on.resize

The event on.resize is fired when the user resizes the window where the lua script is.

It has no argument.

It's a good place to put your global window-size-related variable since this event only fires when the script's frame's size changes (see Example).

Example

Below is an example of a program that creates/updates the "theHeight" and "theWidth" global variables whenever the user resizes the widget's frame:

function on.resize() --Define a function for the events
    theWidth = platform.window:width()
    theHeight = platform.window:height()
end

This is a better way, though :

function on.resize(x, y) -- Yes, on.resize can pass the new width and height, so why not use it ;-)
    theWidth = x
    theHeight = y
end

You can then refer to the height and the width of the widget by calling the global variables instead of the platform.window methods.