LibGfx+LibWeb: Reuse DisplayListPlayer and PaintingSurface when possible

Previously, we were reinstantiating the DisplayListPlayer and
PaintingSurface on every paint.

Libraries/LibGfx/PaintingSurface.cpp

@@ -24,7 +24,6 @@ struct PaintingSurface::Impl {
     IntSize size;
     sk_sp<SkSurface> surface;
     RefPtr<Bitmap> bitmap;
-    RefPtr<SkiaBackendContext> context;
 };
 
 NonnullRefPtr<PaintingSurface> PaintingSurface::create_with_size(RefPtr<SkiaBackendContext> context, IntSize size, BitmapFormat color_type, AlphaType alpha_type)
@@ -37,12 +36,12 @@ NonnullRefPtr<PaintingSurface> PaintingSurface::create_with_size(RefPtr<SkiaBack
         auto bitmap = Bitmap::create(color_type, alpha_type, size).value();
         auto surface = SkSurfaces::WrapPixels(image_info, bitmap->begin(), bitmap->pitch());
         VERIFY(surface);
-        return adopt_ref(*new PaintingSurface(make<Impl>(size, surface, bitmap, context)));
+        return adopt_ref(*new PaintingSurface(make<Impl>(size, surface, bitmap)));
     }
 
     auto surface = SkSurfaces::RenderTarget(context->sk_context(), skgpu::Budgeted::kNo, image_info);
     VERIFY(surface);
-    return adopt_ref(*new PaintingSurface(make<Impl>(size, surface, nullptr, context)));
+    return adopt_ref(*new PaintingSurface(make<Impl>(size, surface, nullptr)));
 }
 
 NonnullRefPtr<PaintingSurface> PaintingSurface::wrap_bitmap(Bitmap& bitmap)
@@ -52,7 +51,7 @@ NonnullRefPtr<PaintingSurface> PaintingSurface::wrap_bitmap(Bitmap& bitmap)
     auto size = bitmap.size();
     auto image_info = SkImageInfo::Make(bitmap.width(), bitmap.height(), color_type, alpha_type, SkColorSpace::MakeSRGB());
     auto surface = SkSurfaces::WrapPixels(image_info, bitmap.begin(), bitmap.pitch());
-    return adopt_ref(*new PaintingSurface(make<Impl>(size, surface, bitmap, nullptr)));
+    return adopt_ref(*new PaintingSurface(make<Impl>(size, surface, bitmap)));
 }
 
 #ifdef AK_OS_MACOS
@@ -76,7 +75,7 @@ NonnullRefPtr<PaintingSurface> PaintingSurface::wrap_iosurface(Core::IOSurfaceHa
         VERIFY_NOT_REACHED();
     }
     auto surface = SkSurfaces::WrapBackendRenderTarget(context->sk_context(), backend_render_target, sk_origin, kBGRA_8888_SkColorType, nullptr, nullptr);
-    return adopt_ref(*new PaintingSurface(make<Impl>(size, surface, nullptr, context)));
+    return adopt_ref(*new PaintingSurface(make<Impl>(size, surface, nullptr)));
 }
 #endif
 
@@ -136,11 +135,10 @@ sk_sp<SkImage> PaintingSurface::sk_image_snapshot() const
     return m_impl->surface->makeImageSnapshot();
 }
 
-void PaintingSurface::flush() const
+void PaintingSurface::flush()
 {
-    if (auto context = m_impl->context) {
-        context->flush_and_submit(m_impl->surface.get());
-    }
+    if (on_flush)
+        on_flush(*this);
 }
 
 }

Libraries/LibGfx/PaintingSurface.h

@@ -6,6 +6,7 @@
 
 #pragma once
 
+#include <AK/Function.h>
 #include <AK/NonnullOwnPtr.h>
 #include <AK/RefCounted.h>
 #include <AK/RefPtr.h>
@@ -29,6 +30,8 @@ public:
         BottomLeft,
     };
 
+    Function<void(PaintingSurface&)> on_flush;
+
     static NonnullRefPtr<PaintingSurface> create_with_size(RefPtr<SkiaBackendContext> context, IntSize size, BitmapFormat color_type, AlphaType alpha_type);
     static NonnullRefPtr<PaintingSurface> wrap_bitmap(Bitmap&);
 
@@ -50,7 +53,7 @@ public:
     template<typename T>
     T sk_image_snapshot() const;
 
-    void flush() const;
+    void flush();
 
     ~PaintingSurface();
 

Libraries/LibGfx/SkiaBackendContext.cpp

@@ -6,6 +6,7 @@
 
 #include <AK/NonnullOwnPtr.h>
 #include <AK/RefPtr.h>
+#include <LibGfx/Bitmap.h>
 #include <LibGfx/SkiaBackendContext.h>
 
 #include <core/SkSurface.h>

Libraries/LibWeb/HTML/Navigable.h

@@ -170,7 +170,7 @@ public:
 
     CSSPixelPoint viewport_scroll_offset() const { return m_viewport_scroll_offset; }
     CSSPixelRect viewport_rect() const { return { m_viewport_scroll_offset, m_size }; }
-    void set_viewport_size(CSSPixelSize);
+    virtual void set_viewport_size(CSSPixelSize);
     void perform_scroll_of_viewport(CSSPixelPoint position);
 
     void set_needs_display(InvalidateDisplayList = InvalidateDisplayList::Yes);

Libraries/LibWeb/HTML/TraversableNavigable.cpp

@@ -53,8 +53,12 @@ TraversableNavigable::TraversableNavigable(GC::Ref<Page> page)
     , m_session_history_traversal_queue(vm().heap().allocate<SessionHistoryTraversalQueue>())
 {
     auto display_list_player_type = page->client().display_list_player_type();
-    if (display_list_player_type == DisplayListPlayerType::SkiaGPUIfAvailable)
+    if (display_list_player_type == DisplayListPlayerType::SkiaGPUIfAvailable) {
         m_skia_backend_context = get_skia_backend_context();
+        m_skia_player = make<Painting::DisplayListPlayerSkia>(m_skia_backend_context);
+    } else {
+        m_skia_player = make<Painting::DisplayListPlayerSkia>();
+    }
 }
 
 TraversableNavigable::~TraversableNavigable() = default;
@@ -1384,6 +1388,45 @@ GC::Ptr<DOM::Node> TraversableNavigable::currently_focused_area()
     return candidate;
 }
 
+void TraversableNavigable::set_viewport_size(CSSPixelSize size)
+{
+    Navigable::set_viewport_size(size);
+
+    // Invalidate the surface cache if the traversable changed size.
+    m_bitmap_to_surface.clear();
+}
+
+NonnullRefPtr<Gfx::PaintingSurface> TraversableNavigable::painting_surface_for_backing_store(Painting::BackingStore& backing_store)
+{
+    auto& bitmap = backing_store.bitmap();
+    auto cached_surface = m_bitmap_to_surface.find(&bitmap);
+    if (cached_surface != m_bitmap_to_surface.end())
+        return cached_surface->value;
+
+    RefPtr<Gfx::PaintingSurface> new_surface;
+    if (page().client().display_list_player_type() == DisplayListPlayerType::SkiaGPUIfAvailable && m_skia_backend_context) {
+#ifdef USE_VULKAN
+        // Vulkan: Try to create an accelerated surface.
+        new_surface = Gfx::PaintingSurface::create_with_size(m_skia_backend_context, backing_store.size(), Gfx::BitmapFormat::BGRA8888, Gfx::AlphaType::Premultiplied);
+        new_surface->on_flush = [&bitmap = bitmap](auto& surface) { surface.read_into_bitmap(bitmap); };
+#endif
+#ifdef AK_OS_MACOS
+        // macOS: Wrap an IOSurface if available.
+        if (is<Painting::IOSurfaceBackingStore>(backing_store)) {
+            auto& iosurface_backing_store = static_cast<Painting::IOSurfaceBackingStore&>(backing_store);
+            new_surface = Gfx::PaintingSurface::wrap_iosurface(iosurface_backing_store.iosurface_handle(), *m_skia_backend_context);
+        }
+#endif
+    }
+
+    // CPU and fallback: wrap the backing store bitmap directly.
+    if (!new_surface)
+        new_surface = Gfx::PaintingSurface::wrap_bitmap(bitmap);
+
+    m_bitmap_to_surface.set(&bitmap, *new_surface);
+    return *new_surface;
+}
+
 void TraversableNavigable::paint(DevicePixelRect const& content_rect, Painting::BackingStore& target, PaintOptions paint_options)
 {
     auto document = active_document();
@@ -1391,10 +1434,9 @@ void TraversableNavigable::paint(DevicePixelRect const& content_rect, Painting::
         return;
 
     for (auto& navigable : all_navigables()) {
-        if (auto active_document = navigable->active_document(); active_document && active_document->paintable()) {
+        if (auto active_document = navigable->active_document(); active_document && active_document->paintable())
             active_document->paintable()->refresh_scroll_state();
     }
-    }
 
     DOM::Document::PaintConfig paint_config;
     paint_config.paint_overlay = paint_options.paint_overlay == PaintOptions::PaintOverlay::Yes;
@@ -1402,43 +1444,12 @@ void TraversableNavigable::paint(DevicePixelRect const& content_rect, Painting::
     paint_config.has_focus = paint_options.has_focus;
     paint_config.canvas_fill_rect = Gfx::IntRect { {}, content_rect.size() };
     auto display_list = document->record_display_list(paint_config);
-    if (!display_list) {
+    if (!display_list)
         return;
-    }
 
-    switch (page().client().display_list_player_type()) {
-    case DisplayListPlayerType::SkiaGPUIfAvailable: {
-#ifdef USE_VULKAN
-        if (m_skia_backend_context) {
-            Painting::DisplayListPlayerSkia player(*m_skia_backend_context, target.bitmap());
-            player.execute(*display_list);
-            return;
-        }
-#endif
-
-#ifdef AK_OS_MACOS
-        if (m_skia_backend_context && is<Painting::IOSurfaceBackingStore>(target)) {
-            auto& iosurface_backing_store = static_cast<Painting::IOSurfaceBackingStore&>(target);
-            auto painting_surface = Gfx::PaintingSurface::wrap_iosurface(iosurface_backing_store.iosurface_handle(), *m_skia_backend_context);
-            Painting::DisplayListPlayerSkia player(*m_skia_backend_context, painting_surface);
-            player.execute(*display_list);
-            return;
-        }
-#endif
-
-        // Fallback to CPU backend if GPU is not available
-        Painting::DisplayListPlayerSkia player(target.bitmap());
-        player.execute(*display_list);
-        break;
-    }
-    case DisplayListPlayerType::SkiaCPU: {
-        Painting::DisplayListPlayerSkia player(target.bitmap());
-        player.execute(*display_list);
-        break;
-    }
-    default:
-        VERIFY_NOT_REACHED();
-    }
+    auto painting_surface = painting_surface_for_backing_store(target);
+    m_skia_player->set_surface(painting_surface);
+    m_skia_player->execute(*display_list);
 }
 
 }

Libraries/LibWeb/HTML/TraversableNavigable.h

@@ -14,15 +14,16 @@
 #include <LibWeb/Page/Page.h>
 #include <LibWeb/Painting/DisplayListPlayerSkia.h>
 #include <LibWeb/StorageAPI/StorageShed.h>
-
-#ifdef USE_VULKAN
-#    include <LibGfx/VulkanContext.h>
-#endif
+#include <WebContent/BackingStoreManager.h>
 
 #ifdef AK_OS_MACOS
 #    include <LibGfx/MetalContext.h>
 #endif
 
+#ifdef USE_VULKAN
+#    include <LibGfx/VulkanContext.h>
+#endif
+
 namespace Web::HTML {
 
 // https://html.spec.whatwg.org/multipage/document-sequences.html#traversable-navigable
@@ -110,6 +111,8 @@ public:
     StorageAPI::StorageShed& storage_shed() { return m_storage_shed; }
     StorageAPI::StorageShed const& storage_shed() const { return m_storage_shed; }
 
+    void set_viewport_size(CSSPixelSize) override;
+
 private:
     TraversableNavigable(GC::Ref<Page>);
 
@@ -131,6 +134,8 @@ private:
 
     [[nodiscard]] bool can_go_forward() const;
 
+    NonnullRefPtr<Gfx::PaintingSurface> painting_surface_for_backing_store(Painting::BackingStore&);
+
     // https://html.spec.whatwg.org/multipage/document-sequences.html#tn-current-session-history-step
     int m_current_session_history_step { 0 };
 
@@ -154,6 +159,8 @@ private:
     String m_window_handle;
 
     RefPtr<Gfx::SkiaBackendContext> m_skia_backend_context;
+    OwnPtr<Painting::DisplayListPlayerSkia> m_skia_player;
+    HashMap<Gfx::Bitmap*, NonnullRefPtr<Gfx::PaintingSurface>> m_bitmap_to_surface;
 };
 
 struct BrowsingContextAndDocument {

Libraries/LibWeb/Painting/DisplayList.cpp

@@ -41,6 +41,8 @@ void DisplayListPlayer::execute(DisplayList& display_list)
     auto const& scroll_state = display_list.scroll_state();
     auto device_pixels_per_css_pixel = display_list.device_pixels_per_css_pixel();
 
+    VERIFY(m_surface);
+
     size_t next_command_index = 0;
     while (next_command_index < commands.size()) {
         auto scroll_frame_id = commands[next_command_index].scroll_frame_id;
@@ -128,6 +130,8 @@ void DisplayListPlayer::execute(DisplayList& display_list)
         else VERIFY_NOT_REACHED();
         // clang-format on
     }
+
+    flush();
 }
 
 }

Libraries/LibWeb/Painting/DisplayList.h

@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2024, Aliaksandr Kalenik <kalenik.aliaksandr@gmail.com>
+ * Copyright (c) 2025, Jelle Raaijmakers <jelle@ladybird.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -25,9 +26,14 @@ class DisplayListPlayer {
 public:
     virtual ~DisplayListPlayer() = default;
 
-    void execute(DisplayList& display_list);
+    void execute(DisplayList&);
+    void set_surface(NonnullRefPtr<Gfx::PaintingSurface> surface) { m_surface = surface; }
+
+protected:
+    Gfx::PaintingSurface& surface() const { return *m_surface; }
 
 private:
+    virtual void flush() = 0;
     virtual void draw_glyph_run(DrawGlyphRun const&) = 0;
     virtual void fill_rect(FillRect const&) = 0;
     virtual void draw_painting_surface(DrawPaintingSurface const&) = 0;
@@ -65,6 +71,8 @@ private:
     virtual void apply_transform(ApplyTransform const&) = 0;
     virtual void apply_mask_bitmap(ApplyMaskBitmap const&) = 0;
     virtual bool would_be_fully_clipped_by_painter(Gfx::IntRect) const = 0;
+
+    RefPtr<Gfx::PaintingSurface> m_surface;
 };
 
 class DisplayList : public RefCounted<DisplayList> {

Libraries/LibWeb/Painting/DisplayListPlayerSkia.cpp

@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2024, Aliaksandr Kalenik <kalenik.aliaksandr@gmail.com>
+ * Copyright (c) 2025, Jelle Raaijmakers <jelle@ladybird.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -29,36 +30,13 @@
 
 namespace Web::Painting {
 
-#ifdef USE_VULKAN
-DisplayListPlayerSkia::DisplayListPlayerSkia(Gfx::SkiaBackendContext& context, Gfx::Bitmap& bitmap)
+DisplayListPlayerSkia::DisplayListPlayerSkia(RefPtr<Gfx::SkiaBackendContext> context)
     : m_context(context)
 {
-    m_surface = Gfx::PaintingSurface::create_with_size(m_context, bitmap.size(), Gfx::BitmapFormat::BGRA8888, Gfx::AlphaType::Premultiplied);
-    m_flush_context = [&bitmap, surface = m_surface] mutable {
-        surface->read_into_bitmap(bitmap);
-    };
-}
-#endif
-
-#ifdef AK_OS_MACOS
-DisplayListPlayerSkia::DisplayListPlayerSkia(Gfx::SkiaBackendContext& context, NonnullRefPtr<Gfx::PaintingSurface> surface)
-    : m_context(context)
-    , m_surface(move(surface))
-{
-}
-#endif
-
-DisplayListPlayerSkia::DisplayListPlayerSkia(Gfx::Bitmap& bitmap)
-{
-    m_surface = Gfx::PaintingSurface::wrap_bitmap(bitmap);
 }
 
-DisplayListPlayerSkia::~DisplayListPlayerSkia()
+DisplayListPlayerSkia::DisplayListPlayerSkia()
 {
-    m_surface->flush();
-    if (m_flush_context) {
-        m_flush_context();
-    }
 }
 
 static SkRRect to_skia_rrect(auto const& rect, CornerRadii const& corner_radii)
@@ -88,9 +66,11 @@ static SkMatrix to_skia_matrix(Gfx::AffineTransform const& affine_transform)
     return matrix;
 }
 
-Gfx::PaintingSurface& DisplayListPlayerSkia::surface() const
+void DisplayListPlayerSkia::flush()
 {
-    return *m_surface;
+    if (m_context)
+        m_context->flush_and_submit(&surface().sk_surface());
+    surface().flush();
 }
 
 void DisplayListPlayerSkia::draw_glyph_run(DrawGlyphRun const& command)
@@ -850,10 +830,10 @@ void DisplayListPlayerSkia::add_mask(AddMask const& command)
 
     auto mask_surface = Gfx::PaintingSurface::create_with_size(m_context, rect.size(), Gfx::BitmapFormat::BGRA8888, Gfx::AlphaType::Premultiplied);
 
-    auto previous_surface = move(m_surface);
-    m_surface = mask_surface;
+    NonnullRefPtr old_surface = surface();
+    set_surface(mask_surface);
     execute(*command.display_list);
-    m_surface = move(previous_surface);
+    set_surface(old_surface);
 
     SkMatrix mask_matrix;
     mask_matrix.setTranslate(rect.x(), rect.y());

Libraries/LibWeb/Painting/DisplayListPlayerSkia.h

@@ -14,21 +14,13 @@ class GrDirectContext;
 
 namespace Web::Painting {
 
-class DisplayListPlayerSkia : public DisplayListPlayer {
+class DisplayListPlayerSkia final : public DisplayListPlayer {
 public:
-    DisplayListPlayerSkia(Gfx::Bitmap&);
-
-#ifdef USE_VULKAN
-    DisplayListPlayerSkia(Gfx::SkiaBackendContext&, Gfx::Bitmap&);
-#endif
-
-#ifdef AK_OS_MACOS
-    DisplayListPlayerSkia(Gfx::SkiaBackendContext&, NonnullRefPtr<Gfx::PaintingSurface>);
-#endif
-
-    virtual ~DisplayListPlayerSkia() override;
+    DisplayListPlayerSkia(RefPtr<Gfx::SkiaBackendContext>);
+    DisplayListPlayerSkia();
 
 private:
+    void flush() override;
     void draw_glyph_run(DrawGlyphRun const&) override;
     void fill_rect(FillRect const&) override;
     void draw_painting_surface(DrawPaintingSurface const&) override;
@@ -68,12 +60,7 @@ private:
 
     bool would_be_fully_clipped_by_painter(Gfx::IntRect) const override;
 
-    Gfx::PaintingSurface& surface() const;
-
-    RefPtr<Gfx::SkiaBackendContext> m_context {};
-    RefPtr<Gfx::PaintingSurface> m_surface {};
-
-    Function<void()> m_flush_context;
+    RefPtr<Gfx::SkiaBackendContext> m_context;
 };
 
 }

Libraries/LibWeb/Painting/SVGMaskable.cpp

@@ -90,7 +90,9 @@ RefPtr<Gfx::ImmutableBitmap> SVGMaskable::calculate_mask_of_svg(PaintContext& co
         paint_context.set_svg_transform(graphics_element.get_transform());
         paint_context.set_draw_svg_geometry_for_clip_path(is<SVGClipPaintable>(paintable));
         StackingContext::paint_svg(paint_context, paintable, PaintPhase::Foreground);
-        DisplayListPlayerSkia display_list_player { *mask_bitmap };
+        auto painting_surface = Gfx::PaintingSurface::wrap_bitmap(*mask_bitmap);
+        DisplayListPlayerSkia display_list_player;
+        display_list_player.set_surface(painting_surface);
         display_list_player.execute(display_list);
         return mask_bitmap;
     };

Libraries/LibWeb/SVG/SVGDecodedImageData.cpp

@@ -103,7 +103,9 @@ RefPtr<Gfx::Bitmap> SVGDecodedImageData::render(Gfx::IntSize size) const
     switch (painting_command_executor_type) {
     case DisplayListPlayerType::SkiaGPUIfAvailable:
     case DisplayListPlayerType::SkiaCPU: {
-        Painting::DisplayListPlayerSkia display_list_player { *bitmap };
+        auto painting_surface = Gfx::PaintingSurface::wrap_bitmap(*bitmap);
+        Painting::DisplayListPlayerSkia display_list_player;
+        display_list_player.set_surface(painting_surface);
         display_list_player.execute(*display_list);
         break;
     }