Ugh

code/_helpers/icons_ch.dm

@@ -642,4 +642,20 @@ world
 //Images have dir without being an atom, so they get their own definition.
 //Lame.
 /image/proc/setDir(newdir)
-	dir = newdir
+	dir = newdir
+
+/* Gives the result RGB of a RGB string after a matrix transformation. No alpha.
+ * Input: rr, rg, rb, gr, gg, gb, br, bg, bb, cr, cg, cb
+ * Output: RGB string
+ */
+/proc/RGBMatrixTransform(list/color, list/cm)
+	ASSERT(cm.len >= 9)
+	if(cm.len < 12)		// fill in the rest
+		for(var/i in 1 to (12 - cm.len))
+			cm += 0
+	if(!islist(color))
+		color = ReadRGB(color)
+	color[1] = color[1] * cm[1] + color[2] * cm[2] + color[3] * cm[3] + cm[10] * 255
+	color[2] = color[1] * cm[4] + color[2] * cm[5] + color[3] * cm[6] + cm[11] * 255
+	color[3] = color[1] * cm[7] + color[2] * cm[8] + color[3] * cm[9] + cm[12] * 255
+	return rgb(color[1], color[2], color[3])