gre.SCRIPT_ROOT
                    

This is a variable that is filled in by the Storyboard Engine to contain the value of the project's scripts directory.

The gre.SCRIPT_ROOT variable provides a convenient way to reference the file resources in a location independent, project relative, fashion. When used in conjunction with the gre.env() function, the gre.SCRIPT_ROOT can provide an effective way to configure the search path for extra Lua modules.

 local data_file = gre.SCRIPT_ROOT .. "/input_data.csv"
                    

 gre.set_data(
    table
 )
            

Sets one or more items in the Storyboard application's data manager.  Each index and value in the table passed in will be set in the data manager using the index’s name as the key.

function lua_func( mapargs )
  local data_table  = {}
  data_table["variable_name"] = "variable data"
  gre.set_data( data_table )
end
            

gre.get_data(
    key
    [, key2, ...]
)
            

Gets one or more values from the data manager. Each argument to the function is interpreted as a data manager key whose value should be extracted from the data manager. This function returns a table using all the values as indexes and the corresponding value is the data returned from the data manager. A nil is returned for any values that do not match a key in the data manager.

function get_data_fuc( mapargs )
  --When accessing control variables, use the following qualified
  --model path Layer.Control.Variable
  local data_table = gre.get_data("my_layer.my_control.variable_name")
  local value = data_table["my_layer.my_control.variable_name"]
  print("control_variable_name = " .. tostring(value))
end
            

function get_control_width( mapargs )
	--This will extract the width (grd_width) of the contro
    --'my_control' on the layer 'my_layer'
	local data = gre.get_data("my_layer.my_control.grd_width")
	local value = data["my_layer.my_control.grd_width"]
	print("The width of the control is " .. tostring(value))
end
            

gre.set_value(
	key,
	value
	[, key2, value2, ...]
)
            

Set a variable in the data manager to a particular value. This function is a convenience function on top of gre.set_data that allows the key and value to be passed as a set of arguments to the function instead of having to create a table containing the key/value pairs.

function lua_func( mapargs )
  -- Assign the string 'variable_data' to the application variable
  -- 'variable_name'
  -- This example is the same as gre.set_data()
  gre.set_value("variable_name", "variable_data")
end
            

gre.get_value(
	key
	[, key2, ...]
)
            

Get the value of a variable from the data manager. This function is a convenience function on top of gre.get_data that allows the value to be returned directly to the caller instead of a single table return value. A nil is returned for any values that do not match a key in the data manager.

function get_control_width( mapargs )
	-- This will extract the width of the control 'my_control'
    -- on the layer 'my_layer'
	-- This is the same example as gre.get_data()
	local value = gre.get_value("my_layer.my_control.grd_width")
	print("The width of the control is " .. tostring(value))
end
            

gre.send_event(
    event_name,
    [channel]
)
            

Send an event to the application or to a Storyboard IO channel.  channel is an optional parameter and if channel is not passed then the channel will be chosen as follows:

If the environment variable GREIONAME is set then it will be used otherwise the default channel is used.

-- Send to the event  to the application :
gre.send_event("my_event")

--To send the event to a Storyboard IO channel via parameters:
gre.send_event("my_event", “io_channel_name”)
            

gre.send_event_target(
    event_name,
    target,
    [channel]
)
            

Send an event to a targeted model element (control, layer instance or screen) using the model's fully qualified path. The channel is an optional parameter.

-- Send to the event directed at a particular control target:
gre.send_event("my_event", "my_layer.my_control")
            

gre.send_event_data (  
    event_name,
    format_string,
    data,
    [channel]
)
            

Send an event with custom data to the application or to a Storyboard IO channel. The data parameter is a Lua table where the indexes match the values from the format string. channel is an optional parameter.

Special consideration is required for sending data that is to be formatted as an array (ie N[suf]M where M is greater than 0). In this case the data entry should be provided as a Lua table and not as a raw value parameter.

-- Send a 'int32_update' event with a 32bit signed integer (int32_t)
-- payload to the 'controller' channel
function send_integer(value) 
	loca  format = "4s1 value"
	local data = {}
	data["value"] = value
	gre.send_event_data("int32_update", format, data, "controller") 
end

-- Send a 'int16_update' event with two 16bit signed integers (int16_t)
-- payload to the 'controller' channel
function send_two_integers(value1, value2) 
	loca  format = "2s1 first 2s1 second"
	local data = {}
	data["first"] = value1
	data["second"] = value2
	gre.send_event_data("int16_update", format, data, "controller") 
end

-- Send an 'array_update' event with an array of int32_t numbers (provided
-- as a table) to the client
function send_integer_array(values)
	-- Generate the format string dynamically based on the number of entries
	local count = #values
	local format = string.format("4s%d values", count)
	local data = {}
	data["values"] = values
	gre.send_event_data("array_update", format, data, "controller") 
end

send_integer(12)
send_two_integers(10, 20)
send_integer_array({10, 20, 30, 40})

gre.receive_event(
    channel
)
            

Receive an event from a Storyboard IO channel.  This is a blocking call and works best when used on a separate Lua thread.

-- Receive a Storyboard IO event with data payload x, y, z:
ev = gre.receive_event("my_channel")

if ev ~= nil then
    print(ev.name)

    for k,v in pairs(ev.data) do
        print(tostring(k).." "..tostring(v))
    end
end

--To disconnect from my_channel:
gre.greio_disconnect("my_channel", true)
            

gre.greio_disconnect(
    channel,
    [is_receive_channel]
)
		    

This function forces any cached Storyboard IO channel connections to the specified channel to be closed. Subsequent calls using the same channel name will re-establish the connection to the channel if required.

-- Send an event to a custom channel
gre.send_event("StoryboardRocks", "my_channel")
-- Close the cached connection to that channel
gre.greio_disconnect("my_channel")
            

gre.touch(
    x ,
    y,
    [channel]
)
            

Send a touch event to the application at the co-ordinates passed in through the parameters.  channel is an optional parameter

gre.key_up(
    code,
    [channel]
)
            

Send a key_up event to the application with the scancode passed in the parameters. channel is an optional parameter

gre.key_down(
    code,
    [channel]
)
            

Send a key_down event to the application with the scancode passed in the parameters. channel is an optional parameter

gre.key_repeat(
    code,
    [channel]
)
            

Send a key_repeat event to the application with the scancode passed in the parameters. channel is an optional parameter

gre.redraw(
    x,
    y,
    width,
    height,
    [channel]
)
            

Force a screen redraw.  channel is an optional parameter. Specifying a x,y,width,height of 0 will result in a full screen refresh occurring.

gre.quit(
    [channel]
)
            

Send QUIT event to application to force shutdown.  channel is an optional parameter.

-- Send a quit message to the application
gre.quit()
            

gre.move_layer(
    layer_name,
    dx,
    dy,
    x,
    y
)
            

Move a layer to a new position.  The layer_name is the name of the layer or a variable that is associated with the layer name. Setting dx or dy will move the layer by the specified delta from its current position. The  dx and dy values can be 0 to set an absolute position using the x and y values only.

gre.move_control(
    control_name,
    dx,
    dy,
    x,
    y
)
            

Move a controls to a new position.  The control_name is the name of the control or a variable.  Setting dx and or dy will move the layer by the specified delta from its current position.  The  dx and dy values can be 0 to set an absolute position using the x and y values only.

gre.clone_control(
    reference_control_name,
    new_control_name,
    layer_name,
    data
)
            

Create a new control (new_control_name) on an existing layer (layer_name) by copying all of the properties of an existing control (reference_control_name). This new control will have all of the same actions, variables and it's current state will match the state of the reference control that is being copied.

The data argument is a table of control attributes that match the attributes available in the gre.set_control_attrs() function, for example x, y, width, height, hidden

function create_new_control()
  local data = {}
  data["x"] = 10
  data["y"] = 10
  gre.clone_control("my_control", "my_new_control", "my_layer", data)       
end
            

gre.delete_control(
    control_name,
)
            

Delete a control from the model. The control must be a control which was dynamically created with the gre.clone_control() function.

function delete_control()
  gre.delete_control("my_control")       
end
            

gre.get_control_attrs(
    control_name
    tags ...
)
            

Get attributes for a control.  Key name is the name of the control or a variable.  Tags can be a list of the following values:

        x, y, width, height, hidden, active, zindex, findex

A table with the results is returned.

function check_if_hidden()
  local dk_data = {}
  -- check if my_control is currently hidden
  dk_data = gre.get_control_attrs("my_control", "hidden")
  if dk_data["hidden"] == 1 then
    print("my_control is currently hidden")
  else
    print("my_control is currently visible")
  end
end
            

gre.set_control_attrs(
    control_name,
    tag_table
)
            

Set attributes for a control.  The control_name is the name of the control or a variable. The tag_table contains the tags and values for the attributes to set.

        x,  y, width, height, hidden, active, zindex, findex, effect

In the case of the focus index (findex), the initial value set in Storyboard Designer must be non-zero in order for it to be changed dynamically at runtime

function set_control_hidden()
  local dk_data = {}
  dk_data["hidden"] = 1
  gre.set_control_attrs("my_control", dk_data)       
end
            

function set_control_blur_effect()
  local dk_data = {}
  local effect = {}
 
  effect["name"] = "blur"
  effect["passes"] = 3
  effect["radius"] = 1
  effect["composite"] = true
 
  dk_data["effect"] = effect
  gre.set_control_attrs("my_control", dk_data)
end
                        
                    

 gre.get_layer_attrs(
    layer_name
    tags...
 )
            

Get attributes for a layer instance associated with a particular screen.   The layer_name specifies either the fully qualified name of a layer instance using the ScreenName.LayerName naming convention or, if only the layer name is specified, the name will refer to a layer instance associated with the current screen

The tags are a list of string attributes associated with the layer instance and can include one or more of the following values:

        x, y, alpha, hidden, active, zindex, xoffset, yoffset

A table containing the keys and their respective values is returned or nil if the layer can not be found.

function check_if_hidden()
  -- check if my_layer is currently hidden
  local data = gre.get_layer_attrs("my_layer", "hidden")
  if data.hidden == 1 then
    print("my_layer is currently hidden")
  else
    print("my_layer is currently visible")
  end
end
            

gre.set_layer_attrs(
    layer_name,
    tag_table
)
            

Set attributes for a layer instance associated with a particular screen.   The layer_name specifies either the fully qualified name of a layer instance using the ScreenName.LayerName naming convention or, if only the layer name is specified, the name will refer to a layer instance associated with the current screen

        alpha, hidden, active, x, y, zindex, width, height, xoffset, yoffset

function set_layer_hidden()
  local data = {}
  data.hidden = 1
  gre.set_layer_attrs("my_layer", data)       
end
            

gre.set_layer_attrs_global(
    layer_name,
    table
)
            

Set attributes for a layer globally on all instances of the layer on all screens.  The layer_name is the name of the layer.  Table contains the tags and values for the attributes to set.

        alpha, hidden, active, x, y, width, height

gre.get_table_attrs(
    table_name,
    tags
)
            

Get attributes for a table.  Key name is the name of the control or a variable.  Tags can be any of the control tags mentioned in section 6.1.12 and any of the following values:

function check_if_hidden()
  local dk_data = {}
  -- Get the active row/column
  dk_data = gre.get_table_attrs("my_table", "active_row", "active_col")
  print("Active Cell: " .. tostring(dk_data["active_row"] .. ","
  .. tostring(dk_data["active_col"]))
end
            

gre.set_table_attrs(
    table_name,
    tag_table
)
            

Set attributes for a table.  The table_name is the name of the control or a variable. The tag_table contains the tags and values for the attributes to set.

        x,  y, width, height, hidden, active, rows, cols, xoffset, yoffset

function resize_table()
  local dk_data = {}
  dk_data["rows"] = 5
  dk_data["cols"] = 10
  gre.set_table_attrs("my_table", dk_data)       
end
            

gre.get_table_cell_attrs(
    table_name,
    row,
    col,
    tags ...
)
            

Get attributes for a table cell.  table_name is the name of the table.  Tags can be a list of the following values:

        x, y, width, height, hidden

A table with the results is returned.

function check_if_hidden()
  local dk_data = {}
  -- check if my_control is currently hidden
  dk_data = gre.get_table_cell_attrs("my_table", 1, 1, "hidden")
  if dk_data["hidden"] == 1 then
    print("cell 1.1 of my_table is currently hidden")
  else
    print("cell 1.1 of my_table is currently visible")
  end
end
            

gre.get_string_size(
    font,
    font_size,
    string,
    length,
    width
)
            

Calculate the area in pixels which the given string will occupy on the screen. Optionally calculate how many characters can fit into a predefined screen area.

gre.poly_string(
    x_values,
    y_values
)
  or
gre.poly_string(
    {{x=, y=}, ...}
)
            

This is a higher performance function for generating a polygon string based on a set of numeric data points maintained in Lua table arrays.

In the two argument form, the function receives as inputs two Lua tables whose content represents the numeric x and y data points to be converted to a string. The tables are 1 based arrays and must be of the same length.

In the single argument form, the function receives as input a single Lua table whose array content are tables with an "x" and "y" member value.

The string returned is designed to be compatible with the Storyboard polygon plugin and is in the form of X1:Y1 X1:Y2 ...

-- Create a triangle polygon in a 100x100 square
local x_points = { 0, 50, 100 }         -- Left, Middle, Right
local y_points = { 100, 0, 100 }        -- Bottom, Top, Bottom
local x_y_string = gre.poly_string(x_points, y_points)
print("X Y String: " .. x_y_string)

-- Create the same triangle, but with x,y member variables
local xy_points = { {x=0,y=100}, {x=50,y=0}, {x=100,y=100} }
local xy_string = gre.poly_string(xy_points)
print("XY String: " .. xy_string)
                

gre.resolve_data_key(
    key1
    [, key2, ...]
)
		    

This function allows Lua scripts to resolve Storyboard context variables to a fully qualified name based on the current execution context.

-- Resolve the application my_var to a fully qualified name
local varname = "${app:my_var}"
local dv = gre.resolve_data_key(varname)
print("Full path for ${app:my_var} is " .. dv[varname])
		    

gre.load_resource(
    pool_name,
    resource_name,
    [pool parameters]
)
		    

This function will force the loading of a resource, such as an image or font, into the Storyboard application. This can be used in order to avoid load time delays that may be incurred as resources are lazy loaded into the application.

-- Call this on app init to pre-load the image and font into the cache
function on_app_init(mapargs)
    gre.load_resource("image", "images/tree.jpg")
    gre.load_resource("font", "fonts/DejaVu.ttf")
-- Call this on app init to pre-load the image and scale it to 100x100
    gre.load_resource("image", "images/scaledtree.jpg", 100, 100)
    local tbl = {}
    tbl["w"]=100
    tbl["h"]=100
    tbl["background"]=1
-- Call this on app init to pre-load the image and scale it to 100x100
-- asynchronously
    gre.load_resource("image", "images/scaledtreebg.jpg", tbl)
end
            

gre.load_image(
    image_name,
    [optional table of parameters]
)
		    

This function will force the loading of an image into the Storyboard application. This can be used in order to avoid load time delays that may be incurred as resources are lazy loaded into the application.

gre.dump_resource(
    pool_name,
    resource_name
)
		    

This function performs the opposite of the gre.load_resource call and removes a resource from the specified resource pool cache.

-- Force the tree.jpg image out of the cache, image will reload as required
function flush_tree_image()
    gre.dump_resource("image", "images/tree.jpg")
    gre.dump_resource("font", "fonts/DejaVu.ttf")
end
            

gre.walk_pool(
    pool_name,
)
		    

This function reports on the memory used by all of the resources loaded into a particular resource pool.

-- Display the content of the current image cache
function show_image_cache(mapargs)
    print("Images")
    local data = gre.walk_pool("image")
    for k,v in pairs(data) do
        print("  ".. tostring(k) .. "=" .. tostring(v))
    end
end
            

gre.timer_set_timeout(
    function,
    timeout
)
		    

This function creates a one-shot timer which fires after "timeout" milliseconds and then executes "function"

local idval = {}
function cb_func()
	print("CB FUNC HAS BEEN CALLED")
end

--Call cb_func after 1 second
function cb_set_timeout()
	idval = gre.timer_set_timeout(cb_func, 1000)
end
            

gre.timer_set_interval(
    function,
    interval
)
		    

This function creates a repeating timer which fires every "interval" milliseconds and then executes "function"

local idval = {}
function cb_func()
	print("CB FUNC HAS BEEN CALLED")
end

--Call cb_func every 2 seconds
function cb_set_interval()
	idval = gre.timer_set_interval(cb_func, 2000)
end
            

gre.timer_clear_timeout(
    id
)
		    

This function stops an existing timer from firing

local idval = {}
function cb_func()
	print("CB FUNC HAS BEEN CALLED")
end

--Call cb_func after 5 seconds
function cb_set_timeout()
	idval = gre.timer_set_timeout(cb_func, 2000)
end

function cb_clear_timeout()
	local data

	data = gre.timer_clear_timeout(idval)
end
            

gre.timer_clear_interval(
    id
)
		    

This function stops an existing timer from firing

local idval = {}
function cb_func()
	print("CB FUNC HAS BEEN CALLED")
end

--Call cb_func every 5 seconds
function cb_set_interval()
	idval = gre.timer_set_interval(cb_func, 2000)
end

function cb_clear_interval()
	local data

	data = gre.timer_clear_interval(idval)
end
            

gre.thread_create(func)
		    

This function starts a new operating system thread of execution that is independent from Storyboard's main thread. The function provided as an argument indicates the starting context for this new thread of execution.

The Storyboard data and event (get_data/set_data/send_event) API are thread safe. However the execution of data changes outside of the main thread of execution can have a significant impact on performance of the application and the preferred way of synchronizing data obtained in a thread with the Storyboard UI thread is by using a Storyboard IO event and sending the data via gre.send_event or gre.send_event_data. There are no thread specific synchronization primitives, such as mutexes, for synchronizing Lua data access, serialize to the main thread using an event if this is a requirement.

In scenarios where a controlled shutdown and restart of a Storyboard application is required, separate threads of execution pose a synchronization challenge. In these situations all created thread(s) must have their execution interrupted and terminate in order for a clean shutdown to be observed. This can be accomplished nominally by intercepting the gre.quit event and then taking appropriate action to flag a shutdown variable or send an unblocking event.

This function is not available on all systems and is not available if gre.thread_create is set to nil.

-- Flag to indicate that we want our threads to quit executing
local quit_threads = false

-- Run a poll loop waiting for a file (a_file) to appear and
-- then send an event
function async_function()
	while(not quit_threads) do
		local fp = io.open("a_file")
		if(fp ~= nil) then
			fp:close()
			gre.send_event("file_created")
			return
		end
	end
end

-- Create the monitoring thread of execution
gre.thread_create(async_function)
		    

gre.vfs_open(filename)
		    

This function provides read-only file access to resources packaged in the Storyboard virtual filesystem for embedded targets with no filesystem support. The function works similarly to the Lua io.open() and returns a FILE type object based on a project relative path. The returned object provides the file:read(), file:lines(), file:seek() and file:close() operations as described in the standard Lua documentation.

The use of this function can incur significant memory overhead if large files are read entirely into memory.

This function is not available on all systems and is not available if gre.vfs_open is set as nil.

-- Use a simple CSV parser that assumes a single delimiter between
-- variable and value
function load_translation()
	local fp = gre.vfs_open("translations/french.csv")
	if(fp ~= nil) then
		local comma, var, value
		for l in fp:lines()
		do
			comma = string.find(l, ',', 0, true)
			if(comma ~= nil)
			then
				var = string.sub(l, 1, comma - 1)
				value = string.sub(l, comma + 1)
				gre.set_data({ [var] = value })
			end
		end
		fp:close()
	end
end
		    

gre.mstime()
gre.mstime(app_relative)
		    

Retrieve the current time in milliseconds in the default, no argument flavour. This call provides a higher resolution than the standard Lua os.clock()or os.date() functions.

When true is passed in as an argument, then the time returned will be relative to the application start time and aligned with the timestamps that are generated by the Storyboard logging API.

-- Time an operation
local s = gre.mstime()
my_function()
local e = gre.mstime()
print("my_function took " .. tostring(e - s) .. "ms")

-- Determine how long from app start to this point
local delta = gre.mstime(true)
print(string.format("Application start to now: %d ms", delta)
		    

gre.env(
    string_key
)
or
gre.env(
    table
)
		    

Return information about the Storyboard runtime environment. The input can be either a single string containing the key to look up or a table of keys for variables to match. The following table describes the available keys:

-- Get the target OS for dynamic module loading
local os = gre.env("target_os")
print("Running on target OS: " .. tostring(os))

-- Report on the storyboard version and rendering technology
local info = gre.env({"version", "renderer"})
local msg = string.format("Storyboard version %s (%s renderer)", info.version, info.renderer)
print(msg)
		    

gre.animation_create(fps, [auto_destroy], [end_callback])
                    

Create a new animation at the desired frame rate (fps). The second parameter (optional), auto_destroy, tells if the animation should be released once completed. If you specify a value of 1 the animation will be released and the returned id is not valid once the animation has completed. The third parameter (optional) indicates a callback function to be invoked when the animation is complete.

function animation_create(mapargs, fps)
	local id
	id = gre.animation_create(fps)
end
        

gre.animation_add_step(id, data)

Add a step to a created animation. The id must be from a call to gre.animation_create. The data parameter defines the animation step values.

function create_animation(mapargs)
	local data = {}

	-- slide the x position 400 pixels over 2000 msec and auto-destroy
	-- it on completion
	id  = gre.animation_create(60, 1)
	data["rate"] = "linear"
	data["duration"] = 2000
	data["offset"] = 0
	data["delta"] = 400
	data["key"] = "mylayer.mycontrol.grd_x"
	gre.animation_add_step(id, data)
end
                    

gre.animation_destroy(id)

function create_animation(mapargs)
	local data = {}

	-- slide the x position 400 pixels over 2000 msec
	id = gre.animation_create(60)
	data["rate"] = "linear"
	data["duration"] = 2000
	data["offset"] = 0
	data["delta"] = 400
	data["key"] = "mylayer.mycontrol.grd_x"
	gre.animation_add_step(id, data)

	-- destroy it
	gre.animation_destroy(id)
end
                    

gre.animation_trigger(animation_id, data)

gre.animation_trigger("animation_name")

Trigger an animation to run. If an animation_id is used to trigger the animation, then it must be the return value from gre.animation_create(). If a name is used to trigger an animation, then that name must be the name of the animation specified in Designer. This function can take an optional parameter, data_table. The data_table contains the tags and values for the extra arguments to set.

function create_animation(mapargs)
	local data = {}

	-- slide the x position 400 pixels over 2000 msec and auto-destroy
	-- it on completion
	id = gre.animation_create(60, 1)
	data["rate"] = "linear"
	data["duration"] = 2000
	data["offset"] = 0
	data["delta"] = 400
	data["key"] = "mylayer.mycontrol.grd_x"
	gre.animation_add_step(id, data)

	gre.animation_trigger(id)
end

--Example of using gre.animation_trigger passing animation names.
function cb_toggle_cur_5day()
  if cur_5day_toggle == false then
      gre.animation_trigger("show_5day")
  else
      gre.animation_trigger("hide_mon_to_fri")
  end
end

--Example of using gre.animation_trigger with context.
function cb_toggle_cur_5day()
	local data = {}

	data["context"] = "Layer1.mycontrol"
    gre.animation_trigger("show_5day", data)
end