答案1
似乎还留有一点空隙。它比\topskip
或\dblfloatsep
或小\dbltextfloatsep
,所以可能不是故意的。
\documentclass[conference]{IEEEtran}
\usepackage{graphicx}
\usepackage{lipsum}
\begin{document}
\begin{figure*}[tp]% AFAICT, adding ! does nothing useful
\vspace*{\dimexpr -1in-\topmargin-\headheight-\headsep}%
\makebox[\textwidth]{%
\includegraphics[width=\paperwidth]{example-image}}
\caption{aaa}% do not put inside \makebox
\label{aaa}
\end{figure*}
\lipsum[1-16]
\end{document}