Allow composite widgets to inject linked groups

data/gui/schema.cfg

@@ -481,6 +481,26 @@
                         type="unsigned"
                         default=0
                     [/key]
+                    [tag]
+                        name="linked_group"
+                        min="0"
+                        max="-1"
+                        [key]
+                            name="fixed_height"
+                            type="bool"
+                            default=false
+                        [/key]
+                        [key]
+                            name="fixed_width"
+                            type="bool"
+                            default=false
+                        [/key]
+                        [key]
+                            name="id"
+                            type="string"
+                            mandatory="true"
+                        [/key]
+                    [/tag]
                     [key]
                         name="text_extra_height"
                         type="unsigned"

src/gui/core/widget_definition.cpp

@@ -16,9 +16,11 @@
 
 #include "gui/core/widget_definition.hpp"
 
+#include "formula/string_utils.hpp"
 #include "gettext.hpp"
 #include "gui/core/log.hpp"
 #include "gui/widgets/helper.hpp"
+#include "serialization/string_utils.hpp"
 #include "wml_exception.hpp"
 
 namespace gui2
@@ -98,6 +100,7 @@ resolution_definition::resolution_definition(const config& cfg)
 	, default_height(cfg["default_height"])
 	, max_width(cfg["max_width"])
 	, max_height(cfg["max_height"])
+	, linked_groups()
 	, text_extra_width(cfg["text_extra_width"])
 	, text_extra_height(cfg["text_extra_height"])
 	, text_font_size(cfg["text_font_size"])
@@ -107,6 +110,29 @@ resolution_definition::resolution_definition(const config& cfg)
 {
 	DBG_GUI_P << "Parsing resolution " << window_width << ", " << window_height
 			  << '\n';
+
+	for(const config& lg : cfg.child_range("linked_group")) {
+		linked_group linked_group;
+		linked_group.id = lg["id"].str();
+		linked_group.fixed_width = lg["fixed_width"].to_bool();
+		linked_group.fixed_height = lg["fixed_height"].to_bool();
+
+		VALIDATE(!linked_group.id.empty(),
+			missing_mandatory_wml_key("linked_group", "id"));
+
+		if(!(linked_group.fixed_width || linked_group.fixed_height)) {
+			utils::string_map symbols;
+			symbols["id"] = linked_group.id;
+			t_string msg
+				= vgettext("Linked '$id' group needs a 'fixed_width' or "
+					"'fixed_height' key.",
+					symbols);
+
+			FAIL(msg);
+		}
+
+		linked_groups.push_back(linked_group);
+	}
 }
 
 /*WIKI

src/gui/core/widget_definition.hpp

@@ -19,6 +19,7 @@
 #include "font/font_options.hpp"
 #include "font/text.hpp"
 #include "gui/core/canvas.hpp"
+#include <vector>
 
 namespace gui2
 {
@@ -55,6 +56,19 @@ struct resolution_definition
 	unsigned max_width;
 	unsigned max_height;
 
+	struct linked_group
+	{
+		linked_group() : id(), fixed_width(false), fixed_height(false)
+		{
+		}
+
+		std::string id;
+		bool fixed_width;
+		bool fixed_height;
+	};
+
+	std::vector<linked_group> linked_groups;
+
 	unsigned text_extra_width;
 	unsigned text_extra_height;
 	unsigned text_font_size;

src/gui/widgets/container_base.cpp

@@ -17,6 +17,7 @@
 #include "gui/widgets/container_base.hpp"
 
 #include "gui/core/log.hpp"
+#include "gui/widgets/window.hpp"
 
 #include <algorithm>
 
@@ -37,6 +38,8 @@ void container_base::layout_initialise(const bool full_initialisation)
 	// Inherited.
 	styled_widget::layout_initialise(full_initialisation);
 
+	inject_linked_groups();
+
 	grid_.layout_initialise(full_initialisation);
 }
 
@@ -264,4 +267,13 @@ point container_base::border_space() const
 	return point();
 }
 
+void container_base::inject_linked_groups()
+{
+	for(const auto& lg : config()->linked_groups) {
+		if(!get_window()->has_linked_size_group(lg.id)) {
+			get_window()->init_linked_size_group(lg.id, lg.fixed_width, lg.fixed_height);
+		}
+	}
+}
+
 } // namespace gui2

src/gui/widgets/container_base.hpp

@@ -260,6 +260,8 @@ private:
 	 * set_active so we only need to change the state.
 	 */
 	virtual void set_self_active(const bool active) = 0;
+
+	void inject_linked_groups();
 };
 
 } // namespace gui2