Make ui styles update elements on change

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

@@ -61,7 +61,7 @@ namespace psemek::ui
 		virtual void draw(painter & p) const = 0;
 		virtual void post_draw(painter & /* p */) const {}
 
-		virtual ~element() {}
+		virtual ~element();
 
 		virtual void post(util::function<void()> f) const;
 		virtual void post_reshape();

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

@@ -4,6 +4,7 @@
 #include <psemek/gfx/color.hpp>
 
 #include <optional>
+#include <unordered_set>
 
 namespace psemek::ui
 {
@@ -14,6 +15,8 @@ namespace psemek::ui
 		down,
 	};
 
+	struct element;
+
 	struct style
 	{
 		std::optional<int> scale;
@@ -48,6 +51,18 @@ namespace psemek::ui
 		std::optional<geom::vector<int, 2>> text_shadow_offset;
 
 		std::shared_ptr<struct font> font;
+
+		mutable std::unordered_set<element *> use_as_style;
+		mutable std::unordered_set<element *> use_as_own_style;
+
+		style() = default;
+		style(style &&) = default;
+		style(style const &);
+
+		style & operator = (style &&) = default;
+		style & operator = (style const &) = delete;
+
+		void on_changed();
 	};
 
 	void merge(style & dst, style const & src);

libs/ui/source/element.cpp

@@ -57,8 +57,14 @@ namespace psemek::ui
 
 	std::shared_ptr<style const> element::set_style(std::shared_ptr<struct style const> st)
 	{
+		if (style_)
+			style_->use_as_style.erase(this);
+
 		std::swap(st, style_);
 
+		if (style_)
+			style_->use_as_style.insert(this);
+
 		auto visitor = util::recursive([](auto && self, element * e) -> void {
 			e->merged_style_ = nullptr;
 			e->merged_own_style_ = nullptr;
@@ -72,8 +78,14 @@ namespace psemek::ui
 
 	std::shared_ptr<struct style const> element::set_own_style(std::shared_ptr<struct style const> st)
 	{
+		if (style_)
+			style_->use_as_own_style.erase(this);
+
 		std::swap(st, own_style_);
 
+		if (style_)
+			style_->use_as_own_style.insert(this);
+
 		auto visitor = util::recursive([](auto && self, element * e) -> void {
 			e->merged_style_ = nullptr;
 			e->merged_own_style_ = nullptr;
@@ -122,6 +134,12 @@ namespace psemek::ui
 		return merged_own_style_;
 	}
 
+	element::~element()
+	{
+		set_style(nullptr);
+		set_own_style(nullptr);
+	}
+
 	void element::post(util::function<void()> f) const
 	{
 		auto l = loop();

libs/ui/source/style.cpp

@@ -1,4 +1,5 @@
 #include <psemek/ui/style.hpp>
+#include <psemek/ui/element.hpp>
 
 namespace psemek::ui
 {
@@ -34,6 +35,20 @@ namespace psemek::ui
 
 	}
 
+	style::style(style const & other)
+	{
+		merge(*this, other);
+	}
+
+	void style::on_changed()
+	{
+		for (auto e : use_as_style)
+			e->set_style(e->style());
+
+		for (auto e : use_as_own_style)
+			e->set_own_style(e->own_style());
+	}
+
 	void merge(style & dst, style const & src)
 	{
 		merge(dst.scale, src.scale);