Widget Scripts

Overview

Most of the time, widget scripts show some info in a zone either in the top bar or in one of the user defined main views, and they cannot receive direct input from the user via key events like e.g. Telemetry scripts.
But widgets on the main views can also be shown in full screen mode, where they take over the entire screen area. And here they receive user input via key events, and for radios with touch screen, also touch events. Full screen mode can be entered by selecting the widget, pressing ENTER and selecting Full screen on the widget menu, or by double tapping the widget on radios with a touch screen. Full screen mode can be exited by long pressing the RETURN button, or by calling the Lua function lcd.exitFullScreen().
Each model can have up to five main views, with up to 8 widgets per screen, depending on their size and layout. Each instance of a widget has his own options table.
Please note: Widget scripts are only available on radios with color screens, e.g. FrSky Horus models, Radiomaster TX16 and Jumper T16.

Lifetime

All widget scripts on the SD card are loaded into memory when the model is selected; even widgets that are not used. This has the side effect that any global functions defined in a widget script will always be available to other widget scripts. It also means that any script on the SD card will consume part of the radio's memory - even if it is not being used. Therefore, it is important to either keep widget scripts small, or to use Lua's loadScript() function to load code dynamically.
They can be added to the top bar or a main view through the telemetry setup menu. When a widget has been added to a screen, then the widget functions are called as follows:
  • create is called once when the widget instance is registered (started).
  • update is called when widget settings are changed by the user.
  • background is called periodically when the widget instance is not visible. Note: this is different from the way that telemetry scripts are handled.
  • refresh is called periodically when the widget instance is visible. Note: if you want background to run when the widget is visible, then call it from refresh.
  • A widget script is stopped and disabled if it misbehaves (e.g. too long runtime, run-time error, or low memory)
  • All widgets are stopped while a One-Time script is running (see One-Time scripts).

File Location

Widgets are located on the SD card, each in their specific folder /WIDGETS/<name>/main.lua (<name> must be in 8 characters or less).

Interface

Every script must include a return statement at the end, defining its interface to EdgeTX. This statement returns a table with the following fields:
  • name string
  • options table
  • create function
  • update function
  • background function (optional)
  • refresh function

Example

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local name = "WidgetName"
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-- Create a table with default options
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-- Options can be changed by the user from the Widget Settings menu
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-- Notice that each line is a table inside { }
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local options = {
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{ "Source", SOURCE, 1 },
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-- BOOL is actually not a boolean, but toggles between 0 and 1
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{ "Boolean", BOOL, 1 },
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{ "Value", VALUE, 1, 0, 10},
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{ "Color", COLOR, ORANGE },
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{ "Text", STRING, "Max8chrs" }
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}
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local function create(zone, options)
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-- Runs one time when the widget instance is registered
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-- Store zone and options in the widget table for later use
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local widget = {
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zone = zone,
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options = options
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}
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-- Add local variables to the widget table,
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-- unless you want to share with other instances!
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widget.someVariable = 3
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-- Return widget table to EdgeTX
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return widget
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end
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local function update(widget, options)
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-- Runs if options are changed from the Widget Settings menu
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widget.options = options
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end
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local function background(widget)
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-- Runs periodically only when widget instance is not visible
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end
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local function refresh(widget, event, touchState)
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-- Runs periodically only when widget instance is visible
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-- If full screen, then event is 0 or event value, otherwise nil
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end
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return {
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name = name,
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options = options,
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create = create,
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update = update,
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refresh = refresh,
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background = background
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}
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Notes

  • The name must be max. 10 characters long.
  • options is passed to create and then stored in Lua. Changing it has no effect on EdgeTX.
  • If options is changed by the user in the Widget Settings menu, then update will be called with a new options table, unaffected by any changes made by Lua code to the old options table.
  • Maximum five options are allowed, with names of max. 10 characters, and no spaces.
  • If local variables are declared outside functions in the widget script, then they are shared between all instances of the widget.
  • Therefore, local variables that are private for each instance should be added to the widget table in the create function before returning the widget table to EdgeTX.
  • When the widget is in full screen mode, then event is either 0, a key event value, or a touch event value.
  • If event is a touch event value, then touchState is a table. Otherwise, it is nil.
  • When the widget is not in full screen mode, then both event and touchState are nil.
  • The size of the widget's screen area is as follows:
    • Full screen mode: LCD_W by LCD_H
    • Not full screen mode: zone.w by zone.h