Hi! I noticed a lot of on_entity_color_changed events being raised in a saved game I received for debugging one of my own mods. While it's great that we can get informed about entities changing their color, the implementation isn't optimal: The event will be raised each time LuaEntity::color is set -- even if the new color is the same as the old one!

In my own mods, I make sure that old color and new color differ before setting LuaEntity::color, using something like this:

  -- Get color from name, hex, or table
  ascertain_color = function(color)

    assert(color, {"table", "string", "nil"}, "color, string, or nil")

    local ret
    local c = type(color)
    -- Named colors or hex colors
    if c == "string" then
      ret = color:match("^#*[0-9a-fA-F]+$") and util.color(color)
      if ret then
        ret.a = 1
      end

    -- Lua color
    elseif c == "table" then
      -- Make sure we've got a table that only contains valid color data (empty table,
      -- named keys, or index 1…4)!
      if next(color) then
        -- Make a copy of the color table, then remove all valid keys from it
        local copy = table.deepcopy(color)
        for _, i in pairs({1, 2, 3, 4, "r", "g", "b", "a"}) do
          copy[i] = nil
        end

        -- If the copied table is not empty, the input wasn't a valid color!
        if next(copy) then
          return
        end
      end

      ret = {
        r = color.r or color[1] or 0,
        g = color.g or color[2] or 0,
        b = color.b or color[3] or 0,
        a = color.a or color[4] or 1,
      }
    end

    return ret
  end

  -- Compare two colors. Returns true if the colors are the same
  compare_colors = function(c1, c2)

    c1 = ascertain_color(c1)
    c2 = ascertain_color(c2)

    return c1 and c2 and util.table.compare(c1, c2)
  end

It would be great if you'd add such checks as well. :-)

Thanks, I'll look into this for the 2.0 update