapshot point)
+    {
+        return new InkStylusPoint(point.X, point.Y, (float)Math.Clamp(point.Pressure, 0f, 1f))
+        {
+            Width = point.Width > 0 ? point.Width : null,
+            Height = point.Height > 0 ? point.Height : null
+        };
+    }
+
+    private static SKColor ParseStrokeColor(string? value)
+    {
+        if (!string.IsNullOrWhiteSpace(value))
+        {
+            try
+            {
+                var color = Color.Parse(value);
+                return new SKColor(color.R, color.G, color.B, color.A);
+            }
+            catch
+            {
+                // Fall through to the default color.
+            }
+        }
+
+        return SKColors.Black;
+    }
+
+    private static string ToHexColor(SKColor color)
+    {
+        return $"#{color.Alpha:X2}{color.Red:X2}{color.Green:X2}{color.Blue:X2}";
+    }
+
+    private void ClearAllStrokes()
+    {
+        var strokeList = InkCanvas.Strokes.ToList();
+        foreach (var stroke in strokeList)
+        {
+            try
+            {
+                if (ReferenceEquals(stroke.InkCanvas, InkCanvas.AvaloniaSkiaInkCanvas))
+                {
+                    InkCanvas.AvaloniaSkiaInkCanvas.RemoveStaticStroke(stroke);
+                }
+            }
+            catch
+            {
+                // Keep the widget alive even if one stroke removal fails.
+            }
+        }
+
+        InkCanvas.AvaloniaSkiaInkCanvas.UseBitmapCache(false);
+        InkCanvas.AvaloniaSkiaInkCanvas.InvalidateBitmapCache();
+        InkCanvas.InvalidateVisual();
+    }
+
+    private bool HasValidPersistenceContext()
+    {
+        return !string.IsNullOrWhiteSpace(_componentId) &&
+               !string.IsNullOrWhiteSpace(_placementId);
+    }
+
+    private static IReadOnlyList<InkStylusPoint> TryGetStrokePoints(SkiaStroke stroke)
+    {
+        if (StrokePointListProperty?.GetValue(stroke) is IReadOnlyList<InkStylusPoint> pointList)
+        {
+            return pointList;
+        }
+
+        return Array.Empty<InkStylusPoint>();
+    }
 }

LanMountainDesktop/Views/MainWindow.axaml

@@ -1,4 +1,4 @@
-<Window xmlns="https://github.com/avaloniaui"
+<Window xmlns="https://github.com/avaloniaui"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         xmlns:vm="using:LanMountainDesktop.ViewModels"
         xmlns:ui="using:FluentAvalonia.UI.Controls"
@@ -158,7 +158,7 @@
 
                                     <Border x:Name="LauncherPagePanel"
                                             Grid.Column="1"
-                                            Classes="glass-panel"
+                                            Classes="surface-translucent-panel"
                                             ClipToBounds="False"
                                             CornerRadius="36"
                                             Padding="18">
@@ -166,11 +166,9 @@
                                             <StackPanel Spacing="4">
                                                 <TextBlock x:Name="LauncherTitleTextBlock"
                                                            FontSize="24"
-                                                           FontWeight="SemiBold"
-                                                           Text="App Launcher" />
+                                                           FontWeight="SemiBold" />
                                                 <TextBlock x:Name="LauncherSubtitleTextBlock"
-                                                           Foreground="{DynamicResource AdaptiveTextSecondaryBrush}"
-                                                           Text="Apps and folders from Windows Start Menu." />
+                                                           Foreground="{DynamicResource AdaptiveTextSecondaryBrush}" />
                                             </StackPanel>
 
                                             <Grid Grid.Row="1"
@@ -188,7 +186,7 @@
                                                       Opacity="{DynamicResource AdaptiveGlassOverlayOpacity}"
                                                       PointerPressed="OnLauncherFolderOverlayPointerPressed">
                                                     <Border x:Name="LauncherFolderPanel"
-                                                            Classes="mica-strong"
+                                                            Classes="surface-solid-strong"
                                                             HorizontalAlignment="Center"
                                                             VerticalAlignment="Center"
                                                             Margin="52"
@@ -216,8 +214,7 @@
                                                                            Grid.Column="1"
                                                                            HorizontalAlignment="Center"
                                                                            VerticalAlignment="Center"
-                                                                           FontWeight="SemiBold"
-                                                                           Text="Folder" />
+                                                                           FontWeight="SemiBold" />
                                                                 <Button x:Name="LauncherFolderCloseButton"
                                                                         Grid.Column="2"
                                                                         Width="38"
@@ -266,7 +263,7 @@
                         </Border>
 
                         <Border x:Name="BottomTaskbarContainer"
-                                Classes="glass-island"
+                                Classes="surface-translucent-island"
                                 Grid.Row="0"
                                 Grid.Column="0"
                                 Grid.ColumnSpan="1"
@@ -434,7 +431,7 @@
         <Border x:Name="ComponentLibraryWindow"
                 IsVisible="False"
                 Opacity="0"
-                Classes="glass-strong"
+                Classes="surface-translucent-strong"
                 HorizontalAlignment="Center"
                 VerticalAlignment="Bottom"
                 Width="620"
@@ -479,7 +476,7 @@
                 </Grid>
 
                 <Border Grid.Row="1"
-                        Classes="glass-panel"
+                        Classes="surface-translucent-panel"
                         CornerRadius="12"
                         Padding="14">
                     <Grid>