Merge branch 'port-c'

src/ContentView.cpp

@@ -11,6 +11,7 @@
 #include "UI/ShapeControls.h"
 #include "UI/TypeControls.h"
 #include "UI/LassoControls.h"
+#include "UI/LayerMaskMenu.h"
 #include "UI/NavigationToolHeader.h"
 #include "UI/TransformInspector.h"
 #include "UI/NewCanvasSheet.h"
@@ -196,7 +197,8 @@ protected:
 
 ContentView::ContentView(EditorSession &session, ProjectController *projects, QWidget *parent)
     : QWidget(parent), m_session(session), m_projects(projects), m_column(new QVBoxLayout(this)), m_canvasSlot(new QGridLayout),
-      m_canvas(new CanvasView(session, this)), m_layersPanel(new LayersPanel(session, this)), m_dock(new QWidget(this)), m_dropRing(new DropRing(this)), m_zoom(statusText(new QLabel(this))), m_dimensions(statusText(new QLabel(this))), m_colour(statusText(new QLabel(this))),
+      m_canvas(new CanvasView(session, this)), m_layersPanel(new LayersPanel(session, this)), m_dock(new QWidget(this)), m_dropRing(new DropRing(this)),
+      m_maskAloneBadge(new MaskAloneBadge(session, this)), m_zoom(statusText(new QLabel(this))), m_dimensions(statusText(new QLabel(this))), m_colour(statusText(new QLabel(this))),
       m_activity(statusText(new ElidedLabel(this))),
       m_spinner(new QProgressBar(this))
 {
@@ -240,6 +242,12 @@ ContentView::ContentView(EditorSession &session, ProjectController *projects, QW
     // The welcome sits over the canvas, as Swift's ZStack.
     m_canvasSlot->addWidget(m_canvas, 0, 0);
     m_canvasSlot->addWidget(m_dropRing, 0, 0);
+    // A layout takes no clicks; the canvas keeps the rest.
+    auto *foot = new QVBoxLayout;
+    foot->addStretch(1);
+    foot->addWidget(m_maskAloneBadge, 0, Qt::AlignHCenter);
+    foot->addSpacing(14);
+    m_canvasSlot->addLayout(foot, 0, 0);
     setAcceptDrops(true);
 
     auto *middle = new QHBoxLayout;
@@ -390,6 +398,10 @@ void ContentView::synchronize()
     }
     const std::optional<CanvasDocument> &document = m_session.document();
     showWelcome(!document);
+    const std::optional<ImageLayer> alone = m_session.maskAloneLayer();
+    if (alone)
+        m_maskAloneBadge->setLayerName(alone->name);
+    m_maskAloneBadge->setVisible(alone.has_value());
     for (QWidget *ruler : m_rulers)
         ruler->setVisible(m_session.showsRulers() && document);
     m_zoom->setVisible(document.has_value());

src/ContentView.h

@@ -14,6 +14,7 @@
 #include <QWidget>
 
 class LayersPanel;
+class MaskAloneBadge;
 class ToolButton;
 class ProjectWorkspace;
 class QFileDialog;
@@ -74,6 +75,8 @@ private:
     QWidget *const m_dock;
     // An accent ring while a drop may land.
     QWidget *const m_dropRing;
+    // Over the canvas's foot while a mask shows alone.
+    MaskAloneBadge *const m_maskAloneBadge;
     // Swift 1.1.7's rulers: the corner, then the two strips.
     std::vector<QWidget *> m_rulers;
     ProjectWorkspace *m_workspace = nullptr;

src/Document/BlurTool+Session.h

@@ -1,4 +1,4 @@
 // Swift's BlurTool extension: what a Blur stroke paints.
 public:
-    // The active layer, or its mask, softened at document size.
-    std::optional<QImage> blurSample(const CanvasDocument &document, bool mask = false) const;
+    // The stroke's pixels or mask softened, in its own grid.
+    std::optional<BrushStroke::Clone> blurSample(const BrushStroke &stroke) const;

src/Document/BlurTool.cpp

@@ -2,49 +2,39 @@
 #include "Document/PixelAdjust.h"
 #include "IO/ImageExporter.h"
 #include "Logging.h"
-#include "Rendering/LayerRenderer.h"
 #include <cmath>
 
-// Swift's BlurTool extension: the layer, or its mask, softened.
-std::optional<QImage> EditorSession::blurSample(const CanvasDocument &document, bool mask) const
+// Swift's BlurTool extension: the layer's pixels, or mask, softened.
+std::optional<BrushStroke::Clone> EditorSession::blurSample(const BrushStroke &stroke) const
 {
-    const std::optional<ImageLayer> layer = activeLayer();
-    if (!layer)
+    const ImageLayer &layer = stroke.layer;
+    const std::optional<ImportedImage> &asset = stroke.isMask ? (layer.mask ? std::optional(layer.mask->asset) : std::nullopt) : layer.asset;
+    if (!asset)
         return std::nullopt;
-    // The softening follows the brush's size.
-    const double sigma = std::min(30.0, std::max(1.5, m_brushSettings.diameter / 10));
+    // The canvas's softening carried into the layer's pixels.
+    const QTransform &map = stroke.pixelToDocument;
+    const double perPixel = std::max(1e-6, std::sqrt(std::abs(map.m11() * map.m22() - map.m12() * map.m21())));
+    const double sidePixels = std::max(stroke.sourceRect.width(), stroke.sourceRect.height());
+    const double sigma = std::min(std::min(30.0, std::max(1.5, m_brushSettings.diameter / 10)) / perPixel, sidePixels / 2);
+    // Room for the blur to spread past the pixels' edges.
+    const double margin = std::ceil(3 * sigma);
+    const QRectF region = stroke.sourceRect.adjusted(-margin, -margin, margin, margin);
+    // A huge layer's sample is made coarser, within several canvases.
+    const qint64 canvas = m_document ? qint64(m_document->width) * m_document->height : 0;
+    const double budget = double(std::min(DocumentLimits::maxSurfacePixels, std::max<qint64>(16'000'000, 4 * canvas)));
+    const double fit = std::min(1.0, std::sqrt(budget / (region.width() * region.height())));
+    const int width = std::max(1, int(std::ceil(region.width() * fit))), height = std::max(1, int(std::ceil(region.height() * fit)));
+    const QRectF placed(margin * fit, margin * fit, stroke.sourceRect.width() * fit, stroke.sourceRect.height() * fit);
     try {
-        if (mask) {
-            if (!layer->mask)
-                return std::nullopt;
-            QImage context = BrushRaster::context(document.width, document.height, true);
-            // Past its pixels a mask keeps its edge tone.
-            const int tone = int(std::round(LayerMask::background(layer->mask->asset.thumbnail) * 255));
-            context.fill(QColor(tone, tone, tone));
-            QPainter painter(&context);
-            // Coverage only adds white: the mask's area starts black.
-            const LayerTransform placement = layer->maskTransform();
-            painter.save();
-            QTransform box;
-            box.translate(placement.center().x(), placement.center().y());
-            box.rotateRadians(placement.radians());
-            painter.setTransform(box, true);
-            painter.fillRect(QRectF(-placement.size.width() / 2, -placement.size.height() / 2, placement.size.width(), placement.size.height()),
-                             Qt::black);
-            painter.restore();
-            LayerRenderer::drawCoverage(layer->mask->asset.image(), placement, painter);
-            painter.end();
-            return PixelAdjust::gaussianBlur(context, sigma, true);
-        }
-        if (!layer->asset)
-            return std::nullopt;
-        QImage context = BrushRaster::context(document.width, document.height, false);
+        QImage context = BrushRaster::context(width, height, stroke.isMask);
+        // Past its pixels a mask keeps its edge tone.
+        if (stroke.isMask && layer.mask)
+            context.fill(int(std::round(LayerMask::background(layer.mask->asset.thumbnail) * 255)));
         QPainter painter(&context);
         // A painted asset flattens here; the catch covers it too.
-        const LayerTransform transform = displayedTransform(*layer);
-        LayerRenderer::draw(layer->asset->image(), transform, transform.center(), painter, {});
+        BrushRaster::draw(asset->image(), placed, painter);
         painter.end();
-        return PixelAdjust::gaussianBlur(context, sigma, false);
+        return BrushStroke::Clone{PixelAdjust::gaussianBlur(context, sigma * fit, stroke.isMask), region, true};
     } catch (const ExportError &error) {
         qCWarning(lcApp) << "the Blur tool cannot sample the layer:" << error.what();
         return std::nullopt;

src/Document/BrushStroke+Commit.cpp

@@ -58,6 +58,14 @@ LayerTransform BrushStroke::transform(const QRectF &bounds) const
     return result;
 }
 
+// Offset into grid pixels, turned and scaled as the layer.
+QRectF BrushStroke::gridRect(const QRectF &rect, QSizeF offset) const
+{
+    const QTransform toGrid = pixelToDocument.inverted();
+    const QPointF shift = toGrid.map(QPointF(offset.width(), offset.height())) - toGrid.map(QPointF(0, 0));
+    return rect.translated(-shift);
+}
+
 // Swift's heal: the painted spot rebuilt from nearby texture.
 void BrushStroke::heal()
 {

src/Document/BrushStroke+Stroke.cpp

@@ -273,11 +273,12 @@ QImage BrushStroke::clonePixels(const Tile &tile) const
     if (!clone)
         return QImage();
     const int width = int(tile.rect.width()), height = int(tile.rect.height());
-    // Tile pixels to clone pixels: grid, document, then offset.
-    const QTransform toClone = QTransform::fromTranslate(tile.rect.left(), tile.rect.top()) * pixelToDocument
-        * QTransform::fromTranslate(clone->offset.width(), clone->offset.height());
     // Colour even for gray clones: edges carry their coverage.
     const QImage &image = clone->image;
+    // Tile pixels to clone pixels: grid, maybe document, then placed.
+    const QRectF &placed = clone->placed;
+    const QTransform toClone = QTransform::fromTranslate(tile.rect.left(), tile.rect.top()) * (clone->inGrid ? QTransform() : pixelToDocument)
+        * QTransform::fromTranslate(-placed.left(), -placed.top()) * QTransform::fromScale(image.width() / placed.width(), image.height() / placed.height());
     if (toClone.type() > QTransform::TxTranslate) {
         // Swift's medium quality: bilinear under a scale or turn.
         QImage sample = BrushRaster::context(width, height, false);

src/Document/BrushStroke.h

@@ -111,10 +111,11 @@ public:
     qint64 pixelLimit = DocumentLimits::documentPixelBudget();
     // Limits every edit to the document selection; nil when none.
     std::optional<SelectionClip> selectionClip;
-    // Clone Stamp: a document-sized image, and each point's offset.
+    // Painted through the tip, placed: document or `inGrid` pixels.
     struct Clone {
         QImage image;
-        QSizeF offset;
+        QRectF placed;
+        bool inGrid;
     };
     std::optional<Clone> clone;
     // Blur: the clone is the layer softened, in place.
@@ -148,6 +149,8 @@ public:
     QRectF committedBounds() const;
     LayerTransform committedTransform() const;
     LayerTransform transform(const QRectF &bounds) const;
+    // `rect` shifted to copy from `offset` document pixels away.
+    QRectF gridRect(const QRectF &rect, QSizeF offset) const;
     // Spot Healing's end: the painted spot rebuilt from around it.
     void heal();
     PaintSnapshot paintSnapshot() const;

src/Document/CloneStamp+Session.h

@@ -6,5 +6,5 @@ public:
     std::optional<QSizeF> cloneStrokeOffset(QPointF point) const;
     // The source for a brush at `point`: the canvas's crosshair.
     std::optional<QPointF> cloneSamplePoint(QPointF point) const;
-    // What a stroke copies from, document-sized, taken as it starts.
-    std::optional<QImage> cloneSample(const CanvasDocument &document) const;
+    // What `stroke` copies, `offset` away: its pixels or the canvas.
+    std::optional<BrushStroke::Clone> cloneSample(const CanvasDocument &document, const BrushStroke &stroke, QSizeF offset) const;

src/Document/CloneStamp.cpp

@@ -1,7 +1,6 @@
 #include "Document/EditorSession.h"
 #include "IO/ImageExporter.h"
 #include "Logging.h"
-#include "Rendering/LayerRenderer.h"
 #include <cmath>
 
 // Swift's CloneStamp extension: the source, its offset, the sample.
@@ -40,20 +39,20 @@ std::optional<QPointF> EditorSession::cloneSamplePoint(QPointF point) const
     return point + QPointF(m_cloneOffset->width(), m_cloneOffset->height());
 }
 
-std::optional<QImage> EditorSession::cloneSample(const CanvasDocument &document) const
+std::optional<BrushStroke::Clone> EditorSession::cloneSample(const CanvasDocument &document, const BrushStroke &stroke, QSizeF offset) const
 {
     try {
+        // A painted asset flattens here; the catch covers it too.
+        if (!m_cloneSettings.sampleAllLayers) {
+            if (!stroke.layer.asset)
+                return std::nullopt;
+            return BrushStroke::Clone{stroke.layer.asset->image(), stroke.gridRect(stroke.sourceRect, offset), true};
+        }
         QImage context = BrushRaster::context(document.width, document.height, false);
         QPainter painter(&context);
-        // A painted asset flattens here; the catch covers it too.
-        if (m_cloneSettings.sampleAllLayers) {
-            drawLiveComposite(document, painter);
-        } else if (const std::optional<ImageLayer> layer = activeLayer(); layer && layer->asset) {
-            const LayerTransform transform = displayedTransform(*layer);
-            LayerRenderer::draw(layer->asset->image(), transform, transform.center(), painter, {});
-        }
+        drawLiveComposite(document, painter);
         painter.end();
-        return context;
+        return BrushStroke::Clone{context, QRectF(-offset.width(), -offset.height(), context.width(), context.height()), false};
     } catch (const ExportError &error) {
         qCWarning(lcApp) << "Clone Stamp cannot sample the canvas:" << error.what();
         return std::nullopt;

src/Document/EditorSession+Brush.cpp

@@ -37,6 +37,27 @@ bool EditorSession::canPaint() const
         && (m_isMaskSelected || !layer->adjustment);
 }
 
+std::optional<QString> EditorSession::paintRefusal() const
+{
+    const std::optional<ImageLayer> layer = activeLayer();
+    if (!canEditLayers() || !layer || canPaint())
+        return std::nullopt;
+    if (m_selectedLayerIDs.size() > 1)
+        return QStringLiteral("Several layers are selected. Select just one to paint on it.");
+    if (layer->isGroup && !m_isMaskSelected)
+        return QStringLiteral("“%1” is a folder, which has no pixels of its own. Paint on a layer inside it, or on the folder’s mask.").arg(layer->name);
+    if (!m_document->effectiveVisibleIDs().contains(layer->id))
+        return QStringLiteral("“%1” is hidden, or inside a hidden folder. Show it to paint on it.").arg(layer->name);
+    if (m_isMaskSelected && !(layer->mask && layer->mask->isEnabled))
+        return QStringLiteral("The layer mask is turned off. Shift-click its thumbnail to turn it on, then paint.");
+    if (!m_isMaskSelected && layer->adjustment)
+        return QStringLiteral("“%1” is an adjustment layer, with no pixels to paint. Paint on its mask instead.").arg(layer->name);
+    const std::optional<DocumentSelection> current = selection();
+    if (current && current->isEmpty())
+        return QStringLiteral("Nothing is selected, so there’s nowhere to paint. Choose Select › Deselect (Ctrl+D) to paint anywhere.");
+    return std::nullopt;
+}
+
 // A tiled raster edit of pixels or mask, within budget.
 std::unique_ptr<BrushStroke> EditorSession::makeRasterEdit(const ImageLayer &layer, const BrushSettings &settings, bool growsMask) const
 {
@@ -74,28 +95,20 @@ void EditorSession::beginBrush(QPointF point)
     }
     // Spot Healing and Clone Stamp rework pixels, never a mask.
     const bool paintsMasks = m_tool == NavigationTool::brush || m_tool == NavigationTool::blur;
-    if ((!paintsMasks && (!isBrushTool(m_tool) || m_isMaskSelected)) || !canPaint())
+    if (!paintsMasks && (!isBrushTool(m_tool) || m_isMaskSelected))
         return;
+    if (!canPaint()) {
+        setBrushError(paintRefusal());
+        return;
+    }
     const ImageLayer layer = activeLayer().value();
-    std::optional<BrushStroke::Clone> clone;
+    std::optional<QSizeF> sourceOffset;
     if (m_tool == NavigationTool::cloneStamp) {
-        const std::optional<QSizeF> offset = cloneStrokeOffset(point);
-        if (!offset) {
+        sourceOffset = cloneStrokeOffset(point);
+        if (!sourceOffset) {
             setBrushError(QStringLiteral("Alt-click where Clone Stamp should copy from first."));
             return;
         }
-        const std::optional<QImage> image = cloneSample(m_document.value());
-        if (!image)
-            return;
-        m_cloneOffset = offset;
-        clone = BrushStroke::Clone{*image, *offset};
-    }
-    // Blur paints a softened copy of the layer, in place.
-    if (m_tool == NavigationTool::blur) {
-        const std::optional<QImage> image = blurSample(m_document.value(), m_isMaskSelected);
-        if (!image)
-            return;
-        clone = BrushStroke::Clone{*image, QSizeF(0, 0)};
     }
     finishOpacityEdit();
     try {
@@ -108,9 +121,21 @@ void EditorSession::beginBrush(QPointF point)
             settings.green = settings.red;
             settings.blue = settings.red;
         }
-        m_brushStroke = makeRasterEdit(layer, settings, m_tool == NavigationTool::brush);
-        m_brushStroke->clone = clone;
-        m_brushStroke->isBlur = m_tool == NavigationTool::blur;
+        std::unique_ptr<BrushStroke> stroke = makeRasterEdit(layer, settings, m_tool == NavigationTool::brush);
+        if (sourceOffset) {
+            stroke->clone = cloneSample(m_document.value(), *stroke, *sourceOffset);
+            if (!stroke->clone)
+                return;
+            m_cloneOffset = sourceOffset;
+        }
+        // Blur paints a softened copy of the layer, in place.
+        if (m_tool == NavigationTool::blur) {
+            stroke->clone = blurSample(*stroke);
+            if (!stroke->clone)
+                return;
+        }
+        stroke->isBlur = m_tool == NavigationTool::blur;
+        m_brushStroke = std::move(stroke);
         m_brushStroke->append(point);
         m_brushAnchor = point;
         m_brushPointer = point;

src/Document/EditorSession+Brush.h

@@ -1,6 +1,8 @@
 // Swift's EditorSession+Brush extension: a stroke from press to commit.
 public:
     bool canPaint() const;
+    // Why the target refuses a stroke; none while busy.
+    std::optional<QString> paintRefusal() const;
     std::unique_ptr<BrushStroke> makeRasterEdit(const ImageLayer &layer, const BrushSettings &settings = BrushSettings(), bool growsMask = false) const;
     void beginBrush(QPointF point);
     void continueBrush(QPointF point);

src/Document/EditorSession+Projects.cpp

@@ -27,7 +27,7 @@ std::optional<ProjectSnapshot> EditorSession::projectSnapshot() const
 void EditorSession::installProject(const ProjectSnapshot &snapshot, const QString &path)
 {
     m_collapsedGroupIDs.clear();
-    m_isMaskSelected = false;
+    setIsMaskSelected(false);
     m_cropRect.reset();
     m_guideDrag = std::nullopt;
     m_transformEdit = std::nullopt;
@@ -78,7 +78,7 @@ void EditorSession::setProjectPath(std::optional<QString> path)
 void EditorSession::clearProject()
 {
     m_collapsedGroupIDs.clear();
-    m_isMaskSelected = false;
+    setIsMaskSelected(false);
     m_cropRect.reset();
     m_transformEdit = std::nullopt;
     m_guideDrag = std::nullopt;

src/Document/EditorSession.cpp

@@ -35,7 +35,7 @@ void EditorSession::setActiveLayerID(std::optional<QUuid> id)
 {
     // Another layer: its pixels are the target again.
     if (id != m_activeLayerID)
-        m_isMaskSelected = false;
+        setIsMaskSelected(false);
     m_activeLayerID = id;
     m_selectedLayerIDs = id ? QSet<QUuid>{*id} : QSet<QUuid>();
     notify();
@@ -234,7 +234,7 @@ void EditorSession::restore(const DocumentHistory::Snapshot &snapshot)
     m_document = snapshot.document;
     setActiveLayerID(snapshot.activeLayerID);
     const std::optional<ImageLayer> active = activeLayer();
-    m_isMaskSelected = keepsMaskTarget && active && active->mask;
+    setIsMaskSelected(keepsMaskTarget && active && active->mask);
     if (changedCanvas && m_document)
         viewport.fit(m_document->size());
     qCInfo(lcApp) << "restored a history snapshot of" << (m_document ? int(m_document->layers.size()) : 0) << "layers";
@@ -381,3 +381,18 @@ void EditorSession::requestCanvasFocus()
     ++m_canvasFocusRequest;
     notify();
 }
+
+void EditorSession::setIsMaskSelected(bool value)
+{
+    m_isMaskSelected = value;
+    if (!value)
+        m_viewsMaskAlone = false;
+}
+
+void EditorSession::setViewsMaskAlone(bool value)
+{
+    if (m_viewsMaskAlone == value)
+        return;
+    m_viewsMaskAlone = value;
+    notify();
+}

src/Document/EditorSession.h

@@ -93,10 +93,11 @@ public:
     void selectTool(NavigationTool value);
     // Tab: the current tool's next mode.
     void cycleToolMode();
-
     // Whether the mask thumbnail, not the layer's, is the target.
     bool isMaskSelected() const { return m_isMaskSelected; }
-
+    // Alt-click: the targeted mask alone, gray, on the canvas.
+    bool viewsMaskAlone() const { return m_viewsMaskAlone; }
+    void setViewsMaskAlone(bool value);
     // A blend mode tried on by hovering; nothing is saved.
     struct BlendPreview {
         QUuid layerID;
@@ -132,7 +133,6 @@ public:
     // An unlinked mask, selected, transforms without its layer.
     bool transformTargetsMask() const;
     void nudgeLayer(double dx, double dy);
-
     const std::optional<LassoDraft> &lassoDraft() const { return m_lassoDraft; }
     LassoKind lassoKind() const { return m_lassoKind; }
     void setLassoKind(LassoKind kind);
@@ -350,6 +350,7 @@ private:
     std::optional<BlendPreview> m_blendPreview;
     std::optional<QUuid> m_opacityEditLayerID;
     bool m_isMaskSelected = false;
+    bool m_viewsMaskAlone = false;
     std::optional<QUuid> m_activeLayerID;
     bool m_isProjectBusy = false;
     bool m_showsNewDocument = false;

src/Document/Filters+Session.cpp

@@ -347,7 +347,7 @@ void EditorSession::finishFilterCommit()
         mask.isEnabled = true;
         mask.placement = std::nullopt;
         m_document->layers[index].mask = mask;
-        m_isMaskSelected = true;
+        setIsMaskSelected(true);
         endEdit();
         finish();
         return;

src/Document/Gradient.cpp

@@ -35,8 +35,13 @@ void EditorSession::setGradientSettings(const GradientSettings &settings)
 void EditorSession::beginGradient(QPointF point)
 {
     const std::optional<ImageLayer> layer = activeLayer();
-    if (m_tool != NavigationTool::gradient || !(canPaint() || m_gradientEdit) || !layer)
+    if (m_tool != NavigationTool::gradient || !layer)
         return;
+    // Swift explains only past this guard, where nothing refuses.
+    if (!canPaint() && !m_gradientEdit) {
+        setBrushError(paintRefusal());
+        return;
+    }
     // A new line on this target replaces the pending one.
     if (m_gradientEdit && m_gradientEdit->raster->layer.id == layer->id && m_gradientEdit->raster->isMask == m_isMaskSelected) {
         m_gradientEdit->start = point;

src/Document/LayerEffects+Session.cpp

@@ -97,7 +97,7 @@ void EditorSession::selectEffect(LayerEffectKind kind, QUuid id, bool editing)
         finishEffectsEditing(false);
     // Swift's `selectedLayerIDs = [id]`: selectLayer sets it, unrefused here.
     selectLayer(id);
-    m_isMaskSelected = false;
+    setIsMaskSelected(false);
     m_effectSelection = selection;
     if (editing && m_effectsEditing != selection) {
         m_effectsEditingOriginal = m_document->layers[size_t(indexOf(m_document->layers, id))].effects.value_or(LayerEffects());

src/Document/LayerMask+Alone.cpp

@@ -0,0 +1,21 @@
+#include "Document/EditorSession.h"
+
+// Swift's mask shown alone, an Alt-click on its thumbnail.
+std::optional<ImageLayer> EditorSession::maskAloneLayer() const
+{
+    const std::optional<ImageLayer> layer = activeLayer();
+    if (!m_viewsMaskAlone || !m_isMaskSelected || !layer || !layer->mask)
+        return std::nullopt;
+    return layer;
+}
+
+void EditorSession::toggleMaskAlone(QUuid id)
+{
+    const std::optional<ImageLayer> shown = maskAloneLayer();
+    const bool showing = shown && shown->id == id;
+    selectLayerTarget(id, true);
+    if (m_activeLayerID != id || !m_isMaskSelected)
+        return;
+    m_viewsMaskAlone = !showing;
+    notify();
+}

src/Document/LayerMask+Session.h

@@ -15,6 +15,12 @@ public:
     std::optional<QImage> maskDistortPreview(const ImageLayer &layer) const;
     // The selection made a mask; without one, a solid mask.
     void addMask(bool revealing = true);
+    // The layer whose mask the canvas shows alone, if any.
+    std::optional<ImageLayer> maskAloneLayer() const;
+    // Alt-click on a mask thumbnail: alone, or the composite again.
+    void toggleMaskAlone(QUuid id);
 
 private:
+    // Swift's didSet: the pixels targeted end the mask view.
+    void setIsMaskSelected(bool value);
     void commitMaskTransform();

src/Document/LayerMask.cpp

@@ -262,7 +262,7 @@ void EditorSession::selectLayerTarget(QUuid id, bool mask)
     resolveGradient();
     selectLayer(id);
     const std::optional<ImageLayer> active = activeLayer();
-    m_isMaskSelected = mask && active && active->mask;
+    setIsMaskSelected(mask && active && active->mask);
     notify();
 }
 
@@ -286,14 +286,15 @@ void EditorSession::addMask(bool revealing)
         // The selection's coverage, soft where it is feathered.
         QImage image = PixelAdjust::coverage(current->clip(m_document->size()), width, height,
                                              BrushRaster::pixelToDocument(active->transform, width, height));
-        if (revealing)
+        // Revealing, white inside; hiding, black inside.
+        if (!revealing)
             image.invertPixels();
         const LayerMask mask(LayerMask::assetFrom(image));
         finishOpacityEdit();
-        beginEdit(QStringLiteral("Add Mask from Selection"));
+        beginEdit(revealing ? QStringLiteral("Reveal Selection") : QStringLiteral("Hide Selection"));
         m_document->layers[size_t(index)].mask = mask;
         m_document->selection = std::nullopt;
-        m_isMaskSelected = true;
+        setIsMaskSelected(true);
         endEdit();
     } catch (const std::runtime_error &error) {
         qCWarning(lcApp).noquote() << "cannot make a mask from the selection:" << error.what();
@@ -312,7 +313,7 @@ void EditorSession::addLayerMask(bool revealing)
         if (layer.id == active->id)
             layer.mask = LayerMask::solid(revealing);
     }
-    m_isMaskSelected = true;
+    setIsMaskSelected(true);
     endEdit();
 }
 
@@ -341,7 +342,7 @@ void EditorSession::deleteLayerMask()
         if (layer.id == active->id)
             layer.mask = std::nullopt;
     }
-    m_isMaskSelected = false;
+    setIsMaskSelected(false);
     endEdit();
 }
 
@@ -371,7 +372,7 @@ void EditorSession::copyMask(QUuid source, QUuid target)
     beginEdit(find(target)->mask ? QStringLiteral("Replace Layer Mask") : QStringLiteral("Copy Layer Mask"));
     find(target)->mask = mask;
     selectLayer(target);
-    m_isMaskSelected = true;
+    setIsMaskSelected(true);
     endEdit();
 }
 

src/Document/Selection.cpp

@@ -420,5 +420,7 @@ void EditorSession::invertSelection()
     const std::optional<DocumentSelection> current = selection();
     if (!m_document || !current)
         return;
-    setSelection(DocumentSelection{canvasPath(*m_document).subtracted(current->path), current->antialiased, current->feather}, QStringLiteral("Inverse"));
+    const DocumentSelection inverse{canvasPath(*m_document).subtracted(current->path), current->antialiased, current->feather};
+    // The inverse of everything is no selection, as Photoshop's.
+    setSelection(inverse.isEmpty() ? std::nullopt : std::optional(inverse), QStringLiteral("Inverse"));
 }

src/Document/SmudgeLiquify.cpp

@@ -196,8 +196,7 @@ void EditorSession::beginWarp(QPointF point)
 {
     const std::optional<ImageLayer> layer = activeLayer();
     if (!canPaint() || m_isMaskSelected || !layer || !layer->asset || !m_document) {
-        if (m_isMaskSelected)
-            setBrushError(QStringLiteral("Smudge and Liquify work on a layer's pixels, not its mask."));
+        setBrushError(m_isMaskSelected ? std::optional(QStringLiteral("Smudge and Liquify work on a layer's pixels, not its mask.")) : paintRefusal());
         return;
     }
     finishOpacityEdit();
@@ -235,7 +234,7 @@ void EditorSession::finishWarp()
                 settings.hardness = 1;
                 settings.opacity = 1;
                 const std::unique_ptr<BrushStroke> stroke = makeRasterEdit(current, settings);
-                stroke->clone = BrushStroke::Clone{warp->image(), QSizeF(0, 0)};
+                stroke->clone = BrushStroke::Clone{warp->image(), QRectF(QPointF(0, 0), warp->image().size()), false};
                 stroke->replacesWithClone = true;
                 stroke->editName = rawValue(warp->mode);
                 for (const QPointF step : warp->points())

src/Rendering/EditorCanvas+MaskAlone.cpp

@@ -0,0 +1,23 @@
+#include "Rendering/EditorCanvas.h"
+
+// Swift's drawMaskAlone: gray across the canvas, edge tone past it.
+void CanvasView::drawMaskAlone(const ImageLayer &layer, const CanvasDocument &document, double scale, const Center &center, QPainter &context)
+{
+    const LayerMask &mask = layer.mask.value();
+    const int tone = qRound(LayerMask::background(mask.asset.thumbnail) * 255);
+    context.fillRect(QRectF(center(QPointF(0, 0)), document.size() * scale), QColor(tone, tone, tone));
+    const std::optional<GradientEdit> &gradient = m_session.gradientEdit();
+    const BrushStroke *stroke = m_session.brushStroke() ? m_session.brushStroke() : gradient ? gradient->raster.get() : nullptr;
+    // A stroke or gradient laid into it shows at once.
+    if (stroke && stroke->isMask && stroke->layer.id == layer.id) {
+        const LayerTransform &placed = stroke->paintTransform;
+        const std::shared_ptr<const RasterSnapshot> &raster = mask.asset.raster;
+        LayerRenderer::drawBrushPreview(raster ? QImage() : mask.asset.image(), placed, center(placed.center()), context, {.scale = scale},
+                                        {.patches = stroke->patches(), .pixelWidth = stroke->width, .pixelHeight = stroke->height,
+                                         .paintingMask = false, .sourceRect = stroke->sourceRect, .raster = raster});
+        return;
+    }
+    // Where a transform drag shows it, as the composite.
+    const LayerTransform placed = m_session.displayedMaskPlacement(layer).value_or(m_session.displayedTransform(layer));
+    LayerRenderer::draw(mask.asset.image(), placed, center(placed.center()), context, {.scale = scale});
+}

src/Rendering/EditorCanvas+Selection.cpp

@@ -85,7 +85,15 @@ bool CanvasView::moveSelectionTool(QPointF point, Qt::KeyboardModifiers modifier
 {
     if (m_pixelDragStart && m_session.document()) {
         const QPointF pixel = m_session.viewport.documentPoint(point, m_session.document()->size());
-        m_session.movePixels(QSizeF(pixel.x() - m_pixelDragStart->x(), pixel.y() - m_pixelDragStart->y()));
+        QSizeF offset(pixel.x() - m_pixelDragStart->x(), pixel.y() - m_pixelDragStart->y());
+        // Shift keeps the pixels on a line, the longer way.
+        if (modifiers.testFlag(Qt::ShiftModifier)) {
+            if (std::abs(offset.width()) >= std::abs(offset.height()))
+                offset.setHeight(0);
+            else
+                offset.setWidth(0);
+        }
+        m_session.movePixels(offset);
         updateCursor();
         synchronizeDisplay();
         return true;

src/Rendering/EditorCanvas.cpp

@@ -85,7 +85,8 @@ CanvasView::DisplayState CanvasView::displayState() const
                        .layers = {},
                        .folderMasks = {},
                        .textStyle = m_session.textDraft() ? std::optional(m_session.textDraft()->style) : std::nullopt,
-                       .textTransform = m_session.textDraft() && m_inlineTextEditor ? std::optional(m_inlineTextEditor->shownTransform()) : std::nullopt};
+                       .textTransform = m_session.textDraft() && m_inlineTextEditor ? std::optional(m_inlineTextEditor->shownTransform()) : std::nullopt,
+                       .maskAlone = m_session.maskAloneLayer() ? std::optional(m_session.maskAloneLayer()->mask->asset.identity()) : std::nullopt};
     if (!document)
         return state;
     // A hidden source still clips: live masks count every layer.
@@ -299,6 +300,10 @@ FolderMaskClip::Applier CanvasView::liveFolderMaskClip(const BrushStroke &edit,
 
 void CanvasView::drawLayers(const CanvasDocument &document, double scale, const Center &center, QPainter &context)
 {
+    if (const std::optional<ImageLayer> alone = m_session.maskAloneLayer()) {
+        drawMaskAlone(*alone, document, scale, center, context);
+        return;
+    }
     handOnDraftEffects(document);
     m_session.effectsPreviews.prepare(document.layers);
     std::map<QUuid, ImageLayer> byID;

src/Rendering/EditorCanvas.h

@@ -122,6 +122,8 @@ private:
         // Typed text, which the canvas draws as pixels.
         std::optional<LayerTextStyle> textStyle;
         std::optional<LayerTransform> textTransform;
+        // The mask shown alone, though the composite may skip it.
+        std::optional<ImageIdentity> maskAlone;
         friend bool operator==(const DisplayState &, const DisplayState &) = default;
     };
     // A Zoom press: drags zoom about it, clicks step.
@@ -146,6 +148,8 @@ private:
     void drawStroke(const BrushStroke &stroke, const ImageLayer &layer, const LayerTransform &transform, const std::optional<QImage> &mask,
                     const LayerRenderer::Options &options, double scale, const Center &center, QPainter &target);
     void drawLayers(const CanvasDocument &document, double scale, const Center &center, QPainter &context);
+    // Alt-click's view: the mask in gray, strokes included.
+    void drawMaskAlone(const ImageLayer &layer, const CanvasDocument &document, double scale, const Center &center, QPainter &context);
     // Typed text as pixels, where the editor shows it.
     struct DraftText {
         QImage image;

src/UI/CompositorMenus.cpp

@@ -2,20 +2,10 @@
 #include "IO/RecentProjects.h"
 #include "Logging.h"
 #include "UI/KeyboardShortcuts.h"
-#include "UI/NativeLayerList.h"
 #include <QApplication>
 #include <QMenu>
 
 namespace {
-// The layer list holding the keys, as Swift's table.
-NativeLayerList *focusedList()
-{
-    for (QWidget *widget = QApplication::focusWidget(); widget; widget = widget->parentWidget())
-        if (auto *list = qobject_cast<NativeLayerList *>(widget))
-            return list;
-    return nullptr;
-}
-
 // An entry's name: Hue/Saturation is newHueSaturationAdjustment.
 QString adjustmentName(AdjustmentKind kind)
 {
@@ -186,8 +176,6 @@ CompositorMenus::CompositorMenus(ProjectWorkspace &workspace, QMenuBar &bar, QWi
             m_field->selectAll();
         else if (InlineTextEditor *text = typedText())
             text->selectAll();
-        else if (NativeLayerList *list = focusedList())
-            list->selectAllRows();
         else
             session().selectAll();
     });

src/UI/LayerIcons.cpp

@@ -313,6 +313,12 @@ void LayerIcons::paint(QPainter &painter, LayerIcon icon, QPointF origin, double
     case LayerIcon::dottedCircle: dottedCircle(painter); break;
     case LayerIcon::plusMagnifyingGlass: magnifyingGlass(painter, true); break;
     case LayerIcon::minusMagnifyingGlass: magnifyingGlass(painter, false); break;
+    // Swift's xmark at bold weight.
+    case LayerIcon::xmark:
+        painter.setPen(QPen(colour, 2.6, Qt::SolidLine, Qt::RoundCap));
+        painter.drawLine(QPointF(4, 4), QPointF(14, 14));
+        painter.drawLine(QPointF(14, 4), QPointF(4, 14));
+        break;
     }
     painter.restore();
 }

src/UI/LayerIcons.h

@@ -8,7 +8,7 @@
 enum class LayerIcon {
     eye, eyeSlash, chevronRight, chevronDown, folder, link, newLayer, newFolder, addMask, trash, layers, text,
     halfFilledCircle, sliders, curvePath, plusMinusCircle, paintPalette, circleGrid, sparkles, rightHalfCircle, hatchedCircle, axes,
-    scope, lineDiagonal, drop, wind, dottedCircle, plusMagnifyingGlass, minusMagnifyingGlass
+    scope, lineDiagonal, drop, wind, dottedCircle, plusMagnifyingGlass, minusMagnifyingGlass, xmark
 };
 
 namespace LayerIcons {

src/UI/LayerMaskMenu.cpp

@@ -1,6 +1,9 @@
 #include "UI/LayerMaskMenu.h"
 #include "UI/LayerIcons.h"
 #include <QEvent>
+#include <QGuiApplication>
+#include <QHBoxLayout>
+#include <QPainter>
 
 LayerMaskMenu::LayerMaskMenu(EditorSession &session, QWidget *parent) : QToolButton(parent), m_session(session)
 {
@@ -8,7 +11,8 @@ LayerMaskMenu::LayerMaskMenu(EditorSession &session, QWidget *parent) : QToolBut
     setAccessibleName(QStringLiteral("Add layer mask"));
     setAutoRaise(true);
     setFixedSize(32, 40);
-    connect(this, &QToolButton::clicked, this, [this] { m_session.addMask(); });
+    // Swift reads Option from the event that clicked.
+    connect(this, &QToolButton::clicked, this, [this] { m_session.addMask(!QGuiApplication::keyboardModifiers().testFlag(Qt::AltModifier)); });
     connect(&m_session, &EditorSession::changed, this, &LayerMaskMenu::synchronize);
     synchronize();
 }
@@ -17,7 +21,8 @@ void LayerMaskMenu::synchronize()
 {
     const std::optional<ImageLayer> active = m_session.activeLayer();
     setEnabled(m_session.canEditMask() && !(active && active->mask));
-    setToolTip(m_session.selection() ? QStringLiteral("Add layer mask (the selection becomes black)") : QStringLiteral("Add layer mask"));
+    setToolTip(m_session.selection() ? QStringLiteral("Add layer mask revealing the selection (Alt-click to hide it)")
+                                     : QStringLiteral("Add layer mask (Alt-click for a black mask)"));
     setIcon(LayerIcons::pixmap(LayerIcon::addMask, 16, palette().color(QPalette::PlaceholderText), devicePixelRatio()));
 }
 
@@ -27,3 +32,54 @@ void LayerMaskMenu::changeEvent(QEvent *event)
     if (event->type() == QEvent::PaletteChange)
         synchronize();
 }
+
+MaskAloneBadge::MaskAloneBadge(EditorSession &session, QWidget *parent) : QWidget(parent), m_name(new QLabel(this))
+{
+    setObjectName(QStringLiteral("maskAloneBadge"));
+    setFixedHeight(26);
+    const auto font = [](QLabel *label, bool semibold, double alpha) {
+        QFont face = label->font();
+        face.setPixelSize(12);
+        face.setWeight(semibold ? QFont::DemiBold : QFont::Normal);
+        label->setFont(face);
+        QPalette colours = label->palette();
+        colours.setColor(QPalette::WindowText, QColor::fromRgbF(1, 1, 1, alpha));
+        label->setPalette(colours);
+    };
+    auto *icon = new QLabel(this);
+    icon->setPixmap(LayerIcons::pixmap(LayerIcon::addMask, 11, Qt::white, devicePixelRatioF()));
+    auto *title = new QLabel(QStringLiteral("Layer Mask"), this);
+    title->setObjectName(QStringLiteral("maskAloneTitle"));
+    font(title, true, 1);
+    m_name->setObjectName(QStringLiteral("maskAloneName"));
+    m_name->setTextFormat(Qt::PlainText);
+    m_name->setMaximumWidth(220);
+    font(m_name, false, 0.6);
+    auto *close = new QToolButton(this);
+    close->setObjectName(QStringLiteral("maskAloneClose"));
+    close->setAutoRaise(true);
+    close->setIcon(LayerIcons::pixmap(LayerIcon::xmark, 9, Qt::white, devicePixelRatioF()));
+    close->setToolTip(QStringLiteral("Show the image again (or Alt-click the mask thumbnail)"));
+    close->setAccessibleName(QStringLiteral("Stop viewing the mask"));
+    connect(close, &QToolButton::clicked, this, [&session] { session.setViewsMaskAlone(false); });
+    auto *row = new QHBoxLayout(this);
+    row->setContentsMargins(11, 0, 8, 0);
+    row->setSpacing(7);
+    for (QWidget *widget : std::initializer_list<QWidget *>{icon, title, m_name, close})
+        row->addWidget(widget);
+}
+
+// Swift's byTruncatingTail within 220 points.
+void MaskAloneBadge::setLayerName(const QString &name)
+{
+    m_name->setText(m_name->fontMetrics().elidedText(name, Qt::ElideRight, 220));
+}
+
+void MaskAloneBadge::paintEvent(QPaintEvent *)
+{
+    QPainter painter(this);
+    painter.setRenderHint(QPainter::Antialiasing);
+    painter.setPen(QPen(QColor::fromRgbF(1, 1, 1, 0.14), 1));
+    painter.setBrush(QColor::fromRgbF(0, 0, 0, 0.75));
+    painter.drawRoundedRect(QRectF(rect()).adjusted(0.5, 0.5, -0.5, -0.5), 13, 13);
+}

src/UI/LayerMaskMenu.h

@@ -1,8 +1,9 @@
 #pragma once
 #include "Document/EditorSession.h"
+#include <QLabel>
 #include <QToolButton>
 
-// One click adds a mask: white, or the selection black.
+// One click adds a mask revealing the selection; Alt, hiding.
 class LayerMaskMenu : public QToolButton {
     Q_OBJECT
 public:
@@ -16,3 +17,17 @@ private:
 
     EditorSession &m_session;
 };
+
+// While a mask shows alone: whose, and a way back.
+class MaskAloneBadge : public QWidget {
+    Q_OBJECT
+public:
+    explicit MaskAloneBadge(EditorSession &session, QWidget *parent = nullptr);
+    void setLayerName(const QString &name);
+
+protected:
+    void paintEvent(QPaintEvent *event) override;
+
+private:
+    QLabel *const m_name;
+};

src/UI/NativeLayerList+Buttons.cpp

@@ -70,9 +70,10 @@ LayerThumbnailButton::LayerThumbnailButton(NativeLayerList &list, bool maskTarge
     setAutoRaise(true);
 }
 
-void LayerThumbnailButton::setTargeted(bool targeted)
+void LayerThumbnailButton::setTargeted(bool targeted, bool alone)
 {
     m_targeted = targeted;
+    m_alone = alone;
     QWidget::update();
 }
 
@@ -155,12 +156,9 @@ void LayerThumbnailButton::mouseReleaseEvent(QMouseEvent *event)
     if (!m_altMaskPress || event->button() != Qt::LeftButton)
         return;
     endAltMaskPress();
-    // Released where pressed: a click, not a drag; Shift toggles.
-    if (!rect().contains(event->position().toPoint()))
-        return;
-    m_list.session().selectLayerTarget(layerID, true);
-    if (event->modifiers().testFlag(Qt::ShiftModifier))
-        m_list.session().toggleLayerMask();
+    // Released where pressed: the mask alone, or the image again.
+    if (rect().contains(event->position().toPoint()))
+        m_list.session().toggleMaskAlone(layerID);
 }
 
 // With a modifier the second press is the button's again.
@@ -179,7 +177,7 @@ void LayerThumbnailButton::paintEvent(QPaintEvent *)
     if (!m_targeted)
         return;
     painter.setRenderHint(QPainter::Antialiasing);
-    painter.setPen(QPen(palette().color(QPalette::Highlight), 2));
+    painter.setPen(QPen(m_alone ? QColor(Qt::white) : palette().color(QPalette::Highlight), 2));
     painter.setBrush(Qt::NoBrush);
     painter.drawRoundedRect(QRectF(rect()).adjusted(1, 1, -1, -1), 3, 3);
 }

src/UI/NativeLayerList+Cell.cpp

@@ -4,6 +4,7 @@
 #include <QApplication>
 #include <QContextMenuEvent>
 #include <QKeyEvent>
+#include <QLocale>
 #include <QMenu>
 #include <QMouseEvent>
 #include <QPainter>
@@ -30,7 +31,7 @@ LayerCell::LayerCell(NativeLayerList &list)
     connect(m_disclosure, &QToolButton::clicked, this, [this] { m_list.session().toggleGroupExpansion(m_layerID); });
     m_thumbnail->setObjectName(QStringLiteral("layerThumbnail"));
     m_maskThumbnail->setObjectName(QStringLiteral("maskThumbnail"));
-    m_maskThumbnail->setToolTip(QStringLiteral("Select layer mask; Shift-click to enable/disable; Ctrl-click to select its black areas (Ctrl-Shift adds, Ctrl-Alt subtracts)"));
+    m_maskThumbnail->setToolTip(QStringLiteral("Select layer mask; Alt-click to view it alone; Shift-click to enable/disable; Ctrl-click to select its black areas (Ctrl-Shift adds, Ctrl-Alt subtracts)"));
     m_link->setObjectName(QStringLiteral("maskLink"));
     m_link->setAutoRaise(true);
     m_link->setFixedSize(9, 20);
@@ -115,7 +116,7 @@ void LayerCell::configure(const ImageLayer &layer, bool enabled, int depth, bool
     m_dimensions->setText(m_editableText   ? QStringLiteral("Text · Double-click to edit")
                           : m_isAdjustment ? QStringLiteral("Adjustment · Double-click to edit")
                           : layer.isGroup  ? QStringLiteral("Folder")
-                                          : QStringLiteral("%1 × %2 px").arg(std::lround(layer.size().width())).arg(std::lround(layer.size().height())));
+                                          : sizeLabel(layer));
     m_dimensions->setToolTip(QString());
     if (layer.maskSourceID && session.document()) {
         const int source = indexOf(session.document()->layers, layer.maskSourceID);
@@ -158,7 +159,7 @@ void LayerCell::updateTarget()
     const bool active = session.activeLayerID() == m_layerID && session.selectedLayerIDs().size() == 1;
     const bool mask = session.isMaskSelected();
     m_thumbnail->setTargeted(active && !mask);
-    m_maskThumbnail->setTargeted(active && mask);
+    m_maskThumbnail->setTargeted(active && mask, active && session.maskAloneLayer());
     QWidget::update();
 }
 
@@ -335,3 +336,18 @@ bool LayerCell::eventFilter(QObject *watched, QEvent *event)
         return false;
     return true;
 }
+
+QString sizeLabel(const ImageLayer &layer)
+{
+    const QString text = QStringLiteral("%1 × %2 px").arg(std::lround(layer.size().width())).arg(std::lround(layer.size().height()));
+    const int pixels = layer.asset ? layer.asset->size().width() : 0;
+    if (pixels <= 0)
+        return text;
+    // Across the width, as the Move bar's Scale field.
+    const double percent = layer.size().width() / pixels * 100;
+    if (std::abs(percent - 100) < 0.05)
+        return text;
+    // Swift's .number to one place at most, ties to even.
+    const double rounded = std::nearbyint(percent * 10) / 10;
+    return text + QStringLiteral(" · ") + QLocale().toString(rounded, 'f', rounded == std::trunc(rounded) ? 0 : 1) + QStringLiteral("%");
+}

src/UI/NativeLayerList.cpp

@@ -261,13 +261,3 @@ void NativeLayerList::changeEvent(QEvent *event)
     if (event->type() == QEvent::PaletteChange)
         QMetaObject::invokeMethod(this, &NativeLayerList::update, Qt::QueuedConnection);
 }
-
-void NativeLayerList::selectAllRows()
-{
-    if (m_rows.empty())
-        return;
-    QSet<QUuid> ids;
-    for (const ImageLayer &row : m_rows)
-        ids.insert(row.id);
-    m_session.selectLayers(ids, m_rows.front().id);
-}

src/UI/NativeLayerList.h

@@ -43,8 +43,8 @@ public:
     LayerThumbnailButton(NativeLayerList &list, bool maskTarget, QWidget *parent);
     QUuid layerID;
     const bool isMaskTarget;
-    // An accent ring while the target is selected.
-    void setTargeted(bool targeted);
+    // An accent ring while targeted; white while shown alone.
+    void setTargeted(bool targeted, bool alone = false);
     bool isTargeted() const { return m_targeted; }
 
     ~LayerThumbnailButton() override;
@@ -63,6 +63,7 @@ private:
 
     NativeLayerList &m_list;
     bool m_targeted = false;
+    bool m_alone = false;
     // Alt on a mask: chosen on release, or dragged.
     std::optional<QPoint> m_altMaskPress;
 };
@@ -215,8 +216,6 @@ public:
     QString dragToken() const { return m_dragToken; }
 
     EditorSession &session() const { return m_session; }
-    // The table's Select All: every row, the top one primary.
-    void selectAllRows();
     void update();
     std::vector<LayerCell *> cells() const { return m_cells; }
     // The row under a point of this list, or -1.
@@ -283,3 +282,6 @@ private:
     const QMimeData *m_dragData = nullptr;
     Qt::DropActions m_dragActions;
 };
+
+// The size on the canvas and, once scaled, how much.
+QString sizeLabel(const ImageLayer &layer);

src/UI/TransformInspector.cpp

@@ -101,7 +101,8 @@ TransformInspector::TransformInspector(EditorSession &session, QWidget *parent)
       m_rotation(new TransformValueField(QStringLiteral("°"), QString(), -360, 360, session, [this](double number) {
           change([number](LayerTransform &value) { value.rotation = std::fmod(number, 360.0); });
       })),
-      m_sampling(new QComboBox(this)), m_cancel(new QPushButton(QStringLiteral("Cancel"), this)), m_apply(new QPushButton(QStringLiteral("Apply"), this))
+      m_sampling(new QComboBox(this)), m_cancel(new QPushButton(QStringLiteral("Cancel"), this)), m_apply(new QPushButton(QStringLiteral("Apply"), this)),
+      m_pendingButtons(new QWidget(this)), m_fade(new QGraphicsOpacityEffect(m_pendingButtons)), m_fadeIn(new QPropertyAnimation(m_fade, "opacity", this))
 {
     m_autoSelect->setObjectName(QStringLiteral("transformAutoSelect"));
     m_autoSelect->setToolTip(QStringLiteral("Select layers by clicking the canvas. When off, hold Ctrl to select a layer."));
@@ -162,8 +163,25 @@ TransformInspector::TransformInspector(EditorSession &session, QWidget *parent)
     // Swift's configuredNativeShortcut: Return and Escape, as remapped.
     NativeShortcut::bind(*this, m_apply, m_cancel);
     connect(m_apply, &QPushButton::clicked, this, [this] { m_session.commitTransform(); });
+    m_pendingButtons->setObjectName(QStringLiteral("pendingTransform"));
+    auto *pending = new QHBoxLayout(m_pendingButtons);
+    pending->setContentsMargins(0, 0, 0, 0);
+    pending->setSpacing(12);
+    pending->addWidget(m_cancel);
+    pending->addWidget(m_apply);
+    // Unseen, not hidden: Return and Escape still reach a drag.
+    m_pendingButtons->setGraphicsEffect(m_fade);
+    m_fade->setOpacity(0);
+    m_pendingButtons->setAttribute(Qt::WA_TransparentForMouseEvents);
+    m_cancel->setFocusPolicy(Qt::NoFocus);
+    m_apply->setFocusPolicy(Qt::NoFocus);
+    // SwiftUI's easeOut over 0.12 seconds.
+    QEasingCurve easeOut(QEasingCurve::BezierSpline);
+    easeOut.addCubicBezierSegment(QPointF(0, 0), QPointF(0.58, 1), QPointF(1, 1));
+    m_fadeIn->setEasingCurve(easeOut);
+    m_fadeIn->setDuration(120);
     // Before the stretch ending the row, in Swift's order.
-    for (QWidget *widget : std::initializer_list<QWidget *>{m_autoSelect, m_showControls, m_fields, m_cancel, m_apply})
+    for (QWidget *widget : std::initializer_list<QWidget *>{m_autoSelect, m_showControls, m_fields, m_pendingButtons})
         row->insertWidget(row->count() - 1, widget, widget == m_fields ? 1 : 0);
     // The scroll view takes the spare room, as SwiftUI's does.
     row->setStretch(row->count() - 1, 0);
@@ -278,4 +296,16 @@ void TransformInspector::synchronize()
     m_fields->widget()->setEnabled((m_session.canTransform() || editing) && !distorted);
     m_cancel->setEnabled(editing);
     m_apply->setEnabled(editing);
+    // Typed values, Ctrl+T, a distortion wait; a handle drag applies.
+    const bool pending = editing && m_session.transformEdit()->persistent;
+    if (pending == m_pending)
+        return;
+    m_pending = pending;
+    m_pendingButtons->setAttribute(Qt::WA_TransparentForMouseEvents, !pending);
+    m_cancel->setFocusPolicy(pending ? Qt::StrongFocus : Qt::NoFocus);
+    m_apply->setFocusPolicy(pending ? Qt::StrongFocus : Qt::NoFocus);
+    m_fadeIn->stop();
+    m_fadeIn->setStartValue(m_fade->opacity());
+    m_fadeIn->setEndValue(pending ? 1.0 : 0.0);
+    m_fadeIn->start();
 }

src/UI/TransformInspector.h

@@ -3,7 +3,9 @@
 #include "UI/ToolHeaderStyle.h"
 #include <QCheckBox>
 #include <QComboBox>
+#include <QGraphicsOpacityEffect>
 #include <QLineEdit>
+#include <QPropertyAnimation>
 #include <QPushButton>
 #include <QScrollArea>
 #include <QToolButton>
@@ -76,4 +78,9 @@ private:
     QComboBox *const m_sampling;
     QPushButton *const m_cancel;
     QPushButton *const m_apply;
+    // Cancel and Apply, seen only while an edit waits.
+    QWidget *const m_pendingButtons;
+    QGraphicsOpacityEffect *const m_fade;
+    QPropertyAnimation *const m_fadeIn;
+    bool m_pending = false;
 };