1 million checkboxes

aui.core/src/AUI/Common/ASignal.h

@@ -129,6 +129,10 @@ class ASignal final : public AAbstractSignal {
         return !mOutgoingConnections.empty();
     }
 
+    [[nodiscard]] const auto& outgoingConnections() const noexcept {
+        return mOutgoingConnections;
+    }
+
     [[nodiscard]] bool hasOutgoingConnectionsWith(aui::no_escape<AObjectBase> object) const noexcept override {
         return std::any_of(
             mOutgoingConnections.begin(), mOutgoingConnections.end(),

examples/ui/checkboxes1kk/CMakeLists.txt

@@ -0,0 +1,6 @@
+cmake_minimum_required(VERSION 3.10)
+
+get_filename_component(_t ${CMAKE_CURRENT_SOURCE_DIR} NAME)
+
+aui_executable("aui.example.${_t}")
+aui_link("aui.example.${_t}" PRIVATE aui::core aui::views)

examples/ui/checkboxes1kk/src/main.cpp

@@ -0,0 +1,63 @@
+/*
+ * AUI Framework - Declarative UI toolkit for modern C++20
+ * Copyright (C) 2020-2025 Alex2772 and Contributors
+ *
+ * SPDX-License-Identifier: MPL-2.0
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+/// [ScrollArea_example]
+#include <range/v3/all.hpp>
+#include "AUI/View/AButton.h"
+#include "AUI/View/ACheckBox.h"
+#include "AUI/View/AForEachUI.h"
+
+#include <AUI/Platform/Entry.h>
+#include <AUI/Platform/AWindow.h>
+#include <AUI/Util/UIBuildingHelpers.h>
+#include "AUI/View/AScrollArea.h"
+#include "AUI/View/ATextArea.h"
+
+using namespace ass;
+using namespace declarative;
+
+static constexpr auto COUNT = 1'000'000;
+static constexpr auto DIV = 1'000;
+static const auto INDICES = ranges::views::ints | ranges::view::take(COUNT);
+
+AUI_ENTRY {
+    auto window = _new<AWindow>("1000000 checkboxes", 300_dp, 300_dp);
+    struct State {
+        AProperty<std::vector<bool>> values = std::vector<bool>(COUNT);
+        ScrollAreaViewport::State scrollAreaState;
+        APropertyPrecomputed<size_t> observerCount = [&] {
+            aui::react::DependencyObserverScope::addDependency(scrollAreaState.scroll.changed);
+            return values.changed.outgoingConnections().size();
+        };
+    };
+    auto state = _new<State>();
+    window->setContents(Vertical {
+      ScrollArea {
+        .state = AUI_PTR_ALIAS(state, scrollAreaState),
+        .content =
+            AUI_DECLARATIVE_FOR(row, INDICES | ranges::view::chunk(DIV), AVerticalLayout) {
+                return Horizontal {
+                    Label { "{}"_format(ranges::front(row) / DIV) } AUI_WITH_STYLE { FixedSize { 50_dp, {} } },
+                    // AUI_DECLARATIVE_FOR(i, row, AHorizontalLayout) {
+                    //     return CheckBox {
+                    //         .checked = AUI_REACT(state->values->at(i)),
+                    //         .onCheckedChange = [state, i](bool v) { state->values.writeScope()->at(i) = v; },
+                    //     } AUI_WITH_STYLE { Margin { 2_dp } };
+                    // } AUI_LET { it->setKeyFunction([](int i) { return i; }); },
+                };
+            } AUI_LET { it->setKeyFunction([](const auto& row) { return ranges::front(row); }); },
+      },
+      Label { AUI_REACT("Observers: {}"_format(state->observerCount)) },
+    });
+    window->show();
+    return 0;
+}
+/// [ScrollArea_example]