Cfrgtkky

I would like to make it so that the vertical space below the title of each chapter is the same when using the Bjornstrup package (i.e. so that the descenders do not affect the spacing - as shown by the red arrow in the picture below). I think I'm fairly happy with the spacing around "A chapter", so I'd really like titles without descenders (e.g. "Contents") to have the same vertical spacing as "A chapter" below the title. I would also like to remove the large "0" in the contents title. Any help appreciated, as always.

documentclass[11pt,a4paper]{book}



% Packages[![enter image description here][1]][1]



usepackage[left=3.5cm, right=3.5cm, top=4.3cm, bottom=4.25cm]{geometry}

usepackage[utf8]{inputenc}

usepackage{libertine}

usepackage[libertine]{newtxmath}

usepackage{MnSymbol}

usepackage{xcolor}

usepackage{scrextend}

usepackage[calcwidth]{titlesec}

usepackage{titleps}

usepackage{microtype}

usepackage[Bjornstrup]{fncychap} 

usepackage{tikz}

usepackage{lettrine}

usepackage{enumitem}

usepackage{type1cm} 

usepackage{amsthm,thmtools}

usepackage[framemethod=tikz,%

innerleftmargin=0pt

skipabove=0pt,

skipbelow=0pt,

innertopmargin=0pt,

innerrightmargin=0pt,

topline=false,

rightline=false,

bottomline=false,

topline=false,

leftline=false,

innerbottommargin=0pt]{mdframed}



setlength{parindent}{0.67cm}



% Section



% Fonts 



protecteddefmathbb#1{text{usefont{U}{msb}{m}{n}#1}} 



% Header and Footer



% Chapter



newcommand{chapnumfont}{

  usefont{T1}{pnc}{b}{n}

  fontsize{100}{100}

  selectfont

}



renewcommandDOCH{

  settowidth{py}{CNoVthechapter}

  addtolength{py}{0pt}

  fboxsep=40pt

  colorbox{chapbgcolor}{rule{0pt}{40pt}parbox[b]{textwidth}{hfill}}

  kern-pyraise20pt

  hbox{color{chapnumcolor}CNoVthechapter}\

}



renewcommandDOTI[1]{

  nointerlineskipraggedright

  fboxsep=myhi

  vskip-1ex

  colorbox{chapbgcolor}{parbox[t]{mylen}{CTVFmTi{#1}}}parnobreak

  vskip 40pt

}



renewcommandDOTIS[1]{

  fboxsep=0pt

  colorbox{chapbgcolor}{rule{0pt}{40pt}parbox[b]{textwidth}{hfill}}\

  nointerlineskipraggedright

  fboxsep=myhi

  colorbox{chapbgcolor}{parbox[t]{mylen}{CTVFmTi{#1}}}parnobreak

  vskip 40pt

 }

makeatother





colorlet{chapbgcolor}{gray!75}

colorlet{chapnumcolor}{black!60}



newcommand{chaptitle}[1]{

begin{tikzpicture}

fill[chapbgcolor!70,rounded corners=0pt] (0,2.3) rectangle (linewidth,0);

node[align=right,anchor=south east,inner sep=8pt,font=hugenormalfontbfseries] at (0.987linewidth,0) {#1};

node[font=fontsize{60}{62}usefont{OT1}{ptm}{m}{n}selectfontitshapebfseries,text=chapnumcolor] at 

(0.975linewidth,2.1) {sloppythechapter};

end{tikzpicture}

}



titleformat{chapter}[display]

{normalfonthugebfseriessffamily}{}{25pt}{chaptitle}

titlespacing*{chapter} {0pt}{-126pt}{33pt}



setlengthheadheight{15pt}



begin{document}

tableofcontents

chapter{A chapter}

mbox{}

newpage

More text...

newpage

Even more text...

end{document}

I would refrain from writing two different commands. If you ever want to adjust the appearance, you'll have to do it twice. TikZ has pgfkeys which allow you to switch the numbering on with a simple tikzset{title number=true} and off with tikzset{title number=false}. And to keep the distance the same, you only need to add an appropriate text depth.

documentclass[11pt,a4paper]{book}



% Packages[![enter image description here][1]][1]



usepackage[left=3.5cm, right=3.5cm, top=4.3cm, bottom=4.25cm]{geometry}

usepackage[utf8]{inputenc}

usepackage{libertine}

usepackage[libertine]{newtxmath}

usepackage{MnSymbol}

usepackage{xcolor}

usepackage{scrextend}

usepackage[calcwidth]{titlesec}

usepackage{titleps}

usepackage{microtype}

usepackage[Bjornstrup]{fncychap} 

usepackage{tikz}

usepackage{lettrine}

usepackage{enumitem}

usepackage{type1cm} 

%usepackage{amsthm,thmtools} % see https://tex.stackexchange.com/a/41551/121799

usepackage[framemethod=tikz,%

innerleftmargin=0pt

skipabove=0pt,

skipbelow=0pt,

innertopmargin=0pt,

innerrightmargin=0pt,

topline=false,

rightline=false,

bottomline=false,

topline=false,

leftline=false,

innerbottommargin=0pt]{mdframed}



setlength{parindent}{0.67cm}



% Section



% Fonts 



protecteddefmathbb#1{text{usefont{U}{msb}{m}{n}#1}} 



% Header and Footer



% Chapter



newcommand{chapnumfont}{

  usefont{T1}{pnc}{b}{n}

  fontsize{100}{100}

  selectfont

}



renewcommandDOCH{

  settowidth{py}{CNoVthechapter}

  addtolength{py}{0pt}

  fboxsep=40pt

  colorbox{chapbgcolor}{rule{0pt}{40pt}parbox[b]{textwidth}{hfill}}

  kern-pyraise20pt

  hbox{color{chapnumcolor}CNoVthechapter}\

}



renewcommandDOTI[1]{

  nointerlineskipraggedright

  fboxsep=myhi

  vskip-1ex

  colorbox{chapbgcolor}{parbox[t]{mylen}{CTVFmTi{#1}}}parnobreak

  vskip 40pt

}



renewcommandDOTIS[1]{

  fboxsep=0pt

  colorbox{chapbgcolor}{rule{0pt}{40pt}parbox[b]{textwidth}{hfill}}\

  nointerlineskipraggedright

  fboxsep=myhi

  colorbox{chapbgcolor}{parbox[t]{mylen}{CTVFmTi{#1}}}parnobreak

  vskip 40pt

 }

makeatother





colorlet{chapbgcolor}{gray!75}

colorlet{chapnumcolor}{black!60}



newififShowTitleNo

tikzset{title number/.is if=ShowTitleNo} 

tikzset{title number=false} 



newcommand{chaptitle}[1]{

begin{tikzpicture}

fill[chapbgcolor!70,rounded corners=0pt] (0,2.3) rectangle (linewidth,0);

node[align=right,text depth=0.25ex,anchor=south east,inner sep=8pt,font=hugenormalfontbfseries] at (0.987linewidth,0) {#1};

ifShowTitleNo

node[font=fontsize{60}{62}usefont{OT1}{ptm}{m}{n}selectfontitshapebfseries,text=chapnumcolor] at 

(0.975linewidth,2.1) {sloppythechapter};

fi



end{tikzpicture}

}



titleformat{chapter}[display]

{normalfonthugebfseriessffamily}{}{25pt}{chaptitle}

titlespacing*{chapter} {0pt}{-126pt}{33pt}



setlengthheadheight{15pt}



begin{document}

tableofcontents

tikzset{title number=true}

chapter{A chapter}

mbox{}

newpage

More text...

newpage

Even more text...

end{document}

It's not necessary to load fncychap (is it ever?), as you're completely redefining the chapter heading with titlesec.

The number can be get rid of by defining different styles for numbered and unnumbered chapters.

% openany to make a side by side picture

documentclass[11pt,a4paper,openany]{book}



usepackage{titlesec}

usepackage{titleps}

usepackage{tikz}



newcommand{chapnumfont}{%

  fontsize{100}{100}usefont{T1}{ptm}{b}{n}%

}



colorlet{chapbgcolor}{gray!75}

colorlet{chapnumcolor}{black!60}



newcommand{chaptitlenumbered}[1]{%

  begin{tikzpicture}

  fill[chapbgcolor!70,rounded corners=0pt] (0,2.3) rectangle (linewidth,0);

  node[

    align=right,

    anchor=south east,

    inner sep=8pt,

    font=hugenormalfontbfseries

  ] at (0.987linewidth,0) {strut#1};

  node[

    align=right,

    font=fontsize{60}{62}usefont{OT1}{ptm}{b}{it},

    text=chapnumcolor

  ] at (0.975linewidth,2.1) {thechapter};

  end{tikzpicture}%

}



newcommand{chaptitleunnumbered}[1]{%

  begin{tikzpicture}

  fill[chapbgcolor!70,rounded corners=0pt] (0,2.3) rectangle (linewidth,0);

  node[

    align=right,

    anchor=south east,

    inner sep=8pt,

    font=hugenormalfontbfseries

  ] at (0.987linewidth,0) {strut#1};

  end{tikzpicture}%

}



titleformat{name=chapter}[display]

  {normalfonthugebfseriessffamily}

  {}

  {0pt}

  {chaptitlenumbered}

titleformat{name=chapter,numberless}[display]

  {normalfonthugebfseriessffamily}

  {}

  {25pt}

  {chaptitleunnumbered}

titlespacing*{chapter}

  {0pt}

  {-126pt}

  {33pt}



setlengthheadheight{15pt}



begin{document}

tableofcontents

chapter{A chapter}

mbox{}

newpage

More text...

newpage

Even more text...

end{document}