[MIRROR] [TGUI v6] Migration to CSS Variables, styles refactor & React 19 (#10615)

Co-authored-by: Kashargul <144968721+Kashargul@users.noreply.github.com>

code/modules/client/client defines.dm

@@ -181,3 +181,6 @@
 
 	/// Token used for the external chatlog api. Only valid for the current round.
 	var/chatlog_token
+
+	/// The DPI scale of the client. 1 is equivalent to 100% window scaling, 2 will be 200% window scaling
+	var/window_scaling

code/modules/client/client procs.dm

@@ -298,9 +298,12 @@
 	)
 	addtimer(CALLBACK(src, PROC_REF(check_panel_loaded)), 30 SECONDS)
 
+	INVOKE_ASYNC(src, PROC_REF(acquire_dpi))
+
+	tgui_panel.initialize()
+
 	// Initialize tgui panel
 	tgui_say.initialize()
-	tgui_panel.initialize()
 
 	connection_time = world.time
 	connection_realtime = world.realtime
@@ -814,6 +817,10 @@
 	SEND_SIGNAL(src, COMSIG_CLIENT_CLICK, object, location, control, params, usr)
 	. = ..()
 
+/// This grabs the DPI of the user per their skin
+/client/proc/acquire_dpi()
+	window_scaling = text2num(winget(src, null, "dpi"))
+
 #undef ADMINSWARNED_AT
 #undef CURRENT_MINUTE
 #undef CURRENT_SECOND

code/modules/client/preferences/types/game/ui.dm

@@ -114,3 +114,16 @@
 
 /datum/preference/text/preset_colors/apply_to_client(client/client, value)
 	return
+
+/datum/preference/toggle/ui_scale
+	category = PREFERENCE_CATEGORY_GAME_PREFERENCES
+	savefile_key = "ui_scale"
+	savefile_identifier = PREFERENCE_PLAYER
+	default_value = FALSE // Set to true once lobby screen is migrated to tgui and browse are replaced with datum browser
+
+/datum/preference/toggle/ui_scale/apply_to_client(client/client, value)
+	if(!istype(client))
+		return
+
+	INVOKE_ASYNC(client, TYPE_VERB_REF(/client, refresh_tgui))
+	client.tgui_say?.load()