GUI2/Styled Widget: initialize canvases using range ctor

Also adds a proper move assignment operator to canvas. styled_widget::set_config was removed since it's not needed as of dfa09cd9d9.

src/gui/core/canvas.cpp

@@ -552,7 +552,7 @@ void text_shape::draw(wfl::map_formula_callable& variables)
 
 /***** ***** ***** ***** ***** CANVAS ***** ***** ***** ***** *****/
 
-canvas::canvas()
+canvas::canvas(const config& cfg)
 	: shapes_()
 	, blur_depth_(0)
 	, blur_region_(sdl::empty_rect)
@@ -562,18 +562,7 @@ canvas::canvas()
 	, variables_()
 	, functions_()
 {
-}
-
-canvas::canvas(canvas&& c) noexcept
-	: shapes_(std::move(c.shapes_))
-	, blur_depth_(c.blur_depth_)
-	, blur_region_(c.blur_region_)
-	, deferred_(c.deferred_)
-	, w_(c.w_)
-	, h_(c.h_)
-	, variables_(c.variables_)
-	, functions_(c.functions_)
-{
+	parse_cfg(cfg);
 }
 
 // It would be better if the blur effect was managed at a higher level.

src/gui/core/canvas.hpp

@@ -83,10 +83,13 @@ public:
 		bool immutable_;
 	};
 
-	canvas();
+	explicit canvas(const config& cfg);
+
 	canvas(const canvas&) = delete;
 	canvas& operator=(const canvas&) = delete;
-	canvas(canvas&& c) noexcept;
+
+	canvas(canvas&& c) noexcept = default;
+	canvas& operator=(canvas&&) noexcept = default;
 
 	/**
 	 * Update the background blur texture, if relevant and necessary.

src/gui/core/widget_definition.hpp

@@ -38,6 +38,12 @@ struct state_definition
 	explicit state_definition(const config& cfg);
 
 	config canvas_cfg_;
+
+	/** Allows us to use this object in vector's range constructor */
+	operator const config&() const
+	{
+		return canvas_cfg_;
+	}
 };
 
 struct resolution_definition

src/gui/widgets/styled_widget.cpp

@@ -53,22 +53,12 @@ styled_widget::styled_widget(const implementation::builder_styled_widget& builde
 	, tooltip_(builder.tooltip)
 	, help_message_(builder.help)
 	, config_(get_control(control_type, definition_))
-	, canvases_(config_->state.size()) // One canvas per state
+	, canvases_(config_->state.begin(), config_->state.end())
 	, renderer_()
 	, text_alignment_(PANGO_ALIGN_LEFT)
 	, text_ellipse_mode_(PANGO_ELLIPSIZE_END)
 	, shrunken_(false)
 {
-	/*
-	 * Fill in each canvas from the widget state definitons.
-	 *
-	 * Most widgets have a single canvas. However, some widgets such as toggle_panel
-	 * and toggle_button have a variable canvas count determined by their definitions.
-	 */
-	for(unsigned i = 0; i < config_->state.size(); ++i) {
-		canvases_[i].set_shapes(config_->state[i].canvas_cfg_);
-	}
-
 	// Initialize all the canvas variables.
 	update_canvas();
 

src/gui/widgets/styled_widget.hpp

@@ -306,11 +306,6 @@ protected:
 		return std::static_pointer_cast<const typename T::resolution>(get_config());
 	}
 
-	void set_config(resolution_definition_ptr config)
-	{
-		config_ = std::move(config);
-	}
-
 	/***** ***** ***** ***** miscellaneous ***** ***** ***** *****/
 
 	/**