Implement cached style merging

examples/ui.cpp

@@ -39,7 +39,7 @@ struct ui_example
 		: app("UI example", 1)
 		, ui_controller(&loop)
 	{
-		auto style = std::make_shared<ui::style>(ui::default_style());
+		auto style = std::make_shared<ui::style>();
 		style->font = ui::make_default_9x12_font();
 		style->text_scale = 2;
 

libs/ui/include/psemek/ui/element.hpp

@@ -44,8 +44,9 @@ namespace psemek::ui
 		virtual void enable() { set_enabled(true); }
 		virtual void disable() { set_enabled(false); }
 
-		virtual std::shared_ptr<struct style const> style() const;
+		virtual std::shared_ptr<struct style const> style() const { return style_; }
 		virtual std::shared_ptr<struct style const> set_style(std::shared_ptr<struct style const> st);
+		virtual std::shared_ptr<struct style const> merged_style() const;
 
 		virtual void draw(painter & p) const = 0;
 
@@ -59,6 +60,7 @@ namespace psemek::ui
 		async::executor * loop_ = nullptr;
 		bool enabled_ = true;
 		std::shared_ptr<struct style const> style_;
+		mutable std::shared_ptr<struct style const> merged_style_;
 	};
 
 }

libs/ui/include/psemek/ui/style.hpp

@@ -31,6 +31,8 @@ namespace psemek::ui
 		std::shared_ptr<struct font> font;
 	};
 
+	void merge(style & dst, style const & src);
+
 	style default_style();
 
 }

libs/ui/source/default_element_factory.cpp

@@ -37,9 +37,9 @@ namespace psemek::ui
 			void reshape(geom::box<float, 2> const & bbox) override
 			{
 				shape_.box = bbox;
-				auto s = style();
+				auto st = merged_style();
 				element * c = label() ? (element *)label() : icon();
-				if (s && c) c->reshape(geom::shrink(bbox, 1.f * (*s->border_width + *s->inner_margin)));
+				if (st && c) c->reshape(geom::shrink(bbox, 1.f * (*st->border_width + *st->inner_margin)));
 			}
 
 			void on_state_changed() override
@@ -63,21 +63,21 @@ namespace psemek::ui
 
 			void draw(painter & p) const override
 			{
-				auto s = style();
+				auto st = merged_style();
-				if (!s) return;
+				if (!st) return;
 
-				if (s->shadow_offset != geom::vector{0, 0})
+				if (st->shadow_offset != geom::vector{0, 0})
-					p.draw_rect(shape_.box + geom::cast<float>(*s->shadow_offset), *s->shadow_color);
+					p.draw_rect(shape_.box + geom::cast<float>(*st->shadow_offset), *st->shadow_color);
 
-				if (s->border_width > 0)
+				if (st->border_width > 0)
-					p.draw_rect(shape_.box, *s->border_color);
+					p.draw_rect(shape_.box, *st->border_color);
 
-				gfx::color_rgba color = *s->fg_color;
+				gfx::color_rgba color = *st->fg_color;
 				if (state() == state_t::mouseover)
-					color = *s->highlight_color;
+					color = *st->highlight_color;
 				else if (state() == state_t::mousedown)
-					color = *s->action_color;
+					color = *st->action_color;
-				p.draw_rect(geom::shrink(shape_.box, 1.f * (*s->border_width)), color);
+				p.draw_rect(geom::shrink(shape_.box, 1.f * (*st->border_width)), color);
 			}
 
 			geom::box<float, 2> size_constraints() const override
@@ -90,7 +90,7 @@ namespace psemek::ui
 				{
 					sc = c->size_constraints();
 
-					if (auto st = style())
+					if (auto st = merged_style())
 					{
 						float extra = 2.f * (*st->border_width + *st->inner_margin);
 						sc[0] += extra;
@@ -113,7 +113,7 @@ namespace psemek::ui
 			void reshape(geom::box<float, 2> const & bbox) override
 			{
 				shape_.box = bbox;
-				auto st = style();
+				auto st = merged_style();
 				if (!st) return;
 				for (auto c : children())
 					if (c) c->reshape(geom::shrink(bbox, 1.f * (*st->border_width + *st->outer_margin)));
@@ -127,7 +127,7 @@ namespace psemek::ui
 					if (c)
 						r = c->size_constraints();
 
-				auto st = style();
+				auto st = merged_style();
 				if (st)
 				{
 					float extra = 2.f * (*st->border_width + *st->outer_margin);
@@ -154,7 +154,7 @@ namespace psemek::ui
 
 			void draw(painter & p) const override
 			{
-				auto st = style();
+				auto st = merged_style();
 				if (!st) return;
 
 				if (st->shadow_offset != geom::vector{0, 0})

libs/ui/source/element.cpp

@@ -1,5 +1,7 @@
 #include <psemek/ui/element.hpp>
 
+#include <psemek/util/recursive.hpp>
+
 #include <psemek/log/log.hpp>
 
 namespace psemek::ui
@@ -37,19 +39,46 @@ namespace psemek::ui
 		return {{{0.f, inf}, {0.f, inf}}};
 	}
 
-	std::shared_ptr<struct style const> element::style() const
-	{
-		element const * e = this;
-		while (!e->style_ && e->parent()) e = e->parent();
-		return e->style_;
-	}
-
 	std::shared_ptr<style const> element::set_style(std::shared_ptr<struct style const> st)
 	{
 		std::swap(st, style_);
+
+		auto visitor = util::recursive([](auto && self, element * e) -> void {
+			e->merged_style_ = nullptr;
+			for (auto c : e->children())
+				if (c) self(c);
+		});
+		visitor(this);
+
 		return st;
 	}
 
+	std::shared_ptr<struct style const> element::merged_style() const
+	{
+		if (!merged_style_)
+		{
+			if (!style_)
+			{
+				if (parent())
+					merged_style_ = parent()->merged_style();
+				else
+					merged_style_ = std::make_shared<struct style>(default_style());
+			}
+			else
+			{
+				auto merged_style = std::make_shared<struct style>(*style_);
+				if (parent())
+					merge(*merged_style, *parent()->merged_style());
+				else
+					merge(*merged_style, default_style());
+
+				merged_style_ = merged_style;
+			}
+		}
+
+		return merged_style_;
+	}
+
 	void element::post(std::function<void()> f)
 	{
 		auto l = loop();

libs/ui/source/grid_layout.cpp

@@ -121,7 +121,7 @@ namespace psemek::ui
 
 	geom::box<float, 2> grid_layout::size_constraints() const
 	{
-		auto st = style();
+		auto st = merged_style();
 		if (!st) return element::size_constraints();
 
 		static float const inf = std::numeric_limits<float>::infinity();
@@ -163,7 +163,7 @@ namespace psemek::ui
 
 	void grid_layout::reshape(geom::box<float, 2> const & bbox)
 	{
-		auto st = style();
+		auto st = merged_style();
 		if (!st) return;
 
 		float const margin = *st->outer_margin;

libs/ui/source/label.cpp

@@ -58,7 +58,7 @@ namespace psemek::ui
 
 		if (!cached_state_->font) return;
 
-		auto st = style();
+		auto st = merged_style();
 		if (!st) return;
 
 		if (st->text_shadow_offset != geom::vector{0, 0})
@@ -91,7 +91,7 @@ namespace psemek::ui
 
 		if (text_.empty()) return state;
 
-		auto st = style();
+		auto st = merged_style();
 		if (!st) return state;
 		if (!st->font) return state;
 

libs/ui/source/style.cpp

@@ -3,6 +3,29 @@
 namespace psemek::ui
 {
 
+	template <typename T>
+	void merge(std::optional<T> & dst, std::optional<T> const & src)
+	{
+		if (!dst) dst = src;
+	}
+
+	void merge(style & dst, style const & src)
+	{
+		merge(dst.bg_color, src.bg_color);
+		merge(dst.fg_color, src.fg_color);
+		merge(dst.highlight_color, src.highlight_color);
+		merge(dst.action_color, src.action_color);
+		merge(dst.border_color, src.border_color);
+		merge(dst.border_width, src.border_width);
+		merge(dst.shadow_offset, src.shadow_offset);
+		merge(dst.shadow_color, src.shadow_color);
+		merge(dst.inner_margin, src.inner_margin);
+		merge(dst.outer_margin, src.outer_margin);
+		merge(dst.text_color, src.text_color);
+		merge(dst.text_scale, src.text_scale);
+		merge(dst.text_shadow_offset, src.text_shadow_offset);
+	}
+
 	style default_style()
 	{
 		style s;