How to Remove Horizontal Lines From Colored Multirow Table [duplicate]

Question

I am having some trouble removing the "white lines" from a colored table (where it says 3 and 4).

\documentclass{report}

\usepackage{wrapfig}
\usepackage{colortbl}
\usepackage{booktabs}
\usepackage{multirow}
\usepackage{hhline}
\usepackage[table,xcdraw]{xcolor}
\usepackage{graphicx}

\definecolor{lightgray}{rgb}{0.75,0.75,0.75}
\definecolor{darkgray}{rgb} {0.50,0.50,0.50}

\begin{document}
\begin{wraptable}[12]{r}[0cm]{5cm}
    \vspace{-1cm}
    \resizebox{5cm}{!}{
        \begin{tabular}{c|c|c}
            \hline
            \textbf{Binary}    & \textbf{ICDR}      & \textbf{ETDRS}                                             \\ \hline
            0                  & 0                  & No DR                                                      \\ \hline
            &\cellcolor{lightgray}1                   & \cellcolor{lightgray}Very mild NPDR   \\ \hhline{~|--} 
            &\cellcolor{lightgray}2                   & \cellcolor{lightgray}Mild NPDR        \\ \hhline{~|--}
            &\cellcolor{lightgray}                    & \cellcolor{lightgray}Moderate NPDR    \\ \hhline{~~|-}
            &\cellcolor{lightgray}                    & \cellcolor{lightgray}Severe NPDR      \\ \hhline{~~|-}
            &\cellcolor{lightgray}\multirow{-3}{*}{3} & \cellcolor{lightgray}Very Severe NPDR \\ \hhline{~|--}
            &\cellcolor{darkgray}                     & \cellcolor{darkgray}\begin{tabular}[c]{@{}c@{}}Mild - Moderate\\ PDR\end{tabular}          \\ \hhline{~~|-}
            &\cellcolor{darkgray}                     & \cellcolor{darkgray}High-Risk PDR                                                          \\ \hhline{~~|-}
            \multirow{-8}{*}{1}&\cellcolor{darkgray} \multirow{-3}{*}{4} & \cellcolor{darkgray}\begin{tabular}[c]{@{}c@{}}Advanced Diabetic\\ Eye Disease\end{tabular}\\ \hhline{---}
    \end{tabular}}
    \caption{\label{tab:dr_classes}Sample Caption.}
\end{wraptable}]

\end{document}

Any information is appreciated.

Answer 1

i would redesign your table as follows:

\documentclass{report}

\usepackage{wrapfig}
\usepackage{array, booktabs, multirow}
\newcolumntype{C}[1]{>{\centering\arraybackslash}p{#1}}
\usepackage[table,xcdraw]{xcolor}
\definecolor{lightgray}{rgb}{0.75,0.75,0.75}
\definecolor{darkgray}{rgb} {0.50,0.50,0.50}
\usepackage{hhline}
\newcommand\lightline{%
\hhline{~|>{\arrayrulecolor{lightgray}}-%
          >{\arrayrulecolor{black}}|-}%
                      }
\newcommand\darkline{%
\hhline{~|>{\arrayrulecolor{gray}}-%
          >{\arrayrulecolor{black}}|-}%
                      }

\usepackage{lipsum}
\begin{document}
\lipsum[1]
\begin{wraptable}[12]{r}[0cm]{5cm}
    \setlength\tabcolsep{0pt}
    \footnotesize
    \vspace{-\baselineskip}
    \begin{tabular}{      C{\dimexpr0.22\linewidth-0.66\arrayrulewidth}|@{}
>{\columncolor{lightgray}}C{\dimexpr0.21\linewidth-0.66\arrayrulewidth}|
>{\columncolor{lightgray}}C{\dimexpr0.57\linewidth-0.66\arrayrulewidth}
                                }
                                        \hhline{---}
    \rowcolor{white}
     \textbf{Binary}
        & \textbf{ICDR}
            & \textbf{ETDRS}        \\ \hhline{---}
    \rowcolor{white}
    0   & 0 & No DR                 \\ \hhline{---}
        & 1 & Very mild NPDR        \\ \hhline{~|-|-}
        & 2 & Mild NPDR             \\ \hhline{~|-|-}
        &   & Moderate NPDR         \\ \lightline
        &   & Severe NPDR           \\ \lightline
     \multirow{2}{*}{1}
        & \multirow{-3}{*}{3}
            & Very Severe NPDR      \\
    \end{tabular}\\[-1pt]
    \begin{tabular}{     C{\dimexpr0.22\linewidth-0.66\arrayrulewidth}|
>{\columncolor{darkgray}}C{\dimexpr0.21\linewidth-0.66\arrayrulewidth}|
>{\columncolor{darkgray}}C{\dimexpr0.57\linewidth-0.66\arrayrulewidth}
                                }
        \hhline{~|-|-}
        &   & Mild - Moderate PD    \\ \darkline
        &   & High-Risk PDR         \\ \darkline
        & \multirow{-2}{*}{4}
            & Advanced Diabetic
              Eye Disease           \\ \hhline{---}
    \end{tabular}
\caption{Sample Caption.}
    \label{tab:dr_classes}
\end{wraptable}
\lipsum[2]
\end{document}

still visible white lines are caused by artifacts of pdf previewer (i use sumatra). it should not be visible in printed document.