fl_panel 1.1.0

A docking layout for Flutter: a tree of splits, panels and tab groups you can resize, dock and persist, with ordinary Flutter widgets inside every panel.

1.1.0

The host's own words can be translated, and its menus can be read without reading English. Additive: a host that changes nothing sees exactly what 1.0.0 showed.

Added

• PanelLocalizations, the words the host draws — its menu labels — in the pattern of Flutter's MaterialLocalizations. PanelLocalizations.of(context) answers the one a delegate in scope provides, or DefaultPanelLocalizations (English) when none does, so nothing has to be set up. A host translates by extending the default and listing a delegate for it in localizationsDelegates; extending rather than implementing means a string added later shows in English instead of breaking the build. Strings the host already sets, such as tab titles through titleOf, are not in it. Pinned by every default label comes from the localizations, and keeps its id and says what the delegate in scope says in test/localizations_test.dart.
• DefaultPanelLocalizations.delegate, which answers the English for every locale, for a host that lists its delegates explicitly.
• PanelMenuRequest.localizations (const DefaultPanelLocalizations()). PanelMenus.defaultEntries stays pure and reads its labels from the request, so a test can still assert a menu without pumping one; PanelHost fills it from PanelLocalizations.of.
• PanelMenuEntry.id (null) and PanelMenuEntryId, one per built-in entry, submenu sides included. A builder that keeps, drops or relabels a default matched its English label until now, and would have stopped matching the day the label was translated; it matches the id instead, and copyWith keeps it. Pinned by a builder finds a default by id, whatever it says in test/localizations_test.dart.

1.0.0

The API is stable from here. Nothing about the file format changed — the version is still 1 and a layout saved by 0.1.0 loads as it was — so what follows is names, and four things a host could not do.

Renamed

• PanelApp is PanelWorkspace. The *App name read as a widget at the root of an application, like MaterialApp, and this is neither: it is every window of the layout. Everything that said "app" follows — PanelController(workspace:), controller.workspace, replaceWorkspace, PanelJson.encodeWorkspace/decodeWorkspace.
• PanelTab.forms is allowedForms, beside the allows(form) that already answered from it. The JSON key is still forms.
• DockPolicy.takesFocus is canBeFocusedLeaf (true). It never meant Flutter's keyboard focus — the content of a leaf answering false still takes the keyboard — and now says what it decides in the package's own words: focusedLeafId, focusedLeaf, focusLeaf.

0.1.0	1.0.0
PanelApp(windows: …)	PanelWorkspace(windows: …)
PanelController(app: …), controller.app	PanelController(workspace: …), controller.workspace
controller.replaceApp(…)	controller.replaceWorkspace(…)
PanelJson.encodeApp/decodeApp	PanelJson.encodeWorkspace/decodeWorkspace
PanelTab(forms: …), tab.forms	PanelTab(allowedForms: …), tab.allowedForms
bool takesFocus(LeafNode leaf)	bool canBeFocusedLeaf(LeafNode leaf)
PanelDecorations(onTabSecondaryTap: …)	PanelMenus(build: …) returning [], see below
DockResolver(edgeBand: …, centreFraction: …)	DockResolver(zones: DockZones(…))

Added

• PanelTab.metadataValue<T>(key): the value as a T, or null when it is absent or something else. Metadata comes back from a file, so a wrong type is a stale or hand-edited layout and reads as missing rather than throwing under a host. An int is accepted as a double, because 1.0 comes back as 1 from anything that is not the Dart VM. PanelHost.defaultTitle reads through it. metadata reads typed in test/model_test.dart.
• PanelTheme.copyWith, so a host overrides one field of a theme it was handed; clearTabStyleSpec (false) is how a spec is taken away, and withTabStyle is that. switching style drops a spec made for the old one in test/chrome_test.dart.
• DockZones (edgeBand 24, centreFraction 0.5) and PanelController.dockZones. The two numbers were fields on DockResolver, which the controller built with the defaults, so no host could change them — and a touch screen wants wider bands than a mouse. the drop zones a host sets are the ones a drag resolves with in test/controller_test.dart.

Removed

• PanelDecorations.onTabSecondaryTap. It predates the context menus and survived so a host with its own chip menu did not suddenly show two. That host now returns no entries from PanelMenus.build and opens its own at PanelMenuRequest.globalPosition — the same way on a strip, a header and a divider as on a chip, which the decoration never covered. a right click reaches the menu builder with the position in test/chrome_test.dart.
• TabSlot and StripSlot from the barrel. StripScope.tabSlot and stripSlot are how a chrome applies them and nothing else constructs one.

0.1.0

The first cut: the tree, the solver, the controller, the host.

• PanelApp → PanelWindow → LayoutNode → PanelTab: an immutable tree of splits, single panels and tab groups, edited by the pure functions in LayoutTree, which normalises after every edit so no caller sees a split of one, an empty group or a same-axis nesting. Splits are n-ary and flatten same-axis children rather than binary, so ((A|B)|C) and (A|(B|C)) — which draw the same and resize differently — are one tree. A tab holds a contentId and metadata, never a widget, so the tree serialises and moves between windows without asking anybody. test/model_test.dart.
• PanelSolver: PanelExtent.flex(weight) children share what PanelExtent.fixed(pixels) ones leave; PanelTab.minWidth/minHeight are the only hard constraint, held by taking from siblings with slack, scaled together when even they do not fit. resize trades pixels between two neighbours and nobody else moves. test/layout_test.dart.
• DockResolver: five zones over a leaf (centre joins, edges split), a band along the window's edges splits the root, a strip hit inserts at the index. Every candidate is checked by running the edit, so a drop the policy refuses is never offered. DockPolicy carries the two affinity levels: canTakeForm from PanelTab.forms, canJoin/canSplit for the host's metadata rules. Default permissive. affinity in test/model_test.dart.
• PanelController: a ChangeNotifier over the app; dock, open, close, activate, resize, moveToWindow; the drag session (beginDrag, updateDrag, commitDrag); toJson/load with an integer version (PanelApp.version, 1) refused when newer and a TabResolver that drops what this build cannot show. onSettled fires once per gesture, never per frame.
• PanelHost: one window as one flat Stack, a keyed Positioned per tab, chrome above, preview on top — content is never reparented, so its state survives a move. Strips and headers drag; dividers resize with DragStartBehavior.down so they track the pointer from the first pixel. test/panel_host_test.dart.
• PanelChrome: the contract for everything drawn that is not content, with StripScope.tabSlot/stripSlot as the one rule custom chrome keeps to stay a drop target. DefaultPanelChrome draws three PanelTabStyles — attached, blended (a BlendedChipPainter with Chrome's shoulders, the bottom left open so the active tab and its content are one surface), floating — from a PanelTabStyleSpec per style, per theme or per group through PanelHost.tabStyleOf. PanelDecorations hangs an icon, an unsaved dot, a strip button and a context menu on the default chrome. styles, decorations and custom chrome in test/chrome_test.dart.
• Chips share a strip between PanelTheme.tabMinWidth (96) and tabMaxWidth (200) and the strip scrolls once they would shrink below the floor — by wheel, never by pointer drag, which already means "move". shrink then scroll in test/chrome_test.dart.
• PanelWindow.focusedLeafId, persisted: where open puts content (falling back to the first leaf that accepts, then the right edge) and what nextTab/previousTab/closeActive act on; the focused group's strip shows the full accent. PanelController.focus(tabId, keyboard:) activates, reveals the chip in a scrolled strip and, with keyboard, hands the content the focus. test/controller_test.dart focus, test/chrome_test.dart focus reveals a clipped chip.
• PanelController.events, synchronous: TabOpened, TabClosed, TabMoved from one placement diff per commit, plus TabActivated, LeafFocused, TabUpdated, LayoutReplaced. closeGuard asked before any close, from the × or a verb; closeOthers, closeToTheRight, closeLeaf ask per tab. updateTab for a title or a flag. test/controller_test.dart.
• TabGroup.persistent (false): a group that stays in the tree when its last tab closes — an IDE's editor area, where documents come and go but the place they open into is part of the layout. The rule is window-wide: an empty persistent group is removed as soon as the tree keeps another persistent group, so only the last editor area ever stands empty, and a tab dragged out of a persistent group makes a persistent group, so an editor area split in two is two editor areas that fold back into one as they empty. removeTab empties rather than removes, join keeps the flag, and an empty one cannot be dragged: its strip is a drop target, not a handle. LeafNode.activeTab is nullable for it, and PanelHost.emptyLeafBuilder draws what goes where its content would. The file format carries persistent. a persistent group survives its last tab, an emptied editor area folds away while another remains and a tab dragged out of an editor area makes another editor area in test/model_test.dart; an empty persistent group draws its placeholder and takes a drop in test/panel_host_test.dart.
• A removed child hands its room to the sibling before it — after it when it was first — rather than to every sibling in proportion, so closing the right-hand editor group widens the group beside it and does not nudge the file tree along too; a fixed neighbour keeps its pixels and the room goes to the nearest flex one. In LayoutTree.replace. a removed child hands its room to its neighbour in test/model_test.dart.
• DockPolicy.takesFocus(leaf) (true): which leaves may be the window's focused leaf — where open puts content, what the keyboard verbs act on, whose strip shows the full accent. An IDE answers no for its tool panels, so a click in the file tree never makes the tree where the next document opens, and the accent stays on the editor group it will open into. PanelController.focusedLeaf falls back to the first leaf that does. focus policy in test/controller_test.dart.
• Context menus, in the shape of fl_nodes_v2's: PanelHost.contextMenus (const PanelMenus(); null for none) opens a Material menu on a right click on a chip, a strip's background, a single panel's header or a divider. The entries are PanelMenuEntry data built by PanelMenus.defaultEntries from the controller's verbs — close verbs and a Split submenu on a chip, Close all and Move to edge on a strip or a header, Equalise and Swap on a divider, each greyed when it would not apply — and PanelMenus.build rewrites them with the defaults in hand. A PanelDecorations.onTabSecondaryTap keeps winning on chips. Two verbs came with them: PanelController.equalise and swap, over LayoutTree.equalise/swap, and canDock as the dry run a menu greys by; a leaf moved to the window edge it already sits on is a no-op. test/menus_test.dart.
• PanelTab.closable (true): off for content an application always shows. The chrome draws no close glyph on its chip or header, and PanelController.close refuses without asking the guard, so the group verbs skip it and closeLeaf keeps its leaf; it still moves. In the file format as closable. closable in test/controller_test.dart, an unclosable tab draws no glyph in test/chrome_test.dart.
• PanelDecorations.wrapTab: a wrapper around the whole chip, inside the drop slot — a tooltip, a spotlight target — because a host with a tour needs to point at a tab and neither tabLeading nor tabTrailing is the tab. Same test as above.
• package:fl_panel/model.dart exports the Flutter-free half; test/flutter_free_test.dart keeps it so.
• example/: an IDE-shaped demo with a metadata policy and save/restore.