Tab groups with a tab strip drawn like the system tab bar

README.md

@@ -21,6 +21,7 @@ The app is not notarized yet. If macOS blocks the first launch, try opening it o
 - Open a Markdown or HTML file with **File > Open** (`⌘O`), or drag a file into the app window.
 - Use the **Aa** button in the toolbar to choose Native Reader or Book Reader and set light or dark appearance. The same options are in the **View** menu.
 - In a Markdown task list, click a checkbox to update its marker in the file. Other document text is read-only.
+- Right-click a tab to put it in a group. A group has a colored chip with an optional name: click the chip to collapse the group, right-click it to rename or recolor it, and drag it to move the whole group. Groups reopen with the session.
 - Each file opens in its own tab. **File > Open Files In** switches to new windows instead. `⌘T` and `⌘N` add an empty tab or window, and an empty tab lists your recent files.
 - `⌘F` finds text in the page. The outline button in the toolbar (`⌥⌘O`) jumps to a heading.
 - The page updates when the file changes on disk, so you can keep it open next to your editor. The reload button in the toolbar (`⌘R`) reloads it by hand.

Sources/ZenMarky/ReaderDocument.swift

@@ -156,6 +156,15 @@ struct ReaderSession: Codable, Equatable {
         var files: [String]
         var selected: String?
         var frame: String
+        var groups: [Group] = []
+    }
+
+    // A tab group, with its tabs by file. A file is open in one tab at most, so the path names the tab.
+    struct Group: Codable, Equatable {
+        var name: String
+        var color: GroupColor
+        var collapsed: Bool
+        var files: [String]
     }
 
     static let key = "session"
@@ -171,14 +180,30 @@ struct ReaderSession: Codable, Equatable {
         UserDefaults.standard.set(try? JSONEncoder().encode(self), forKey: Self.key)
     }
 
-    // Drops files that no longer exist and the windows left with none.
+    // Drops files that no longer exist and the groups and windows left with none.
     func existing(_ exists: (String) -> Bool = { FileManager.default.fileExists(atPath: $0) }) -> ReaderSession {
         var kept = self
         kept.windows = windows.compactMap { window in
             var window = window
             window.files = window.files.filter(exists)
+            window.groups = window.groups.compactMap { group in
+                var group = group
+                group.files = group.files.filter(exists)
+                return group.files.isEmpty ? nil : group
+            }
             return window.files.isEmpty ? nil : window
         }
         return kept
     }
 }
+
+// Sessions saved before tab groups have no groups key, so a missing one reads as none.
+extension ReaderSession.Window {
+    init(from decoder: any Decoder) throws {
+        let container = try decoder.container(keyedBy: CodingKeys.self)
+        files = try container.decode([String].self, forKey: .files)
+        selected = try container.decodeIfPresent(String.self, forKey: .selected)
+        frame = try container.decode(String.self, forKey: .frame)
+        groups = try container.decodeIfPresent([ReaderSession.Group].self, forKey: .groups) ?? []
+    }
+}

Sources/ZenMarky/Resources/Shortcuts.md

@@ -5,17 +5,18 @@
 | Open a file | ⌘O |
 | New tab | ⌘T |
 | New window | ⌘N |
-| Close tab or window | ⌘W |
+| Close tab | ⌘W |
+| Close window | ⇧⌘W |
 | Reload the file | ⌘R |
 | Print | ⌘P |
 | Copy / select all | ⌘C / ⌘A |
 | Find | ⌘F |
 | Find next / previous | ⌘G / ⇧⌘G |
 | Show outline | ⌥⌘O |
 | Zoom in / out / actual size | ⌘= / ⌘− / ⌘0 |
-| Previous / next tab | ⇧⌘[ / ⇧⌘] |
+| Previous / next tab | ⇧⌘[ / ⇧⌘], or ⌃⇧⇥ / ⌃⇥ |
 | Go to tab 1–8, last tab | ⌘1–⌘8, ⌘9 |
-| Show tab bar / all tabs | ⇧⌘T / ⇧⌘\\ |
+| Always show the tab bar | ⇧⌘T |
 | Cycle windows | ⌘` |
 | Minimize | ⌘M |
 | Hide / quit the app | ⌘H / ⌘Q |
@@ -27,6 +28,11 @@
 | --- | --- |
 | Open a file | Drop it on any window |
 | Open a linked file in a new tab | ⌘-click the link |
+| Group a tab | Right-click the tab, then Add Tab to New Group |
+| Collapse or expand a group | Click its chip |
+| Rename, recolor, or close a group | Right-click its chip |
+| Move a tab or a whole group | Drag the tab or the chip along the tab bar; pull it away from the bar to drop it on another window's tab bar, or outside every window for a new window |
+| Close a tab | Middle-click it |
 | Check or uncheck a task | Click the box |
 | Copy a code block | Hover over it, then click the copy button |
 | Zoom | Pinch on the trackpad |
@@ -38,4 +44,5 @@
 | Reader style: Native or Book | Aa button, or View > Reader Style |
 | Appearance: System, Light, or Dark | Aa button, or View > Appearance |
 | Open files in a new tab or window | File > Open Files In |
+| Tab bar with a single tab | View > Always Show Tab Bar |
 | Front matter (title, date, tags) | View > Show Front Matter |