Graffiti centers on where you click. (#9255)

* Graffiti centers on where you click.

* Oversights, and pixelshifted engravings.

* Better returns

code/game/turfs/simulated/floor_attackby.dm

@@ -1,4 +1,4 @@
-/turf/simulated/floor/attackby(var/obj/item/C, var/mob/user)
+/turf/simulated/floor/attackby(var/obj/item/C, var/mob/user, attack_modifier, click_parameters)
 
 	if(!C || !user)
 		return 0
@@ -29,7 +29,7 @@
 		if(isliving(user))
 			var/mob/living/L = user
 			if(L.a_intent == I_HELP && L.is_preference_enabled(/datum/client_preference/engrave_graffiti))
-				try_graffiti(L, C)
+				try_graffiti(L, C, click_parameters)
 
 	if(istype(C, /obj/item/stack/tile/roofing))
 		var/expended_tile = FALSE // To track the case. If a ceiling is built in a multiz zlevel, it also necessarily roofs it against weather

code/game/turfs/simulated/wall_attacks.dm

@@ -127,12 +127,12 @@
 		return success_smash(user)
 	return fail_smash(user)
 
-/turf/simulated/wall/attackby(var/obj/item/W, var/mob/user)
+/turf/simulated/wall/attackby(var/obj/item/W, var/mob/user, attack_modifier, click_parameters)
 
 	user.setClickCooldown(user.get_attack_speed(W))
 
 	if(!construction_stage && user.a_intent == I_HELP && user.is_preference_enabled(/datum/client_preference/engrave_graffiti))
-		if(try_graffiti(user,W))
+		if(try_graffiti(user,W,click_parameters))
 			return
 
 	if (!user.IsAdvancedToolUser())
@@ -405,4 +405,4 @@
 		return
 
 	else if(!istype(W,/obj/item/rcd) && !istype(W, /obj/item/reagent_containers))
-		return attack_hand(user)
+		return attack_hand(user)

code/game/turfs/turf.dm

@@ -308,7 +308,7 @@
 /turf/proc/can_engrave()
 	return FALSE
 
-/turf/proc/try_graffiti(var/mob/vandal, var/obj/item/tool)
+/turf/proc/try_graffiti(var/mob/vandal, var/obj/item/tool, click_parameters)
 
 	if(!tool.sharp || !can_engrave())
 		return FALSE
@@ -341,6 +341,18 @@
 	graffiti.message = message
 	graffiti.author = vandal.ckey
 
+	if(click_parameters)
+		var/list/mouse_control = params2list(click_parameters)
+		var/p_x = 0
+		var/p_y = 0
+		if(mouse_control["icon-x"])
+			p_x = text2num(mouse_control["icon-x"]) - 16
+		if(mouse_control["icon-y"])
+			p_y = text2num(mouse_control["icon-y"]) - 16
+
+		graffiti.pixel_x = p_x
+		graffiti.pixel_y = p_y
+
 	if(lowertext(message) == "elbereth")
 		to_chat(vandal, "<span class='notice'>You feel much safer.</span>")