Factorio Forums

I've been wanting to write a mod gui tutorial, I might as well use your questions as inspiration lol. Basically, there are a few places on the screen where you can put player gui: top, left and center. You can access those with player.gui.center etc.
There is also the mod gui, which adds a flow in the gui.left space for buttons and gui. I'd suggest you to use that. For that you access the button flow using: mod_gui.get_button_flow(player). (You need to do require("mod-gui") at the top of the file). You can access the normal flow, where you will place your gui window using: mod_gui.get_frame_flow(player). To add a gui element, you simply add it to the parent gui, so in your case, the frame flow. Example:

Code: Select all

    local frame_flow = mod_gui.get_frame_flow(player)
    local config_frame = frame_flow.add{
        type = "frame",
        name = "new-game-plus-config-frame",
        direction = "vertical"
    }

You can find the possible types here http://lua-api.factorio.com/latest/LuaGuiElement.html
The name for your gui should be prefixed by your mod name, you share the "namepsace" with all other gui elements from all other mods, so prefixing with your mod name prevents weird interactions.

So, for you "choose an item button" you will need to use the type "choose-elem-button" with its "elem_type" set to "item". That makes that little square where you can choose an item when you click on it. Now, if you add more than one of it to you parent element (config_frame in my code example), it will be under the other one. But you want a 4x4 grid. So, you add a gui of the type table to your parent flow (config_frame) and set it colspan to 4, so that you have four columns. Now you can add 16 of the choose element buttons to that table, and voila, you have a 4x4 grid