cartographer/items.lua

local function map_from_meta(meta, player_x, player_y)
    local size = meta:get_int("cartographer:size") or 10;
    local detail = meta:get_int("cartographer:detail") or 1;
    local scale = meta:get_int("cartographer:scale") or 1;

    local total_size = size * scale;

    local map_x = math.floor((player_x + 10)/total_size) * total_size - 10
    local map_y = math.floor((player_y + 10)/total_size) * total_size - 10;

    local id = cartographer.create_map(map_x, map_y, size, size, false, detail, scale);

    meta:set_int("cartographer:map_id", id);
    meta:set_string("description", "Map #" .. tostring(id) .. "\n[" .. tostring(fromchunk(map_x)) .. "," .. tostring(fromchunk(map_y)) .. "] - [" .. tostring(fromchunk(map_x + total_size)) .. "," .. tostring(fromchunk(map_y + total_size)) .. "]")

    return id;
end

-- The map item/node
minetest.register_node("cartographer:map", {
    description = "Map",
    inventory_image = "cartographer_map.png",
    tiles = { "cartographer_map.png" },
    drawtype = "signlike",
    paramtype = "light",
    paramtype2 = "wallmounted",
    stack_max = 1,
    on_use = function(stack, player, _)
        local pos = player:get_pos();
        local name = player:get_player_name();

        local player_x = tochunk(pos.x);
        local player_y = tochunk(pos.z);

        local meta = stack:get_meta();
        local id = meta:get_int("cartographer:map_id");
        if id == 0 then
            id = map_from_meta(meta, player_x, player_y);
        end

        cartographer.fill_local(id, player_x, player_y);

        minetest.show_formspec(player:get_player_name(), "map", cartographer.get_map_formspec_map(data, cartographer.get_map(id), player_x, player_y));

        return stack;
    end,

    -- Called when this node is placed in the world. Copies map data from the
    -- item to the node.
    -- pos: The position of the node
    -- placer: The object that placed this node (can be nil)
    -- stack: The itemstack that was placed
    -- pointed_thing: The current pointed thing
    after_place_node = function(pos, placer, stack, pointed_thing)
        local meta = stack:get_meta():to_table();
        local node_meta = minetest.get_meta(pos);
        node_meta:from_table(meta);

        -- Consume the item after placing
        return false;
    end,

    on_rightclick = function(pos, node, player, itemstack, pointed_thing)
        local meta = minetest.get_meta(pos);

        local player_x = tochunk(pos.x);
        local player_y = tochunk(pos.z);

        local id = meta:get_int("cartographer:map_id");
        if id == 0 then
            id = map_from_meta(meta, player_x, player_y);
        end

        cartographer.fill_local(id, player_x, player_y);

        minetest.show_formspec(player:get_player_name(), "map", cartographer.get_map_formspec_map(data, cartographer.get_map(id), player_x, player_y));
    end,
});

function cartographer.create_map_item(size, detail, scale)
    local map = ItemStack("cartographer:map");
    local meta = map:get_meta();
    meta:set_int("cartographer:size", size);
    meta:set_int("cartographer:detail", detail);
    meta:set_int("cartographer:scale", scale);
    meta:set_string("description", "Empty Map\nUse to set the initial location");

    return map;
end

function cartographer.copy_map_item(stack)
    local meta = stack:get_meta();

    local size = meta:get_int("cartographer:size");
    local detail = meta:get_int("cartographer:detail");
    local scale = meta:get_int("cartographer:scale");

    local copy = cartographer.create_map_item(size, detail, scale);
    local copy_meta = copy:get_meta();

    local id = meta:get_int("cartographer:map_id");
    local new_id = 0;
    if id > 0 then
        local src = cartographer.get_map(id);

        new_id = cartographer.create_map(src.x, src.z, src.w, src.h, false, src.detail, src.scale);
        local dest = cartographer.get_map(new_id);
        for k,v in pairs(src.fill) do
            dest.fill[k] = v;
        end

        copy_meta:set_int("cartographer:map_id", new_id);
        copy_meta:set_string("description", "Map #" .. tostring(new_id) .. "\n[" .. tostring(fromchunk(dest.x)) .. "," .. tostring(fromchunk(dest.z)) .. "] - [" .. tostring(fromchunk(dest.x + dest.w)) .. "," .. tostring(fromchunk(dest.z + dest.h)) .. "]")
    end

    return copy;
end

function cartographer.resize_map_item(meta, size)
    local old_size = meta:get_int("cartographer:size");

    if old_size >= size then
        return;
    end

    meta:set_int("cartographer:size", size);

    local id = meta:get_int("cartographer:map_id");
    if id > 0 then
        local map = cartographer.get_map(id);
        cartographer.resize_map(id, size, size);

        meta:set_string("description", "Map #" .. tostring(id) .. "\n[" .. tostring(fromchunk(map.x)) .. "," .. tostring(fromchunk(map.z)) .. "] - [" .. tostring(fromchunk(map.x + map.w)) .. "," .. tostring(fromchunk(map.z + map.h)) .. "]")
    end
end