GUI2: cleaned up widget resolution config cast fetch code

Also made all the conf variables const since they should never be modified.

src/gui/core/window_builder.cpp

@@ -106,9 +106,7 @@ window* build(CVideo& video, const builder_window::window_resolution* definition
 
 	win->set_click_dismiss(definition->click_dismiss);
 
-	std::shared_ptr<const window_definition::resolution>
-	conf = std::static_pointer_cast<const window_definition::resolution>(
-			win->config());
+	const auto conf = win->cast_config_to<window_definition>();
 	assert(conf);
 
 	if(conf->grid) {

src/gui/widgets/addon_list.cpp

@@ -446,7 +446,7 @@ widget* builder_addon_list::build() const
 	DBG_GUI_G << "Window builder: placed add-on list '" << id <<
 		"' with definition '" << definition << "'.\n";
 
-	auto conf = std::static_pointer_cast<const addon_list_definition::resolution>(widget->config());
+	const auto conf = widget->cast_config_to<addon_list_definition>();
 	assert(conf != nullptr);
 
 	widget->init_grid(conf->grid);

src/gui/widgets/chatbox.cpp

@@ -765,10 +765,7 @@ widget* builder_chatbox::build() const
 	DBG_GUI_G << "Window builder: placed unit preview pane '" << id
 			  << "' with definition '" << definition << "'.\n";
 
-	std::shared_ptr<const chatbox_definition::resolution> conf
-		= std::static_pointer_cast<
-			const chatbox_definition::resolution>(widget->config());
-
+	const auto conf = widget->cast_config_to<chatbox_definition>();
 	assert(conf);
 
 	widget->init_grid(conf->grid);

src/gui/widgets/horizontal_scrollbar.cpp

@@ -35,39 +35,31 @@ REGISTER_WIDGET(horizontal_scrollbar)
 
 unsigned horizontal_scrollbar::minimum_positioner_length() const
 {
-	std::shared_ptr<const horizontal_scrollbar_definition::resolution>
-	conf = std::static_pointer_cast<const horizontal_scrollbar_definition::
-											   resolution>(config());
-
+	const auto conf = cast_config_to<horizontal_scrollbar_definition>();
 	assert(conf);
+
 	return conf->minimum_positioner_length;
 }
 
 unsigned horizontal_scrollbar::maximum_positioner_length() const
 {
-	std::shared_ptr<const horizontal_scrollbar_definition::resolution>
-	conf = std::static_pointer_cast<const horizontal_scrollbar_definition::
-											   resolution>(config());
-
+	const auto conf = cast_config_to<horizontal_scrollbar_definition>();
 	assert(conf);
+
 	return conf->maximum_positioner_length;
 }
 
 unsigned horizontal_scrollbar::offset_before() const
 {
-	std::shared_ptr<const horizontal_scrollbar_definition::resolution>
-	conf = std::static_pointer_cast<const horizontal_scrollbar_definition::
-											   resolution>(config());
-
+	const auto conf = cast_config_to<horizontal_scrollbar_definition>();
 	assert(conf);
+
 	return conf->left_offset;
 }
 
 unsigned horizontal_scrollbar::offset_after() const
 {
-	std::shared_ptr<const horizontal_scrollbar_definition::resolution>
-	conf = std::static_pointer_cast<const horizontal_scrollbar_definition::
-											   resolution>(config());
+	const auto conf = cast_config_to<horizontal_scrollbar_definition>();
 	assert(conf);
 
 	return conf->right_offset;

src/gui/widgets/label.cpp

@@ -151,10 +151,7 @@ void label::load_config_extra()
 {
 	assert(config());
 
-	std::shared_ptr<const label_definition::resolution>
-	conf = std::static_pointer_cast<const label_definition::resolution>(
-			config());
-
+	const auto conf = cast_config_to<label_definition>();
 	assert(conf);
 
 	set_link_aware(conf->link_aware);

src/gui/widgets/listbox.cpp

@@ -991,9 +991,7 @@ widget* builder_listbox::build() const
 	DBG_GUI_G << "Window builder: placed listbox '" << id
 			  << "' with definition '" << definition << "'.\n";
 
-	std::shared_ptr<const listbox_definition::resolution>
-	conf = std::static_pointer_cast<const listbox_definition::resolution>(
-			widget->config());
+	const auto conf = widget->cast_config_to<listbox_definition>();
 	assert(conf);
 
 	widget->init_grid(conf->grid);
@@ -1116,9 +1114,7 @@ widget* builder_horizontal_listbox::build() const
 	DBG_GUI_G << "Window builder: placed listbox '" << id
 			  << "' with definition '" << definition << "'.\n";
 
-	std::shared_ptr<const listbox_definition::resolution>
-	conf = std::static_pointer_cast<const listbox_definition::resolution>(
-			widget->config());
+	const auto conf = widget->cast_config_to<listbox_definition>();
 	assert(conf);
 
 	widget->init_grid(conf->grid);
@@ -1241,9 +1237,7 @@ widget* builder_grid_listbox::build() const
 	DBG_GUI_G << "Window builder: placed listbox '" << id
 			  << "' with definition '" << definition << "'.\n";
 
-	std::shared_ptr<const listbox_definition::resolution>
-	conf = std::static_pointer_cast<const listbox_definition::resolution>(
-			widget->config());
+	const auto conf = widget->cast_config_to<listbox_definition>();
 	assert(conf);
 
 	widget->init_grid(conf->grid);

src/gui/widgets/matrix.cpp

@@ -60,9 +60,7 @@ unsigned state_default::get_state() const
 matrix::matrix(const implementation::builder_matrix& builder)
 	: tbase(builder, "matrix"), content_(), pane_(nullptr)
 {
-	std::shared_ptr<const matrix_definition::resolution>
-	cfg = std::static_pointer_cast<const matrix_definition::resolution>(
-			config());
+	const auto cfg = cast_config_to<matrix_definition>();
 
 	builder_widget::replacements_map replacements;
 	replacements.emplace("_main", builder.builder_main);

src/gui/widgets/multi_page.cpp

@@ -301,9 +301,7 @@ widget* builder_multi_page::build() const
 	DBG_GUI_G << "Window builder: placed multi_page '" << id
 			  << "' with definition '" << definition << "'.\n";
 
-	std::shared_ptr<const multi_page_definition::resolution>
-	conf = std::static_pointer_cast<const multi_page_definition::resolution>(
-					widget->config());
+	const auto conf = widget->cast_config_to<multi_page_definition>();
 	assert(conf);
 
 	widget->init_grid(conf->grid);

src/gui/widgets/panel.cpp

@@ -37,9 +37,7 @@ REGISTER_WIDGET(panel)
 
 SDL_Rect panel::get_client_rect() const
 {
-	std::shared_ptr<const panel_definition::resolution> conf
-			= std::static_pointer_cast<const panel_definition::resolution>(
-					config());
+	const auto conf = cast_config_to<panel_definition>();
 	assert(conf);
 
 	SDL_Rect result = get_rectangle();
@@ -79,9 +77,7 @@ void panel::impl_draw_foreground(surface& frame_buffer, int x_offset, int y_offs
 
 point panel::border_space() const
 {
-	std::shared_ptr<const panel_definition::resolution> conf
-			= std::static_pointer_cast<const panel_definition::resolution>(
-					config());
+	const auto conf = cast_config_to<panel_definition>();
 	assert(conf);
 
 	return point(conf->left_border + conf->right_border, conf->top_border + conf->bottom_border);

src/gui/widgets/scroll_label.cpp

@@ -284,8 +284,7 @@ widget* builder_scroll_label::build() const
 	widget->set_vertical_scrollbar_mode(vertical_scrollbar_mode);
 	widget->set_horizontal_scrollbar_mode(horizontal_scrollbar_mode);
 
-	std::shared_ptr<const scroll_label_definition::resolution>
-	conf = std::static_pointer_cast<const scroll_label_definition::resolution>(widget->config());
+	const auto conf = widget->cast_config_to<scroll_label_definition>();
 	assert(conf);
 
 	widget->init_grid(conf->grid);

src/gui/widgets/scrollbar_panel.cpp

@@ -162,9 +162,7 @@ widget* builder_scrollbar_panel::build() const
 	DBG_GUI_G << "Window builder: placed scrollbar_panel '" << id
 			  << "' with definition '" << definition << "'.\n";
 
-	std::shared_ptr<const scrollbar_panel_definition::resolution> conf
-			= std::static_pointer_cast<const scrollbar_panel_definition::resolution>(
-				panel->config());
+	const auto conf = panel->cast_config_to<scrollbar_panel_definition>();
 	assert(conf);
 
 	panel->init_grid(conf->grid);

src/gui/widgets/size_lock.cpp

@@ -144,7 +144,7 @@ widget* builder_size_lock::build() const
 	DBG_GUI_G << "Window builder: placed fixed size widget '" << id <<
 		"' with definition '" << definition << "'.\n";
 
-	auto conf = std::static_pointer_cast<const size_lock_definition::resolution>(widget->config());
+	const auto conf = widget->cast_config_to<size_lock_definition>();
 	assert(conf != nullptr);
 
 	widget->init_grid(conf->grid);

src/gui/widgets/slider.cpp

@@ -63,10 +63,7 @@ point slider::calculate_best_size() const
 	if(best_slider_length_ != 0) {
 
 		// Override length.
-		std::shared_ptr<const slider_definition::resolution> conf
-				= std::static_pointer_cast<const slider_definition::
-													  resolution>(config());
-
+		const auto conf = cast_config_to<slider_definition>();
 		assert(conf);
 
 		result.x = conf->left_offset + best_slider_length_ + conf->right_offset;
@@ -158,36 +155,28 @@ void slider::child_callback_positioner_moved()
 
 unsigned slider::minimum_positioner_length() const
 {
-	std::shared_ptr<const slider_definition::resolution>
-	conf = std::static_pointer_cast<const slider_definition::resolution>(
-			config());
+	const auto conf = cast_config_to<slider_definition>();
 	assert(conf);
 	return conf->minimum_positioner_length;
 }
 
 unsigned slider::maximum_positioner_length() const
 {
-	std::shared_ptr<const slider_definition::resolution>
-	conf = std::static_pointer_cast<const slider_definition::resolution>(
-			config());
+	const auto conf = cast_config_to<slider_definition>();
 	assert(conf);
 	return conf->maximum_positioner_length;
 }
 
 unsigned slider::offset_before() const
 {
-	std::shared_ptr<const slider_definition::resolution>
-	conf = std::static_pointer_cast<const slider_definition::resolution>(
-			config());
+	const auto conf = cast_config_to<slider_definition>();
 	assert(conf);
 	return conf->left_offset;
 }
 
 unsigned slider::offset_after() const
 {
-	std::shared_ptr<const slider_definition::resolution>
-	conf = std::static_pointer_cast<const slider_definition::resolution>(
-			config());
+	const auto conf = cast_config_to<slider_definition>();
 	assert(conf);
 	return conf->right_offset;
 }

src/gui/widgets/stacked_widget.cpp

@@ -257,9 +257,7 @@ widget* builder_stacked_widget::build() const
 	DBG_GUI_G << "Window builder: placed stacked widget '" << id
 			  << "' with definition '" << definition << "'.\n";
 
-	std::shared_ptr<const stacked_widget_definition::resolution>
-	conf = std::static_pointer_cast<const stacked_widget_definition::resolution>(
-					widget->config());
+	const auto conf = widget->cast_config_to<stacked_widget_definition>();
 	assert(conf);
 
 	widget->init_grid(conf->grid);

src/gui/widgets/styled_widget.hpp

@@ -321,6 +321,24 @@ class styled_widget : public widget
 		return config_;
 	}
 
+	/**
+	 * Casts the current resolution definition config to the respective type of a
+	 * derived widget.
+	 *
+	 * @tparam T         The definition type to cast to. Should have a `resolution`
+	 *                   subclass or struct derived from resolution_definition.
+	 *
+	 * @returns          A shared_ptr with the newly cast config.
+	 */
+	template<typename T>
+	std::shared_ptr<const typename T::resolution> cast_config_to() const
+	{
+		static_assert(std::is_base_of<resolution_definition, typename T::resolution>::value,
+			"Given type's resolution object does not derive from resolution_definition.");
+
+		return std::static_pointer_cast<const typename T::resolution>(config());
+	}
+
 	void set_config(resolution_definition_ptr config)
 	{
 		config_ = config;

src/gui/widgets/text_box.cpp

@@ -264,10 +264,7 @@ void text_box::update_offsets()
 {
 	assert(config());
 
-	std::shared_ptr<const text_box_definition::resolution>
-	conf = std::static_pointer_cast<const text_box_definition::resolution>(
-			config());
-
+	const auto conf = cast_config_to<text_box_definition>();
 	assert(conf);
 
 	// FIXME: This should use pango-cairo code path instead of sdl_ttf code path
@@ -340,10 +337,7 @@ void text_box::load_config_extra()
 {
 	assert(config());
 
-	std::shared_ptr<const text_box_definition::resolution>
-	conf = std::static_pointer_cast<const text_box_definition::resolution>(
-			config());
-
+	const auto conf = cast_config_to<text_box_definition>();
 	assert(conf);
 
 	set_font_size(conf->text_font_size);

src/gui/widgets/toggle_panel.cpp

@@ -141,9 +141,7 @@ unsigned toggle_panel::get_state() const
 
 SDL_Rect toggle_panel::get_client_rect() const
 {
-	std::shared_ptr<const toggle_panel_definition::resolution> conf
-			= std::static_pointer_cast<const toggle_panel_definition::
-												  resolution>(config());
+	const auto conf = cast_config_to<toggle_panel_definition>();
 	assert(conf);
 
 	SDL_Rect result = get_rectangle();
@@ -157,9 +155,7 @@ SDL_Rect toggle_panel::get_client_rect() const
 
 point toggle_panel::border_space() const
 {
-	std::shared_ptr<const toggle_panel_definition::resolution> conf
-			= std::static_pointer_cast<const toggle_panel_definition::
-												  resolution>(config());
+	const auto conf = cast_config_to<toggle_panel_definition>();
 	assert(conf);
 
 	return point(conf->left_border + conf->right_border, conf->top_border + conf->bottom_border);
@@ -188,9 +184,7 @@ void toggle_panel::set_state(const state_t state)
 	state_ = state;
 	set_is_dirty(true);
 
-	std::shared_ptr<const toggle_panel_definition::resolution> conf
-			= std::static_pointer_cast<const toggle_panel_definition::
-												  resolution>(config());
+	const auto conf = cast_config_to<toggle_panel_definition>();
 	assert(conf);
 }
 

src/gui/widgets/tree_view.cpp

@@ -410,9 +410,7 @@ widget* builder_tree_view::build() const
 	DBG_GUI_G << "Window builder: placed tree_view '" << id
 			  << "' with definition '" << definition << "'.\n";
 
-	std::shared_ptr<const tree_view_definition::resolution>
-	conf = std::static_pointer_cast<const tree_view_definition::resolution>(
-					widget->config());
+	const auto conf = widget->cast_config_to<tree_view_definition>();
 	assert(conf);
 
 	widget->init_grid(conf->grid);

src/gui/widgets/unit_preview_pane.cpp

@@ -595,10 +595,7 @@ widget* builder_unit_preview_pane::build() const
 	DBG_GUI_G << "Window builder: placed unit preview pane '" << id
 			  << "' with definition '" << definition << "'.\n";
 
-	std::shared_ptr<const unit_preview_pane_definition::resolution> conf
-		= std::static_pointer_cast<
-			const unit_preview_pane_definition::resolution>(widget->config());
-
+	const auto conf = widget->cast_config_to<unit_preview_pane_definition>();
 	assert(conf);
 
 	widget->init_grid(conf->grid);