u h g. I hate this

code/datums/components/decals/blood.dm

@@ -15,21 +15,21 @@
 		_icon_state = "itemblood"
 	var/icon = initial(I.icon)
 	var/icon_state = initial(I.icon_state)
+	var/color = initial(I.blood_DNA_to_color(I.blood_mix_types))
 	if(!icon || !icon_state)
 		// It's something which takes on the look of other items, probably
 		icon = I.icon
 		icon_state = I.icon_state
 	var/static/list/blood_splatter_appearances = list()
 	//try to find a pre-processed blood-splatter. otherwise, make a new one
-	var/index = "[REF(icon)]-[icon_state]"
+	var/index = "[REF(icon)]-[icon_state]-[color]"
 	pic = blood_splatter_appearances[index]
 
 	if(!pic)
 		var/icon/blood_splatter_icon = icon(initial(I.icon), initial(I.icon_state), , 1)		//we only want to apply blood-splatters to the initial icon_state for each object
 		blood_splatter_icon.Blend("#fff", ICON_ADD) 			//fills the icon_state with white (except where it's transparent)
 		blood_splatter_icon.Blend(icon(_icon, _icon_state), ICON_MULTIPLY) //adds blood and the remaining white areas become transparant
-		GET_COMPONENT(D, /datum/component/forensics)
-		blood_splatter_icon.Blend(D.blood_DNA_to_color(), ICON_MULTIPLY)
+		blood_splatter_icon.color = I.blood_DNA_to_color(I.blood_mix_types) //Colors it based upon blood color mix
 		blood_splatter_appearances[index] = pic
 	return TRUE
 

code/datums/components/forensics.dm

@@ -4,25 +4,26 @@
 	var/list/hiddenprints		//assoc ckey = realname/gloves/ckey
 	var/list/blood_DNA			//assoc dna = bloodtype
 	var/list/fibers				//assoc print = print
+	var/list/blood_mix_types	// data("[blood_type]" = sting list
 
 /datum/component/forensics/InheritComponent(datum/component/forensics/F, original)		//Use of | and |= being different here is INTENTIONAL.
 	fingerprints = fingerprints | F.fingerprints
 	hiddenprints = hiddenprints | F.hiddenprints
 	blood_DNA = blood_DNA | F.blood_DNA
 	fibers = fibers | F.fibers
+	blood_mix_types = blood_mix_types | F.blood_mix_types
 	check_blood()
-	blood_DNA_to_color()
 	return ..()
 
-/datum/component/forensics/Initialize(new_fingerprints, new_hiddenprints, new_blood_DNA, new_fibers)
+/datum/component/forensics/Initialize(new_fingerprints, new_hiddenprints, new_blood_DNA, new_fibers, new_blood_mix_types)
 	if(!isatom(parent))
 		return COMPONENT_INCOMPATIBLE
 	fingerprints = new_fingerprints
 	hiddenprints = new_hiddenprints
 	blood_DNA = new_blood_DNA
 	fibers = new_fibers
+	blood_mix_types = new_blood_mix_types
 	check_blood()
-	blood_DNA_to_color()
 	RegisterSignal(parent, COMSIG_COMPONENT_CLEAN_ACT, .proc/clean_act)
 
 /datum/component/forensics/proc/wipe_fingerprints()
@@ -34,6 +35,7 @@
 
 /datum/component/forensics/proc/wipe_blood_DNA()
 	blood_DNA = null
+	blood_mix_types = null
 	return TRUE
 
 /datum/component/forensics/proc/wipe_fibers()
@@ -149,35 +151,61 @@
 	for(var/i in dna)
 		blood_DNA[i] = dna[i]
 	check_blood()
-	blood_DNA_to_color()
 	return TRUE
 
 /datum/component/forensics/proc/check_blood()
-	if(!isitem(parent))
+	if(!isitem(parent) || !ismob(parent))
 		return
 	if(!length(blood_DNA))
 		return
 
-/datum/component/forensics/proc/blood_DNA_to_color()
-	var/list/colors = list()//first we make a list of all bloodtypes present
-	for(var/bloop in blood_DNA)
-		if(colors[blood_DNA[bloop]])
-			colors[blood_DNA[bloop]]++
+/datum/component/forensics/proc/add_blood_list_check(list/_blood_mix_types)
+	if(!length(_blood_mix_types))
+		return
+	LAZYINITLIST(blood_mix_types)
+	for(var/i in _blood_mix_types)	//We use an associative list, because all the other cool kids are doing it
+		blood_mix_types[i] = i
+	return TRUE
+
+/datum/component/forensics/proc/blood_list_checks(Atom/A, var/blood_type) //This is a messy attempt at trying to reduce lists of items and mobs with blood colors on them
+	if(blood_type in GLOB.regular_bloods)
+		blood_type = "A+" //generic so we don't have 8 different types of human blood
+	if(is_cleanable(src))
+		var/obj/effect/decal/cleanable/CL = src
+		if(blood_type in CL.blood_mix_types)
+			return
 		else
-			colors[blood_DNA[bloop]] = 1
+			LAZYSET(blood_type,CL.blood_mix_types, CL.blood_mix_types)
+			CL.blood_color = blood_DNA_to_color(CL.blood_mix_types)
+	else if(isitem(src))
+		var/obj/item/I = src
+		if(blood_type in I.blood_mix_types)
+			return
+		else
+			LAZYSET(blood_type,I.blood_mix_types, I.blood_mix_types)
+			I.blood_color = blood_DNA_to_color(I.blood_mix_types)
+	else if(iscarbon(src))
+		var/mob/living/carbon/C = src
+		if(blood_type in C.blood_mix_types)
+			return
+		else
+			LAZYSET(blood_type,C.blood_mix_types, C.blood_mix_types)
+			C.blood_color = blood_DNA_to_color(C.blood_mix_types)
+	return TRUE
 
-	var/final_rgb = "#940000"
-
-	if(colors.len)
+/datum/component/forensics/proc/blood_DNA_to_color(list/bloods)
+	var/final_rgb = "#940000" //We default to red just in case
+	if(bloods.len)
 		var/sum = 0 //this is all shitcode, but it works; trust me
-		final_rgb = bloodtype_to_color(colors[1])
-		sum = colors[colors[1]]
-		if(colors.len > 1)
+		final_rgb = bloodtype_to_color(bloods[1])
+		sum = bloods[bloods[1]]
+		if(bloods.len > 1)
 			var/i = 2
-			while(i <= colors.len)
-				var/tmp = colors[colors[i]]
-				final_rgb = BlendRGB(final_rgb, bloodtype_to_color(colors[i]), tmp/(tmp+sum))
+			while(i <= bloods.len)
+				var/tmp = bloods[bloods[i]]
+				final_rgb = BlendRGB(final_rgb, bloodtype_to_color(bloods[i]), tmp/(tmp+sum))
 				sum += tmp
 				i++
-
+		else
+			final_rgb = BlendRGB(final_rgb, bloodtype_to_color(bloods))
 	return final_rgb