How to bold custom calligraphic text

Question

I'm using a custom calligraphic font via newenvironemnt and manual encoding,... (thus without theh math package). It works quite well except when I try to write things bold. From looking around I've seen that there are 2 possibilities: a.) The font I'm using has no bold variant or b.) I'm doing something wrong there (thus with how I set things it overwrites all attempts to make the text bold).

So my question here is twofold: Am I doing something wrong there or if not and I'm really using the wrong font, which font would be better applicable there for what I want to do (having calligraphic fonts in a book and being able to also bold the text)?

\documentclass[10pt,a4paper,BCOR10mm,DIV11,toc=listof,parskip=full, openany]{scrbook}


\newenvironment{calligraphic}%
{
\fontencoding{T1}
\fontfamily{pzc}
\fontseries{m}
\fontshape{it}
\fontsize{12pt}{12pt}
\selectfont
}
{}%

\renewcommand*{\sectfont}{\normalcolor\usefont{T1}{pzc}{m}{it}}

\begin{document}
   \begin{calligraphic}
   \chapter{test1}
   Test \textbf{this is bold}
   \end{calligraphic}
   Test2 \textbf{this is bold}
\end{document}

Edit: I added a chapter there not sure if its only optical illusion but interestingly chapters SEEM bold there. Edit after Johannes comment: was only an optical illusion because of the size it looks bold but is only a sideeffect of the size itself.

Answer 1

Proper kerning is not preserved with this approach (nor hyphenation), but it may still suffice. It does line wrapping.

I achieve the result by overlaying the character with a shifted version of itself. Shift is controlled by \defs of \calup and \calover. The macro to use is \calbf.

The helper routine \calbfhelpA parses the interword spaces, while \calbfhelpB parses the characters of each word.

With this implementation, the font spacing is not widened. However, if one wishes to allow the font spacing to widen, just change the value of \useanchorwidth to {F}.

Obviously, the key here is to be subtle with the shifting. Too much, and it looks awful.

\documentclass[10pt,a4paper,BCOR10mm,DIV11,toc=listof,parskip=full, openany]{scrbook}
\usepackage{stackengine}
\def\useanchorwidth{T}
\def\stacktype{L}
\def\stackalignment{l}
\def\calup{.2pt}
\def\calover{.15pt}
\def\calbf#1{\calbfhelpA#1 \relax\relax}
\def\calbfhelpA#1 #2\relax{%
  \calbfhelpB#1\relax\relax%
  \ifx\relax#2\else\ \calbfhelpA#2\relax\fi
}
\def\calbfhelpB#1#2\relax{%
  \stackon[\calup]{#1}{\kern\calover#1}%
  \ifx\relax#2\else
    \calbfhelpB#2\relax%
  \fi
}
\newenvironment{calligraphic}%
{\fontencoding{T1}\fontfamily{pzc}\fontseries{m}\fontshape{it}\fontsize{12pt}{12pt}\selectfont}{}%
\renewcommand*{\sectfont}{\normalcolor\usefont{T1}{pzc}{m}{it}}
\begin{document}
   \begin{calligraphic}
   \chapter{test1}
   Test \textbf{this is not bold}\par
   Test \calbf{this is bold with .2pt up shift and .15pt right shift}\par
 \def\calup{.0pt}
 \def\calover{.2pt}
   Test \calbf{this is bold with .0pt up shift and .2pt right shift}\par
   \calbf{cvxc This is a test. This is a test. This is a test. This is a test. 
    This is a test. This is a test. This is a test. This is a test. This is a 
    test. This is a test. This is a test. This fdsfsd is a test. This is a test. 
    This is a test. This is a test. This is adfsdf  test. This is a test. }
   \end{calligraphic}\par
   Test2 \textbf{this is bold}
\end{document}

ZOOM:

LINE WRAPPING: