By changing the font of the Panel, you also change the font of any newly created child controls.
Panel.font read/write property
Get the Panel font, a string value that represent the font name.
To set the Panel.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 Panel.fontstyle and the Panel.fontsize properties).
Example
local ui = require "ui"
-- create a fixed Panel
local win = ui.Window("Panel.font sample", "fixed", 320, 200)
-- create a Panel
local panel = ui.Panel(win, 0, 0, 100, 100)
panel.bgcolor = 0x00a060
panel:center()
-- change its font
panel.font = "Segoe Print"
-- add a child Label
ui.Label(panel, "Label"):center()
ui.run(win):wait()