Beamer 内容默认顶部边距-如何抑制？

Question

如何抑制投影仪框架内容框的顶部边距？

这是我的代码

\documentclass{beamer}
\usepackage{beamerthemesplit} % new 
\usepackage{eqnarray,amsmath, amsfonts, amssymb, cancel}
\usepackage{tcolorbox}
\usepackage{color,xcolor }

\tcbset{%
    noparskip,
    colback=gray!10, %background color of the box
    colframe=gray!40, %color of frame and title background
    coltext=black, %color of body text
    coltitle=black, %color of title text 
    fonttitle=\bfseries,
    alerted/.style={coltitle=red, 
        colframe=gray!40},
    example/.style={coltitle=black, 
        colframe=green!20,             
        colback=green!5},
}

\addtobeamertemplate{frametitle}{}{\vspace{-0.2 cm}}
\newcommand{\disponslide}[2]{%
    \alt<#1>{#2}{\phantom{#2}}}

\begin{document}


\begin{frame}[t]
    \frametitle{Expansion}
    \begin{tcolorbox}
        For all real numbers $a,b \in \mathbb{R}$,
        \begin{align*}
        &(a+b)^2 =  a^2 + 2ab + b^2&&\\
        &(a+b)(a-b) =  a^2 - 2ab + b^2&&
        \end{align*}
    \end{tcolorbox}
    \begin{align*}
    (a+b)^2&= (a+b)(a+b)\\
    &= a^2+ab+ba+b^2\\
    &= a^2+2ab+b^2 \quad\text{(since ba=ab)}\\
    (a+b)(a-b)&= a^2-ab+ba-b^2 \\
    &= a^2-b^2 \quad\text{(since ba=ab)}
    \end{align*}
\end{frame}



\end{document}

参见下文，公式框和方程式之间存在明显的差距。我从未在公式框后指定换行符，但 Latex 仍然会插入几行换行符。

提前致谢。

Answer 1

您必须使用[nobeforeafter]选项来tcolorbox取消那些顶部和底部空格，并且该框将放置在没有上下空格的段落中。

\documentclass{beamer}
\usepackage{beamerthemesplit} % new
\usepackage{eqnarray,amsmath, amsfonts, amssymb, cancel}
\usepackage{tcolorbox}
\usepackage{color,xcolor }

\tcbset{%
    noparskip,
    colback=gray!10, %background color of the box
    colframe=gray!40, %color of frame and title background
    coltext=black, %color of body text
    coltitle=black, %color of title text
    fonttitle=\bfseries,
    alerted/.style={coltitle=red,
        colframe=gray!40},
    example/.style={coltitle=black,
        colframe=green!20,
        colback=green!5},
}

\addtobeamertemplate{frametitle}{}{\vspace{-0.2 cm}}
\newcommand{\disponslide}[2]{%
    \alt<#1>{#2}{\phantom{#2}}}

\begin{document}


\begin{frame}[t]
    \frametitle{Expansion}
    \begin{tcolorbox}[nobeforeafter]
        For all real numbers $a,b \in \mathbb{R}$,
        \begin{align*}
        &(a+b)^2 =  a^2 + 2ab + b^2&&\\
        &(a+b)(a-b) =  a^2 - 2ab + b^2&&
        \end{align*}
    \end{tcolorbox}
    \begin{align*}
    (a+b)^2&= (a+b)(a+b)\\
    &= a^2+ab+ba+b^2\\
    &= a^2+2ab+b^2 \quad\text{(since ba=ab)}\\
    (a+b)(a-b)&= a^2-ab+ba-b^2 \\
    &= a^2-b^2 \quad\text{(since ba=ab)}
    \end{align*}
\end{frame}



\end{document}

您可以使用键before skip、after skip等beforeafter skip来更好地控制它们。