Relax if i understand correctly you want to print the content of your clipboard in your AutoIt Gui with a font of your choise ?
Something like that
#include <GUIConstantsEx.au3>
Example()
Func Example()
Local $font, $msg
GUICreate("My GUI default font") ; will create a dialog box that when displayed is centered
$font = "Comic Sans MS"
GUISetFont(9, 400, 4, $font) ; will display underlined characters
GUICtrlCreateLabel("underlined label", 10, 20)
GUISetFont(9, 400, 2, $font) ; will display underlined characters
GUICtrlCreateLabel("italic label", 10, 40)
GUISetFont(9, 400, 8, $font) ; will display underlined characters
GUICtrlCreateLabel("strike label", 10, 60)
GUISetState()
; Run the GUI until the dialog is closed
While 1
$msg = GUIGetMsg()
If $msg = $GUI_EVENT_CLOSE Then ExitLoop
WEnd
EndFunc ;==>Example