diff --git a/autofill.lua b/autofill.lua
new file mode 100644
index 0000000..58502e2
--- /dev/null
+++ b/autofill.lua
@@ -0,0 +1,37 @@
+chunk, scanner = ...;
+
+-- Periodically-called function to fill in maps and queue chunks for manual
+-- scanning
+local function fill_loop()
+    -- Fill in all player-held maps
+    for _,p in ipairs(minetest.get_connected_players()) do
+        local inventory = p:get_inventory();
+        local pos = p:get_pos();
+        if pos.y > -10 then
+            for i = 1,inventory:get_size("main") do
+                local stack = inventory:get_stack("main", i);
+                local map = maps.get(stack:get_meta():get_int("cartographer:map_id"));
+
+                if map then
+                    map:fill_local(pos.x, pos.z);
+                end
+            end
+            for i = -2,2 do
+                for j = -2,2 do
+                    local adjusted_pos = {
+                        x = pos.x + chunk.from(i),
+                        y = pos.y,
+                        z = pos.z + chunk.from(j),
+                    }
+                    scanner.queue_region(adjusted_pos);
+                end
+            end
+        end
+    end
+
+    for _ = 1,10 do
+        scanner.scan_regions();
+    end
+    minetest.after(5, fill_loop);
+end
+minetest.after(5, fill_loop);
diff --git a/init.lua b/init.lua
index 1df584a..3909a96 100644
--- a/init.lua
+++ b/init.lua
@@ -8,7 +8,7 @@ local map_data = {
 
     maps = minetest.deserialize(mod_storage:get_string("maps")) or {},
     next_map_id = mod_storage:get_int("next_map_id"),
-}
+};
 
 if map_data.next_map_id == 0 then
     map_data.next_map_id = 1;
@@ -57,6 +57,7 @@ local map_formspec = loadfile(modpath .. "/map_formspec.lua") (map_data, gui, sk
 local map_item = loadfile(modpath .. "/items.lua") (chunk, marker_lookup, gui, skin, audio, maps, map_formspec);
 loadfile(modpath .. "/commands.lua") (chunk, audio, map_formspec);
 loadfile(modpath .. "/table.lua") (gui, skin, audio, maps, materials, map_item);
+loadfile(modpath .. "/autofill.lua") (chunk, scanner);
 
 -- The API object
 cartographer = {
diff --git a/map_api.lua b/map_api.lua
index b45f69f..1ea2f8f 100644
--- a/map_api.lua
+++ b/map_api.lua
@@ -108,40 +108,4 @@ local maps = {
     end,
 }
 
--- Periodically-called function to fill in maps and queue chunks for manual
--- scanning
-local function fill_loop()
-    -- Fill in all player-held maps
-    for _,p in ipairs(minetest.get_connected_players()) do
-        local inventory = p:get_inventory();
-        local pos = p:get_pos();
-        if pos.y > -10 then
-            for i = 1,inventory:get_size("main") do
-                local stack = inventory:get_stack("main", i);
-                local map = maps.get(stack:get_meta():get_int("cartographer:map_id"));
-
-                if map then
-                    map:fill_local(pos.x, pos.z);
-                end
-            end
-            for i = -2,2 do
-                for j = -2,2 do
-                    local adjusted_pos = {
-                        x = pos.x + chunk.from(i),
-                        y = pos.y,
-                        z = pos.z + chunk.from(j),
-                    }
-                    scanner.queue_region(adjusted_pos);
-                end
-            end
-        end
-    end
-
-    for _ = 1,10 do
-        scanner.scan_regions();
-    end
-    minetest.after(5, fill_loop);
-end
-minetest.after(5, fill_loop);
-
 return maps;
diff --git a/material_api.lua b/material_api.lua
new file mode 100644
index 0000000..c3a855d
--- /dev/null
+++ b/material_api.lua
@@ -0,0 +1,56 @@
+local materials_by_name = {};
+local materials_by_group = {};
+
+return {
+    -- Get the converted material value of the given itemstack
+    -- stack: The itemstack to convert
+    --
+    -- Returns a table with the material values
+    get_stack_value = function(stack)
+        local item_name = stack:get_name();
+        local item_count = stack:get_count();
+
+        for name,mats in pairs(materials_by_name) do
+            if name == item_name then
+                return {
+                    paper = (mats.paper or 0) * item_count,
+                    pigment = (mats.pigment or 0) * item_count,
+                }
+            end
+        end
+
+        for group,mats in pairs(materials_by_group) do
+            if minetest.get_item_group(item_name, group) ~= 0 then
+                return {
+                    paper = (mats.paper or 0) * item_count,
+                    pigment = (mats.pigment or 0) * item_count,
+                }
+            end
+        end
+
+        return {
+            paper = 0,
+            pigment = 0,
+        };
+    end,
+
+    register_by_name = function(name, material, value)
+        if materials_by_name[name] then
+            materials_by_name[name][material] = value or 1;
+        else
+            materials_by_name[name] = {
+                [material] = value or 1,
+            };
+        end
+    end,
+
+    register_by_group = function(name, material, value)
+        if materials_by_group[name] then
+            materials_by_group[name][material] = value or 1;
+        else
+            materials_by_group[name] = {
+                [material] = value or 1,
+            };
+        end
+    end,
+};