%!TEX lualatex

\documentclass[a4paper]{article}
\usepackage{fontspec}
\usepackage[margin=1.5cm]{geometry}
\usepackage{tikz}
\usepackage{codehigh}
\usetikzlibrary{shapes.callouts}
\usepackage[french]{babel}

\begin{document}

\begin{demohigh}[language=latex/latex2]
	\newfontface\qtbd{QTImpromptu}[Scale=MatchLowercase]
	\tikzset{bullebd/.style args={#1#2}{%
			inner sep=1mm,line join=round,rectangle callout,rounded corners,
			draw,ultra thick,text width=#1,align=flush center,
			callout relative pointer=#2,font=\Large\qtbd
		}
	}
	
	{\tikz\node[bullebd={4.5cm}{(-150:0.75)}]{Une petite bulle, façon BD :-)};}
\end{demohigh}

\end{document}