From e8ea3e0fd404bfa72687497579689bc85d151e93 Mon Sep 17 00:00:00 2001
From: lisyarus <lisyarus@gmail.com>
Date: Fri, 21 Apr 2023 17:26:44 +0300
Subject: [PATCH] New UI library automatic layout wip

---
 libs/ui/include/psemek/ui/box_layout.hpp      |   7 +-
 .../psemek/ui/impl/box_layout_base.hpp        |  51 +++++
 libs/ui/include/psemek/ui/impl/component.hpp  |  14 ++
 .../include/psemek/ui/impl/rectangle_base.hpp |  21 ++
 .../psemek/ui/impl/single_container.hpp       |   5 +
 .../psemek/ui/impl/single_container_base.hpp  |  21 ++
 .../psemek/ui/impl/stack_layout_base.hpp      |  20 ++
 libs/ui/source/impl/box_layout_base.cpp       | 186 ++++++++++++++++++
 libs/ui/source/impl/component.cpp             |  15 ++
 libs/ui/source/impl/rectangle_base.cpp        |  19 ++
 libs/ui/source/impl/single_container_base.cpp |  28 +++
 libs/ui/source/impl/stack_layout_base.cpp     |  24 +++
 libs/ui/tests/layout.cpp                      |  92 +++++++++
 13 files changed, 502 insertions(+), 1 deletion(-)
 create mode 100644 libs/ui/include/psemek/ui/impl/box_layout_base.hpp
 create mode 100644 libs/ui/include/psemek/ui/impl/rectangle_base.hpp
 create mode 100644 libs/ui/include/psemek/ui/impl/single_container_base.hpp
 create mode 100644 libs/ui/include/psemek/ui/impl/stack_layout_base.hpp
 create mode 100644 libs/ui/source/impl/box_layout_base.cpp
 create mode 100644 libs/ui/source/impl/rectangle_base.cpp
 create mode 100644 libs/ui/source/impl/single_container_base.cpp
 create mode 100644 libs/ui/source/impl/stack_layout_base.cpp
 create mode 100644 libs/ui/tests/layout.cpp

diff --git a/libs/ui/include/psemek/ui/box_layout.hpp b/libs/ui/include/psemek/ui/box_layout.hpp
index b4dae01c..9ca357d6 100644
--- a/libs/ui/include/psemek/ui/box_layout.hpp
+++ b/libs/ui/include/psemek/ui/box_layout.hpp
@@ -15,12 +15,17 @@ namespace psemek::ui
 		struct minimized
 		{};
 
+		struct fixed
+		{
+			float value = 0.f;
+		};
+
 		struct weight
 		{
 			float value = 1.f;
 		};
 
-		using size_policy = std::variant<weight, minimized>;
+		using size_policy = std::variant<minimized, fixed, weight>;
 
 		struct element
 		{
diff --git a/libs/ui/include/psemek/ui/impl/box_layout_base.hpp b/libs/ui/include/psemek/ui/impl/box_layout_base.hpp
new file mode 100644
index 00000000..913cce96
--- /dev/null
+++ b/libs/ui/include/psemek/ui/impl/box_layout_base.hpp
@@ -0,0 +1,51 @@
+#pragma once
+
+#include <psemek/ui/impl/container.hpp>
+#include <psemek/ui/box_layout.hpp>
+#include <psemek/react/value.hpp>
+
+namespace psemek::ui::impl
+{
+
+	namespace detail
+	{
+
+		template <int Dimension>
+		struct box_layout_type;
+
+		template <>
+		struct box_layout_type<0>
+		{
+			using type = box_layout::horizontal;
+		};
+
+		template <>
+		struct box_layout_type<1>
+		{
+			using type = box_layout::vertical;
+		};
+
+	}
+
+	// Dimension == 0 is horizontal layout
+	// Dimension == 1 is vertical layout
+	template <int Dimension>
+	struct box_layout_base
+		: container
+	{
+		box_layout_base(react::value<float> margin);
+
+		void reshape(geom::box<float, 2> const & new_shape) override;
+		geom::interval<float> size_constraints(int dimension, float other_dimension_size) const override;
+
+		void update(typename detail::box_layout_type<Dimension>::type const & box_layout);
+
+	private:
+		react::value<float> margin_;
+		react::value<std::vector<react::value<box_layout::size_policy>>> size_policies_;
+	};
+
+	extern template struct box_layout_base<0>;
+	extern template struct box_layout_base<1>;
+
+}
diff --git a/libs/ui/include/psemek/ui/impl/component.hpp b/libs/ui/include/psemek/ui/impl/component.hpp
index 34021a4a..66a9900c 100644
--- a/libs/ui/include/psemek/ui/impl/component.hpp
+++ b/libs/ui/include/psemek/ui/impl/component.hpp
@@ -1,6 +1,8 @@
 #pragma once
 
 #include <psemek/util/span.hpp>
+#include <psemek/geom/box.hpp>
+#include <psemek/geom/interval.hpp>
 
 #include <memory>
 
@@ -9,9 +11,21 @@ namespace psemek::ui::impl
 
 	struct component
 	{
+		static constexpr float infinity = std::numeric_limits<float>::infinity();
+
 		virtual util::span<std::unique_ptr<component> const> children() const;
 
+		virtual geom::box<float, 2> const & shape() const;
+		virtual void reshape(geom::box<float, 2> const & new_shape);
+
+		// size_constraints(0, height) is width_constraints(height)
+		// size_constraints(1, width) is height_constraints(width)
+		virtual geom::interval<float> size_constraints(int dimension, float other_dimension_size) const;
+
 		virtual ~component() {}
+
+	private:
+		geom::box<float, 2> shape_;
 	};
 
 }
diff --git a/libs/ui/include/psemek/ui/impl/rectangle_base.hpp b/libs/ui/include/psemek/ui/impl/rectangle_base.hpp
new file mode 100644
index 00000000..ce177d09
--- /dev/null
+++ b/libs/ui/include/psemek/ui/impl/rectangle_base.hpp
@@ -0,0 +1,21 @@
+#pragma once
+
+#include <psemek/ui/impl/component.hpp>
+#include <psemek/ui/rectangle.hpp>
+#include <psemek/react/value.hpp>
+
+namespace psemek::ui::impl
+{
+
+	struct rectangle_base
+		: component
+	{
+		geom::interval<float> size_constraints(int dimension, float other_dimension_size) const override;
+
+		void update(rectangle const & value);
+
+	private:
+		react::value<bool> square_;
+	};
+
+}
diff --git a/libs/ui/include/psemek/ui/impl/single_container.hpp b/libs/ui/include/psemek/ui/impl/single_container.hpp
index cd7f60b5..2efae3cb 100644
--- a/libs/ui/include/psemek/ui/impl/single_container.hpp
+++ b/libs/ui/include/psemek/ui/impl/single_container.hpp
@@ -22,6 +22,11 @@ namespace psemek::ui::impl
 			child_token_ = std::move(token);
 		}
 
+		component * child() const
+		{
+			return child_.get();
+		}
+
 		std::unique_ptr<component> release_child()
 		{
 			return std::move(child_);
diff --git a/libs/ui/include/psemek/ui/impl/single_container_base.hpp b/libs/ui/include/psemek/ui/impl/single_container_base.hpp
new file mode 100644
index 00000000..da154183
--- /dev/null
+++ b/libs/ui/include/psemek/ui/impl/single_container_base.hpp
@@ -0,0 +1,21 @@
+#pragma once
+
+#include <psemek/ui/impl/single_container.hpp>
+#include <psemek/react/value.hpp>
+
+namespace psemek::ui::impl
+{
+
+	struct single_container_base
+		: single_container
+	{
+		single_container_base(react::value<geom::vector<float, 2>> margin);
+
+		void reshape(geom::box<float, 2> const & new_shape) override;
+		geom::interval<float> size_constraints(int dimension, float other_dimension_size) const override;
+
+	private:
+		react::value<geom::vector<float, 2>> margin_;
+	};
+
+}
diff --git a/libs/ui/include/psemek/ui/impl/stack_layout_base.hpp b/libs/ui/include/psemek/ui/impl/stack_layout_base.hpp
new file mode 100644
index 00000000..0b33aeeb
--- /dev/null
+++ b/libs/ui/include/psemek/ui/impl/stack_layout_base.hpp
@@ -0,0 +1,20 @@
+#pragma once
+
+#include <psemek/ui/impl/container.hpp>
+#include <psemek/ui/stack_layout.hpp>
+#include <psemek/react/value.hpp>
+
+namespace psemek::ui::impl
+{
+
+	struct stack_layout_base
+		: container
+	{
+		void reshape(geom::box<float, 2> const & new_shape) override;
+		geom::interval<float> size_constraints(int dimension, float other_dimension_size) const override;
+
+		void update(stack_layout const &)
+		{}
+	};
+
+}
diff --git a/libs/ui/source/impl/box_layout_base.cpp b/libs/ui/source/impl/box_layout_base.cpp
new file mode 100644
index 00000000..e778fb5a
--- /dev/null
+++ b/libs/ui/source/impl/box_layout_base.cpp
@@ -0,0 +1,186 @@
+#include <psemek/ui/impl/box_layout_base.hpp>
+#include <psemek/react/map.hpp>
+#include <psemek/react/join.hpp>
+
+namespace psemek::ui::impl
+{
+
+	namespace
+	{
+
+		static constexpr box_layout::size_policy default_policy = box_layout::weight{};
+
+		template <int Dimension>
+		std::vector<float> allocate(float total_size, float other_dimension_size,
+			std::vector<react::value<box_layout::size_policy>> const & policies, util::span<std::unique_ptr<component> const> children)
+		{
+			std::vector<float> result(policies.size(), 0.f);
+
+			float total_weight = 0.f;
+
+			// First, allocate minimized & fixed elements
+			// Also compute the total weight for weighted elements
+			for (std::size_t i = 0; i < policies.size(); ++i)
+			{
+				auto const policy = policies[i] ? *policies[i] : default_policy;
+
+				if (std::get_if<box_layout::minimized>(&policy))
+				{
+					result[i] = children[i]->size_constraints(Dimension, other_dimension_size).min;
+					total_size -= result[i];
+				}
+				else if (auto fixed = std::get_if<box_layout::fixed>(&policy))
+				{
+					result[i] = fixed->value;
+					total_size -= result[i];
+				}
+				else if (auto weight = std::get_if<box_layout::weight>(&policy))
+				{
+					total_weight += weight->value;
+				}
+			}
+
+			// Next, allocate weighted elements
+			for (std::size_t i = 0; i < policies.size(); ++i)
+			{
+				auto const policy = policies[i] ? *policies[i] : default_policy;
+
+				if (auto weight = std::get_if<box_layout::weight>(&policy))
+				{
+					result[i] = total_size * weight->value / total_weight;
+				}
+			}
+
+			return result;
+		}
+
+	}
+
+	template <int Dimension>
+	box_layout_base<Dimension>::box_layout_base(react::value<float> margin)
+		: margin_(margin)
+	{}
+
+	template <int Dimension>
+	void box_layout_base<Dimension>::reshape(geom::box<float, 2> const & new_shape)
+	{
+		container::reshape(new_shape);
+
+		if (children().empty())
+			return;
+
+		float const margin = *margin_;
+
+		auto sizes = allocate<Dimension>(new_shape[Dimension].length() - (children().size() - 1) * margin, new_shape[Dimension ^ 1].length(), *size_policies_, children());
+
+		float pen = new_shape[Dimension].min;
+		for (std::size_t i = 0; i < children().size(); ++i)
+		{
+			if (!children()[i]) continue;
+
+			geom::box<float, 2> child_shape;
+			child_shape[Dimension] = {pen, pen + sizes[i]};
+			child_shape[Dimension ^ 1] = new_shape[Dimension ^ 1];
+			children()[i]->reshape(child_shape);
+
+			pen += sizes[i];
+			pen += margin;
+		}
+	}
+
+	template <int Dimension>
+	geom::interval<float> box_layout_base<Dimension>::size_constraints(int dimension, float other_dimension_size) const
+	{
+		if (children().empty())
+			return container::size_constraints(dimension, other_dimension_size);
+
+		float const margin = *margin_;
+
+		if (dimension == Dimension)
+		{
+			auto result = geom::interval{0.f, 0.f};
+
+			auto const & policies = *size_policies_;
+
+			auto weighted_unit_constraints = geom::interval{0.f, infinity};
+			float weight_sum = 0.f;
+
+			for (std::size_t i = 0; i < children().size(); ++i)
+			{
+				auto const & child = children()[i];
+				auto const policy = policies[i] ? *policies[i] : default_policy;
+
+				if (auto fixed = std::get_if<box_layout::fixed>(&policy))
+					result += fixed->value;
+				else if (std::get_if<box_layout::minimized>(&policy))
+				{
+					if (child)
+					{
+						auto child_constraints = child->size_constraints(dimension, other_dimension_size);
+						result.min += child_constraints.min;
+						result.max += child_constraints.max;
+					}
+					else
+					{
+						result.max = infinity;
+					}
+				}
+				else if (auto weight = std::get_if<box_layout::weight>(&policy))
+				{
+					if (child)
+					{
+						auto child_constraints = child->size_constraints(dimension, other_dimension_size);
+						child_constraints.min /= weight->value;
+						child_constraints.max /= weight->value;
+						weighted_unit_constraints &= child_constraints;
+					}
+
+					weight_sum += weight->value;
+				}
+			}
+
+			// Prevent NaN in result.max (inf * 0)
+			if (weight_sum > 0.f)
+			{
+				result.min += weighted_unit_constraints.min * weight_sum;
+				result.max += weighted_unit_constraints.max * weight_sum;
+			}
+
+			result += (children().size() - 1) * margin;
+
+			return result;
+		}
+		else
+		{
+			float const margin = *margin_;
+
+			auto sizes = allocate<Dimension>(other_dimension_size - (children().size() - 1) * margin, shape()[1].length(), *size_policies_, children());
+
+			auto result = container::size_constraints(dimension, other_dimension_size);
+
+			for (std::size_t i = 0; i < children().size(); ++i)
+			{
+				if (!children()[i]) continue;
+				result &= children()[i]->size_constraints(dimension, sizes[i]);
+			}
+
+			return result;
+		}
+	}
+
+	template <int Dimension>
+	void box_layout_base<Dimension>::update(typename detail::box_layout_type<Dimension>::type const & box_layout)
+	{
+		size_policies_ = react::map([](auto const & children){
+			std::vector<react::value<box_layout::size_policy>> size_policies;
+			size_policies.reserve(children.size());
+			for (auto const & child : children)
+				size_policies.push_back(child.policy);
+			return size_policies;
+		}, box_layout.children);
+	}
+
+	template struct box_layout_base<0>;
+	template struct box_layout_base<1>;
+
+}
diff --git a/libs/ui/source/impl/component.cpp b/libs/ui/source/impl/component.cpp
index 381defcd..c425f382 100644
--- a/libs/ui/source/impl/component.cpp
+++ b/libs/ui/source/impl/component.cpp
@@ -8,4 +8,19 @@ namespace psemek::ui::impl
 		return {};
 	}
 
+	geom::box<float, 2> const & component::shape() const
+	{
+		return shape_;
+	}
+
+	void component::reshape(geom::box<float, 2> const & new_shape)
+	{
+		shape_ = new_shape;
+	}
+
+	geom::interval<float> component::size_constraints(int, float) const
+	{
+		return {0.f, infinity};
+	}
+
 }
diff --git a/libs/ui/source/impl/rectangle_base.cpp b/libs/ui/source/impl/rectangle_base.cpp
new file mode 100644
index 00000000..a70040d0
--- /dev/null
+++ b/libs/ui/source/impl/rectangle_base.cpp
@@ -0,0 +1,19 @@
+#include <psemek/ui/impl/rectangle_base.hpp>
+
+namespace psemek::ui::impl
+{
+
+	geom::interval<float> rectangle_base::size_constraints(int dimension, float other_dimension_size) const
+	{
+		if (square_ && *square_)
+			return {other_dimension_size, other_dimension_size};
+		else
+			return component::size_constraints(dimension, other_dimension_size);
+	}
+
+	void rectangle_base::update(rectangle const & value)
+	{
+		square_ = value.square;
+	}
+
+}
diff --git a/libs/ui/source/impl/single_container_base.cpp b/libs/ui/source/impl/single_container_base.cpp
new file mode 100644
index 00000000..81cc1b98
--- /dev/null
+++ b/libs/ui/source/impl/single_container_base.cpp
@@ -0,0 +1,28 @@
+#include <psemek/ui/impl/single_container_base.hpp>
+
+namespace psemek::ui::impl
+{
+
+	single_container_base::single_container_base(react::value<geom::vector<float, 2>> margin)
+		: margin_(std::move(margin))
+	{}
+
+	void single_container_base::reshape(geom::box<float, 2> const & new_shape)
+	{
+		single_container::reshape(new_shape);
+
+		if (child())
+			child()->reshape(geom::shrink(new_shape, *margin_));
+	}
+
+	geom::interval<float> single_container_base::size_constraints(int dimension, float other_dimension_size) const
+	{
+		geom::interval<float> result = single_container::size_constraints(dimension, other_dimension_size);
+
+		if (child())
+			result = child()->size_constraints(dimension, other_dimension_size - 2.f * (*margin_)[dimension ^ 1]);
+
+		return result + 2.f * (*margin_)[dimension];
+	}
+
+}
diff --git a/libs/ui/source/impl/stack_layout_base.cpp b/libs/ui/source/impl/stack_layout_base.cpp
new file mode 100644
index 00000000..676a0387
--- /dev/null
+++ b/libs/ui/source/impl/stack_layout_base.cpp
@@ -0,0 +1,24 @@
+#include <psemek/ui/impl/stack_layout_base.hpp>
+
+namespace psemek::ui::impl
+{
+
+	void stack_layout_base::reshape(geom::box<float, 2> const & new_shape)
+	{
+		for (auto const & child : children())
+			if (child)
+				child->reshape(new_shape);
+	}
+
+	geom::interval<float> stack_layout_base::size_constraints(int dimension, float other_dimension_size) const
+	{
+		auto result = container::size_constraints(dimension, other_dimension_size);
+
+		for (auto const & child : children())
+			if (child)
+				result &= child->size_constraints(dimension, other_dimension_size);
+
+		return result;
+	}
+
+}
diff --git a/libs/ui/tests/layout.cpp b/libs/ui/tests/layout.cpp
new file mode 100644
index 00000000..65a53b9a
--- /dev/null
+++ b/libs/ui/tests/layout.cpp
@@ -0,0 +1,92 @@
+#include <psemek/test/test.hpp>
+
+#include <psemek/ui/impl/component_factory_base.hpp>
+#include <psemek/ui/impl/rectangle_base.hpp>
+#include <psemek/ui/impl/single_container_base.hpp>
+#include <psemek/ui/impl/stack_layout_base.hpp>
+#include <psemek/ui/impl/box_layout_base.hpp>
+
+#include <psemek/react/source.hpp>
+
+using namespace psemek;
+using namespace psemek::ui;
+
+namespace
+{
+
+	constexpr float layout_margin = 5.f;
+	constexpr float infinity = impl::component::infinity;
+
+	struct test_component_factory
+		: impl::component_factory_base
+	{
+		test_component_factory()
+		{
+			register_type<rectangle, impl::rectangle_base>();
+			register_type<stack_layout, impl::stack_layout_base>();
+			register_type<box_layout::horizontal, impl::box_layout_base<0>>([]{ return std::make_unique<impl::box_layout_base<0>>(layout_margin); });
+			register_type<box_layout::vertical, impl::box_layout_base<1>>([]{ return std::make_unique<impl::box_layout_base<1>>(layout_margin); });
+		}
+	};
+
+}
+
+test_case(ui_layout_rectangle)
+{
+	test_component_factory factory;
+
+	auto square = react::source(false);
+
+	auto test_ui = rectangle{.square = square};
+
+	auto ui_root = factory.reconciliate(nullptr, test_ui);
+
+	expect_equal(ui_root->size_constraints(0, 100.f), geom::interval<float>(0.f, infinity));
+	expect_equal(ui_root->size_constraints(1, 100.f), geom::interval<float>(0.f, infinity));
+
+	square.set(true);
+
+	expect_equal(ui_root->size_constraints(0, 100.f), geom::interval<float>(100.f, 100.f));
+	expect_equal(ui_root->size_constraints(1, 100.f), geom::interval<float>(100.f, 100.f));
+
+	ui_root->reshape({{{0.f, 10.f}, {0.f, 10.f}}});
+
+	expect_equal(ui_root->shape(), (geom::box<float, 2>{{{0.f, 10.f}, {0.f, 10.f}}}));
+}
+
+
+test_case(ui_layout_hbox__2__rectangles)
+{
+	test_component_factory factory;
+
+	auto square0 = react::source(false);
+	auto square1 = react::source(false);
+
+	auto policy0 = react::source<box_layout::size_policy>(box_layout::minimized{});
+	auto policy1 = react::source<box_layout::size_policy>(box_layout::minimized{});
+
+	auto test_ui = box_layout::horizontal{{
+		{
+			.element = rectangle{.square = square0},
+			.policy = policy0,
+		},
+		{
+			.element = rectangle{.square = square1},
+			.policy = policy1,
+		}
+	}};
+
+	auto ui_root = factory.reconciliate(nullptr, test_ui);
+
+	expect_equal(ui_root->size_constraints(0, 100.f), geom::interval<float>(layout_margin, infinity));
+	expect_equal(ui_root->size_constraints(1, 100.f), geom::interval<float>(0.f, infinity));
+
+	square0.set(true);
+
+	expect_equal(ui_root->size_constraints(0, 100.f), geom::interval<float>(100.f + layout_margin, infinity));
+	expect_equal(ui_root->size_constraints(1, 100.f), geom::interval<float>(100.f, 100.f));
+
+	ui_root->reshape({{{0.f, 10.f}, {0.f, 10.f}}});
+
+	expect_equal(ui_root->shape(), (geom::box<float, 2>{{{0.f, 10.f}, {0.f, 10.f}}}));
+}