具有大纵横比的云标注

Question

我正在尝试使用云形标注来记住在上一个方程式的投影仪演示中人们所见过的情况。由于方程式很长，我必须使用较大的纵横比来标注，结果却产生了奇怪的形状。除了更改纵横比（即分别更改高度和宽度）之外，还有其他方法可以更改云形标注的形状吗？

以下是 MWE：

\documentclass[8pt]{beamer}
\usepackage[utf8]{inputenc}
\usepackage[OT1]{fontenc}
\usepackage[USenglish]{babel} 
\usepackage{amsmath,amsthm,amssymb} 
\usepackage{tikz}
\usetikzlibrary{shapes.callouts,tikzmark}


\begin{document}
\begin{frame}
Frame with some text, some items and a long formula, part of which should remind people on a previous formula
\begin{itemize}
\item first item
\item second item
\item third item
\item fourth item
\item fifth item
\item sixth item
\end{itemize}

\begin{equation}
\begin{split}
\dot{f}(x,y)=&a \sin(x) \frac{\partial f(x,y)}{\partial y}-\left(2xy+b+\frac{y}{\sqrt{x^2-y^2}}\cos(y)\right) \frac{\partial{f}(x,y)}{\partial y} +x^3-y^2\\
&\alert{-\frac{y}{2}\left(y-\frac{x^2}{y^2}\right)\frac{\partial^2{f}(x,y)}{\partial x \partial y}}
\end{split} \nonumber
\end{equation}
\pause
\begin{tikzpicture}[overlay,remember picture]
\pgftransformshift{\pgfpointanchor{current page}{center}}
\node[cloud callout,draw,thick,fill=cyan,cloud puffs=50,cloud puff arc=100,callout relative pointer=(270:2cm),align=center,anchor=center,aspect=8] at (0,3) {$\dot g(x,y)=a \sin(x) \frac{\partial g(x,y)}{\partial y}-\left(2xy+b+\frac{y}{\sqrt{x^2-y^2}}\cos(y)\right) \frac{\partial{g}(x,y)}{\partial y} +x^3-y^2$};
\end{tikzpicture}
\end{frame}
\end{document}

如您所见，尽管方程式适合框架，但云比框架大。我可以让云标注的左侧和右侧更陡峭吗？是否也可以让两个小椭圆（指针？）更圆？

编辑：我的目标是这样的：

Answer 1

像这样？

\documentclass[8pt]{beamer}
\usepackage[utf8]{inputenc}
\usepackage[OT1]{fontenc}
\usepackage[USenglish]{babel}
\usepackage{amsmath,amsthm,amssymb}
\usepackage{tikz}
\usetikzlibrary{shapes.callouts,tikzmark}

\begin{document}
\begin{frame}
\frametitle{Title}
Frame with some text, some items and a long formula, part of which should remind people on a previous formula
\begin{itemize}
\item first item
\item second item
\item third item
\item fourth item
\item fifth item
\item sixth item
\end{itemize}

\begin{equation}
\begin{split}
\dot{f}(x,y)& = a \sin(x) 
                \frac{\partial f(x,y)}
                     {\partial y} - 
                \left(2xy+b+\frac{y}{\sqrt{x^2-y^2}}\cos(y)\right) 
                \frac{\partial{f}(x,y)}
                     {\partial y} +x^3-y^2  \\
            &\qquad \alert{-\frac{y}{2}
                    \left(y-\frac{x^2}{y^2}\right)
                    \frac{\partial^2{f}(x,y)}
                         {\partial x \partial y}}
\end{split} \nonumber
\end{equation}
\pause
\begin{tikzpicture}[overlay,remember picture]
\pgftransformshift{\pgfpointanchor{current page}{center}}
\node[cloud callout,cloud puffs=50,cloud puff arc=100,
      callout relative pointer=(240:3cm),
      callout pointer segments=3, % added
      draw,thick, fill=cyan, 
      %fill opacity=0.9, text opacity=1, % if you like to see background text
      align=center, anchor=center, 
      aspect=7, % changed
      inner xsep=-4em % <--- negative inner ysep
      ] at (1,3) {$\dot g(x,y)=a \sin(x) \frac{\partial g(x,y)}{\partial y}-\left(2xy+b+\frac{y}{\sqrt{x^2-y^2}}\cos(y)\right) \frac{\partial{g}(x,y)}{\partial y} +x^3-y^2$};
\end{tikzpicture}
\end{frame}
\end{document}