Vrftjkry

I am formatting a book and I am using LuaLaTex. I am trying to obtain the following formatting for the chapters,

The following code correctly generates the chapter title

usepackage{titlesec}



%Chapter heading

newfontfamilychapterfont[Color=black]{Avenir Light}% set font



titlespacing{chapter}% {left}{before}{after}[right]

{50pt}%left

{3ex plus 2ex}%before

{1.7cm}%after



titleformat{chapter}% command to be modified

  {fontsize{24}{27}bfseriesscshapechapterfont} %format

  {thechapter.}% label

  {1em}% sep

  {} % before-code

  [{color{red}titlerule[1pt]}] % after-code

but I cannot find a way to make the graphical chapter number, and also to extend the red rule to the right page border. Any help would be much appreciated. Thank you in advance.

A solution based on tcolorbox package

% !TeX program = lualatex                                   

% !TeX encoding = utf8

documentclass[14pt]{book}

usepackage{fontspec}

usepackage[svgnames]{xcolor}

usepackage{titlesec}

usepackage{lipsum}

usepackage[many]{tcolorbox}

usepackage[

    a4paper,

    left=2cm,

    right=2cm,

    top=2.5cm,

    bottom=2cm,

]{geometry}



newtcbox{mychapternum}{enhanced,nobeforeafter,tcbox raise base,boxrule=1pt,top=0mm,bottom=0mm,

  colframe=cyan,coltext=cyan,colback=cyan!10!white, halign = right,

    width=50pt,arc=7mm, sharp corners=west, boxsep=4mm,

    overlay={draw[thick] ([yshift=3ex]frame.north west) -- ([yshift=-3ex]frame.south west);



      }

  }  



%Chapter heading

%newfontfamilychapterfont[Color=black]{Avenir Light}% set font

titlespacing{chapter}% {left}{before}{after}[right]

{60pt}%left

{1ex plus 2ex}%before

{1.7cm}%after



titleformat{chapter}% command to be modified

  {fontsize{24}{27}bfseriesscshape} %format

  {hspace*{-70pt}

    mychapternum{thechapter}

    }% label

  {0em}% sep

  {} % before-code

  [{color{red}

    begingroup

      setlength{titlewidth}{textwidth}

      titleline*{titlerule[1pt]}

    endgroup  

    }] % after-code



begin{document}





chapter{My title}



lipsum[20-30]



chapter{My title}



lipsum[20-30]

end{document}

A solution based on TikZ package. This solution more flexible for adjustemets.

% !TeX program = lualatex                                   

% !TeX encoding = utf8    

documentclass[14pt]{book}      

usepackage{fontspec}      

usepackage[svgnames]{xcolor}

usepackage{titlesec}

usepackage{lipsum}

usepackage[many]{tcolorbox}

usetikzlibrary{shapes.misc, positioning}

usetikzlibrary{calc}   

usepackage[

    a4paper,

    left=2cm,

    right=2cm,

    top=2.5cm,

    bottom=2cm,

]{geometry}   

%Chapter heading

%newfontfamilychapterfont[Color=black]{Avenir Light}% set font

titlespacing{chapter}% {left}{before}{after}[right]

{2cm}%left

{2ex}%before

{1.7cm}%after



titleformat{chapter}% command to be modified

  {Hugebfseriesscshape} %format

  {hspace*{-1cm}

      tikz [anchor=base, baseline,remember picture, overlay]{%

        node[line width = 2pt, draw=cyan, fill =cyan!10, anchor=base, rectangle,  text width=2cm, align=right, rounded rectangle,rounded rectangle west arc=5pt, minimum height=4ex,

           inner sep=11pt] (A)

              {color{cyan}thechapter};

    draw[line width = 2.5pt] ([yshift=3ex]A.north west) -- ([yshift=-3ex]A.south west);

    draw[line width = 1pt, red] let p1=(A.south east), p2=(current page.east) in  ([xshift=2.6ex]A.south east) -- +(x2,0);

    }%

    }% label

  {dimexpr2emrelax}% sep

  {} % before-code

   % after-code



begin{document}

chapter{My title}

lipsum[20-30]

addtocounter{chapter}{20}

chapter{My title}

lipsum[20-30]

end{document}