By changing the font of the window, you also change the font of any newly created child controls.
Window.font read/write property
Get the window font, a string value that represent the font name.
To set the Window.font property, you can assign a string that represent either a font name of an installed system font, or a font file (*.ttf, *.fon...). A File can also be provided, representing a font file.
Note that only the font family is changed. The font style and font size are not affected (see the Window.fontstyle and the Window.fontsize properties).
Example
local ui = require "ui"
-- create a simple window
local win = ui.Window("Window.font sample", 320, 200)
win.fontsize = 18
local label = ui.Label(win, "Hello World in '"..win.font.."' font, with "..win.fontsize.."px")
win:show()
-- update the user interface until the user closes the window
repeat
ui.update()
until not win.visible