Adding a Letter to an Image in a Do-It-Yourself Lettrine

Question

Consider the code

\documentclass{book}
\usepackage{lettrine}
\usepackage{tikz}
\setlength{\textwidth}{5.25in}
\begin{document}
\thispagestyle{empty}
\LARGE
\lettrine[nindent = .4em]{\tikz\fill[black] (0,0) rectangle (5ex,7ex);\,}{} would like this box to be a lettered lettrine; more specifically, I would like it to contain a fitted-to-the-box, white, bold capital I. How may this be accomplished? Thank you.
\end{document} 

which produces

QUESTION: How may I add within the box a big, bold (white-colored) letter (such as I) in order to obtain a fairly respectable homemade lettrine? (I got this idea after looking at the post lettrine with image which does not show how to do this.)

Thank you.

Answer 1

Here, I use a simple \colorbox to contain the versal and then scale it to the desired size. EDITED to handle descenders, such as capital Q.

\documentclass{book}
\usepackage{lettrine}
\usepackage{xcolor,scalerel,stackengine}
\setlength{\textwidth}{5.25in}
\fboxsep=1pt
\newcommand\my[1]{\scaleto{\colorbox{black}{%
  \textcolor{white}{\abovebaseline[0pt]{#1}}}}{7ex}\,}
\begin{document}
\thispagestyle{empty}
\LARGE
\lettrine[nindent = .4em]{\my I}{} would like this box to be a
  lettered lettrine; more specifically, I would like it to contain 
  a fitted-to-the-box, white, bold capital I. How may this be 
  accomplished? Thank you.
\lettrine[nindent = .4em]{\my W}{ould} this work as I desire it?  Who 
  can say?  Let us give it the old ``college try'' and see what results.
\lettrine[nindent = .4em]{\my Q}{uestions} remain on the proper method
  to handle descenders.  In this case, I shift all letters up to sit
  fully upn the baseline, even if it means the ``Q'' gets diminished
  slightly in size.
\end{document} 

This approach provides ample opportunity for customization. For example, colors and versal font can easily be adjusted (I also increased \fboxsep by .5 pt, to contain the protruding points on W):

\documentclass{book}
\usepackage{lettrine}
\usepackage{xcolor,scalerel,stackengine}
\setlength{\textwidth}{5.25in}
\fboxsep=1.5pt
\newcommand\my[1]{\scaleto{\colorbox{black!70}{%
  \textcolor{white}{\abovebaseline[0pt]{$\mathcal{#1}$}}}}{7ex}\,}
\begin{document}
\thispagestyle{empty}
\LARGE
\lettrine[nindent = .4em]{\my I}{} would like this box to be a
  lettered lettrine; more specifically, I would like it to contain 
  a fitted-to-the-box, white, bold capital I. How may this be 
  accomplished? Thank you.
\lettrine[nindent = .4em]{\my W}{ould} this work as I desire it?  Who 
  can say?  Let us give it the old ``college try'' and see what results.
\lettrine[nindent = .4em]{\my Q}{uestions} remain on the proper method
  to handle descenders.  In this case, I shift all letters up to sit
  fully upn the baseline, even if it means the ``Q'' gets diminished
  slightly in size.
\end{document} 

Alternately, with the mathrsfs package, defining the color as red!50!black and the versal as $\mathscr{#1}$. Further, I reduce the versal height from 7ex to 6ex:

\documentclass{book}
\usepackage{lettrine}
\usepackage{xcolor,scalerel,stackengine,mathrsfs}
\setlength{\textwidth}{5.25in}
\fboxsep=1.5pt
\newcommand\my[1]{\scaleto{\colorbox{red!50!black}{%
  \textcolor{white}{\abovebaseline[0pt]{$\mathscr{#1}$}}}}{6ex}\,}
\begin{document}
\thispagestyle{empty}
\LARGE
\lettrine[nindent = .4em]{\my I}{} would like this box to be a
  lettered lettrine; more specifically, I would like it to contain 
  a fitted-to-the-box, white, bold capital I. How may this be 
  accomplished? Thank you.
\lettrine[nindent = .4em]{\my W}{ould} this work as I desire it?  Who 
  can say?  Let us give it the old ``college try'' and see what results.
\lettrine[nindent = .4em]{\my Q}{uestions} remain on the proper method
  to handle descenders.  In this case, I shift all letters up to sit
  fully upn the baseline, even if it means the ``Q'' gets diminished
  slightly in size.
\end{document} 

---

SPECIAL SUPPLEMENT FOR BARBARA BEETON

To address the dismay brought on by my handling of descenders like Q in the above approach, I felt compelled to remedy the situation. It still requires a little manual intervention with the Q, both to extend the lettrine lines from 2 to 3, as well as to grow the vertical extent of the Q from the default 7ex height to something larger (here 9ex).

\documentclass{book}
\usepackage{lettrine}
\usepackage{xcolor,scalerel,stackengine}
\setlength{\textwidth}{5.25in}
\fboxsep=1pt
\newcommand\my[2][7ex]{\scaleto{\colorbox{black}{%
  \textcolor{white}{\abovebaseline[0pt]{#2}}}}{#1}\,}
\begin{document}
\thispagestyle{empty}
\LARGE
\lettrine[nindent = .4em]{\my I}{} would like this box to be a
  lettered lettrine; more specifically, I would like it to contain 
  a fitted-to-the-box, white, bold capital I. How may this be 
  accomplished? Thank you.
\lettrine[nindent = .4em]{\my W}{ould} this work as I desire it?  Who 
  can say?  Let us give it the old ``college try'' and see what results.
\lettrine[nindent = .4em, lines=3]{\my[9ex] Q}{uestions} remain on the
  proper method to handle descenders.  In this case, I increase the number
  of lettrine lines from 2 to 3, and I have modified \textbackslash my
  to take an optional argument length, to revise the height of the 
  encased letter.
\end{document}