Merge branch 'main' into port-d

src/Document/BrushStroke.cpp

@@ -3,6 +3,7 @@
 #include "IO/ImageExporter.h"
 #include <QtConcurrent>
 #include <cmath>
+#include <cstring>
 #include <numeric>
 #include <stdexcept>
 
@@ -28,6 +29,37 @@ QImage BrushRaster::context(int width, int height, bool mask)
     return surface;
 }
 
+QImage BrushRaster::copy(const QImage &image)
+{
+    QImage result = context(image.width(), image.height(), false);
+    if (image.format() != QImage::Format_RGBA8888_Premultiplied) {
+        QPainter painter(&result);
+        draw(image, QRectF(0, 0, image.width(), image.height()), painter);
+        return result;
+    }
+    for (int y = 0; y < image.height(); ++y)
+        std::memcpy(result.scanLine(y), image.constScanLine(y), size_t(image.width()) * 4);
+    return result;
+}
+
+void BrushRaster::inBands(qsizetype count, const std::function<void(qsizetype, qsizetype)> &body)
+{
+    const int bands = count < 250'000 ? 1 : QThread::idealThreadCount() * 2;
+    const qsizetype size = (count + bands - 1) / bands;
+    try {
+        std::vector<int> indices(static_cast<size_t>(bands));
+        std::iota(indices.begin(), indices.end(), 0);
+        PoolMap::blocking(indices, [&](int band) {
+            const qsizetype start = band * size;
+            if (start < count)
+                body(start, std::min(size, count - start));
+        });
+    } catch (const std::bad_alloc &) {
+        // Out of memory fails as a context would.
+        throw ExportError(ExportError::Kind::render);
+    }
+}
+
 void BrushRaster::draw(const QImage &image, const QRectF &rect, QPainter &context, const QRectF &source)
 {
     context.save();

src/Document/BrushStroke.h

@@ -46,6 +46,10 @@ struct BrushSettings {
 // Shared raster drawing; coverage is copied without color conversion.
 namespace BrushRaster {
 QImage context(int width, int height, bool mask);
+// A colour context holding `image`; its own layout copies bytewise.
+QImage copy(const QImage &image);
+// Runs `body` over `count` pixels, band by band: start, length.
+void inBands(qsizetype count, const std::function<void(qsizetype, qsizetype)> &body);
 // Copies `image`, or its `source` part, into `rect`.
 void draw(const QImage &image, const QRectF &rect, QPainter &context, const QRectF &source = QRectF());
 // A solid colour through gray coverage, and a clip, 1:1.

src/Document/CameraRawColor.cpp

@@ -79,25 +79,34 @@ bool CameraRawCurveSettings::adjusts() const
         || !isLinear(green) || !isLinear(blue);
 }
 
-double CameraRawCurveSettings::parametric(double tone) const
+// Bends tones below `lower` by `low`, above `upper` by `high`.
+double CameraRawCurveSettings::bend(double tone, double lower, double low, double upper, double high)
 {
-    const double shadow = shadowSplit / 100, dark = darkSplit / 100, light = lightSplit / 100;
-    double amount, lo, hi;
-    if (tone < shadow)
-        amount = shadows, lo = 0, hi = shadow;
-    else if (tone < dark)
-        amount = darks, lo = shadow, hi = dark;
-    else if (tone < light)
-        amount = lights, lo = dark, hi = light;
-    else
-        amount = highlights, lo = light, hi = 1;
-    const double span = std::max(0.02, hi - lo);
-    const double weight = 1 - std::abs(tone - (lo + hi) / 2) / (span / 2);
-    // A tone in its region weighs 0 to 1, unfloored.
-    return std::min(1.0, std::max(0.0, tone + (amount / 100) * weight * 0.22));
+    // Fitted to Photoshop: Darks −51 dips 0.1 there.
+    const double strength = 1.66;
+    if (tone < lower)
+        return lower * std::pow(tone / lower, std::pow(2, -low / 100 * strength));
+    if (tone > upper) {
+        const double rest = 1 - upper;
+        return 1 - rest * std::pow((1 - tone) / rest, std::pow(2, high / 100 * strength));
+    }
+    return tone;
 }
 
-std::vector<float> CameraRawCurveSettings::lumaTable() const
+double CameraRawCurveSettings::parametric(double tone) const
+{
+    if (shadows == 0 && darks == 0 && lights == 0 && highlights == 0)
+        return tone;
+    // Gamma bends, smoothed as Image › Curves smooths.
+    std::vector<CurvePoint> anchors;
+    for (int index = 0; index <= 32; ++index) {
+        const double x = index / 32.0;
+        anchors.push_back({x, bend(bend(x, shadowSplit / 100, shadows, lightSplit / 100, highlights), darkSplit / 100, darks, darkSplit / 100, lights)});
+    }
+    return point(tone, anchors);
+}
+
+std::vector<float> CameraRawCurveSettings::toneTable() const
 {
     std::vector<float> table(256);
     for (int index = 0; index < 256; ++index)
@@ -262,10 +271,10 @@ void CameraRawSettings::applyCurveColor(uchar *pixels, int width, int height, qs
     const CameraRawCurveSettings shape = curve.normalized();
     const CameraRawMixerSettings mixing = mixer.normalized();
     const CameraRawGradingSettings grade = grading.normalized();
-    const std::vector<float> luma = shape.lumaTable(), redTable = shape.channelTable(shape.red), greenTable = shape.channelTable(shape.green),
+    const std::vector<float> tone = shape.toneTable(), redTable = shape.channelTable(shape.red), greenTable = shape.channelTable(shape.green),
                              blueTable = shape.channelTable(shape.blue), mixerFloats = mixing.mixerFloats(), pointFloats = mixing.pointFloats(),
                              gradeFloats = grade.gradeFloats();
-    adjust_camera_raw_curve_color(pixels, size_t(width), size_t(height), size_t(stride), luma.data(), redTable.data(), greenTable.data(),
+    adjust_camera_raw_curve_color(pixels, size_t(width), size_t(height), size_t(stride), tone.data(), redTable.data(), greenTable.data(),
                                   blueTable.data(), shape.refineSaturation / 100, mixerFloats.data(), int(mixing.points.size()), pointFloats.data(),
                                   gradeFloats.data(), grade.blending / 100, grade.balance / 100, visualize);
 }

src/Document/CameraRawColor.h

@@ -33,15 +33,19 @@ struct CameraRawCurveSettings {
     static std::vector<CurvePoint> strongContrast();
     static bool isLinear(const std::vector<CurvePoint> &points);
     bool adjusts() const;
-    // Lifts or lowers the region a tone belongs to.
+    // Photoshop's parametric curve: gamma bends, smoothed as Curves.
     double parametric(double tone) const;
-    std::vector<float> lumaTable() const;
+    // Applied to red, green and blue alike.
+    std::vector<float> toneTable() const;
     std::vector<float> channelTable(const std::vector<CurvePoint> &points) const;
     CameraRawCurveSettings nudged(CameraRawPointChannel channel, double tone, double delta) const;
     // Swift's region(for:): the parametric amount a tone moves.
     double &region(double tone);
     CameraRawCurveSettings normalized() const;
     friend bool operator==(const CameraRawCurveSettings &, const CameraRawCurveSettings &) = default;
+
+private:
+    static double bend(double tone, double lower, double low, double upper, double high);
 };
 
 // One picked colour and how far its adjustment reaches.

src/Document/Dither.cpp

@@ -1,17 +1,28 @@
 #include "Document/Dither.h"
 #include "Document/BrushStroke.h"
+#include "Document/PixelAdjust.h"
 #include "IO/ImageExporter.h"
+#include "Rendering/PoolMap.h"
 #include <QFontMetricsF>
 #include <QPainter>
 #include <QPainterPath>
 #include <QTextBoundaryFinder>
 #include <algorithm>
 #include <cmath>
+#include <numeric>
 #include <set>
 extern "C" {
 #include "DitherPixels.h"
 }
 
+// The kernel's bands, where Swift's kernel calls dispatch_apply.
+extern "C" void dither_bands(size_t bands, void (*band)(void *context, size_t index), void *context)
+{
+    std::vector<size_t> indices(bands);
+    std::iota(indices.begin(), indices.end(), size_t(0));
+    PoolMap::blocking(indices, [band, context](size_t index) { band(context, index); });
+}
+
 // Swift's Dither.swift: the settings, the chunky pixels, the glyphs.
 namespace {
 // Swift's Characters: the text's graphemes.
@@ -53,6 +64,7 @@ QString rawValue(DitherStyle style)
     case DitherStyle::diamonds: return QStringLiteral("Halftone Diamonds");
     case DitherStyle::patterns: return QStringLiteral("Mac Patterns");
     case DitherStyle::ascii: return QStringLiteral("ASCII");
+    case DitherStyle::scanlines: return QStringLiteral("Scanlines (CRT)");
     }
     throw std::logic_error("unknown dither style");
 }
@@ -80,7 +92,12 @@ bool isHalftone(DitherStyle style)
 
 bool drawsMarks(DitherStyle style)
 {
-    return !hasTones(style);
+    return !hasTones(style) && style != DitherStyle::scanlines;
+}
+
+bool usesPixelSize(DitherStyle style)
+{
+    return style != DitherStyle::ascii && style != DitherStyle::scanlines;
 }
 
 QString rawValue(DitherPixelShape shape)
@@ -105,6 +122,10 @@ DitherSettings DitherSettings::normalized() const
     result.pixelSize = std::round(clamp(pixelSize, pixelSizeLow, pixelSizeHigh, 2));
     result.cellSize = std::round(clamp(cellSize, cellSizeLow, cellSizeHigh, 8));
     result.textSize = std::round(clamp(textSize, textSizeLow, textSizeHigh, 14));
+    result.lineSpacing = std::round(clamp(lineSpacing, lineSpacingLow, lineSpacingHigh, 4));
+    result.glow = clamp(glow, 0, 100, 35);
+    result.dots = clamp(dots, 0, 100, 0);
+    result.wobble = clamp(wobble, wobbleLow, wobbleHigh, 0);
     result.angle = clamp(angle, -90, 90, 45);
     result.levels = std::round(clamp(levels, levelsLow, levelsHigh, 2));
     result.diffusion = clamp(diffusion, 0, 100, 100);
@@ -125,8 +146,8 @@ DitherSettings DitherSettings::normalized() const
 QImage DitherSettings::apply(const QImage &image) const
 {
     const DitherSettings settings = normalized();
-    // ASCII draws at full resolution: chunks would blur its letters.
-    const int block = settings.style == DitherStyle::ascii ? 1 : int(settings.pixelSize);
+    // ASCII and Scanlines draw full size: chunks would blur them.
+    const int block = usesPixelSize(settings.style) ? int(settings.pixelSize) : 1;
     const QImage source = image.convertToFormat(QImage::Format_RGBA8888_Premultiplied);
     if (source.isNull())
         throw ExportError(ExportError::Kind::render);
@@ -153,6 +174,8 @@ QImage DitherSettings::apply(const QImage &image) const
         }
     }
     const QImage dithered = settings.dither(working);
+    if (settings.style == DitherStyle::scanlines && settings.glow > 0)
+        return settings.glowing(dithered);
     if (block <= 1)
         return dithered;
     // Blown back up without smoothing.
@@ -171,9 +194,42 @@ QImage DitherSettings::apply(const QImage &image) const
     return full;
 }
 
+// The lines' light blurred wide and added back: phosphor bloom.
+QImage DitherSettings::glowing(const QImage &image) const
+{
+    // Blurred small, scaled back up: same light, less work.
+    const double sigma = lineSpacing * 3 + 3, shrink = std::max(1.0, std::floor(sigma / 4));
+    const int width = image.width(), height = image.height();
+    // Swift clamps first: edges repeat outward before shrinking.
+    const int step = int(shrink), pad = int(std::ceil(sigma * 3 / shrink)) * step;
+    QImage padded = BrushRaster::context(width + 2 * pad, height + 2 * pad, false);
+    for (int y = 0; y < padded.height(); ++y) {
+        const uchar *source = image.constScanLine(std::clamp(y - pad, 0, height - 1));
+        uchar *out = padded.scanLine(y);
+        for (int x = 0; x < padded.width(); ++x)
+            std::copy_n(source + std::clamp(x - pad, 0, width - 1) * 4, 4, out + x * 4);
+    }
+    const int smallWidth = (padded.width() + step - 1) / step, smallHeight = (padded.height() + step - 1) / step;
+    const QImage small = padded.scaled(smallWidth, smallHeight, Qt::IgnoreAspectRatio, Qt::SmoothTransformation);
+    if (small.isNull())
+        throw ExportError(ExportError::Kind::render);
+    const QImage blurred = PixelAdjust::gaussianBlur(small, sigma / shrink, true)
+                               .scaled(smallWidth * step, smallHeight * step, Qt::IgnoreAspectRatio, Qt::SmoothTransformation)
+                               .convertToFormat(QImage::Format_RGBA8888_Premultiplied);
+    QImage result = image.copy();
+    if (blurred.isNull() || result.isNull())
+        throw ExportError(ExportError::Kind::render);
+    // The scaled light's own rows, cropped to the image.
+    QImage bloom = BrushRaster::context(width, height, false);
+    for (int y = 0; y < height; ++y)
+        std::copy_n(blurred.constScanLine(y + pad) + pad * 4, width * 4, bloom.scanLine(y));
+    dither_glow(result.bits(), bloom.constBits(), size_t(width), size_t(height), size_t(result.bytesPerLine()), float(glow / 100 * 2.5));
+    return result;
+}
+
 QImage DitherSettings::dither(const QImage &image) const
 {
-    const int cell = int(cellSize);
+    const int cell = int(style == DitherStyle::scanlines ? lineSpacing : cellSize);
     const Glyphs glyphs = style == DitherStyle::ascii ? DitherSettings::glyphs(characters.isEmpty() ? defaultCharacters() : characters, int(textSize)) : Glyphs();
     const bool two = colors == DitherColors::twoColors;
     const std::array<uint8_t, 3> darkColor = two ? bytes(dark) : std::array<uint8_t, 3>{0, 0, 0};
@@ -184,7 +240,8 @@ QImage DitherSettings::dither(const QImage &image) const
                             .contrast = float(contrast / 100), .cell = cell, .angle = float(angle * M_PI / 180), .lightOnDark = lightOnDark ? 1 : 0,
                             .originalColors = colors == DitherColors::original ? 1 : 0, .dark = {darkColor[0], darkColor[1], darkColor[2]},
                             .light = {lightColor[0], lightColor[1], lightColor[2]}, .glyphWidth = glyphs.width, .glyphHeight = glyphs.height, .glyphs = glyphs.maps.data(),
-                            .glyphCoverage = glyphs.coverage.data(), .glyphCount = int(glyphs.coverage.size())};
+                            .glyphCoverage = glyphs.coverage.data(), .glyphCount = int(glyphs.coverage.size()), .dots = float(dots / 100),
+                            .wobble = float(wobble)};
         failed = dither_apply(pixels, size_t(width), size_t(height), size_t(stride), &params) == 0;
     });
     if (failed)

src/Document/Dither.h

@@ -6,10 +6,10 @@
 #include <vector>
 
 // Filter › Dither's looks, in the panel's order and DitherPixels.h's.
-enum class DitherStyle { atkinson, floydSteinberg, bayer2, bayer4, bayer8, dots, lines, diamonds, patterns, ascii };
-inline constexpr std::array allDitherStyles{DitherStyle::atkinson, DitherStyle::floydSteinberg, DitherStyle::bayer2, DitherStyle::bayer4,
-                                            DitherStyle::bayer8,   DitherStyle::dots,           DitherStyle::lines,  DitherStyle::diamonds,
-                                            DitherStyle::patterns, DitherStyle::ascii};
+enum class DitherStyle { atkinson, floydSteinberg, bayer2, bayer4, bayer8, dots, lines, diamonds, patterns, ascii, scanlines };
+inline constexpr std::array allDitherStyles{DitherStyle::atkinson, DitherStyle::floydSteinberg, DitherStyle::bayer2,   DitherStyle::bayer4,
+                                            DitherStyle::bayer8,   DitherStyle::dots,           DitherStyle::lines,    DitherStyle::diamonds,
+                                            DitherStyle::patterns, DitherStyle::ascii,          DitherStyle::scanlines};
 QString rawValue(DitherStyle style);
 // Swift's groups: diffusion, ordered, halftone, marks.
 int ditherGroup(DitherStyle style);
@@ -19,6 +19,8 @@ bool diffuses(DitherStyle style);
 bool hasTones(DitherStyle style);
 bool isHalftone(DitherStyle style);
 bool drawsMarks(DitherStyle style);
+// ASCII and Scanlines draw at full resolution, not chunky.
+bool usesPixelSize(DitherStyle style);
 
 // A chunky pixel: a square, or a dot on dark.
 enum class DitherPixelShape { square, dot };
@@ -35,6 +37,8 @@ struct DitherSettings {
     static constexpr double cellSizeLow = 4, cellSizeHigh = 64;
     static constexpr double textSizeLow = 6, textSizeHigh = 64;
     static constexpr double levelsLow = 2, levelsHigh = 8;
+    static constexpr double lineSpacingLow = 2, lineSpacingHigh = 32;
+    static constexpr double wobbleLow = 0, wobbleHigh = 64;
     static QString defaultCharacters() { return QStringLiteral(" .:-=+*#%@"); }
     DitherStyle style = DitherStyle::atkinson;
     // Each dithered pixel covers this many layer pixels a side.
@@ -44,6 +48,12 @@ struct DitherSettings {
     double cellSize = 8;
     // ASCII's line height in layer pixels; letters about 0.6 wide.
     double textSize = 14;
+    // Scanlines: the lines' distance apart, in layer pixels.
+    double lineSpacing = 4;
+    // Glow and dots 0–100%; wobble sideways in pixels.
+    double glow = 35;
+    double dots = 0;
+    double wobble = 0;
     // The halftone screen's angle, in degrees.
     double angle = 45;
     // Tones per channel; 2 is 1-bit.
@@ -76,4 +86,5 @@ struct DitherSettings {
 
 private:
     QImage dither(const QImage &image) const;
+    QImage glowing(const QImage &image) const;
 };

src/Document/EditorSession+Jobs.h

@@ -104,8 +104,8 @@ struct SessionJobs {
         FilterSettings settings;
         // Camera Raw's scope of the grade itself.
         std::optional<CameraRawScope> scope = std::nullopt;
-        // Its grid's version: a newer grid drops it.
-        quint64 sourceVersion = 0;
+        // The grown layer it was made from: it shows there.
+        std::optional<LayerTransform> placement = std::nullopt;
     };
     struct FilterMade {
         std::optional<ImportedImage> asset;

src/Document/EditorSession+Model.h

@@ -75,7 +75,8 @@ struct CanvasDocument {
 
     QSizeF size() const { return QSizeF(width, height); }
     static std::optional<int> validDimension(const QString &value);
-    std::vector<LayerHierarchy::Entry> hierarchyEntries() const;
+    // Drawing order and what shows (LayerOrder), kept between asks.
+    LayerOrder::Result hierarchy() const;
     QSet<QUuid> effectiveVisibleIDs() const;
     QHash<QUuid, double> effectiveOpacities() const;
     std::vector<ImageLayer> renderLayers() const;

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+Transform.cpp

@@ -257,8 +257,8 @@ LayerTransform EditorSession::displayedTransform(const ImageLayer &layer) const
     if (const std::optional<LayerTransform> pending = pendingTransform(layer))
         return *pending;
     // Content-Aware Fill past the edge previews on the grown layer.
-    if (m_filterEdit && m_filterEdit->grownTransform && m_filterEdit->previewImage(layer.id))
-        return *m_filterEdit->grownTransform;
+    if (m_filterEdit && m_filterEdit->preparedTransform && m_filterEdit->previewImage(layer.id))
+        return *m_filterEdit->preparedTransform;
     return layer.transform;
 }
 

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

@@ -80,10 +80,6 @@ void EditorSession::updateFilter(const FilterSettings &settings, bool preview)
     if (FilterEdit::blurMargin(edit.kind, edit.settings) > edit.grownMargin) {
         try {
             edit.growForBlur();
-            edit.preparedPreview.reset();
-            // A waiting job moves to the grid its version names.
-            if (edit.pending)
-                edit.pending = edit.previewJob();
         } catch (const ProjectError &error) {
             setBrushError(QString::fromUtf8(error.what()));
         } catch (const ExportError &error) {
@@ -111,6 +107,7 @@ void EditorSession::updateFilter(const FilterSettings &settings, bool preview)
         return;
     }
     edit.pending = edit.previewJob();
+    edit.pendingTransform = edit.grownTransform;
     renderFilterPreview();
 }
 
@@ -127,22 +124,22 @@ void EditorSession::renderFilterPreview()
         const FilterJob job = *std::exchange(edit.pending, std::nullopt);
         m_filterPreviewFor = edit.id;
         m_filterRendering = true;
-        m_filterPreview.setFuture(QtConcurrent::run([job, version = edit.previewSourceVersion]() -> Filtered {
+        m_filterPreview.setFuture(QtConcurrent::run([job, placement = edit.pendingTransform]() -> Filtered {
             try {
                 if (job.kind == FilterKind::cameraRaw) {
                     auto [image, scope] = CameraRawScope::preview(job);
-                    return Filtered{std::move(image), std::nullopt, job.settings, std::move(scope), version};
+                    return Filtered{std::move(image), std::nullopt, job.settings, std::move(scope), placement};
                 }
-                return Filtered{PixelFilter::run(job), std::nullopt, job.settings, std::nullopt, version};
+                return Filtered{PixelFilter::run(job), std::nullopt, job.settings, std::nullopt, placement};
             } catch (const ContentFillError &error) {
-                return Filtered{std::nullopt, QString::fromUtf8(error.what()), job.settings, std::nullopt, version};
+                return Filtered{std::nullopt, QString::fromUtf8(error.what()), job.settings, std::nullopt, placement};
             } catch (const SubjectRemovalError &error) {
-                return Filtered{std::nullopt, QString::fromUtf8(error.what()), job.settings, std::nullopt, version};
+                return Filtered{std::nullopt, QString::fromUtf8(error.what()), job.settings, std::nullopt, placement};
             } catch (const ExportError &error) {
-                return Filtered{std::nullopt, QString::fromUtf8(error.what()), job.settings, std::nullopt, version};
+                return Filtered{std::nullopt, QString::fromUtf8(error.what()), job.settings, std::nullopt, placement};
             } catch (const ProjectError &error) {
                 // Settings past their bounds: Black & White, Color Balance.
-                return Filtered{std::nullopt, QString::fromUtf8(error.what()), job.settings, std::nullopt, version};
+                return Filtered{std::nullopt, QString::fromUtf8(error.what()), job.settings, std::nullopt, placement};
             }
         }));
     }
@@ -153,18 +150,17 @@ void EditorSession::finishFilterPreview()
 {
     m_filterRendering = false;
     const Filtered result = m_filterPreview.result();
-    // A cancelled edit takes nothing; an older grid renders again.
-    if (m_filterEdit && m_filterEdit->id == m_filterPreviewFor && result.sourceVersion != m_filterEdit->previewSourceVersion) {
-        m_filterEdit->preparing = false;
-        notify();
-    } else if (m_filterEdit && m_filterEdit->id == m_filterPreviewFor) {
+    // A cancelled edit takes nothing.
+    if (m_filterEdit && m_filterEdit->id == m_filterPreviewFor) {
         FilterEdit &edit = *m_filterEdit;
         edit.preparing = false;
         edit.previewError = result.failure;
         if (result.scope)
             edit.rawPanel.scope = result.scope;
+        // Made before the layer grew, it shows there till replaced.
         if (edit.preview || isAutomatic(edit.kind)) {
             edit.preparedPreview = result.image;
+            edit.preparedTransform = result.placement;
             edit.preparedSettings = result.settings;
             ++m_brushRevision;
         }
@@ -351,7 +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/Filters.cpp

@@ -272,7 +272,6 @@ void FilterEdit::grow(const QRectF &extent)
 void FilterEdit::prepare(const ImportedImage &source, const LayerTransform &placed)
 {
     const QSize size = source.size();
-    ++previewSourceVersion;
     mapping = BrushRaster::pixelToDocument(placed, size.width(), size.height());
     // Noise, grain and dither preview whole: enlarged, they look coarse.
     const bool whole = kind == FilterKind::addNoise || kind == FilterKind::grain || kind == FilterKind::dither || kind == FilterKind::contentAwareFill

src/Document/Filters.h

@@ -171,10 +171,12 @@ public:
     // Add Noise's grain, fixed while the panel is open.
     const quint32 seed = QRandomGenerator::global()->generate();
     std::optional<QImage> preparedPreview;
+    // Where the prepared preview sits; none: the layer's own place.
+    std::optional<LayerTransform> preparedTransform;
+    // The grown layer `pending` is made from.
+    std::optional<LayerTransform> pendingTransform;
     // The settings the prepared preview was made with.
     std::optional<FilterSettings> preparedSettings;
-    // Moves with each new grid: an older render lands nothing.
-    quint64 previewSourceVersion = 0;
     std::optional<FilterJob> pending;
     CameraRawPanel rawPanel;
     // Vignette on an empty layer: the canvas it fills.

src/Document/HueSaturation+Filter.cpp

@@ -1,13 +1,14 @@
 #include "Document/BrushStroke.h"
-#include "Rendering/PoolMap.h"
 #include "Document/HueSaturation.h"
 #include "Document/PixelAdjust.h"
 #include "IO/ImageExporter.h"
-#include <QPainter>
-#include <QtConcurrent>
 #include <algorithm>
 #include <cmath>
-#include <numeric>
+#include <deque>
+#include <mutex>
+extern "C" {
+#include "LevelsPixels.h"
+}
 
 namespace {
 struct HSL {
@@ -48,38 +49,38 @@ HueSaturationFilter::Color toRGB(double hue, double saturation, double lightness
     return {clamp(color.red), clamp(color.green), clamp(color.blue)};
 }
 
-// Core Image's colour cube: unpremultiplied, trilinear, premultiplied back.
-void applyCube(uchar *bits, qsizetype stride, int width, const std::vector<float> &cube, const std::vector<int> &rows)
+// The last tables built: building costs more than applying.
+struct CubeCache {
+    std::mutex lock;
+    std::deque<std::pair<HueSaturationSettings, std::vector<float>>> cubes;
+};
+
+CubeCache &cubeCache()
 {
-    constexpr int size = HueSaturationFilter::dimension, last = size - 1;
-    PoolMap::blocking(rows, [&](int y) {
-        uchar *pixel = bits + y * stride;
-        for (int x = 0; x < width; ++x, pixel += 4) {
-            const float alpha = pixel[3];
-            if (alpha == 0) {
-                std::fill_n(pixel, 3, uchar(0));
-                continue;
+    static CubeCache cache;
+    return cache;
+}
+
+std::vector<float> built(const HueSaturationSettings &settings)
+{
+    const std::vector<HueSaturationFilter::HueResponse> response = HueSaturationFilter::hueResponse(settings);
+    constexpr int dimension = HueSaturationFilter::dimension;
+    std::vector<float> values(size_t(dimension * dimension * dimension * 4));
+    size_t index = 0;
+    const double step = dimension - 1;
+    for (int blue = 0; blue < dimension; ++blue) {
+        for (int green = 0; green < dimension; ++green) {
+            for (int red = 0; red < dimension; ++red) {
+                const HueSaturationFilter::Color color = HueSaturationFilter::adjust(red / step, green / step, blue / step, settings, response);
+                values[index] = float(color.red);
+                values[index + 1] = float(color.green);
+                values[index + 2] = float(color.blue);
+                values[index + 3] = 1;
+                index += 4;
             }
-            float place[3], fraction[3];
-            int low[3];
-            for (int channel = 0; channel < 3; ++channel) {
-                place[channel] = std::min(1.0f, pixel[channel] / alpha) * last;
-                low[channel] = std::min(int(place[channel]), last - 1);
-                fraction[channel] = place[channel] - float(low[channel]);
-            }
-            float out[3] = {0, 0, 0};
-            for (int corner = 0; corner < 8; ++corner) {
-                const int r = low[0] + (corner & 1), g = low[1] + (corner >> 1 & 1), b = low[2] + (corner >> 2 & 1);
-                const float share = ((corner & 1) ? fraction[0] : 1 - fraction[0]) * ((corner >> 1 & 1) ? fraction[1] : 1 - fraction[1])
-                    * ((corner >> 2 & 1) ? fraction[2] : 1 - fraction[2]);
-                const float *entry = &cube[size_t(((b * size + g) * size + r) * 4)];
-                for (int channel = 0; channel < 3; ++channel)
-                    out[channel] += share * entry[channel];
-            }
-            for (int channel = 0; channel < 3; ++channel)
-                pixel[channel] = uchar(std::lround(std::min(1.0f, std::max(0.0f, out[channel])) * alpha));
         }
-    });
+    }
+    return values;
 }
 }
 
@@ -104,22 +105,20 @@ std::vector<HueSaturationFilter::HueResponse> HueSaturationFilter::hueResponse(c
 
 std::vector<float> HueSaturationFilter::cube(const HueSaturationSettings &settings)
 {
-    const std::vector<HueResponse> response = hueResponse(settings);
-    std::vector<float> values(size_t(dimension * dimension * dimension * 4));
-    size_t index = 0;
-    const double step = dimension - 1;
-    for (int blue = 0; blue < dimension; ++blue) {
-        for (int green = 0; green < dimension; ++green) {
-            for (int red = 0; red < dimension; ++red) {
-                const Color color = adjust(red / step, green / step, blue / step, settings, response);
-                values[index] = float(color.red);
-                values[index + 1] = float(color.green);
-                values[index + 2] = float(color.blue);
-                values[index + 3] = 1;
-                index += 4;
-            }
+    CubeCache &cache = cubeCache();
+    {
+        const std::lock_guard<std::mutex> held(cache.lock);
+        for (const auto &[known, values] : cache.cubes) {
+            if (known == settings)
+                return values;
         }
     }
+    std::vector<float> values = built(settings);
+    const std::lock_guard<std::mutex> held(cache.lock);
+    std::erase_if(cache.cubes, [&](const auto &entry) { return entry.first == settings; });
+    cache.cubes.emplace_front(settings, values);
+    if (cache.cubes.size() > 8)
+        cache.cubes.pop_back();
     return values;
 }
 
@@ -144,8 +143,7 @@ HueSaturationFilter::Color HueSaturationFilter::adjust(double red, double green,
         hue = std::fmod(hue + sampled.shift, 360);
         if (hue < 0)
             hue += 360;
-        // Multiplied, so neutral grays stay neutral.
-        saturation = std::min(1.0, std::max(0.0, saturation * (1 + sampled.saturation / 100)));
+        saturation = adjustedSaturation(saturation, sampled.saturation);
     }
     // Toward white above zero, black below, reaching either at 100.
     const double amount = std::min(1.0, std::max(-1.0, lightnessAmount));
@@ -153,6 +151,15 @@ HueSaturationFilter::Color HueSaturationFilter::adjust(double red, double green,
     return toRGB(hue, saturation, std::min(1.0, std::max(0.0, lightness)));
 }
 
+double HueSaturationFilter::adjustedSaturation(double saturation, double amount)
+{
+    const double share = std::min(1.0, std::max(-1.0, amount / 100));
+    // Multiplied both ways, so neutral grays stay neutral.
+    if (!(share > 0))
+        return std::max(0.0, saturation * (1 + share));
+    return share >= 1 ? (saturation > 0 ? 1 : 0) : std::min(1.0, saturation / (1 - share));
+}
+
 double HueSaturationFilter::shiftedHue(double hue, const HueSaturationSettings &settings)
 {
     double shift = 0;
@@ -166,23 +173,19 @@ double HueSaturationFilter::shiftedHue(double hue, const HueSaturationSettings &
 
 AdjustedPixels HueSaturationFilter::run(const HueSaturationJob &job)
 {
-    const int width = job.image.width(), height = job.image.height();
-    QImage result = BrushRaster::context(width, height, false);
-    {
-        QPainter painter(&result);
-        BrushRaster::draw(job.image, QRectF(0, 0, width, height), painter);
-    }
+    // Across the cores: it runs over the view each frame.
+    QImage result = BrushRaster::copy(job.image);
     std::vector<float> table;
-    std::vector<int> rows;
     try {
         table = cube(job.settings);
-        rows.resize(size_t(height));
     } catch (const std::bad_alloc &) {
         // Out of memory fails as a context would.
         throw ExportError(ExportError::Kind::render);
     }
-    std::iota(rows.begin(), rows.end(), 0);
-    applyCube(result.bits(), result.bytesPerLine(), width, table, rows);
+    // The lookup unpremultiplies around itself.
+    uchar *const pixels = result.bits();
+    BrushRaster::inBands(qsizetype(result.width()) * result.height(),
+                         [&](qsizetype start, qsizetype length) { cube_apply(pixels + start * 4, size_t(length), table.data(), dimension); });
     // Swift blends over the image drawn again: the same pixels.
     if (job.selection)
         result = PixelAdjust::blend(result, job.image, *job.selection, job.pixelToDocument, false);

src/Document/HueSaturation.h

@@ -131,6 +131,8 @@ std::vector<HueResponse> hueResponse(const HueSaturationSettings &settings);
 std::vector<float> cube(const HueSaturationSettings &settings);
 Color adjust(double red, double green, double blue, const HueSaturationSettings &settings);
 Color adjust(double red, double green, double blue, const HueSaturationSettings &settings, const std::vector<HueResponse> &response);
+// Photoshop's: down toward gray, up by dividing by what's left.
+double adjustedSaturation(double saturation, double amount);
 // The hue a spectrum swatch becomes.
 double shiftedHue(double hue, const HueSaturationSettings &settings);
 }

src/Document/LayerAdjustment.cpp

@@ -242,7 +242,8 @@ QImage LayerAdjustment::apply(const QImage &image, std::optional<QRectF> region,
         FilterJob job{filterKind(kind).value(), image, settings, scale, std::nullopt, QTransform(), resolvedNoiseSeed()};
         // Swift's region origin, counted in the image's own pixels.
         if (region)
-            job.noiseOrigin = region->topLeft() * (image.width() / region->width());
+            job.noiseOrigin = QPointF(region->left() * image.width() / std::max(1.0, region->width()),
+                                      region->top() * image.height() / std::max(1.0, region->height()));
         return PixelFilter::run(job);
     }
     case AdjustmentKind::invert: return PixelInvert::run(PixelInvert::Job{image, false, QTransform(), std::nullopt});

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/LayerGroups+Order.cpp

@@ -0,0 +1,108 @@
+#include "Document/EditorSession.h"
+#include "Document/LayerGroups.h"
+#include <map>
+#include <mutex>
+#include <stdexcept>
+
+namespace {
+using Children = std::map<std::optional<QUuid>, std::vector<const LayerOrder::Node *>>;
+
+void visit(const Children &children, const std::optional<QUuid> &parent, int depth, bool shown, LayerOrder::Result &result)
+{
+    if (depth > 64)
+        return;
+    const auto found = children.find(parent);
+    if (found == children.end())
+        return;
+    for (const LayerOrder::Node *node : found->second) {
+        const bool effective = shown && node->isVisible;
+        result.order.push_back(node->id);
+        if (effective) {
+            result.visible.insert(node->id);
+            if (!node->isGroup)
+                result.drawn.push_back(node->id);
+        }
+        if (node->isGroup)
+            visit(children, node->id, depth + 1, effective, result);
+    }
+}
+
+// The last nodes asked about and their answer.
+struct Known {
+    std::mutex lock;
+    std::optional<std::pair<std::vector<LayerOrder::Node>, LayerOrder::Result>> last;
+};
+
+Known &known()
+{
+    static Known value;
+    return value;
+}
+}
+
+LayerOrder::Result LayerOrder::resolve(const std::vector<ImageLayer> &layers)
+{
+    std::vector<Node> nodes;
+    nodes.reserve(layers.size());
+    for (const ImageLayer &layer : layers)
+        nodes.push_back(Node{layer.id, layer.parentID, layer.isGroup, layer.isVisible});
+    Known &cache = known();
+    {
+        const std::lock_guard<std::mutex> held(cache.lock);
+        if (cache.last && cache.last->first == nodes)
+            return cache.last->second;
+    }
+    Children children;
+    for (const Node &node : nodes)
+        children[node.parentID].push_back(&node);
+    Result result;
+    visit(children, std::nullopt, 0, true, result);
+    const std::lock_guard<std::mutex> held(cache.lock);
+    cache.last.emplace(std::move(nodes), result);
+    return result;
+}
+
+LayerOrder::Result CanvasDocument::hierarchy() const
+{
+    return LayerOrder::resolve(layers);
+}
+
+QSet<QUuid> CanvasDocument::effectiveVisibleIDs() const
+{
+    return hierarchy().visible;
+}
+
+QHash<QUuid, double> CanvasDocument::effectiveOpacities() const
+{
+    // Each layer's opacity and folder, no whole layers copied.
+    QHash<QUuid, std::pair<double, std::optional<QUuid>>> folders;
+    for (const ImageLayer &layer : layers) {
+        if (folders.contains(layer.id))
+            throw std::logic_error("two layers share an id");
+        folders.insert(layer.id, {layer.opacity, layer.parentID});
+    }
+    QHash<QUuid, double> result;
+    for (auto entry = folders.cbegin(); entry != folders.cend(); ++entry) {
+        result.insert(entry.key(), LayerOpacity::effective(entry->first, entry->second, [&folders](QUuid id) {
+                          return folders.contains(id) ? std::optional(folders.value(id)) : std::nullopt;
+                      }));
+    }
+    return result;
+}
+
+std::vector<ImageLayer> CanvasDocument::renderLayers() const
+{
+    const std::vector<QUuid> order = hierarchy().drawn;
+    if (order.empty())
+        return {};
+    std::map<QUuid, size_t> index;
+    for (size_t place = 0; place < layers.size(); ++place) {
+        if (!index.emplace(layers[place].id, place).second)
+            throw std::logic_error("two layers share an id");
+    }
+    std::vector<ImageLayer> result;
+    result.reserve(order.size());
+    for (const QUuid id : order)
+        result.push_back(layers[index.at(id)]);
+    return result;
+}

src/Document/LayerGroups+Session.h

@@ -7,6 +7,9 @@ public:
     void selectLayers(const QSet<QUuid> &ids, std::optional<QUuid> primary);
     void extendSelection(QUuid id);
     void groupSelectedLayers();
+    // The active layer is a folder: something to unwrap.
+    bool canUngroupLayers() const;
+    void ungroupLayers();
     std::vector<LayerHierarchy::Entry> layerRows() const;
     bool canPlaceLayer(QUuid id, std::optional<QUuid> parent) const;
     bool placeLayer(QUuid id, std::optional<QUuid> parent, std::optional<QUuid> above = std::nullopt, bool atBottom = false);

src/Document/LayerGroups.cpp

@@ -121,19 +121,6 @@ double ProjectLayerRecord::effectiveOpacity(const std::map<QUuid, ProjectLayerRe
     });
 }
 
-QHash<QUuid, double> CanvasDocument::effectiveOpacities() const
-{
-    std::map<QUuid, ImageLayer> byID;
-    for (const ImageLayer &layer : layers) {
-        if (!byID.emplace(layer.id, layer).second)
-            throw std::logic_error("two layers share an id");
-    }
-    QHash<QUuid, double> result;
-    for (const ImageLayer &layer : layers)
-        result.insert(layer.id, layer.effectiveOpacity(byID));
-    return result;
-}
-
 ProjectLayerRecord ImageLayer::hierarchyRecord() const
 {
     const QString file = id.toString(QUuid::WithoutBraces).toUpper();
@@ -159,40 +146,6 @@ ProjectLayerRecord ImageLayer::hierarchyRecord() const
             .text = typed ? std::optional(typed->style) : std::nullopt};
 }
 
-std::vector<LayerHierarchy::Entry> CanvasDocument::hierarchyEntries() const
-{
-    std::vector<ProjectLayerRecord> records;
-    for (const ImageLayer &layer : layers)
-        records.push_back(layer.hierarchyRecord());
-    return LayerHierarchy::entries(records);
-}
-
-QSet<QUuid> CanvasDocument::effectiveVisibleIDs() const
-{
-    QSet<QUuid> result;
-    for (const LayerHierarchy::Entry &entry : hierarchyEntries()) {
-        if (entry.visible)
-            result.insert(entry.layer.id);
-    }
-    return result;
-}
-
-std::vector<ImageLayer> CanvasDocument::renderLayers() const
-{
-    QHash<QUuid, const ImageLayer *> byID;
-    for (const ImageLayer &layer : layers) {
-        if (byID.contains(layer.id))
-            throw std::logic_error("two layers share an id");
-        byID.insert(layer.id, &layer);
-    }
-    std::vector<ImageLayer> result;
-    for (const LayerHierarchy::Entry &entry : hierarchyEntries()) {
-        if (entry.visible && entry.layer.isGroup != true)
-            result.push_back(*byID.value(entry.layer.id));
-    }
-    return result;
-}
-
 void EditorSession::selectLayers(const QSet<QUuid> &ids, std::optional<QUuid> primary)
 {
     dropEffectSelection();
@@ -264,10 +217,10 @@ void EditorSession::groupSelectedLayers()
     }
     std::vector<QUuid> ordered;
     std::vector<Chain> chains;
-    for (const LayerHierarchy::Entry &entry : m_document->hierarchyEntries()) {
-        if (rootIDs.contains(entry.layer.id)) {
-            ordered.push_back(entry.layer.id);
-            chains.push_back(ancestors(entry.layer.id));
+    for (const QUuid id : m_document->hierarchy().order) {
+        if (rootIDs.contains(id)) {
+            ordered.push_back(id);
+            chains.push_back(ancestors(id));
         }
     }
     // The nearest folder they all share; the root when none.
@@ -317,6 +270,44 @@ void EditorSession::groupSelectedLayers()
     endEdit();
 }
 
+bool EditorSession::canUngroupLayers() const
+{
+    const std::optional<ImageLayer> active = activeLayer();
+    return canEditLayers() && active && active->isGroup;
+}
+
+// The folder's children take its place, in order.
+void EditorSession::ungroupLayers()
+{
+    if (!canUngroupLayers())
+        return;
+    const ImageLayer group = activeLayer().value();
+    std::vector<ImageLayer> children;
+    for (const ImageLayer &layer : m_document->layers) {
+        if (layer.parentID == group.id) {
+            children.push_back(layer);
+            children.back().parentID = group.parentID;
+        }
+    }
+    std::vector<ImageLayer> layers;
+    QSet<QUuid> childIDs;
+    for (const ImageLayer &child : children)
+        childIDs.insert(child.id);
+    for (const ImageLayer &layer : m_document->layers) {
+        if (layer.id == group.id)
+            layers.insert(layers.end(), children.begin(), children.end());
+        else if (!childIDs.contains(layer.id))
+            layers.push_back(layer);
+    }
+    releaseDetachedClipping(layers);
+    finishOpacityEdit();
+    beginEdit(QStringLiteral("Ungroup Layers"));
+    m_document->layers = layers;
+    selectLayers(childIDs, children.empty() ? std::nullopt : std::optional(children.front().id));
+    m_collapsedGroupIDs.remove(group.id);
+    endEdit();
+}
+
 std::vector<LayerHierarchy::Entry> EditorSession::layerRows() const
 {
     std::vector<ProjectLayerRecord> records;

src/Document/LayerGroups.h

@@ -23,3 +23,26 @@ namespace LayerOpacity {
 using Node = std::function<std::optional<std::pair<double, std::optional<QUuid>>>(QUuid)>;
 double effective(double own, std::optional<QUuid> parent, const Node &folder);
 }
+
+struct ImageLayer;
+
+// Swift's LayerOrder: the hierarchy from ids, folders and visibility alone.
+namespace LayerOrder {
+struct Node {
+    QUuid id;
+    std::optional<QUuid> parentID;
+    bool isGroup;
+    bool isVisible;
+    friend bool operator==(const Node &, const Node &) = default;
+};
+struct Result {
+    // Every layer and folder, as LayerHierarchy::entries lists them.
+    std::vector<QUuid> order;
+    // Visible, in folders that are.
+    QSet<QUuid> visible;
+    // The layers that show, folders left out, bottom to top.
+    std::vector<QUuid> drawn;
+};
+// Kept until a node changes: the canvas asks each event.
+Result resolve(const std::vector<ImageLayer> &layers);
+}

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();
 }
 
@@ -392,7 +393,7 @@ std::optional<LayerTransform> EditorSession::displayedMaskPlacement(const ImageL
     if (!layer.mask)
         return std::nullopt;
     // Previewed on a grown layer, the mask keeps its bounds.
-    if (m_filterEdit && m_filterEdit->grownTransform && m_filterEdit->previewImage(layer.id))
+    if (m_filterEdit && m_filterEdit->preparedTransform && m_filterEdit->previewImage(layer.id))
         return layer.mask->placement.value_or(layer.transform);
     if (m_transformEdit && m_transformEdit->group) {
         const TransformGroup &group = *m_transformEdit->group;

src/Document/Levels.cpp

@@ -104,15 +104,17 @@ QImage LevelsFilter::run(const LevelsJob &job)
 {
     if (job.settings.isIdentity())
         return job.image;
-    QImage context = drawn(job.image);
+    QImage context = BrushRaster::copy(job.image);
     // On the stack: a heap failure would escape the catch.
     std::array<float, 3 * 256> tables;
     for (size_t channel = 0; channel < 3; ++channel) {
         for (size_t value = 0; value <= 255; ++value)
             tables[channel * 256 + value] = float(job.settings.apply(double(value) / 255, allLevelsChannels[channel + 1]));
     }
-    // The kernel unpremultiplies each edge itself (Swift's cc5aac4 does twice).
-    levels_apply(context.bits(), size_t(context.width()) * size_t(context.height()), tables.data());
+    // The kernel unpremultiplies edges itself; bands use every core.
+    uchar *const pixels = context.bits();
+    BrushRaster::inBands(qsizetype(context.width()) * context.height(),
+                         [&](qsizetype start, qsizetype length) { levels_apply(pixels + start * 4, size_t(length), tables.data()); });
     if (job.selection)
         return PixelAdjust::blend(context, job.image, *job.selection, job.mapping, false);
     return context;

src/Document/ProjectWorkspace.cpp

@@ -4,6 +4,7 @@
 #include <QFileDialog>
 #include <QFileInfo>
 #include <QTimer>
+#include <algorithm>
 
 const QString ProjectWorkspace::layerType = QStringLiteral("com.compositor.layer-row");
 
@@ -96,6 +97,20 @@ void ProjectWorkspace::select(QUuid id)
     emit changed();
 }
 
+void ProjectWorkspace::moveTab(QUuid id, int index)
+{
+    const auto from = std::ranges::find_if(m_tabs, [id](const std::shared_ptr<ProjectTab> &tab) { return tab->id == id; });
+    if (from == m_tabs.end())
+        return;
+    const auto target = std::clamp<std::ptrdiff_t>(index, 0, std::ptrdiff_t(m_tabs.size()) - 1);
+    if (target == from - m_tabs.begin())
+        return;
+    const std::shared_ptr<ProjectTab> tab = *from;
+    m_tabs.erase(from);
+    m_tabs.insert(m_tabs.begin() + target, tab);
+    emit changed();
+}
+
 void ProjectWorkspace::newCanvas()
 {
     if (!canSwitch())
@@ -220,14 +235,40 @@ bool ProjectWorkspace::finishTextEditing()
     return true;
 }
 
+void ProjectWorkspace::settlePendingEdits(std::function<void()> done)
+{
+    // Canvas edits are applied; dialogs cancelled, as their Cancel.
+    const std::shared_ptr<ProjectTab> settled = tab(current().id);
+    settled->session.commitGradient([self = QPointer<ProjectWorkspace>(this), settled, done] {
+        settled->session.finishPixelMove([self, settled, done] {
+            EditorSession &session = settled->session;
+            session.cancelFilter();
+            session.cancelHueSaturation();
+            session.cancelLevels();
+            session.cancelColorRange();
+            session.setSelectionAmountOperation(std::nullopt);
+            session.closeColorPicker(false);
+            if (self)
+                done();
+        });
+    });
+}
+
 void ProjectWorkspace::confirmQuit(std::function<void(bool)> done)
 {
-    if (!finishTextEditing() || !canSwitch()) {
+    if (m_isManaging || !finishTextEditing()) {
         finish(done, false);
         return;
     }
-    setManaging(true);
-    askNext(quitOrder(), 0, std::move(done));
+    settlePendingEdits([this, done] {
+        if (!canSwitch()) {
+            qCWarning(lcApp) << "Quit refused: the project is still busy";
+            finish(done, false);
+            return;
+        }
+        setManaging(true);
+        askNext(quitOrder(), 0, done);
+    });
 }
 
 void ProjectWorkspace::askNext(std::vector<std::shared_ptr<ProjectTab>> order, size_t index, std::function<void(bool)> done)

src/Document/ProjectWorkspace.h

@@ -36,12 +36,16 @@ public:
     bool canSwitch() const;
     ProjectTab &addTab(bool reuseEmpty = true);
     void select(QUuid id);
+    // A dragged tab lands at `index`, clamped; chrome, never undone.
+    void moveTab(QUuid id, int index);
     void newCanvas();
     // Each `done` runs from the event loop, never inline.
     void open(std::optional<QString> path = std::nullopt, std::function<void(bool)> done = {});
     void close(QUuid id, std::function<void()> done = {});
     void removeTab(QUuid id);
     std::vector<std::shared_ptr<ProjectTab>> quitOrder() const;
+    // Applies canvas edits and cancels dialogs before a quit.
+    void settlePendingEdits(std::function<void()> done);
     void confirmQuit(std::function<void(bool)> done);
     void closeWindow(QWidget *closing);
     void receive(const QList<QUrl> &urls, std::optional<QUuid> destination = std::nullopt,