Helpers

event_subscribe

Simulation Instrument Studio 1

Overloads

event_subscribe(callback)

Subscribe to global events. E.g., when the instrument or panel is starting, showing or closing.

Parameters

Example

function event_callback(event)
  print("Received event: " .. event)
end

event_subscribe(event_callback)

Example: the sim changed

event_subscribe(function(event)
    if event == "FLIGHT_SIM_CHANGED" then
        visible(flag, not xpl_connected())
    end
end)

geo_rotate_coordinates

Simulation Instrument Studio 1

Overloads

geo_rotate_coordinates(degrees, radius_x, radius_y)

Get the x and y coordinates from a circle with a certain radius and angle.

Parameters

Example

-- Calculate the x and y coordinate on 45 degrees with a radius of 200 pixels
face = img_add("face.png", 100, 100, 200, 200)

x, y = geo_rotate_coordinates(45,200)

move(face, x, y, nil, nil)

-- Calculate the x and y coordinate (oval) on 45 degrees with a radius x of 200 pixels and radius y of 100 pixels
myimage2 = img_add("face.png", 100, 100, 200, 200)

x, y = geo_rotate_coordinates(45,200,100)

move(myimage2, x, y, nil, nil)

has_feature

Simulation Instrument Studio 1

Overloads

has_feature(name)

Has_feature can be used to check if the current version of Studio or Studio supports the asked feature.

Parameters

Example

if has_feature("TIMER") then
  timer_start(0, 100, function()
    print("timer callback")
  end)
end

instrument_prop

Simulation Instrument Studio 1

Overloads

instrument_prop(property)

Returns a value from info.xml. Width and height are the instrument size, not the panel size.

Parameters

Properties

Example

-- Preferred size from info.xml. Do not use the panel size.
w = instrument_prop("PREF_WIDTH")
h = instrument_prop("PREF_HEIGHT")

interpolate_linear

Simulation Instrument Studio 1

Overloads

interpolate_linear(settings, value)
interpolate_linear(settings, value, cap)

Interpolate a value with given settings.

Parameters

Example

-- 0 kt is 0 degrees, 200 kt is 300 degrees
deg = interpolate_linear(ias, {0, 0}, {200, 300})

Example: a table, and a pilot table

-- 0 kt is 0 degrees, 100 kt is 140, 200 kt is 300
local curve = { {0, 0}, {100, 140}, {200, 300} }
local deg = interpolate_linear(curve, 150)

-- Same curve, filled in by the pilot before launch
local prop = user_prop_add_table("Airspeed curve", "Knots against needle degrees", "Knots", "DOUBLE", 0, "Indicated", "Degrees", "DOUBLE", 0, "Needle")
local from_pilot = interpolate_settings_from_user_prop(user_prop_get(prop))
local deg2 = interpolate_linear(from_pilot, 150)

log

Simulation Instrument Studio 1

Overloads

log(message, ...)
log(type, message, ...)

Writes a line to the Studio log.

Parameters

Example

log("altitude " .. alt_ft)

panel_prop

Simulation Instrument Studio 1

Overloads

panel_prop(property)

Get the settings from the current panel.

Parameters

Properties

Example

-- Print the panel author
print( panel_prop("AUTHOR") )

-- See if we started from the create/edit tab
if panel_prop("DEVELOPMENT") then
  print("We are running in development mode!")
end

resource_info

Simulation Instrument Studio 1

Overloads

resource_info(filename)

Resource_info can be used to get information of a resource file. This can also be used to check if a resource exists.

Parameters

Example

-- We are looking for more information about the bla.png image
resource_meta = resource_info("bla.png")

-- Check if the image could be found
if resource_meta == nil then
  print("bla.png not found!")
elseif resource_meta["TYPE"] == "IMAGE" then
  print("bla.png is an image and has w=" .. resource_meta["WIDTH"] .. " h=" .. resource_meta["HEIGHT"])
else
  print("bla.png is not an image!")
end

shut_down

Simulation Instrument Studio 1

Overloads

shut_down(type)

Shut down the application (Studio or Studio) or the system where the instrument runs on.

Parameters

Example

-- Shut down Windows or the Raspberry Pi
shut_down("SYSTEM")

var_cap

Simulation Instrument Studio 1

Overloads

var_cap(value,min,max)

Limit a value to a given minimum and maximum value.

Parameters

Example

-- Keep the needle on the card
deg = var_cap(deg, 0, 360)

var_format

Simulation Instrument Studio 1

Overloads

var_format(value,decimals)

Round a number to a certain number of decimals and always shows that selected amount of decimals.

Parameters

Example

txt_set(alt, var_format(alt_ft, 0))

var_round

Simulation Instrument Studio 1

Overloads

var_round(value,decimals)

Round a number to a certain number of decimals.

Parameters

Example

alt_txt = var_round(alt_ft, 10)

variable_subscribe

Simulation Instrument Studio 1

Overloads

variable_subscribe(source,variable_name,type,...,callback_function)

Subscribe to more different data sources, such as X-Plane, FSX and SI variables.

Example

-- Note that the order in which the variables are given to the variable_subscribe function determines the order in which the variables will enter this function

-- In our case 
-- "sim/cockpit2/gauges/indicators/altitude_ft_pilot" maps to "altitude"
-- "TIME ZULU" maps to "time_seconds"
-- "MY_CUSTOM_VARIABLE" maps to "my_custom_variable"
function callback_function(altitude, time_seconds, my_custom_variable)
  print("Altitude from X-Plane=" .. altitude)
  print("Time seconds from FSX=" .. time_seconds)
  print("My Custom variable from SI=" .. my_custom_variable)
end

-- multi subscribe
variable_subscribe("XPLANE", "sim/cockpit2/gauges/indicators/altitude_ft_pilot",  "FLOAT",
                   "FSX", "TIME ZULU", "Seconds",
                   "SI", "MY_CUSTOM_VARIABLE", "INT", callback_function)

request_callback

Simulation Instrument Studio 1

Overloads

request_callback(callback_function)

Force a callback on a given data subscription (X-Plane, FSX, FS2, FS2020, IIC or external sources).

Parameters

Example

-- This function will be called when new data is available from X-Plane
  function new_altitude_callback(altitude)
    print("New altitude: " .. altitude)
  end

  -- Subscribe X-Plane datarefs
  xpl_dataref_subscribe("sim/cockpit2/gauges/indicators/altitude_ft_pilot", "FLOAT", new_altitude_callback)

  -- Force a callback. The 'new_altitude_callback' function will be called here with its current arguments.
  request_callback(new_altitude_callback)