add(colours): Ports matrix/colormate stuff from CHOMP

Original PR: https://github.com/CHOMPStation2/CHOMPStation2/pull/6159
Original Author:
https://github.com/BlackMajor

code/modules/client/preference_setup/loadout/gear_tweaks.dm

@@ -40,7 +40,48 @@
 /datum/gear_tweak/color/tweak_item(var/obj/item/I, var/metadata)
 	if(valid_colors && !(metadata in valid_colors))
 		return
-	I.color = metadata
+	if(!metadata || (metadata == "#ffffff"))
+		return
+	if(istype(I))
+		I.add_atom_colour(metadata, FIXED_COLOUR_PRIORITY)
+	else
+		I.color = metadata
+
+GLOBAL_DATUM_INIT(gear_tweak_free_matrix_recolor, /datum/gear_tweak/matrix_recolor, new)
+
+/datum/gear_tweak/matrix_recolor
+
+/datum/gear_tweak/matrix_recolor/get_contents(var/metadata)
+	if(islist(metadata) && length(metadata))
+		return "Matrix Recolor: [english_list(metadata)]"
+	return "Matrix Recolor"
+
+/datum/gear_tweak/matrix_recolor/get_default()
+	return null
+
+/datum/gear_tweak/matrix_recolor/get_metadata(user, metadata)
+	var/list/returned = color_matrix_picker(user, "Pick a color matrix for this item", "Matrix Recolor", "Ok", "Erase", "Cancel", TRUE, 10 MINUTES, islist(metadata) && metadata)
+	var/list/L = returned["matrix"]
+	if(returned["button"] == 3)
+		return metadata
+	if((returned["button"] == 2) || !islist(L) || !ISINRANGE(L.len, 9, 20))
+		return list()
+	var/identity = TRUE
+	var/static/list/ones = list(1, 5, 9)
+	for(var/i in 1 to L.len)
+		if(L[i] != ((i in ones)? 1 : 0))
+			identity = FALSE
+			break
+	return identity? list() : L
+
+/datum/gear_tweak/matrix_recolor/tweak_item(obj/item/I, metadata)
+	. = ..()
+	if(!islist(metadata) || (length(metadata) < 12))
+		return
+	if(istype(I))
+		I.add_atom_colour(metadata, FIXED_COLOUR_PRIORITY)
+	else
+		I.color = metadata
 
 /*
 * Path adjustment