reference to a specific part of a subfigure in text

Question

Hi there I was working on a subfigure and since it's part of a pipeline I wanted to have something in my main text saying: ... (Figure 4, top right) ... (Figure 4, middle) ... (Figure 4, bottom).

Now, the subfigure part it's pretty straightforward and it appears to be correct; however, when clicking on the in-text links I'm always prompted to the whole Figure 4... What I would actually like to happens is a close-in look at the top/middle/bottom of the figure according to where I click.

Below the packages I use and how I implemented the subfigure.

\documentclass[12pt]{report}
\usepackage{float}
\usepackage{graphicx} % for inserting images
\usepackage[inkscapearea=page]{svg} %for SVG import
\usepackage[letterpaper,margin=1in]{geometry}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{titlesec}
\usepackage{textcomp}
\usepackage{setspace}
\usepackage{csquotes}
\usepackage{authblk}
\usepackage{xurl}
\usepackage{hyperref}
\hypersetup{
    colorlinks,
    citecolor=blue,
    filecolor=.,
    linkcolor=maroon,
    urlcolor=teal,
    linktoc=all
}
\usepackage{cleveref}
\usepackage{caption}
\usepackage{orcidlink}
\usepackage{subcaption}
%\captionsetup[table]{font=small}
\captionsetup[figure]{font=small}
\renewcommand{\thefigure}{\arabic{figure}}
\definecolor{teal}{rgb}{0.0, 0.5, 0.5}
\definecolor{maroon}{rgb}{0.69, 0.19, 0.38}
\definecolor{coolblack}{rgb}{0.0, 0.18, 0.39}
\definecolor{MSBlue}{rgb}{0.204, 0.353, 0.541}
\definecolor{darkcerulean}{rgb}{0.03, 0.27, 0.49}
\usepackage{tocloft}
\usepackage{tocbasic}
\usepackage[nottoc]{tocbibind} % automatically adds LOF and LOT to TOC
\renewcommand{\cftdot}{}
\renewcommand{\baselinestretch}{1.5}
\renewcommand{\cftchapfont}{\Large\bfseries\color{MSBlue}}
\renewcommand{\cfttoctitlefont}{\Large\bfseries\color{black}}
\renewcommand{\cftloftitlefont}{\Large\bfseries\color{black}}
\renewcommand{\cftsecfont}{\large\bfseries\color{darkcerulean}}
\renewcommand{\cftsubsecfont}{\normalsize\bfseries\color{coolblack}}
\makeatletter
\renewcommand@dotsep{10000}
\makeatother
\DeclareTOCStyleEntry[
  entrynumberformat=\entrynumberwithprefix{\figurename},
  dynnumwidth,
  numsep=1em
]{tocline}{figure}
\newcommand\entrynumberwithprefix[2]{#1\enspace#2:\hfill}
\title{\Huge\bfseries{Pangenome-based Demographic Inference}}
\author{\LARGE{Matteo Tommaso Ungaro}}
\date{}
\usepackage{microtype}
\usepackage[main=english]{babel}
\usepackage[sorting=ynt, backend=biber, giveninits]{biblatex}
\addbibresource{references.bib}
\DeclareNameAlias{author}{family-given}
\titleformat{\chapter}[hang]{\Large\bfseries\color{MSBlue}}{\thechapter}{1em}{}
\titleformat{\section}{\large\bfseries\color{darkcerulean}}
\titleformat{\subsection}{\normalsize\bfseries\color{coolblack}}
\begin{document}
...
%referring to part of the figure/specific subfigures
(\textbf{\hyperref[figure:construction]{Figure 4, top right}})
(\textbf{\hyperref[figure:mapping]{Figure 4, middle}})
(\textbf{\hyperref[figure:analyses]{Figure 4, bottom}})
%subfigure part
\begin{figure}[htbp]
    \centering
    \begin{subfigure}{\textwidth}
    \centering
        \includesvg[width=6.5in]{figure4_flowchart_pt1}
        \vspace{-1.1\baselineskip}
        \label{figure:construction}
    \end{subfigure}
    \begin{subfigure}{\textwidth}
    \centering
        \includesvg[width=6.5in]{figure4_flowchart_pt2}
        \vspace{-1.1\baselineskip}
        \label{figure:mapping}
    \end{subfigure}
    \begin{subfigure}{\textwidth}
    \centering
        \includesvg[width=6.5in]{figure4_flowchart_pt3}
        \label{figure:analyses}
    \end{subfigure}
\caption[\textbf{Workflow from pangenome construction to downstream analyses}]{\textbf{Workflow from pangenome construction to downstream analyses.} } 
\label{figure:workflow}
\end{figure}
\end{document}

I didn't use \caption for subfigures as I didn't need it, I only require a global caption for the workflow. Also, I got rid of extra white spaces between the subfigures since I want the workflow to appear as a single item. See image below.

I'm not sure what I've done wrong, any help is greatly appreciated!

Answer 1

Since you've chosen not to provide \caption directives for the three subfigure environments, the associated \label statements cannot work correctly. That's what you've (re)discovered.

Fortunately, since you're employing the hyperref package, an alternative method for creating cross-references is available: the \hypertarget/\hyperlink pair of directives. Its application to the problem at hand is illustrated in the example below. (Note that I chose to simplify the OP's code considerably since most of it has no bearing on the problem at hand.) \hypertarget and \hyperlink each take two arguments. The first argument is akin to the (single) argument of the well-known \label and \ref statements, while the second argument should be the text string you want to see typeset. Observe that the second argument can be empty.

\documentclass[12pt]{report}
\usepackage[demo]{graphicx} % don't use 'demo' option in real document
\usepackage[letterpaper,margin=1in]{geometry}
%%%\usepackage[utf8]{inputenc} % that's the default nowadays
\usepackage[T1]{fontenc}
\usepackage{caption}
\captionsetup{textfont=bf}
\usepackage{xcolor}
\usepackage{microtype}
\usepackage[english]{babel}
\usepackage{hyperref} % for '\hypertarget' and '\hyperlink' macros
\hypersetup{colorlinks,allcolors=blue,linktoc=all}
\usepackage[noabbrev,nameinlink]{cleveref}
\begin{document}
Cross-references to the \hyperlink{fig:upper}{upper}, 
\hyperlink{fig:middle}{middle}, and \hyperlink{fig:lower}{lower} 
parts of \cref{figure:workflow}.
\clearpage
\begin{figure}[htbp]
    \begin{minipage}{\textwidth} % no need for 'subfigure' overhead
    \color{red} % omit this instruction in the real document
    \hypertarget{fig:upper}{} % note: 2nd arg. is empty
    \includegraphics[width=\textwidth]{figure4_flowchart_pt1}
    \end{minipage}%
    \vspace{-0.6mm}
    \begin{minipage}{\textwidth}
    \color{yellow} % omit this instruction in the real document
    \hypertarget{fig:middle}{} % note: 2nd arg. is empty
    \includegraphics[width=\textwidth]{figure4_flowchart_pt2}
    \end{minipage}%
    \vspace{-0.6mm}
    \begin{minipage}{\textwidth}
    \color{blue} % omit this instruction in the real document
    \hypertarget{fig:lower}{} % note: 2nd arg. is empty
    \includegraphics[width=\textwidth]{figure4_flowchart_pt3}
    \end{minipage}
\caption{Workflow from pangenome construction to downstream analyses.} 
\label{figure:workflow}
\end{figure}
\end{document}