如何在 LaTeX 中将图像插入到放大部分的顶部？

Question

我想放大 LaTeX 中的图像，使原始图像在缩放部分内可见。如果我使用 spy 库，则缩放部分始终位于顶部。我找不到如何将放大部分移到主图像下方。请参阅以下最小示例。我希望左侧图像（在输出 PDF 中）位于右侧图像（缩放图像）的顶部。换句话说，我希望主图像作为插图位于缩放部分的右下角，并用红色矩形显示哪个区域被缩放。

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{spy}

\begin{document}

\begin{tikzpicture}

  [spy using outlines={rectangle,red,magnification=7,size= 8 cm}]   
  \node   {\includegraphics[width=.3\linewidth]{example-image}};
  \spy on (-1,0) in node at (4.5,3);

\end{tikzpicture}

\end{document}

Answer 1

更新：Paul Gaborit 提供了更简单的解决方案。

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{spy,backgrounds}
\pgfdeclarelayer{background}
\pgfdeclarelayer{foreground}
\pgfsetlayers{background,main,foreground}

\begin{document}

\begin{tikzpicture}[spy using outlines={rectangle,red,magnification=7,size= 8 cm}]   
  \node   {\includegraphics[width=.3\linewidth]{example-image-a}};
  \spy[on background layer,
  spy connection path={  \draw (tikzspyonnode) -- (tikzspyinnode);
  \begin{pgfonlayer}{foreground}
  \draw[red] (tikzspyonnode.south west) rectangle (tikzspyonnode.north east);
  \end{pgfonlayer}}] on (-1,0) in node at (4.5,3);
\end{tikzpicture}

\end{document}

**老旧且糟糕的解决方案**：

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{spy,backgrounds}
\pgfdeclarelayer{background}
\pgfdeclarelayer{foreground}
\pgfsetlayers{background,main,foreground}
\begin{document}

\begin{tikzpicture}
 \begin{scope}[spy using outlines={rectangle,red,magnification=7,size= 8 cm}]   
  \node (x)  {\includegraphics[width=.3\linewidth]{example-image}};
  \spy[spy connection path={\draw (tikzspyonnode) -- (tikzspyinnode);
  \path coordinate (bl) at (tikzspyonnode.south west);
  \path coordinate (tr) at (tikzspyonnode.north east);}] on (-1,0) in node at (4.5,3);
 \end{scope}  
 \begin{pgfonlayer}{foreground}
  \node (y) at (x) {\includegraphics[width=.3\linewidth]{example-image}};
  \draw[red] (bl) rectangle (tr);
 \end{pgfonlayer}
\end{tikzpicture}
\end{document}

我为什么要发布所有这些解决方案？只是因为“更明显”的解决方案似乎不起作用。例如，

\begin{tikzpicture}[spy using outlines={rectangle,red,magnification=7,size= 8 cm}]   
  \node (x)  {\includegraphics[width=.3\linewidth]{example-image}};
  \begin{pgfonlayer}{background}
  \spy on (-1,0) in node at (4.5,3);
  \end{pgfonlayer}
\end{tikzpicture}

产量

即放大的图片是不是在背景上，更令人惊讶的是

\begin{tikzpicture}[spy using outlines={rectangle,red,magnification=7,size= 8 cm}]   
  \begin{pgfonlayer}{foreground}
  \node (x)  {\includegraphics[width=.3\linewidth]{example-image}};
  \end{pgfonlayer}
  \spy on (-1,0) in node at (4.5,3);
\end{tikzpicture}

给出