diff --git a/AGENTS.md b/AGENTS.md index cdb8112..d25f4ab 100644 --- a/AGENTS.md +++ b/AGENTS.md @@ -68,7 +68,7 @@ Platform adaptations, each forced by a missing Qt analog: - The Move tool on the canvas (6.1): `TransformOverlay` is no widget. Swift's overlay view exists so that a selection never redraws the pixels; a transparent Qt child would repaint the canvas beneath it anyway, so the canvas draws the handles and guides itself, after its pixels, and `synchronizeDisplay` repaints only the union of the old and the new `drawnRect` (a guide spans the canvas) when the geometry or `snapGuides` changed, leaving its return value to the pixel state. `TransformOverlayGeometry` keeps Swift's handles, rotation grip and `hit`; `showsRotation` and the corner constructor arrive with 6.2. `resizeCursor` maps Swift's frame positions onto Qt's four resize shapes (right, bottom right, bottom, top right). `EditorCanvas+Transform.cpp` holds the drags (`beginTransformDrag`, `dragTransform`, `endTransformDrag`, `cancelTransformDrag`, Swift's `resignFirstResponder`), `transformPressLayer` and `transformCursor`; Ctrl stands for Cmd in picking, Ctrl+Shift extends the selection. The drag's cursor is kept in `m_dragCursor` until the release and outranks Space, where Swift disables the window's cursor rects; hover reaches `updateCursor` through mouse tracking and the last hover point, the application filter reads Alt and Ctrl as it read Alt, and a shown canvas reads both from the keyboard. The release synchronizes the display, so a Ctrl+T edit's guides go without a commit. `moveCursor` (the arrow with Swift's four-way badge) and `rotationCursor` (two arrows round a ring, for the SF symbol) are drawn as paths; the distort cursor arrives with 6.2. `SnapGuides` is a struct where Swift has a tuple, a public member like `viewport`, unannounced; `commitTransform` and `cancelTransform` clear it. `transformSnapTargets` and `snappedMove` live in `Document/Crop.cpp`, Swift's file. `TransformEdit.persistent` sits last, so the positional initialisers keep their order; a drag's edit and a duplicate's are not persistent. `transformAutoSelect`, `showsTransformControls` and `locksTransformRatio` are getters and setters that notify. Escape and Return end a drag with its edit and put the hover cursor back. A press that never moves commits an unchanged edit, which the history drops. The pixel tests hide the controls (`CanvasDisplayTests`, `HighDpiCanvasTests`) and preview through a drag's edit, since Swift's overlay never reaches its `draw` tests. - Distort (6.2): `DistortWarp` keeps Swift's tests of usability and convexity, `homography` (a projective `QTransform` where Swift returns a closure, Qt dividing by the third row as Swift by `w`), `warp`, `warpTrimmed`, `carried` and `warpMask`. Core Image's perspective filter is `QTransform::quadToQuad` on the image's pixel rect and a `drawImage` under it, antialiased and smooth; a folded shape is two triangles under their affine maps, each a hard device-pixel region of the pixels whose centres the triangle holds, built per scanline from each edge's ends ordered by y, the left bound inclusive, so the halves partition the diagonal and meet a fractional shared edge with one x (a path clip turns soft once the image draws antialiased, and `QRegion`'s integer polygons round the vertices), copied through `BrushRaster::draw` without interpolation, as Swift's. In `distortPreview` a mask warp that throws is caught on its own, as Swift's `try?`: a linked mask covering its layer then draws none, a placed one falls back, with a folded shape, to its stored placement clipped over the warp. Its `Warped` and `Trimmed` structs stand for Swift's tuples; `mapPath` arrived with 8.2b and `distortedEffects` arrived with 9.6c. Swift's `DistortTests` agree since 1.2.1 (`7111885`): a bow tie is usable and folds as two triangles, not convex, and a collapsed corner is refused by both tests; the preview takes a folded shape. `TransformEdit.corners` sits last, after `persistent`. The session's `distortPreview` and `maskDistortPreview` are `const` with mutable caches (`DistortPreviewCache` by layer, `MaskDistortPreviewCache`), keyed by `ImageIdentity` where Swift compares `CGImage` identity, because the canvas reads them from a const session; a warp that throws leaves a cached empty result, as Swift's `try?`. `commitDistort` catches `ProjectError` and `ExportError` into `brushError` as Swift catches its errors; `commitTransform` runs it after the mask path, before the plain one, and ends a duplicate after it. `commitMaskTransform` takes the corners path with `Distort Layer Mask`, `displayedMaskPlacement` its corners cases, `nudgeLayer` moves the corners with the draft. The overlay's corners constructor sets `showsRotation` false, `hit` skips the grip then, and the drawing leaves the stem and disc out; `geometry` returns the corners' geometry for a group or the edited layer. The canvas's `DisplayState` carries the edit's corners, so a moved corner repaints; `drawOwn` draws `distortPreview` first and takes `maskDistortPreview` for the mask. A Ctrl-drag on a handle begins the distortion and drags in `distort` mode with the white `distortCursor`; the cursor shows it over a handle under Ctrl or once distorted. The inspector's numbers rest while corners are set, as Swift's `.disabled`. - `TransformInspector` is the Move tool's `ToolHeaderBar`: Auto Select and Show Controls as `QCheckBox`es, the numbers in a `QScrollArea` without bars (Swift's horizontal `ScrollView`, which takes the row's spare room and keeps its content at its own size: the row's end stretch rests, the content ends in a stretch of its own), the ratio lock a checkable `QToolButton` with the panel's link icon, the sampling a `QComboBox`, Flip H and V and Cancel and Apply as `QPushButton`s. `TransformValueField` applies as typed (Swift's `isFinite` test is left out: `previewTransform` refuses every transform an infinite number makes), shows the session's number while unfocused and puts it back on `FocusOut`, steps with Up and Down (Shift ten) writing the number it applied, keeps its typing while a menu or popup borrows the focus (`MenuBarFocusReason`, `PopupFocusReason`), and on Return or Escape hands the canvas the keys as Swift's `onSubmit` and `onExitCommand`; the pending edit waits there for the canvas's Return or Escape. From any other control of the bar, Return applies and Escape cancels, Swift's default and cancel actions. The lock's icon is redrawn on `PaletteChange`, as the panel's. Swift's `.id(activeLayerID)` remake is `synchronize` clearing any focus of its own when the active layer changes. `resizeBox` is Swift's `resize`, whose name would hide `QWidget::resize`; its `number >= 1` guard and the scale's `number > 0` are left out: a side under a pixel is a box `previewTransform` refuses. The Layer menu's Transform Layer entry calls `beginTransform` (Swift's `transformCommand` does the same without a selection; 7.4 brings the selection) and the View menu's Show Transform Controls is checkable under Ctrl+H, enabled in the Move tool with a document. -- Selections (7.1): `DocumentSelection` holds a `QPainterPath` where Swift holds a `CGPath`, `SelectionClip` a `QImage` coverage; `SelectionClip::apply` has no twin, because QPainter has no soft clip: `PixelAdjust::coverage` draws the clip's coverage through the layer's inverse `pixelToDocument` into a mask surface (smooth, as CoreGraphics filters a mask clip) and `PixelAdjust::blend` mixes two images through it byte for byte, rounded, where Swift runs `CIBlendWithMask`. Qt's `united`, `subtracted` and `intersected` honour each path's own fill rule and return odd-even paths whose fill is the region they name (probed, `QPathClipper`), so an outline made here is `WindingFill` (a lasso crossing itself fills like Swift's `.winding`, a traced mask keeps its holes) and a result keeps the rule Qt gave it; every fill and `contains` reads the path's own rule, and `QTransform::map` keeps it. Expand and Contract stroke the outline with `QPainterPathStroker` (round cap and join, Swift's `copy(strokingWithWidth:)`; Swift's miter limit is idle under a round join and left out), and a contraction past the middle leaves Qt's empty path, `isEmpty`. `DragBox::rect` rounds with `std::round`, Swift's `rounded()`. The session's selection state is private with getters and setters (`lassoKind`, `marqueeKind`, `selectionModeChoice`, `selectionAntialiased`, the two amounts), `lassoDraft` and `heldSelectionMode` getters alone; `selectTool` cancels a lasso, as Swift's does. `pressMarqueeKey` and `pressLassoKey` arrive with the canvas keys of 7.2; `displayedSelection` with the ants. `PixelInvert::run` is a byte loop where Swift calls vImage (alpha − colour keeps premultiplied transparency), reading any other format as premultiplied first; `invertPixels` takes a completion callback, runs the job through `QtConcurrent::run` and a `QFutureWatcher` with the project busy, and writes back only when the layer still holds the pixels it computed from (identities compared, Swift's `===`); the worker catches `ExportError` alone, the UI side `std::runtime_error` (the clip, the expanded 1×1 mask, the thumbnail), each a warning on `omaphoto.app` and `brushError`. `invertPixels` moves `brushRevision` after its step, as Swift's does. `addMask` from a selection draws the outline through the inverse of `pixelToDocument` into the layer's own grid; a blank layer's grid is its rounded size, as Swift's. `deleteLayerOrMask` is the session function the panel's trash, the Layer menu's Delete and (from 8.x) the Delete key share. The loaders in `MaskTracing.cpp` warn on `omaphoto.app` where Swift beeps, and fetch the pixels inside a try: a painted asset flattens on first use, and a flatten that cannot allocate loads nothing, where Swift's `CGImage` already exists. The Select menu and the Image menu's Invert sit between View and Layer, as macOS places `CommandMenu`s; Select All in a text field is the field's, like Undo (`QLineEdit` takes Ctrl+A itself through `ShortcutOverride`, so the entry's own branch matters only when triggered); Swift agrees since 1.2.0 (`90ee29f`, the responder chain first), and the entry never rests, as Swift's: without a canvas or a field it does nothing. The focus takes it first: a text field, open text, then a focused layer list, which selects every row with the top one primary, as `NSTableView`'s `selectAll(_:)` does in Swift's chain (`NativeLayerList::selectAllRows`), and only then the canvas. The panel's Ctrl-click on a thumbnail loads it (Ctrl-Shift adds, Ctrl-Alt subtracts, as Swift's `loadMode`), the row untouched; with Ctrl held over an enabled thumbnail the list shows `CanvasView::loadSelectionCursor`, a pointing hand drawn as paths with Swift's dashed badge, since `QCursor::pixmap` is empty for a shape cursor. `LayerMaskMenu` calls `addMask` and says in its tooltip what the selection becomes. +- Selections (7.1): `DocumentSelection` holds a `QPainterPath` where Swift holds a `CGPath`, `SelectionClip` a `QImage` coverage; `SelectionClip::apply` has no twin, because QPainter has no soft clip: `PixelAdjust::coverage` draws the clip's coverage through the layer's inverse `pixelToDocument` into a mask surface (smooth, as CoreGraphics filters a mask clip) and `PixelAdjust::blend` mixes two images through it byte for byte, rounded, where Swift runs `CIBlendWithMask`. Qt's `united`, `subtracted` and `intersected` honour each path's own fill rule and return odd-even paths whose fill is the region they name (probed, `QPathClipper`), so an outline made here is `WindingFill` (a lasso crossing itself fills like Swift's `.winding`, a traced mask keeps its holes) and a result keeps the rule Qt gave it; every fill and `contains` reads the path's own rule, and `QTransform::map` keeps it. Expand and Contract stroke the outline with `QPainterPathStroker` (round cap and join, Swift's `copy(strokingWithWidth:)`; Swift's miter limit is idle under a round join and left out), and a contraction past the middle leaves Qt's empty path, `isEmpty`. `DragBox::rect` rounds with `std::round`, Swift's `rounded()`. The session's selection state is private with getters and setters (`lassoKind`, `marqueeKind`, `selectionModeChoice`, `selectionAntialiased`, the two amounts), `lassoDraft` and `heldSelectionMode` getters alone; `selectTool` cancels a lasso, as Swift's does. `pressMarqueeKey` and `pressLassoKey` arrive with the canvas keys of 7.2; `displayedSelection` with the ants. `PixelInvert::run` is a byte loop where Swift calls vImage (alpha − colour keeps premultiplied transparency), reading any other format as premultiplied first; `invertPixels` takes a completion callback, runs the job through `QtConcurrent::run` and a `QFutureWatcher` with the project busy, and writes back only when the layer still holds the pixels it computed from (identities compared, Swift's `===`); the worker catches `ExportError` alone, the UI side `std::runtime_error` (the clip, the expanded 1×1 mask, the thumbnail), each a warning on `omaphoto.app` and `brushError`. `invertPixels` moves `brushRevision` after its step, as Swift's does. `addMask` from a selection draws the outline through the inverse of `pixelToDocument` into the layer's own grid; a blank layer's grid is its rounded size, as Swift's. `deleteLayerOrMask` is the session function the panel's trash, the Layer menu's Delete and (from 8.x) the Delete key share. The loaders in `MaskTracing.cpp` warn on `omaphoto.app` where Swift beeps, and fetch the pixels inside a try: a painted asset flattens on first use, and a flatten that cannot allocate loads nothing, where Swift's `CGImage` already exists. The Select menu and the Image menu's Invert sit between View and Layer, as macOS places `CommandMenu`s; Select All in a text field is the field's, like Undo (`QLineEdit` takes Ctrl+A itself through `ShortcutOverride`, so the entry's own branch matters only when triggered); Swift agrees since 1.2.0 (`90ee29f`, the responder chain first), and the entry never rests, as Swift's: without a canvas or a field it does nothing. The focus takes it first: a text field, open text, and then the canvas, a focused layer list included: Swift's table hands Select All to the canvas since 1.4 (`451281e`), so the list's own Select All of every row (12.5b) is gone. The panel's Ctrl-click on a thumbnail loads it (Ctrl-Shift adds, Ctrl-Alt subtracts, as Swift's `loadMode`), the row untouched; with Ctrl held over an enabled thumbnail the list shows `CanvasView::loadSelectionCursor`, a pointing hand drawn as paths with Swift's dashed badge, since `QCursor::pixmap` is empty for a shape cursor. `LayerMaskMenu` calls `addMask` and says in its tooltip what the selection becomes. - The Marquee and the Lasso on the canvas (7.2): Swift's lasso gestures live in `EditorCanvas+Selection.cpp`, the selection cursors in `EditorCanvas+Cursors.cpp`. The canvas tracks Shift as it tracks Alt and Ctrl (the application filter sees the key from any window, as Swift's `flagsChanged` monitor), and a key change reshapes a Marquee draft and the cursor's badge at once. A press with a selection tool is `lassoMouseDown`; a move is `moveSelectionTool` (a hover moves a polygonal draft's rubber band and refreshes the held keys, as Swift's `mouseMoved`); a release is `releaseSelectionTool`; the draft's keys and the outline's nudges are `selectionKey`, ahead of every other key; losing focus is `endSelectionGestures`. A double click closes a polygonal outline from `mouseDoubleClickEvent`, since Qt delivers the second press there (its first press adds the corner, as Swift's first `mouseDown` does), never while Space pans. A held M or L's repeats are swallowed, as Swift ignores them, so a tool chosen meanwhile stays. An outline drag keeps `moveSelectionCursor` under Space, as the transform drag keeps its own. The ants are a 120 ms `QTimer` stepping `TransformOverlay::antsPhase`, repainting `selectionRect` alone (the outline's own rect, not the handles beside it); `drawnRect` spans the handles, the outline and the draft, the last two stroked antialiased with butt caps (`Qt::FlatCap`, as CoreGraphics dashes: Qt's square caps would stretch each dash by the pen's width) as CoreGraphics strokes them (a 1-point line on whole coordinates blurs over two rows at 1×, on macOS too); `synchronizeDisplay` repaints the overlay when the displayed selection or draft changes, refreshes the overlay's cached rect with every full repaint (a pan moves the outline) and refreshes the cursor when a kind or the displayed mode changes. The two timers are named children of the canvas (`antsTimer`, `marqueeAutoscroll`), as the session's busy timer is, so tests read whether they run. Autoscroll is a 16 ms `QTimer` with Swift's speed curve; each step translates the viewport, drags the draft or the outline again under the still pointer, notifies and synchronizes. `moveSelectionCursor`, `selectionCursor` and `wandCursor` are drawn as paths: the crosshair, the icon haloed by eight white offsets and the badge, and the wand with Swift's own strokes (hot spot 7, 7 at the sparkle, the stick down right, the badge at 17, 5), since `QCursor::pixmap` is empty for a shape cursor; the icons are `Rendering/SelectionIcons`, which the rail's `ToolIcons` and the cursors share, so nothing in `Rendering/` includes `UI/`. `SelectionIcon` is that header's enum, not nested in `CanvasView`. Ctrl over the selection shows the move pointer until 7.4 brings the scissors; the wand's click and cursor are 7.3's. `pressMarqueeKey` and `pressLassoKey` choose their tools and nothing more, as Swift's functions do: Swift's tests once expected a second press to switch the kind, which no Swift code does (its `cycleToolMode` on Tab does, 8.x); since 1.2.0 (`b5cb4fa`) they test the code's rule, as the twin does (`…AndKeepsTheShapeLastSet`), and the twin's tooltips name no key. `LassoControls` is the selection tools' `ToolHeaderBar`: Swift's segmented pickers are checkable `QToolButton`s in a `QButtonGroup`, the amounts are `SelectionAmountField`s (a `QLineEdit` taking digits alone, every typed value clamped to 1–500 as Swift's binding clamps it, stepped by arrows within the bounds, Return and Escape handing the canvas the keys, a menu's borrowed focus keeping the typing as `TransformValueField` does), the wand's controls arrive with 7.3. `ContentView::hint` takes a `ToolIconKind` for the ellipse Marquee's and the polygonal Lasso's words, and the rail's buttons repaint with the kind. - The Magic Wand (7.3): `WandPixels.c` compiles in place beside the other kernels, and `Document/MagicWand.cpp` wraps it as Swift's `MagicWand` does: `select` draws the image into a premultiplied `RGBA8888` context (the kernel's byte order, rows top down), floors the point, clamps the tolerance and hands the mask to `wand_mask`; `outline` frees the kernel's arrays through `unique_ptr` and builds a `WindingFill` path from its loops. `MagicWandError` carries Swift's two messages (`what()`), `tooDetailed` for the kernel's −2 and `memory` for −1. The session's `magicWand` takes a completion callback and runs the job through `QtConcurrent::run` and a `QFutureWatcher` with the project busy, like the invert; the worker catches `MagicWandError` and `ExportError`, and the UI side applies the outline only while the same document is open (its id, as Swift compares), New with no match deselecting, New with a match `setSelection` without the canvas clip (Swift's shortcut), the other modes `applySelection`. `wandSample` draws the composite through `drawLiveComposite` or the active layer's own pixels through `LayerRenderer::draw` at 1:1, a folder or blank layer as clear; a context that cannot be allocated logs and refuses, as Swift's `try?` returns nil. `wandSettings` is a struct with a setter that notifies; `title` and `radius` stand for Swift's computed properties of `WandSampleSize`. The canvas hands a wand press to `magicWand` with the press's mode, and a click inside the selection to `magicWand` in New mode where another tool would deselect. `LassoControls` shows the wand's controls with the wand alone: the tolerance is a `SelectionAmountField` bounded 0–255, the sample size a `QComboBox` of Swift's titles, the source two checkable buttons, Contiguous a `QCheckBox`; `changeWand` rewrites one field of the settings. The mutant that pins `m_thisLayer` checked is equivalent, since the exclusive group's later `m_allLayers` line decides, as with the marquee's kinds. - The clipboard (7.4): `SelectionClipboard.cpp` twins Swift's extension as far as the raster edits exist. `PixelClipboard` and `CopiedPixels` (Swift's tuple) live in `Document/SelectionClipboard.h`. `renderSelectedPixels` and `renderMergedPixels` draw into the copy region and multiply the selection's coverage in with `DestinationIn` through `BrushRaster::alphaView` (`clipTo`), where Swift clips the context (`SelectionClip::apply` has no twin); a mask copies as opaque gray with `LayerMask::background` for its ground when placed apart and `LayerRenderer::drawCoverage` for its white, each pass multiplied on its own (the white in a second surface), because CoreGraphics clips both and a soft edge then stacks: half coverage under a white mask is alpha 192, not 128. `store` gives the system clipboard the image and a PNG through `QMimeData`, and keeps a `QPointer` to the `QMimeData` it hands the clipboard where Swift reads the pasteboard's change count (since 12.10b; Qt's `dataChanged` is no count, since Wayland announces one copy twice): while this app owns the clipboard Qt returns that very object (offscreen, X11's client clipboard, Wayland's selection source), any other copy, a history manager's restore of the same bytes included, is another object, and a replaced object is deleted, which nulls the pointer, so a copy once replaced never counts again, as a change count never returns; a paste puts our pixels back in place while the clipboard still holds that object (`clipboardHolds`), else takes another app's image through `QMimeData::imageData`, converted to sRGB first when it carries another colour space (CoreGraphics converts as it draws; `QPainter` copies the numbers), then to the working format, tagged sRGB and centred. A cleared clipboard has no `QMimeData` at all, so `canPaste` checks the pointer. A working copy that cannot be allocated is a warning, as Swift's `try?` beeps there, where a failed Layer via Copy sets `brushError` as Swift's `catch` does. The clipboard is touched only by a copy or a paste, so session tests without one run under `QTEST_GUILESS_MAIN` still; `SelectionClipboardTests` runs under `QTEST_MAIN`. `addPixelLayer`'s shape and text arrived with 8.8 and 8.9a. Swift's `cutSelection`, `PixelMove` and the whole `FloatingSelection` extension need `clearSelectedPixels` and the brush raster, so the cut arrived with 8.2 and the rest with 8.2b, where `canEditLayers` and `ProjectWorkspace::canSwitch` gained their `pixelMove` terms. The Edit menu's Copy and Paste check when chosen, as Swift's (a text field keeps its own, as with Select All); Copy Merged follows `canCopyMerged`; the Layer menu's Ctrl+J is `layerViaCopy`, titled by the selection and enabled as Swift's: `canCopyPixels`, or no selection on an editable layer (a folder too since 12.10b). Swift's beeps are warnings on `omaphoto.app`. @@ -170,6 +170,9 @@ Platform adaptations, each forced by a missing Qt analog: - Compositor 1.4, part one (13.8: `8c0417b`, `fe7a83d`, `af3b568`, `3ccc125`, `d0135c8`, `dcf1c66`). A sharper canvas: `LayerRenderer::interpolation` takes Swift's `upright` (a layer whose `radians()` is 0, drawn within a thousandth of pixel for pixel, takes no filter), from `LayerRenderer::draw` and `TiledLayerRenderer`'s frames alike. The twin's adjustment surfaces already held device pixels (9.5b) and its adjustments already ran at the surface's scale (12.8c), so 1.4's surface and `adjustmentScale` changes were held; what was missing is ported: `AdjustmentSurface::draw` falls back to a pixel a painter unit when device pixels pass the budget (Swift's "falls back to points"), drawn back smoothly (Swift's `.high`), and nothing only when that passes too; `LayerAdjustment::apply` counts the noise origin per axis (`top × height / max(1, region height)`), where the twin used the width's scale for both. PSD (`IO/PSD`): Levels gamma in hundredths; `hue2` read as Swift's: 16 bytes at least, Colorize's own values or the Master's, then for each of the six ranges its band (degrees wrapped into 0–360) and values, 14 bytes each, until the data runs out; the reader keeps each mask's bounds and default byte (`PSDRecord::maskBounds`, `maskDefault`), and `PSDDocumentBuilder::maskOnLayerGrid` draws the stored patch, unfiltered, onto the layer's grid (its pixels, or the canvas for a layer without) at its place, the default round it; already the grid, or with no size, the patch is kept; a grid that cannot be allocated logs on `omaphoto.io` and takes the builder's existing "couldn't be converted" note, as Swift's nil does. `PSDAdjustments::levels` and `hue` are public, as Swift made them for its tests. Photoshop's Saturation: `HueSaturationFilter::adjustedSaturation`, Swift's to the letter. All cores: `kernels/LevelsPixels.c/.h` are Swift's file again (`cube_apply`); `BrushRaster::copy` (bytewise for the context's own format, drawn otherwise) and `BrushRaster::inBands` (one band under 250,000 pixels, else twice the ideal thread count, through `PoolMap`; a `bad_alloc` there is `ExportError(render)`, since the workers' callers catch that alone); `LevelsFilter::run` copies and runs `levels_apply` in bands; `HueSaturationFilter::run` copies and runs `cube_apply` in bands, where the twin had its own trilinear loop (the kernel's float order now: within a level of it, Swift's tests allow eight); `cube` keeps the last eight tables under a mutex, Swift's `cubes`. A blur's preview kept while the layer grows: `FilterEdit` gains `preparedTransform` and `pendingTransform`; a render carries the grown layer it was made from (`Filtered::placement`) and lands there, shown until the next replaces it; `displayedTransform` and `displayedMaskPlacement` read `preparedTransform`. Left out as dead in the twin: Swift's `current` terms (only a blur grows its grid, and only the automatic kinds, which never grow, refuse a stale preview or read `preparedSettings`), so the grid's version (`previewSourceVersion`, `Filtered::sourceVersion`) goes with nothing left to read it, and so does the twin's own remaking of a waiting job on growth (with Preview off nothing lands; with it on, the update makes a new job). The hierarchy kept: `LayerOrder` (`Document/LayerGroups.h`, its code in `LayerGroups+Order.cpp` with the document's hierarchy members, since `LayerGroups.cpp` would pass 500 lines): `Node`, `Result` (`order`, `visible`, `drawn`) and `resolve`, which keeps the last nodes and answer under a mutex; `CanvasDocument::hierarchy()` replaces `hierarchyEntries()`; `effectiveVisibleIDs`, `renderLayers` (a checked `std::map` index, after Swift's empty-order guard) and `effectiveOpacities` (a map of opacity and folder, no whole layers) read it; `groupSelectedLayers` reads `hierarchy().order`. `dcf1c66` was held: the canvas's `DisplayState` already works out the visible set once. Tests: `SharpCanvasTests` (the rule's edges; plain, masked and tiled layers crisp within the tolerance, filtered past it), `PSDAdjustmentTests` (Swift's three, plus the wrap, Colorize leaving the ranges, a cut record, the builder, a pixel layer's grid, a stretched layer, the patch kept, bounds or a layer of no height or width, the grid's bounds with a smaller patch, a patch the grid's size a pixel along), `PSDReaderTests` (the new layouts, the mask's bounds and default read and placed), `HueSaturationTests::positiveSaturationMatchesPhotoshop` (Swift's values, the clamps, a pixel), `AdjustmentBandsTests` (bands cover each pixel once, the copy's bytes, Levels and Hue/Saturation in bands against one pass of the kernels, cached tables), `HueSaturationFailureTests` (the filter now fails at its copy, the row list being gone), `FilterTests::growingABlurKeepsThePreviewUpUntilTheNextOne` (Swift's) and `aMaskKeepsItsPlaceUnderAPreview` (a covering mask under a preview that did not grow, and on a grown one the old bounds), `FilterSessionTests` and `FinishingFilterTests` (an older grid's preview shows on that grid: `aPreviewForAnOlderGridShowsOnThatGrid`, `aJobWaitingBehindAnotherEditShowsOnItsGrid`), `LayerOrderTests` (order, visibility and drawing against `LayerHierarchy::entries`, each shaping change seen, 64 deep, nothing shown draws nothing, opacities up known folders alone and a repeated id refused), `GroupTests`, `BlurNoiseAdjustmentTests::noiseStaysOneFieldAcrossRegions` (each axis by its own scale, a region under a unit), `AdjustmentSurfaceTests::pastItsPixelBudgetNothingIsDrawn` (the fallback, enlarged smoothly; a quarter of a pixel makes one). Equivalent mutants: `adjustedSaturation`'s clamps of the amount to ±1, its `max(0, …)` below zero and `share > 0` for `>= 0` (each branch gives the same number there; Swift's to the letter); the cube cache's insert, its removal of an older entry for the same settings and its trim to eight (each only spares work or memory); `BrushRaster::copy`'s bytewise branch taken never (drawing copies the same bytes), `inBands`' threshold moved by one and its `start < count` guard (Swift's; no start reaches the count unless the thread count passes some 500); `LevelsFilter::run` drawing its copy (the same bytes); `LayerOrder::resolve` keeping nothing (the cache only spares work). Untested failure path: `maskOnLayerGrid` out of memory (only an allocation that fails reaches it). Judgments: the adjustment surfaces' device resolution and `adjustmentScale` were held (9.5b, 12.8c); `dcf1c66` was held (the canvas already works out the visible set once); the rest ported. Mutants: 60 run, every one caught or recorded above (two unbuildable forms rewritten and caught). - Blending (13.9a: `6dc2219`, `8ab32c9`, `5a8f6ce`, `e6c964b`). Held, proven: clipping stacks and live-mask coverage at device resolution (the twin's `LiveMaskRenderer` has no `bounds`: its group, alpha and coverage surfaces are the painter's device since 4.x, so Swift's `resolution` and `pixelSize` have no twin); an adjustment in any mode, over the document and inside a stack, blended at full coverage, its alpha restored, then mixed through mask and opacity (`adjust`'s `blended` goes through `LayerRenderer::composite`, which hand-blends every mode QPainter lacks through `HslBlend`, so Swift's `SeparableBlend.blend` has no twin); a clipping stack composited in its base's mode in every mode (`drawComposite` hands `m_stackModes` to `LayerRenderer::composite`, the same path), on the canvas, in export and in Copy Merged alike. Ported: Soft Light by Photoshop's formula, as Core Image computes it (2bs + b²(1 − 2s) up to half, 2b(1 − s) + √b(2s − 1) above), in `SeparableBlend::channel`, and `needsSurface` names Soft Light, so `HslBlend` blends it by hand everywhere a layer, a stack or an adjustment is drawn; `LayerRenderer::compositionMode` loses its Soft Light case (dead now). Compared first: Qt's `CompositionMode_SoftLight` is the PDF's (W3C) formula, which equals Photoshop's below a source of half and above it wherever the backdrop passes 0.25; under that it takes the PDF's cubic for √b and runs up to 17 levels darker (backdrop 5/255, source 1: 19 where Photoshop gives 36). Swift's 0.9 over 0.5 gives 170 under either formula. Known difference: Swift's Core Image is "within 5 levels of Photoshop's"; the twin is Photoshop's own formula, so it may differ from Swift's by those few levels. Tests: `BlendingTests` (Swift's `clippingStacksBlendInTheirBasesMode` for Linear Dodge, Color Dodge and Multiply: Swift's numbers, Copy Merged equal to export, the canvas within a level; adjustments in Difference and Linear Light over the document and Vivid Light and Subtract inside a stack, by the numbers, at full and half opacity, in all three places; Swift's `softLightMatchesPhotoshop` plus a dark backdrop and the lower branch; Swift's `softEdgedLayersBlendTheSame` for Soft Light, Overlay, Multiply and Color Dodge: a radial soft layer over noise, Copy Merged equal to export, the canvas within a level), `BlendModeTests::everyBlendModeMatchesThePdfFormulas` (its Soft Light reference is Photoshop's now; its backdrops of 0.1 and 0.25 under sources past half catch the PDF's cubic), `ClippingStackTests::stacksAndCoverageTakeTheDevicesPixels` (a half-unit stripe stays sharp at a device scale of two, in a stack and through coverage from a source further down). Equivalent mutant: Soft Light's `source <= 0.5` for `< 0.5` (both branches give the backdrop at a half). Judgments: stacks and coverage at device resolution, adjustments in any mode and a stack in its base's mode were held (proven by the tests above); Soft Light ported. Mutants: 5 on Soft Light, 4 caught, one equivalent (above). - The Metal canvas (13.9b: `cdf8674`, `4b04323`, `5708ed3`, `93de9e7`, `54dd707`, `91cb0b1`, `f773f7b`, `4c5e1a6`, `d04f159`, `b1b7490`). OmaPhoto stays a CPU canvas (the port's decision): Swift's GPU canvas, its `GPUCanvas`, `GPUNoise`, `MetalWarp` and `CanvasLinesOverlay` and the GPU branches of `EditorCanvas`, have no twin; the twin's canvas is the Core Graphics canvas those commits compare against. Ported: Grain and Add Noise anchored to the document (`54dd707`): `LiveMaskRenderer::adjustmentRegion` (Swift's `adjustmentRegion`) maps what the painter shows into the document, and the canvas's `drawLayers` sets it from its centre mapping and zoom, so the smooth path counts noise in frame pixels from the document's corner and Grain in document pixels, as export does, and the crisp path's surface maps to document pixels, so a partial repaint keeps one field; the blur's scale still comes from the unmapped region. This retires 9.5b's and 12.8c's known differences (Grain and noise following the view, a partial repaint's own field); `CanvasDisplayTests::grainFollowsTheViewOnTheCanvas` is gone. Export and `drawLiveComposite` already draw in document pixels and set no region, as Swift's. Tests: `AdjustmentCanvasTests` (Swift's `matchesEveryAdjustment`: every kind through a ramp mask at 80% over a photo and a translucent layer, the canvas within a level of the export over its checkerboard; Swift's `patternsStayWithTheDocument` for Add Noise and Grain: equal to export at 100% and 200%, panned and not, and at 80% a whole-pixel pan moving the pattern with the image and a partial repaint showing the whole's pattern within two levels of resampling), `CanvasEditContractTests` (Swift's `aNewMaskRevealsTheWholeLayer`, upright and turned: a one-pixel mask on a scaled layer changes no covered pixel, the canvas as the export; `matchesWhileMovingPixels`, moving and duplicating on a masked layer at 60% under a soft selection: the preview equals the commit and the export outside the ants, the hole only for a move; `matchesWhileDraggingAGradient` in a selection at 70%: the pending gradient equals its commit outside the overlays, nothing outside the selection; `5708ed3`'s failed fill cancelling with `brushError`, no step, the document unchanged; `matchesALiveMaskOutsideAClippingStack`: a turned source with a layer between, the canvas as the export), `CanvasContractFixtures.h` (the scene, the export over the canvas's checkerboard, a gap that skips the overlays' bands, the ramp mask). `cdf8674`: rotation, flips, scale, sharp successive reductions, premultiplied blending in every mode with layer and ancestor opacity, the checkerboard anchored to the document, the crisp composite at high zoom, sampling modes and rounded-up reduction extents, premultiplied blending in sRGB, the surround, shadow and border, placed own masks and multiplied folder masks on pixel layers, filter, Levels and Hue/Saturation previews in the layer's place: held; the CPU paths are the reference and are pinned by `LayerRendererTests` (placement, sampling rules, halvings, overhang), `DownsampleTests`, `BlendModeTests`, `CanvasDisplayTests` (checkerboard, shadow and border, crisp from 200%, the rich scene against the export), `FolderOpacityTests`, `FolderMaskClipTests`, `MaskPlacementTests`, `LevelsCanvasTests`, `HueSaturationCanvasTests`, `VignetteCanvasTests`. `4b04323`: a moved or duplicated selection's preview and commit: held and now proven on a masked, translucent layer (above). Swift's laziness (`PixelMove.applyOffset`, `holed`, `liftedTarget`) only spares the GPU canvas a rebuild per move; the twin rebuilds eagerly in `movePixels`, which realises the tiles before display and commit by construction, and a failure there cancels the move with `brushError` (`PixelMoveTests::aPixelMoveHoldsTheSessionAndAFailedMoveCancels`). `5708ed3`, `91cb0b1`: live paint, erase and mask paint, paint past the old bounds under the old mask (`TiledStrokeTests`, `BrushPreviewTests`, `MaskPaintAnywhereTests`), Smudge and Liquify previews through the mask, opacity and placement (`SmearCanvasTests`, `FolderOpacityTests`): held. `GradientEdit.Fill` and `applyFill` are the GPU's laziness; the twin fills in `refreshGradient`, before display and commit by construction, a failure cancelling with `brushError` (now tested), and the commit publishes what was filled. `MetalWarpTests.matchesTheCPU`: the twin's `WarpStroke` is the CPU reference (`SmudgeLiquifyTests`); nothing to port. `93de9e7`: a one-pixel white mask revealing its layer: held (QPainter's smooth draw clamps an image's edge, as Core Graphics draws it; now tested); the live paint grid's extent and edge sampling: held (`TiledStrokeTests`, `DownsampleTests`, `TiledLayerTests`). `clampedToExtent` is GPU-only. `54dd707`: every adjustment kind with alpha, masks and opacity, blurs at the drawn scale and direction, adjustment results equal to the CPU reference, deterministic seeds: held (the canvas runs the CPU filters themselves; now tested for every kind); Grain and Add Noise anchoring: ported (above). `f773f7b`: non-adjacent live-mask sources (now tested), distortion previews (`DistortCanvasTests`, `DistortMaskTests`, `EffectsCanvasTests`), text previews keeping and handing on effects (`TypedTextCanvasTests`), drafts above the active layer (`ShapeCanvasTests`, `TypedTextCanvasTests`; inside a clipping stack the draft is drawn by `drawOwnWithDraft` inside the stack's group, as Swift's), new text when the active layer cannot draw, effects and placed masks kept while brushing, painting masks, dragging gradients and moving pixels (`EffectsCanvasTests`, `MaskEffectsCanvasTests`, `BrushCanvasTests`, `MaskPaintAnywhereTests`): held. `distortShape`, the now-internal `imageCorners` and `editedText`/`handOffTextEffects` are GPU plumbing or a refactor of what the twin already draws. Known difference: Swift moves the pixel grid and a new text frame into an overlay view below its transform overlay, so the grid draws over the document's border hairline and the text frame under the other overlays; the twin draws the grid inside the document under the hairline and the text frame last. Both sit above the pixels and take no input; the order shows only on the hairline's edge pixels (a 13% white line), and no other overlay shows while a text frame is dragged. A port was tried and left: QPainter's antialiased hairlines make the order unprovable to a level. `4c5e1a6`, `d04f159`: texture retention, eviction and blits are GPU mechanisms; the CPU's sharp reductions are `DownsampleCache`'s, pinned by `DownsampleTests`. `b1b7490` only words a test's diagnostics. Tests tried and left: a distortion's preview against its commit differs on noise (the commit resamples the warp at its trimmed place), which Swift's tests never claim (they compare two previews); `DistortCanvasTests` pins the preview. Mutants: the region's mapping and use in `LiveMaskRenderer::adjust` and each term of the canvas's `adjustmentRegion`: 6, all caught (the width and height terms only once the partial repaint was compared). Judgments (each Swift contract, held unless named above): +- Shift on a pixel drag and Select All from the list (13.10): `CanvasView::moveSelectionTool` (`EditorCanvas+Selection.cpp`) twins Swift's `60bde4f`: with Shift held a Ctrl-drag of selected pixels zeroes the shorter axis of the offset, lengths compared (`std::abs`), a tie keeping across, as `dragSelection` already does for the outline; read from each move's own modifiers, as Swift's `event.modifierFlags`. `451281e`: Swift's table now hands Select All to the canvas (`session.selectAll()`, guarded on a document) instead of selecting every row, so the twin's `NativeLayerList::selectAllRows` (12.5b's round-3 fix) and the menu's `focusedList` branch are gone: a focused list falls through to `session().selectAll()`, which guards on the document itself. A rename's editor is a `QLineEdit`, so it keeps its own Select All first, as Swift's field editor. Tests: `SelectionCanvasTests::shiftKeepsMovedPixelsOnALine` (across, down, a tie, a long left beating a short down, without Shift, the release keeping the last offset), `SelectMenuTests::selectAllInAFieldIsTheFields` (a real Ctrl+A on the focused list selects the canvas, history "Select All", layers and the active one unchanged, the list keeping focus; Swift's `selectAllInTheLayersPanelSelectsTheCanvas`). Mutants: 5 on the Shift branch, all caught (the `abs`-less comparison caught after the left-beats-down step was added). No survivors. +- Why a brush cannot paint (13.11, `133c34a`): `EditorSession::paintRefusal` (`EditorSession+Brush.cpp`, declared in `EditorSession+Brush.h`) twins Swift's `paintRefusal`: none while `canEditLayers` refuses, without an active layer or when `canPaint` holds; then several layers, a folder's pixels, a hidden layer or one in a hidden folder, a mask turned off, an adjustment's pixels, an empty selection, in Swift's order and words, with Ctrl+D for ⌘D and the curly quotes kept. `beginBrush` splits Swift's guard: a tool that cannot paint the target (Spot Healing or Clone Stamp on a mask, a tool that is no brush) returns silently, a refused target sets `brushError` to the refusal (none when busy, so a waiting error is cleared, as Swift's `brushError = paintRefusal`). `beginWarp` sets the mask's words or the refusal. Fix beyond Swift: Swift's gradient sets the refusal only past its first guard, which is reached with a refused target only while a gradient is pending, where `canEditLayers` refuses and the refusal is always nil; so Swift's gradient says nothing on an empty selection, which its commit message says it explains. The twin's `beginGradient` sets the refusal at the first guard (no pending gradient, `canPaint` refusing); Swift's second assignment, always nil there, is left silent. `invertSelection` leaves no selection when the inverse is empty (Select All then Inverse), one `Inverse` step, as Swift's. Tests: `PaintRefusalTests` (every refusal and its order: two layers before a folder, a folder's mask turned off before the folder, an adjustment's mask before the adjustment, a layer inside a hidden folder; the gradient and the Smear; a busy session clearing, another tool silent), `SelectionTests::inverseOfEverythingDeselects` (Swift's). Equivalent mutants: `paintRefusal`'s `canPaint()` term (when `canPaint` holds every later test is false) and the empty-selection test without `isEmpty` (reached only when `canPaint` refuses for no listed reason, which needs an active layer outside `selectedLayerIDs`, which no session call makes). Painting at the layer's own resolution (13.11, `d3170ab`): `BrushStroke::Clone` is Swift's tuple `{image, placed, inGrid}`: the image painted through the tip and where it sits, in document pixels or in the stroke's own grid. `clonePixels` maps tile pixels through the grid (and `pixelToDocument` unless `inGrid`) into `placed`, scaled to the image, so a translation alone still copies or shifts by the fraction as before. `BrushStroke::gridRect` (in `BrushStroke+Commit.cpp`, beside `transform`, as Swift's) carries a document offset into the grid through the inverse map's linear part (`CGSize.applying`), turned, scaled and flipped as the layer. `cloneSample` takes the stroke and the offset: the stroke layer's own pixels placed at `gridRect(sourceRect, offset)`, or, sampling all layers, the composite at document size placed `offset` away; `blurSample` takes the stroke: the layer's pixels or mask drawn nearest at the margin of a region `ceil(3σ)` round `sourceRect`, σ the canvas's tenth of the brush (1.5 to 30) divided by the grid's document size per pixel (`sqrt|det|`) and capped at half the longer side, a mask on its edge tone first, then `PixelAdjust::gaussianBlur` (a mask's edge repeated, pixels clear past theirs) at σ × fit, where fit shrinks the sample to a budget of `min(maxSurfacePixels, max(16 M, four canvases))`; it returns the region as `placed`, `inGrid`. Swift's old mask sample (the placement's black box, `drawCoverage`) is gone with it. `beginBrush` makes the stroke first, then samples into it, as Swift's; a sample that fails returns without a stroke. The Smear's commit places its copy at document size. The brush and eraser: Swift's commit only changes its CPU fallback's stamp (`stampDiameter`), dead in the twin (8.1); the held judgment holds: the twin's coverage is rendered in the stroke's grid, so `NativeResolutionPaintTests` passes Swift's erase cases (scaled down, unequal, turned, and on the canvas scaled back up) and the blank layer's document resolution without any change to `BrushStroke::grid` or `BrushCoverage`. Tests: `NativeResolutionPaintTests` (Swift's seven, plus the offset carried through a flipped and a turned layer, pixel for pixel), `BlurToolTests` (`theSampleFollowsTheBrushSize`, `theSampleIsInTheLayersOwnPixels`: twice as fine, and a tiny layer's cap; `aHugeLayersSampleIsMadeCoarser`: 16 M and four canvases; `aMaskSampleKeepsItsEdgeTone`), the tests' document clones through `documentClone` (`BrushFixtures.h`). Cancel and Apply, and a scaled layer's row (13.11, `67cc31e`): `TransformInspector` puts Cancel and Apply in a row of their own (`pendingTransform`, spaced 12) that shows only while the edit waits (`transformEdit()->persistent`: typed values, Ctrl+T, a distortion begun so); a handle drag's edit leaves it unseen. Swift's `.opacity(0)` keeps the buttons in the layout and their keys alive, so the row keeps its place under a `QGraphicsOpacityEffect` faded over 0.12 s with CSS's ease-out (`QEasingCurve` Bézier 0, 0, 0.58, 1, SwiftUI's `.easeOut`), passes clicks through (`WA_TransparentForMouseEvents`, Swift's `allowsHitTesting(false)`) and takes no focus while unseen; Return and Escape still reach the edit through the bar, and a remapped key through `NativeShortcut` (the buttons stay `isVisible`). Known difference: Qt has no per-widget accessibility hiding short of hiding the widget, so a screen reader still finds the unseen buttons (Swift's `accessibilityHidden`). `sizeLabel(const ImageLayer &)` (declared in `NativeLayerList.h`, defined in `NativeLayerList+Cell.cpp`, Swift's extension in its UI file) gives the row "W × H px", and once the width differs from the asset's by a twentieth of a percent or more, " · " and the percent to one place at most, ties to even, in the user's locale as Swift's `.formatted`; a blank layer has no pixels to measure. Tests: `TransformInspectorTests::cancelAndApplyShowOnlyWhileAnEditWaits` (a drag's edit unseen, its click falling through and Return applying; a waiting edit fading in, clicked; Cancel), `theFieldsTakeTheSpareRoom` (the row's place), `NativeResolutionPaintTests::layersPanelSaysHowFarALayerIsScaled` (Swift's, the threshold either side, a rounded tenth, a blank layer), the row in `NativeLayerListTests`. Mutants (13.11): paint refusal 8 (2 survivors pinned by a folder's mask and an adjustment's mask, 2 equivalent as above), gradient 2, Smear 1, Inverse 1; `blurSample` 19 + 5 reruns (the unbuildable `1.0` replaced by `abs` for `sqrt`; the determinant's sign pinned by a layer turned 45°, the coarse sample's placement, size and σ × fit by an exact comparison of a 4200 × 3900 layer's sample), one survivor left untested: the `maxSurfacePixels` cap on the budget, reached only past a 50-million-pixel canvas with an 800 MB sample; `cloneSample` 4, `clonePixels` 3 (the scale pinned by `aGridCloneIsScaledOntoItsPlace`), `gridRect` 2, `beginBrush` 2 (a blank layer's Blur begins no stroke); `TransformInspector` 14, equivalent: the `pending == m_pending` guard (only restarts a fade toward the same end) and `setStartValue` (an animation without one starts from the property's value); `sizeLabel` 6 + 2 reruns, all caught. +- Masks as Photoshop's (13.12, `b3419ab`): `addMask` with a selection now reveals it (white inside, black outside, the coverage as drawn) and, `revealing` false, hides it (the coverage inverted), one `Reveal Selection` or `Hide Selection` step; the row menu's Reveal All and Hide All call it as before, so Hide All with a selection hides the selection. `LayerMaskMenu` reads Alt from `QGuiApplication::keyboardModifiers()` when clicked, Swift's `NSApp.currentEvent`, so Alt-click adds the opposite, with Swift's help in Alt's words. The session keeps `viewsMaskAlone` (a getter and a setter that notifies on a change, the badge's write; `EditorSession.h`, defined in `EditorSession.cpp` beside Swift's `didSet`) and `maskAloneLayer()` (Swift's computed property: the view asked, the mask targeted, the active layer with a mask); `isMaskSelected` gains Swift's `didSet` as a private `setIsMaskSelected` (declared in `LayerMask+Session.h`, since `EditorSession.h` sits at 499 lines; defined in `EditorSession.cpp`), which every former write of `m_isMaskSelected` now calls, so targeting the pixels, another layer, a deleted mask or a load ends the view. `maskAloneLayer` and `toggleMaskAlone` live in `LayerMask+Alone.cpp`, since `LayerMask.cpp` already held 494 lines. `toggleMaskAlone` targets the mask through `selectLayerTarget` and shows it unless it already showed, refusing where that refuses. The canvas's `DisplayState` gains `maskAlone` (the mask asset's `ImageIdentity`, whether or not enabled, since the composite may skip it), and `drawLayers` hands off to `drawMaskAlone` (`EditorCanvas+Masks.cpp`, beside `liveFolderMaskClip`, which moved there to keep `EditorCanvas.cpp` under 500 lines): the canvas filled with the mask's edge tone, then a brush stroke or gradient laid into that mask through `LayerRenderer::drawBrushPreview` (the painted mask's own raster when it has one), else the mask at its displayed placement or the layer's transform, gray where it shows; the crisp zoom path draws through `drawLayers` too. The list's mask thumbnail: Alt's release without a drag calls `toggleMaskAlone` (Shift no longer toggles there, as Swift's), the tooltip names Alt-click, and the targeted ring is white while that mask shows alone (`setTargeted`'s `alone`; Swift's `maskAloneLayer?.id == layerID` is left out as dead: the ring shows only on the active row, whose layer is the one shown alone). `LayerListFocusTests` and `LayerDragGestureTests` expected Alt-Shift to toggle the mask; they now expect Swift's view. `MaskAloneBadge` (in `UI/LayerMaskMenu`, Swift's file) is 26 points tall, 75% black with a 14% white rim, radius 13: the mask glyph at 11, "Layer Mask" 12 px semibold, the layer's name 12 px at 60% white, elided within 220 points, and an `xmark` button (a new `LayerIcon`, Swift's bold `xmark` as two round-capped strokes) with Swift's tooltip in Alt's words and accessible name, which ends the view. `ContentView` keeps one badge, shown while `maskAloneLayer` holds, in a layout nested in the canvas slot (it starts hidden through `synchronize`, which the constructor runs) (bottom, centred, 14 points up), so the room beside and below it stays the canvas's; Qt child widgets take their own clicks, so Swift's AppKit hosting has no twin. Swift's GPU fix (a mask stroke's grid starting at the mask's background) is the twin's behaviour already: `allocateTile` fills a mask tile with `maskBackground`. Tests: `MaskAloneTests` (Swift's three, plus another layer ending the view and the setter's signal, a stroke and a gradient shown as committed, a disabled and a placed mask, the crisp zoom, the badge's words, place, elision and clicks, the list's Alt-click, Shift ignored and the white ring), `SelectionEditTests` (Swift's renamed two and the scaled layer's hiding mask), `LayersPanelTests::theMaskButtonUsesTheSelection` (plain and Alt clicks with and without a selection, the tooltips, the row's Hide All). Mutants: the session 10 + 1 rerun (the active-layer term of `toggleMaskAlone` pinned by a busy refusal with another layer's mask targeted), equivalent: `maskAloneLayer`'s `m_isMaskSelected` and `layer->mask` terms (every path that clears either clears the view through `setIsMaskSelected`; Swift's guards, kept); `drawMaskAlone` 6 + 3 reruns (the placement pinned off the old box), equivalent: the stroke's `isMask` and layer terms (a stroke while a mask shows alone is always that mask's: the view needs the mask targeted, and every target switch commits a pending gradient); the canvas branch and state 2; the list 4 + 2 (a release off the thumbnail pinned); the button and badge 5 + 3 (margins and spacing pinned); `ContentView` 5 (the constructor's `hide` was dead and is gone). All caught otherwise. - Drops between projects: `ProjectWorkspace::draggedLayerSource` finds the tab whose document holds the dragged id (Swift reads the drag pasteboard; the twin reads the drag's `QMimeData`, which every drop target has), `canReceiveDrag(data, destination)` refuses only a layer's own tab, and `receiveProviders` copies several ids one after another, as Swift awaits each provider, so a two-row drop on the New button opens two tabs as Swift's does. `ContentView` takes such a drop over its whole area (`setWorkspace` hands it the workspace; `acceptsDrop` keeps Swift's guards: busy, the sheet, the importer, a rename; `levels` arrives with 9.x), shows the 3-point accent ring inside the canvas while targeted and hands the drop's document point on when it fell on the canvas. `ProjectTabButton` takes drops for its tab (accent fill and rim, "Add to