GS13NG/tgui

• tgui
  • Concepts
  • Using It
  • Copypasta

tgui

tgui is the user interface library of /tg/station. It is rendered clientside, based on JSON data sent from the server. Clicks are processed on the server, in a similar method to native BYOND Topic().

Basic tgui consists of defining a few procs. In these procs you will handle a request to open or update a UI (typically by updating a UI if it exists or setting up and opening it if it does not), a request for data, in which you build a list to be passed as JSON to the UI, and an action handler, which handles any user input. In addition, you will write a HTML template file which renders your data and provides actionable inputs.

tgui is very different from most UIs you will encounter in BYOND programming, and is heavily reliant of Javascript and web technologies as opposed to DM. However, if you are familiar with NanoUI (a library which can be found on almost every other SS13 codebase), tgui should be fairly easy to pick up.

tgui is a fork of NanoUI. The server-side code (DM) is similar and derived from NanoUI, while the clientside is a wholly new project with no code in common.

Concepts

tgui is loosely based a MVVM architecture. MVVM stands for model, view, view model.

• A model is the object that a UI represents. This is the atom a UI corresponds to in the game world in most cases, and is known as the src_object in tgui.
• The view model is how data is represented in terms of the view. In tgui, this is the ui_data proc which munges whatever complex data your src_object has into a list.
• The view is how the data is rendered. This is the template, a HTML (plus mustaches and other goodies) file which is compiled into the tgui blob that the browser executes.

Not included in the MVVM model are other important concepts:

• The action/topic handler, ui_act, is what recieves input from the user and acts on it.
• The request/update proc, ui_interact is where you open your UI and set options like title, size, autoupdate, theme, and more.
• Finally, ui_states (set in ui_interact) dictate under what conditions a UI may be interacted with. This may be the standard checks that check if you are in range and conscious, or more.

States are easy to write and extend, and what make tgui interactions so powerful. Because states can over overridden from other procs, you can build powerful interactions for embedded objects or remote access.

Using It

All these examples and abstracts sound great, you might say. But you also might say, "How do I use it?"

Examples can be as simple or as complex as you would like. Let's start with a very basic hello world.

/obj/machinery/my_machine/ui_interact(mob/user, ui_key = "main", datum/tgui/ui = null, force_open = 0, datum/tgui/master_ui = null, datum/ui_state/state = default_state)
  ui = SStgui.try_update_ui(user, src, ui_key, ui, force_open)
  if(!ui)
    ui = new(user, src, ui_key, "my_machine", name, 300, 300, master_ui, state)
    ui.open()

This is the proc that defines our interface. There's a bit going on here, so let's break it down. First, we override the ui_interact proc on our object. This will be called by interact for you, which is in turn called by attack_hand (or attack_self for items). ui_interact is also called to update a UI (hence the try_update_ui), so we accept an existing UI to update. The state is a default argument so that a caller can overload it with named arguments (ui_interact(state = overloaded_state)) if needed.

Inside the if(!ui) block (which means we are creating a new UI), we choose our template, title, and size; we can also set various options like style (for themes), or autoupdate. These options will be elaborated on later (as will ui_states).

After ui_interact, we need to define ui_data. This just returns a list of data for our object to use. Let's imagine our object has a few vars:

/obj/machinery/my_machine/ui_data(mob/user)
  var/list/data = list()
  data["health"] = health
  data["color"] = color

  return data

The ui_data proc is what people often find the hardest about tgui, but its really quite simple! You just need to represent your object as numbers, strings, and lists, instead of atoms and datums.

Finally, the ui_act proc is called by the interface whenever the user used an input. The input's action and params are passed to the proc.

/obj/machinery/my_machine/ui_act(action, params)
  if(..())
    return
  switch(action)
    if("change_color")
      var/new_color = params["color"]
      if(!(color in allowed_coors))
        return
      color = new_color
      . = TRUE
  update_icon()

The ..() (parent call) is very important here, as it is how we check that the user is allowed to use this interface (to avoid so-called href exploits). It is also very important to clamp and sanitize all input here. Always assume the user is attempting to exploit the game.

Also note the use of . = TRUE (or FALSE), which is used to notify the UI that this input caused an update. This is especially important for UIs that do not auto-update, as otherwise the user will never see their change.

Finally, you have a template. This is also a source of confusion for many new users. Some basic HTML knowledge will get you a long way, however.

A template is regular HTML, with mustache for logic and built-in components to quickly build UIs. Here's how we might show some data (components will be elaborated on later).

In a template there are a few special values. config is always the same and is part of core tgui (it will be explained later), data is the data returned from ui_data, and adata is the same, but with certain values (numbers at this time) interpolated in order to allow animation.

<ui-display>
  <ui-section label='Health'>
    <span>{{data.health}}</span>
  </ui-section>
  <ui-section label='Color'>
    <span>{{data.color}}</span>
  </ui-section>
</ui-display>

Templates can be very confusing at first, as ternary operators, computed properties, and iterators are used quite a bit in more complex interfaces. Start with the basics, and work your way up. Much of the complexity stems from performance concerns. If in doubt, take the simpler approach and refactor if performance becomes an issue.

Copypasta

We all do it, even the best of us. If you just want to make a tgui fast, here's what you need (note that you'll probably be forced to clean your shit up upon code review):

/obj/copypasta/ui_interact(mob/user, ui_key = "main", datum/tgui/ui = null, force_open = 0, datum/tgui/master_ui = null, datum/ui_state/state = default_state) // Remember to use the appropriate state.
  ui = SStgui.try_update_ui(user, src, ui_key, ui, force_open)
  if(!ui)
    ui = new(user, src, ui_key, "copypasta", name, 300, 300, master_ui, state)
    ui.open()

/obj/copypasta/ui_data(mob/user)
  var/list/data = list()
  data["var"] = var

  return data

/obj/copypasta/ui_act(action, params)
  if(..())
    return
  switch(action)
    if("copypasta")
      var/newvar = params["var"]
      var = Clamp(newvar, min_val, max_val) // Just a demo of proper input sanitation.
      . = TRUE
  update_icon() // Not applicable to all objects.

And the template:

<ui-display title='My Copypasta Section'>
  <ui-section label='Var'>
    <span>{{data.var}}</span>
  </ui-section>
  <ui-section label='Animated Var'>
    <span>{{adata.var}}</span>
  </ui-section>
</ui-display>