Add pixel scale preference option.

data/gui/window/preferences/03_display.cfg

@@ -51,6 +51,38 @@
 					[/column]
 
 				[/row]
+
+				[row]
+					{GUI_FILLER}
+
+					[column]
+						horizontal_grow = true
+						{_GUI_PREFERENCES_MAIN_COMPOSITE_SLIDER
+							( _ "Pixel scale multiplier:")
+							pixel_scale_slider (
+								minimum_value,maximum_value=1,4
+								step_size=1
+								tooltip= _ "Set the global pixel scale multiplier. A pixel scale multiplier of 2 will make everything look twice as large."
+							)
+						}
+					[/column]
+				[/row]
+
+				[row]
+					{GUI_FILLER}
+
+					[column]
+						border = "all"
+						border_size = 5
+						horizontal_alignment = "left"
+
+						[toggle_button]
+							id = "auto_pixel_scale"
+							label = _ "Automatic pixel scale multiplier"
+							tooltip = _ "Choose pixel scale multiplier automatically based on current resolution"
+						[/toggle_button]
+					[/column]
+				[/row]
 			[/grid]
 		[/column]
 	[/row]

src/gui/dialogs/preferences_dialog.cpp

@@ -71,6 +71,12 @@ void disable_widget_on_toggle(window& window, widget& w, const std::string& id)
 	find_widget<W>(&window, id, false).set_active(dynamic_cast<selectable_item&>(w).get_value_bool());
 }
 
+template<typename W>
+void disable_widget_on_toggle_inverted(window& window, widget& w, const std::string& id)
+{
+	find_widget<W>(&window, id, false).set_active(!dynamic_cast<selectable_item&>(w).get_value_bool());
+}
+
 // Ensure the specified index is between 0 and one less than the max
 // number of pager layers (since get_layer_count returns one-past-end).
 int index_in_pager_range(const int first, const stacked_widget& pager)
@@ -408,6 +414,15 @@ void preferences_dialog::post_build(window& window)
 	connect_signal_notify_modified(res_list,
 		std::bind(&preferences_dialog::handle_res_select, this));
 
+	/* PIXEL SCALE */
+	register_integer("pixel_scale_slider", true,
+		pixel_scale, set_pixel_scale);
+
+	/* AUTOMATIC PIXEL SCALE */
+	register_bool("auto_pixel_scale", true,
+		auto_pixel_scale, set_auto_pixel_scale,
+		[&](widget& w) { disable_widget_on_toggle_inverted<slider>(window, w, "pixel_scale_slider"); }, true);
+
 	/* SHOW FLOATING LABELS */
 	register_bool("show_floating_labels", true,
 		show_floating_labels, set_show_floating_labels);
@@ -985,6 +1000,7 @@ void preferences_dialog::pre_show(window& window)
 
 	gui2::bind_status_label<slider>(&window, "max_saves_slider");
 	gui2::bind_status_label<slider>(&window, "turbo_slider");
+	gui2::bind_status_label<slider>(&window, "pixel_scale_slider");
 
 	//gui2::bind_status_label<slider>(&window, "scaling_slider",   [](slider& s)->std::string {
 	//	return s.get_value_label() + "%";

src/preferences/general.cpp

@@ -72,6 +72,9 @@ const int def_window_height = 720;
 const int min_font_scaling  = 80;
 const int max_font_scaling  = 150;
 
+const int min_pixel_scale = 1;
+const int max_pixel_scale = 4;
+
 class prefs_event_handler : public events::sdl_handler {
 public:
 	virtual void handle_event(const SDL_Event &) {}
@@ -406,6 +409,27 @@ point resolution()
 	);
 }
 
+int pixel_scale()
+{
+	// For now this has a minimum value of 1 and a maximum of 4.
+	return std::max<int>(std::min<int>(prefs["pixel_scale"].to_int(1), max_pixel_scale), min_pixel_scale);
+}
+
+void set_pixel_scale(const int scale)
+{
+	prefs["pixel_scale"] = std::clamp(scale, min_pixel_scale, max_pixel_scale);
+}
+
+bool auto_pixel_scale()
+{
+	return get("auto_pixel_scale", true);
+}
+
+void set_auto_pixel_scale(bool choice)
+{
+	prefs["auto_pixel_scale"] = choice;
+}
+
 bool maximized()
 {
 	return get("maximized", !fullscreen());

src/preferences/general.hpp

@@ -75,6 +75,12 @@ namespace preferences {
 	point resolution();
 	void _set_resolution(const point& res);
 
+	int pixel_scale();
+	void set_pixel_scale(const int scale);
+
+	bool auto_pixel_scale();
+	void set_auto_pixel_scale(bool choice);
+
 	bool maximized();
 	void _set_maximized(bool ison);