Beamer Header 中框之间的白色分隔线

Question

我根据这里得到的宝贵建议修改了蒙彼利埃主题的标题：源自蒙彼利埃的自定义外部主题

现在一切都按要求工作，但现在页眉和页脚中的框之间都有垂直和水平的白线。 MWE：

\documentclass[8pt]{beamer}
\usepackage{tikz}
\title{My title}
\author{My Author}
\institute{My Institute}
\date{April $17^{th}$ 2017}
\usetheme{Montpellier}
\useinnertheme{circles}
\setbeamertemplate{navigation symbols}{}%remove navigation symbols
\definecolor{gold}{RGB}{162,132,72} 
\setbeamercolor{footlinecolor}{fg=white,bg=gold}
\setbeamercolor{footlinecolor1}{fg=gold,bg=white}
\setbeamercolor{footlinecolor2}{fg=gold,bg=black}
\setbeamercolor{footlinecolor3}{fg=white,bg=black}
\setbeamercolor{title in head/foot}{fg=gold,bg=black}
\setbeamercolor{section in head/foot}{fg=white,bg=black}
\setbeamercolor{subsection in head/foot}{fg=white,bg=black}
\setbeamercolor{separation line}{bg=black}

\setbeamertemplate{footline}
{
\leavevmode%
\hbox{%
\begin{beamercolorbox}[wd=.4\paperwidth,ht=2.25ex,dp=1ex,center]{footlinecolor2}%{author in head/foot}%
\usebeamerfont{author in head/foot}My Institution
\end{beamercolorbox}%
\begin{beamercolorbox}[wd=.3\paperwidth,ht=2.25ex,dp=1ex,center]{footlinecolor3}%{title in head/foot}%
\usebeamerfont{title in head/foot}\insertshortdate
\end{beamercolorbox}%
\begin{beamercolorbox}[wd=.3\paperwidth,ht=2.25ex,dp=1ex,right]{footlinecolor3}%{date in head/foot}%
\insertframenumber{} / \inserttotalframenumber\hspace*{2ex} 
\end{beamercolorbox}}%
\vskip0pt%
}
\makeatother

\addtobeamertemplate{headline}{}{%
\begin{tikzpicture}[remember picture,overlay]
\node at([shift={(4.5,-.5)}]current page.north) {\includegraphics[height=.45\headheight]{example-image}};
\end{tikzpicture}}


\begin{document}

\begin{frame}
 \maketitle
\end{frame}
\section{My Section}
\subsection{My Subsection}
\begin{frame}

my frame

\end{frame}

\end{document}

这是我得到的输出：

Answer 1

短的：不要使用Preview和查看器使用相同的pdf渲染库。

长的：问题在于您可能已经smooth text and line art检查过您的预览偏好设置：

尝试不使用，线条会消失，但文字会变得难看。所以不是一个好的解决方案。

解决方法：改用例如Adobe Reader。