Implement UI scaling option

There are still a few minor visual glitches, but it works pretty well

rsrc/dialogs/preferences.xml

@@ -39,6 +39,8 @@
 	<led name='easier' top='389' left='53' width='352'>Make game easier (monsters much weaker)</led>
 	<led name='lesswm' top='409' left='53' width='340'>Fewer wandering monsters</led>
 	<led name='skipsplash' top='429' left='53' width='340'>Skip splash screen on startup</led>
-	<button name='okay' type='regular' top='446' left='354'>OK</button>
-	<button name='cancel' type='regular' def-key='esc' top='446' left='281'>Cancel</button>
+	<led name='scaleui' top='449' left='53' width='340'>Apply UI scaling</led>
+	
+	<button name='okay' type='regular' top='466' left='354'>OK</button>
+	<button name='cancel' type='regular' def-key='esc' top='466' left='281'>Cancel</button>
 </dialog>

src/game/boe.dlgutil.cpp

@@ -1139,6 +1139,11 @@ static bool prefs_event_filter (cDialog& me, std::string id, eKeyMod) {
 		if(dynamic_cast<cLed&>(me["resethelp"]).getState() == led_red) {
 			reset_help = true;
 		}
+		cLed& ui_scale = dynamic_cast<cLed&>(me["scaleui"]);
+		if(ui_scale.getState() == led_off)
+			set_pref("UIScale", 1.0);
+		else if(ui_scale.getState() == led_red)
+			set_pref("UIScale", 2.0);
 	}
 	save_prefs(reset_help);
 	return true;
@@ -1202,12 +1207,15 @@ void pick_preferences() {
 			break;
 	}
 	
+	float ui_scale = get_float_pref("UIScale", 1.0);
+	dynamic_cast<cLed&>(prefsDlog["scaleui"]).setState(ui_scale == 1.0 ? led_off : (ui_scale == 2.0 ? led_red : led_green));
+	
 	void (*give_help)(short,short,cDialog&) = ::give_help;
 	
 	int store_display_mode = get_int_pref("DisplayMode");
 	prefsDlog.run(std::bind(give_help, 55, 0, std::ref(prefsDlog)));
 	
-	if(get_int_pref("DisplayMode") != store_display_mode)
+	if(get_int_pref("DisplayMode") != store_display_mode || get_float_pref("UIScale") != ui_scale)
 		changed_display_mode = true;
 }
 

src/game/boe.graphics.cpp

@@ -131,7 +131,9 @@ void adjust_window_mode() {
 	hideMenuBar();
 	int menubarHeight = getMenubarHeight();
 	bool firstTime = !mainPtr.isOpen();
-	float width = 605, height = 430;
+	float ui_scale = get_float_pref("UIScale", 1.0);
+	if(ui_scale < 0.1) ui_scale = 1.0;
+	float width = 605 * ui_scale, height = 430 * ui_scale;
 	location ul;
 	
 	// TODO: Make display_mode an enum
@@ -165,8 +167,8 @@ void adjust_window_mode() {
 	sf::FloatRect mainPort;
 	mainPort.left = float(ul.x) / windRect.width();
 	mainPort.top = float(ul.y) / windRect.height();
-	mainPort.width = width / windRect.width();
-	mainPort.height = height / windRect.height();
+	mainPort.width = ui_scale * width / windRect.width();
+	mainPort.height = ui_scale * height / windRect.height();
 	mainView.setViewport(mainPort);
 	
 #ifndef __APPLE__ // This overrides Dock icon on OSX, which isn't what we want at all

src/tools/prefs.hpp

@@ -19,6 +19,9 @@ bool get_bool_pref(std::string keypath, bool fallback = false);
 void set_pref(std::string keypath, int value);
 int get_int_pref(std::string keypath, int fallback = 0);
 
+void set_pref(std::string keypath, double value);
+double get_float_pref(std::string keypath, double fallback = 0);
+
 void append_iarray_pref(std::string keypath, int value);
 std::vector<int> get_iarray_pref(std::string keypath);
 

src/tools/prefs.mac.mm

@@ -37,6 +37,16 @@ int get_int_pref(std::string keypath, int fallback) {
 	return fallback;
 }
 
+void set_pref(std::string keypath, double value) {
+	[[NSUserDefaults standardUserDefaults] setDouble: value forKey: convertKey(keypath)];
+}
+
+double get_float_pref(std::string keypath, double fallback) {
+	id val = [[NSUserDefaults standardUserDefaults] objectForKey: convertKey(keypath)];
+	if([val isKindOfClass: [NSNumber class]]) return [val doubleValue];
+	return fallback;
+}
+
 void append_iarray_pref(std::string keypath, int value) {
 	NSString* key = convertKey(keypath);
 	NSArray* list = [[NSUserDefaults standardUserDefaults] arrayForKey: key];

src/tools/prefs.win.cpp

@@ -35,6 +35,17 @@ int get_int_pref(std::string keypath, int fallback) {
 	return fallback;
 }
 
+void set_pref(std::string keypath, double value) {
+	prefsDirty = true;
+	prefs[keypath] = value;
+}
+
+double get_float_pref(std::string keypath, double fallback) {
+	if(prefs.find(keypath) == prefs.end()) return fallback;
+	if(prefs[keypath].type() == typeid(double)) return boost::any_cast<double>(prefs[keypath]);
+	return fallback;
+}
+
 void append_iarray_pref(std::string keypath, int value) {
 	prefsDirty = true;
 	if(prefs.find(keypath) == prefs.end() || prefs[keypath].type() != typeid(iarray))