add background and bgcolor support

init.lua

@@ -1,12 +1,52 @@
 formspeccer = {}
 local forms = {}
 
-formspeccer.newform = function(self,formname,formsize)
+local colours = {
+	red="#ff0000",
+	green="#00ff00",
+	blue="#0000ff",
+	yellow="#ffff00",
+	cyan="#00ffff",
+	magenta="#ff00ff",
+	white="#ffffff",
+	black="#000000",
+	lightgrey="#cccccc",
+	mediumgrey="#999999",
+	darkgrey="#333333",
+}
+
+local lookupcolour = function(colourname)
+	local thecolor = colours[colourname]
+	if thecolour == nil then
+		return colourname -- it might already be a code in itself
+	end
+	return thecolour
+end
+
+formspeccer.newform = function(self,formname,formsize,prefs)
 	if forms[formname] ~= nil then
 		minetest.log("error","Form "..formname.." already exists!!")
 		return -- how to cleanly indicate error and prevent loading?
 	end
 	forms[formname] = 'size['..formsize..']'
+	if prefs then
+		local pstring = ''
+		for prefname,value in pairs(prefs) do
+			if prefname == "bgcolor" then
+				pstring = pstring .. "bgcolor["..lookupcolour(value).."]"
+			elseif prefname == "background" then
+				pstring = pstring .. "background["
+				pstring = pstring .. value.xy .. ';'
+				pstring = pstring .. value.wh .. ';'
+				pstring = pstring .. value.texture
+				if value.auto_clip ~= false then -- anything different from false, including nil
+					pstring = pstring .. ";true"
+				end
+				pstring = pstring .. "]"
+			end
+		end
+		forms[formname] = forms[formname] .. pstring
+	end
 	return formname
 end