Changing arrow parameters

Question

Problem :

I want to make callouts on figures. I use package callouts, its great - but I want to have white shadow behind the arrow (to make them more visible). I also want the window with the number (for example 2.2) to be framed with black color.

This is what I have :

And this is what I want:

My code:

\documentclass[12pt,a4paper,notitlepage, twoside]{article}
\usepackage[utf8]{inputenc}
\usepackage{tabulary} 
\usepackage[OT4]{polski} 
\usepackage[polish]{babel}
\usepackage[export]{adjustbox} 
\usepackage[T1]{fontenc}
\usepackage{graphicx}
%\usepackage{nicematrix,tikz} 
\usepackage[table]{xcolor} 
**\usepackage[margin = 2cm, top=2cm, bottom=2cm, left=2.5cm, right=2.5cm, headsep=1cm]{geometry}**
\usepackage{fancyhdr}
\pagestyle{fancy}
\usepackage{hyperref}
\usepackage{caption}
\usepackage[text= black, background = white , arrow = black ]{callouts} 
\usepackage{tikz} % Rysowanie strzałek, odnośników na figures
\setcounter{tocdepth}{4} 
\setcounter{secnumdepth}{4} 
\usepackage{multirow}
\usepackage{nicematrix} 
\usepackage{calc}
\usepackage[export]{adjustbox} 
\usepackage{enumitem} 

\begin{figure}
    \centering
    \begin{annotate}{\includegraphics[width=0.9\textwidth]{zdj3.png}}{0.9}
        %\helpgrid[black]
        \callout{-6.2,3}{2.2}{-6.2,0.8}
        \callout{-5,3}{2.3}{-5,0.8}
        \callout{-4,3}{2.4}{-4,0.8}
        \callout{-2,3}{2.5}{-2,0.8}
    \end{annotate}
    \caption{FESTO}
    \label{fig:first}
\end{figure}

Answer 1

You could redefine the callout and add a second, white, arrow behind the normal arrow:

\documentclass[12pt,a4paper,notitlepage, twoside]{article}
\usepackage[utf8]{inputenc}
\usepackage{tabulary} 
\usepackage[OT4]{polski} 
\usepackage[polish]{babel}
\usepackage[export]{adjustbox} 
\usepackage[T1]{fontenc}
\usepackage{graphicx}
%\usepackage{nicematrix,tikz} 
\usepackage[table]{xcolor} 
\usepackage[margin = 2cm, top=2cm, bottom=2cm, left=2.5cm, right=2.5cm, headsep=1cm]{geometry}
\usepackage{fancyhdr}
\pagestyle{fancy}
\usepackage{hyperref}
\usepackage{caption}
\usepackage[text= black, background = white , arrow = black ]{callouts} 
\usepackage{tikz} % Rysowanie strzałek, odnośników na figures
\setcounter{tocdepth}{4} 
\setcounter{secnumdepth}{4} 
\usepackage{multirow}
\usepackage{nicematrix} 
\usepackage{calc}
\usepackage[export]{adjustbox} 
\usepackage{enumitem}


\usetikzlibrary{arrows.meta}


\renewcommand{\callout}[3]{%
\node [fill=\bgcol] (text) at (#1) {\scriptsize\color{\focol} #2};
\draw [
    \arcol,
    thick,
    -{Latex},
    preaction={draw=white,line width=4pt,-{Latex[length=3pt 2.5 0.8]},shorten >=-4.5pt}
  ] (text) -- (#3);
}

 
\begin{document}

\begin{figure}
    \centering
    \begin{annotate}{\includegraphics[width=0.9\textwidth]{example-image-duck}}{0.9}
        %\helpgrid[black]
        \callout{-6.2,3}{2.2}{-6.2,0.8}
        \callout{-5,3}{2.3}{-5,0.8}
        \callout{-4,3}{2.4}{-4,0.8}
        \callout{-2,3}{2.5}{-2,0.8}
    \end{annotate}
    \caption{FESTO}
    \label{fig:first}
\end{figure}

\end{document}