Merge pull request #181 from OpenVicProject/ui-state-style

UI polish

10 files changed, 275 insertions, 32 deletions

diff --git a/extension/src/openvic-extension/classes/GFXButtonStateTexture.cpp b/extension/src/openvic-extension/classes/GFXButtonStateTexture.cpp
new file mode 100644
index 0000000..e6dff1f
--- /dev/null
+++ b/extension/src/openvic-extension/classes/GFXButtonStateTexture.cpp
@@ -0,0 +1,106 @@
+#include "GFXButtonStateTexture.hpp"
+
+#include "openvic-extension/utility/ClassBindings.hpp"
+
+using namespace OpenVic;
+using namespace godot;
+
+void GFXButtonStateTexture::_bind_methods() {
+	OV_BIND_METHOD(GFXButtonStateTexture::set_button_state, { "new_button_state" });
+	OV_BIND_METHOD(GFXButtonStateTexture::get_button_state);
+
+	OV_BIND_SMETHOD(get_generate_state_image_func_name);
+
+	OV_BIND_SMETHOD(button_state_to_theme_name, { "button_state" });
+	OV_BIND_METHOD(GFXButtonStateTexture::get_button_state_theme);
+
+	OV_BIND_METHOD(GFXButtonStateTexture::generate_state_image, { "source_image" });
+
+	BIND_ENUM_CONSTANT(HOVER);
+	BIND_ENUM_CONSTANT(PRESSED);
+	BIND_ENUM_CONSTANT(DISABLED);
+}
+
+GFXButtonStateTexture::GFXButtonStateTexture() : button_state { HOVER } {}
+
+Ref<GFXButtonStateTexture> GFXButtonStateTexture::make_gfx_button_state_texture(
+	ButtonState button_state, Ref<Image> const& source_image
+) {
+	Ref<GFXButtonStateTexture> button_state_texture;
+	button_state_texture.instantiate();
+	ERR_FAIL_NULL_V(button_state_texture, nullptr);
+	button_state_texture->set_button_state(button_state);
+	if (source_image.is_valid()) {
+		ERR_FAIL_COND_V(button_state_texture->generate_state_image(source_image) != OK, nullptr);
+	}
+	return button_state_texture;
+}
+
+void GFXButtonStateTexture::set_button_state(ButtonState new_button_state) {
+	ERR_FAIL_COND(new_button_state != HOVER && new_button_state != PRESSED && new_button_state != DISABLED);
+	button_state = new_button_state;
+}
+
+Error GFXButtonStateTexture::generate_state_image(Ref<Image> const& source_image) {
+	ERR_FAIL_COND_V(source_image.is_null() || source_image->is_empty(), FAILED);
+	/* Whether we've already set the ImageTexture to an image of the right dimensions and format,
+	* and so can update it without creating and setting a new image, or not. */
+	const bool can_update = state_image.is_valid() && state_image->get_size() == source_image->get_size()
+		&& state_image->get_format() == source_image->get_format();
+	if (!can_update) {
+		state_image = Image::create(source_image->get_width(), source_image->get_height(), false, source_image->get_format());
+		ERR_FAIL_NULL_V(state_image, FAILED);
+	}
+
+	static constexpr auto hover_colour = [](Color const& colour) -> Color {
+		return { std::min(colour.r + 0.1f, 1.0f), std::min(colour.g + 0.1f, 1.0f), std::min(colour.b + 0.1f, 1.0f), colour.a };
+	};
+	static constexpr auto pressed_colour = [](Color const& colour) -> Color {
+		return { std::max(colour.r - 0.1f, 0.0f), std::max(colour.g - 0.1f, 0.0f), std::max(colour.b - 0.1f, 0.0f), colour.a };
+	};
+	static constexpr auto disabled_colour = [](Color const& colour) -> Color {
+		const float luma = colour.get_luminance();
+		return { luma, luma, luma, colour.a };
+	};
+
+	const auto colour_func = button_state == HOVER ? hover_colour : button_state == PRESSED ? pressed_colour : disabled_colour;
+
+	for (Vector2i point { 0, 0 }; point.y < state_image->get_height(); ++point.y) {
+		for (point.x = 0; point.x < state_image->get_width(); ++point.x) {
+			state_image->set_pixelv(point, colour_func(source_image->get_pixelv(point)));
+		}
+	}
+
+	if (can_update) {
+		update(state_image);
+	} else {
+		set_image(state_image);
+	}
+	return OK;
+}
+
+StringName const& GFXButtonStateTexture::get_generate_state_image_func_name() {
+	static const StringName generate_state_image_func_name = "generate_state_image";
+	return generate_state_image_func_name;
+}
+
+StringName const& GFXButtonStateTexture::button_state_to_theme_name(ButtonState button_state) {
+	static const StringName theme_name_hover = "hover";
+	static const StringName theme_name_pressed = "pressed";
+	static const StringName theme_name_disabled = "disabled";
+	static const StringName theme_name_error = "";
+	switch (button_state) {
+		case HOVER:
+			return theme_name_hover;
+		case PRESSED:
+			return theme_name_pressed;
+		case DISABLED:
+			return theme_name_disabled;
+		default:
+			return theme_name_error;
+	}
+}
+
+StringName const& GFXButtonStateTexture::get_button_state_theme() const {
+	return button_state_to_theme_name(button_state);
+}
diff --git a/extension/src/openvic-extension/classes/GFXButtonStateTexture.hpp b/extension/src/openvic-extension/classes/GFXButtonStateTexture.hpp
new file mode 100644
index 0000000..32f4087
--- /dev/null
+++ b/extension/src/openvic-extension/classes/GFXButtonStateTexture.hpp
@@ -0,0 +1,46 @@
+#pragma once
+
+#include <godot_cpp/classes/image_texture.hpp>
+
+#include <openvic-simulation/utility/Getters.hpp>
+
+namespace OpenVic {
+	class GFXButtonStateTexture : public godot::ImageTexture {
+		GDCLASS(GFXButtonStateTexture, godot::ImageTexture)
+
+	public:
+		enum ButtonState {
+			HOVER,
+			PRESSED,
+			DISABLED
+		};
+
+	private:
+		ButtonState PROPERTY(button_state);
+		godot::Ref<godot::Image> state_image;
+
+	protected:
+		static void _bind_methods();
+
+	public:
+		GFXButtonStateTexture();
+
+		/* Create a GFXButtonStateTexture using the specified godot::Image. Returns nullptr if generate_state_image fails. */
+		static godot::Ref<GFXButtonStateTexture> make_gfx_button_state_texture(
+			ButtonState button_state, godot::Ref<godot::Image> const& source_image = nullptr
+		);
+
+		/* Set the ButtonState to be generated by this class (calling this does not trigger state image generation). */
+		void set_button_state(ButtonState new_button_state);
+
+		/* Generate a modified version of source_image and update the underlying godot::ImageTexture to use it. */
+		godot::Error generate_state_image(godot::Ref<godot::Image> const& source_image);
+
+		static godot::StringName const& get_generate_state_image_func_name();
+
+		static godot::StringName const& button_state_to_theme_name(ButtonState button_state);
+		godot::StringName const& get_button_state_theme() const;
+	};
+}
+
+VARIANT_ENUM_CAST(OpenVic::GFXButtonStateTexture::ButtonState);
diff --git a/extension/src/openvic-extension/classes/GFXIconTexture.cpp b/extension/src/openvic-extension/classes/GFXIconTexture.cpp
index 895bf6b..5d29c07 100644
--- a/extension/src/openvic-extension/classes/GFXIconTexture.cpp
+++ b/extension/src/openvic-extension/classes/GFXIconTexture.cpp
@@ -15,6 +15,11 @@ using OpenVic::Utilities::godot_to_std_string;
 using OpenVic::Utilities::std_view_to_godot_string;
 using OpenVic::Utilities::std_view_to_godot_string_name;
 
+StringName const& GFXIconTexture::_signal_image_updated() {
+	static const StringName signal_image_updated = "image_updated";
+	return signal_image_updated;
+}
+
 void GFXIconTexture::_bind_methods() {
 	OV_BIND_METHOD(GFXIconTexture::clear);
 
@@ -26,16 +31,32 @@ void GFXIconTexture::_bind_methods() {
 	OV_BIND_METHOD(GFXIconTexture::get_icon_count);
 
 	ADD_PROPERTY(PropertyInfo(Variant::INT, "icon_index"), "set_icon_index", "get_icon_index");
+
+	ADD_SIGNAL(
+		MethodInfo(_signal_image_updated(), PropertyInfo(Variant::OBJECT, "source_image", PROPERTY_HINT_RESOURCE_TYPE, "Image"))
+	);
 }
 
 GFXIconTexture::GFXIconTexture()
 	: gfx_texture_sprite { nullptr }, icon_index { GFX::NO_FRAMES }, icon_count { GFX::NO_FRAMES } {}
 
-Ref<GFXIconTexture> GFXIconTexture::make_gfx_icon_texture(GFX::TextureSprite const* gfx_texture_sprite, GFX::frame_t icon) {
+Ref<GFXIconTexture> GFXIconTexture::make_gfx_icon_texture(
+	GFX::TextureSprite const* gfx_texture_sprite, GFX::frame_t icon,
+	std::vector<Ref<GFXButtonStateTexture>> const& button_state_textures
+) {
 	Ref<GFXIconTexture> icon_texture;
 	icon_texture.instantiate();
 	ERR_FAIL_NULL_V(icon_texture, nullptr);
-	icon_texture->set_gfx_texture_sprite(gfx_texture_sprite, icon);
+
+	for (Ref<GFXButtonStateTexture> const& button_state_texture : button_state_textures) {
+		icon_texture->connect(
+			_signal_image_updated(),
+			Callable { *button_state_texture, GFXButtonStateTexture::get_generate_state_image_func_name() },
+			CONNECT_PERSIST
+		);
+	}
+
+	ERR_FAIL_COND_V(icon_texture->set_gfx_texture_sprite(gfx_texture_sprite, icon) != OK, nullptr);
 	return icon_texture;
 }
 
@@ -57,9 +78,15 @@ Error GFXIconTexture::set_gfx_texture_sprite(GFX::TextureSprite const* new_gfx_t
 		ERR_FAIL_NULL_V(asset_manager, FAILED);
 
 		const StringName texture_file = std_view_to_godot_string_name(new_gfx_texture_sprite->get_texture_file());
+
+		/* Needed for GFXButtonStateTexture, AssetManager::get_texture will re-use this image from its internal cache. */
+		const Ref<Image> image = asset_manager->get_image(texture_file);
+		ERR_FAIL_NULL_V_MSG(image, FAILED, vformat("Failed to load image: %s", texture_file));
+
 		const Ref<ImageTexture> texture = asset_manager->get_texture(texture_file);
 		ERR_FAIL_NULL_V_MSG(texture, FAILED, vformat("Failed to load texture: %s", texture_file));
 
+		sprite_image = image;
 		gfx_texture_sprite = new_gfx_texture_sprite;
 		set_atlas(texture);
 		icon_index = GFX::NO_FRAMES;
@@ -98,6 +125,7 @@ Error GFXIconTexture::set_icon_index(int32_t new_icon_index) {
 		}
 		icon_index = GFX::NO_FRAMES;
 		set_region({ {}, size });
+		emit_signal(_signal_image_updated(), sprite_image);
 		return OK;
 	}
 	if (GFX::NO_FRAMES < new_icon_index && new_icon_index <= icon_count) {
@@ -111,5 +139,6 @@ Error GFXIconTexture::set_icon_index(int32_t new_icon_index) {
 		}
 	}
 	set_region({ (icon_index - 1) * size.x / icon_count, 0, size.x / icon_count, size.y });
+	emit_signal(_signal_image_updated(), sprite_image->get_region(get_region()));
 	return OK;
 }
diff --git a/extension/src/openvic-extension/classes/GFXIconTexture.hpp b/extension/src/openvic-extension/classes/GFXIconTexture.hpp
index 176d855..06dac34 100644
--- a/extension/src/openvic-extension/classes/GFXIconTexture.hpp
+++ b/extension/src/openvic-extension/classes/GFXIconTexture.hpp
@@ -4,6 +4,8 @@
 
 #include <openvic-simulation/interface/GFX.hpp>
 
+#include "openvic-extension/classes/GFXButtonStateTexture.hpp"
+
 namespace OpenVic {
 	class GFXIconTexture : public godot::AtlasTexture {
 		GDCLASS(GFXIconTexture, godot::AtlasTexture)
@@ -16,14 +18,22 @@ namespace OpenVic {
 		GFX::frame_t PROPERTY(icon_index);
 		GFX::frame_t PROPERTY(icon_count);
 
+		godot::Ref<godot::Image> sprite_image;
+
+		static godot::StringName const& _signal_image_updated();
+
 	protected:
 		static void _bind_methods();
 
 	public:
 		GFXIconTexture();
 
+		/* Create a GFXIconTexture using the specified GFX::TextureSprite and icon index. Returns nullptr if
+		 * set_gfx_texture_sprite fails. Connects the provided GFXButtonStateTextures (if any) to the
+		* GFXIconTexture's image_updated signal. */
 		static godot::Ref<GFXIconTexture> make_gfx_icon_texture(
-			GFX::TextureSprite const* gfx_texture_sprite, GFX::frame_t icon = GFX::NO_FRAMES
+			GFX::TextureSprite const* gfx_texture_sprite, GFX::frame_t icon = GFX::NO_FRAMES,
+			std::vector<godot::Ref<GFXButtonStateTexture>> const& button_state_textures = {}
 		);
 
 		/* Discard the GFX::TextureSprite, atlas texture and icon index. */
diff --git a/extension/src/openvic-extension/classes/GFXMaskedFlagTexture.cpp b/extension/src/openvic-extension/classes/GFXMaskedFlagTexture.cpp
index 424be33..0a44e56 100644
--- a/extension/src/openvic-extension/classes/GFXMaskedFlagTexture.cpp
+++ b/extension/src/openvic-extension/classes/GFXMaskedFlagTexture.cpp
@@ -13,15 +13,22 @@ using OpenVic::Utilities::godot_to_std_string;
 using OpenVic::Utilities::std_view_to_godot_string;
 using OpenVic::Utilities::std_view_to_godot_string_name;
 
+StringName const& GFXMaskedFlagTexture::_signal_image_updated() {
+	static const StringName signal_image_updated = "image_updated";
+	return signal_image_updated;
+}
+
 Error GFXMaskedFlagTexture::_generate_combined_image() {
 	ERR_FAIL_NULL_V(overlay_image, FAILED);
-	bool can_update = true;
-	if (combined_image.is_null() || combined_image->get_size() != overlay_image->get_size()) {
+	/* Whether we've already set the ImageTexture to an image of the right dimensions and format,
+	 * and so can update it without creating and setting a new image, or not. */
+	const bool can_update = combined_image.is_valid() && combined_image->get_size() == overlay_image->get_size()
+		&& combined_image->get_format() == overlay_image->get_format();
+	if (!can_update) {
 		combined_image = Image::create(
 			overlay_image->get_width(), overlay_image->get_height(), false, overlay_image->get_format()
 		);
 		ERR_FAIL_NULL_V(combined_image, FAILED);
-		can_update = false;
 	}
 
 	if (mask_image.is_valid() && flag_image.is_valid()) {
@@ -55,6 +62,7 @@ Error GFXMaskedFlagTexture::_generate_combined_image() {
 	} else {
 		set_image(combined_image);
 	}
+	emit_signal(_signal_image_updated(), combined_image);
 	return OK;
 }
 
@@ -68,14 +76,29 @@ void GFXMaskedFlagTexture::_bind_methods() {
 	OV_BIND_METHOD(GFXMaskedFlagTexture::set_flag_country_name, { "new_flag_country_name" });
 	OV_BIND_METHOD(GFXMaskedFlagTexture::get_flag_country_name);
 	OV_BIND_METHOD(GFXMaskedFlagTexture::get_flag_type);
+
+	ADD_SIGNAL(
+		MethodInfo(_signal_image_updated(), PropertyInfo(Variant::OBJECT, "source_image", PROPERTY_HINT_RESOURCE_TYPE, "Image"))
+	);
 }
 
 GFXMaskedFlagTexture::GFXMaskedFlagTexture() : gfx_masked_flag { nullptr }, flag_country { nullptr } {}
 
-Ref<GFXMaskedFlagTexture> GFXMaskedFlagTexture::make_gfx_masked_flag_texture(GFX::MaskedFlag const* gfx_masked_flag) {
+Ref<GFXMaskedFlagTexture> GFXMaskedFlagTexture::make_gfx_masked_flag_texture(
+	GFX::MaskedFlag const* gfx_masked_flag, std::vector<Ref<GFXButtonStateTexture>> const& button_state_textures
+) {
 	Ref<GFXMaskedFlagTexture> masked_flag_texture;
 	masked_flag_texture.instantiate();
 	ERR_FAIL_NULL_V(masked_flag_texture, nullptr);
+
+	for (Ref<GFXButtonStateTexture> const& button_state_texture : button_state_textures) {
+		masked_flag_texture->connect(
+			_signal_image_updated(),
+			Callable { *button_state_texture, GFXButtonStateTexture::get_generate_state_image_func_name() },
+			CONNECT_PERSIST
+		);
+	}
+
 	ERR_FAIL_COND_V(masked_flag_texture->set_gfx_masked_flag(gfx_masked_flag) != OK, nullptr);
 	return masked_flag_texture;
 }
diff --git a/extension/src/openvic-extension/classes/GFXMaskedFlagTexture.hpp b/extension/src/openvic-extension/classes/GFXMaskedFlagTexture.hpp
index f71a1d7..294b842 100644
--- a/extension/src/openvic-extension/classes/GFXMaskedFlagTexture.hpp
+++ b/extension/src/openvic-extension/classes/GFXMaskedFlagTexture.hpp
@@ -5,6 +5,8 @@
 #include <openvic-simulation/country/Country.hpp>
 #include <openvic-simulation/interface/GFX.hpp>
 
+#include "openvic-extension/classes/GFXButtonStateTexture.hpp"
+
 namespace OpenVic {
 	class GFXMaskedFlagTexture : public godot::ImageTexture {
 		GDCLASS(GFXMaskedFlagTexture, godot::ImageTexture)
@@ -15,6 +17,8 @@ namespace OpenVic {
 
 		godot::Ref<godot::Image> overlay_image, mask_image, flag_image, combined_image;
 
+		static godot::StringName const& _signal_image_updated();
+
 		godot::Error _generate_combined_image();
 
 	protected:
@@ -23,9 +27,12 @@ namespace OpenVic {
 	public:
 		GFXMaskedFlagTexture();
 
-		/* Create a GFXMaskedFlagTexture using the specific GFX::MaskedFlag.
-		 * Returns nullptr if setting gfx_masked_flag fails. */
-		static godot::Ref<GFXMaskedFlagTexture> make_gfx_masked_flag_texture(GFX::MaskedFlag const* gfx_masked_flag);
+		/* Create a GFXMaskedFlagTexture using the specified GFX::MaskedFlag. Returns nullptr if gfx_masked_flag fails.
+		 * Connects the provided GFXButtonStateTextures (if any) to the GFXMaskedFlagTexture's image_updated signal. */
+		static godot::Ref<GFXMaskedFlagTexture> make_gfx_masked_flag_texture(
+			GFX::MaskedFlag const* gfx_masked_flag,
+			std::vector<godot::Ref<GFXButtonStateTexture>> const& button_state_textures = {}
+		);
 
 		/* Reset gfx_masked_flag, flag_country and flag_type to nullptr/an empty string, and unreference all images.
 		 * This does not affect the godot::ImageTexture, which cannot be reset to a null or empty image. */
diff --git a/extension/src/openvic-extension/classes/GFXPieChartTexture.cpp b/extension/src/openvic-extension/classes/GFXPieChartTexture.cpp
index 63deeda..c9a2a72 100644
--- a/extension/src/openvic-extension/classes/GFXPieChartTexture.cpp
+++ b/extension/src/openvic-extension/classes/GFXPieChartTexture.cpp
@@ -12,6 +12,19 @@ using OpenVic::Utilities::godot_to_std_string;
 using OpenVic::Utilities::std_view_to_godot_string;
 using OpenVic::Utilities::std_view_to_godot_string_name;
 
+StringName const& GFXPieChartTexture::_slice_identifier_key() {
+	static StringName const slice_identifier_key = "identifier";
+	return slice_identifier_key;
+}
+StringName const& GFXPieChartTexture::_slice_colour_key() {
+	static StringName const slice_colour_key = "colour";
+	return slice_colour_key;
+}
+StringName const& GFXPieChartTexture::_slice_weight_key() {
+	static StringName const slice_weight_key = "weight";
+	return slice_weight_key;
+}
+
 static constexpr float PI = std::numbers::pi_v<float>;
 
 Error GFXPieChartTexture::_generate_pie_chart_image() {
@@ -21,14 +34,13 @@ Error GFXPieChartTexture::_generate_pie_chart_image() {
 		vformat("Invalid GFX::PieChart size for GFXPieChartTexture - %d", gfx_pie_chart->get_size())
 	);
 	const int32_t pie_chart_size = 2 * gfx_pie_chart->get_size();
-	bool can_update = true;
-	if (
-		pie_chart_image.is_null() || pie_chart_image->get_width() != pie_chart_size ||
-		pie_chart_image->get_height() != pie_chart_size
-	) {
+	/* Whether we've already set the ImageTexture to an image of the right dimensions,
+	 * and so can update it without creating and setting a new image, or not. */
+	const bool can_update = pie_chart_image.is_valid() && pie_chart_image->get_width() == pie_chart_size
+		&& pie_chart_image->get_height() == pie_chart_size;
+	if (!can_update) {
 		pie_chart_image = Image::create(pie_chart_size, pie_chart_size, false, Image::FORMAT_RGBA8);
 		ERR_FAIL_NULL_V(pie_chart_image, FAILED);
-		can_update = false;
 	}
 
 	static const Color background_colour { 0.0f, 0.0f, 0.0f, 0.0f };
@@ -74,17 +86,14 @@ Error GFXPieChartTexture::_generate_pie_chart_image() {
 }
 
 Error GFXPieChartTexture::set_slices_array(TypedArray<Dictionary> const& new_slices) {
-	static const StringName colour_key = "colour";
-	static const StringName weight_key = "weight";
-
 	slices.clear();
 	total_weight = 0.0f;
 	for (int32_t i = 0; i < new_slices.size(); ++i) {
 		Dictionary const& slice_dict = new_slices[i];
 		ERR_CONTINUE_MSG(
-			!slice_dict.has(colour_key) || !slice_dict.has(weight_key), vformat("Invalid slice keys at index %d", i)
+			!slice_dict.has(_slice_colour_key()) || !slice_dict.has(_slice_weight_key()), vformat("Invalid slice keys at index %d", i)
 		);
-		const slice_t slice = std::make_pair(slice_dict[colour_key], slice_dict[weight_key]);
+		slice_t slice = std::make_pair(slice_dict[_slice_colour_key()], slice_dict[_slice_weight_key()]);
 		ERR_CONTINUE_MSG(slice.second <= 0.0f, vformat("Invalid slice values at index %d", i));
 		total_weight += slice.second;
 		slices.emplace_back(std::move(slice));
diff --git a/extension/src/openvic-extension/classes/GFXPieChartTexture.hpp b/extension/src/openvic-extension/classes/GFXPieChartTexture.hpp
index ad8e751..f8279e4 100644
--- a/extension/src/openvic-extension/classes/GFXPieChartTexture.hpp
+++ b/extension/src/openvic-extension/classes/GFXPieChartTexture.hpp
@@ -17,6 +17,10 @@ namespace OpenVic {
 		float total_weight;
 		godot::Ref<godot::Image> pie_chart_image;
 
+		static godot::StringName const& _slice_identifier_key();
+		static godot::StringName const& _slice_colour_key();
+		static godot::StringName const& _slice_weight_key();
+
 		godot::Error _generate_pie_chart_image();
 
 	protected:
@@ -34,34 +38,31 @@ namespace OpenVic {
 		 * The resulting Array of Dictionaries can be used as an argument for set_slices_array. */
 		template<std::derived_from<HasIdentifierAndColour> T>
 		static godot::TypedArray<godot::Dictionary> distribution_to_slices_array(fixed_point_map_t<T const*> const& dist) {
+			using namespace godot;
 			using entry_t = std::pair<T const*, fixed_point_t>;
 			std::vector<entry_t> sorted_dist;
 			sorted_dist.reserve(dist.size());
 			for (entry_t const& entry : dist) {
 				ERR_CONTINUE_MSG(
-					entry.first == nullptr, godot::vformat("Null distribution key with value %f", entry.second.to_float())
+					entry.first == nullptr, vformat("Null distribution key with value %f", entry.second.to_float())
 				);
 				sorted_dist.push_back(entry);
 			}
 			std::sort(sorted_dist.begin(), sorted_dist.end(), [](entry_t const& lhs, entry_t const& rhs) -> bool {
 				return lhs.second < rhs.second;
 			});
-			static const godot::StringName identifier_key = "identifier";
-			static const godot::StringName colour_key = "colour";
-			static const godot::StringName weight_key = "weight";
-			godot::TypedArray<godot::Dictionary> array;
+			TypedArray<Dictionary> array;
 			for (auto const& [key, val] : sorted_dist) {
-				godot::Dictionary sub_dict;
-				sub_dict[identifier_key] = Utilities::std_view_to_godot_string(key->get_identifier());
-				sub_dict[colour_key] = Utilities::to_godot_color(key->get_colour());
-				sub_dict[weight_key] = val.to_float();
+				Dictionary sub_dict;
+				sub_dict[_slice_identifier_key()] = Utilities::std_view_to_godot_string(key->get_identifier());
+				sub_dict[_slice_colour_key()] = Utilities::to_godot_color(key->get_colour());
+				sub_dict[_slice_weight_key()] = val.to_float();
 				array.push_back(sub_dict);
 			}
 			return array;
 		}
 
-		/* Create a GFXPieChartTexture using the specific GFX::PieChart.
-		 * Returns nullptr if setting gfx_pie_chart fails. */
+		/* Create a GFXPieChartTexture using the specified GFX::PieChart. Returns nullptr if gfx_pie_chart fails. */
 		static godot::Ref<GFXPieChartTexture> make_gfx_pie_chart_texture(GFX::PieChart const* gfx_pie_chart);
 
 		/* Reset gfx_pie_chart, flag_country and flag_type to nullptr/an empty string, and unreference all images.
diff --git a/extension/src/openvic-extension/classes/GUINode.cpp b/extension/src/openvic-extension/classes/GUINode.cpp
index 043f65d..89701e0 100644
--- a/extension/src/openvic-extension/classes/GUINode.cpp
+++ b/extension/src/openvic-extension/classes/GUINode.cpp
@@ -49,6 +49,9 @@ void GUINode::_bind_methods() {
 }
 
 GUINode::GUINode() {
+	set_anchors_and_offsets_preset(PRESET_FULL_RECT);
+	set_h_grow_direction(GROW_DIRECTION_BOTH);
+	set_v_grow_direction(GROW_DIRECTION_BOTH);
 	set_mouse_filter(MOUSE_FILTER_IGNORE);
 }
 
diff --git a/extension/src/openvic-extension/classes/GUIOverlappingElementsBox.cpp b/extension/src/openvic-extension/classes/GUIOverlappingElementsBox.cpp
index ff88781..921f633 100644
--- a/extension/src/openvic-extension/classes/GUIOverlappingElementsBox.cpp
+++ b/extension/src/openvic-extension/classes/GUIOverlappingElementsBox.cpp
@@ -120,6 +120,15 @@ Error GUIOverlappingElementsBox::set_child_count(int32_t new_count) {
 					name, child_count, new_count
 				)
 			);
+
+			static const StringName set_z_index_func_name = "set_z_index";
+			static const StringName mouse_entered_signal_name = "mouse_entered";
+			static const StringName mouse_exited_signal_name = "mouse_exited";
+
+			/* Move the child element in front of its neighbours when moused-over. */
+			child->connect(mouse_entered_signal_name, Callable { child, set_z_index_func_name }.bind(1), CONNECT_PERSIST);
+			child->connect(mouse_exited_signal_name, Callable { child, set_z_index_func_name }.bind(0), CONNECT_PERSIST);
+
 			add_child(child);
 			child_count++;
 		} while (child_count < new_count);