alhassy / ob-latex-as-png

Inline arbitrary LaTeX snippets as PNGs in Emacs (•̀ᴗ•́)و

An Org-babel “language” whose execution produces PNGs from LaTeX snippets; useful for shipping arbitrary LaTeX results in HTML or to inline such snippets in Emacs! (•̀ᴗ•́)و

;; Installation
(use-package ob-latex-as-png
  :ensure t)

Table of Contents

1. Screenshot 1: Fancy Writing
2. Screenshot 2: Bubble Diagrams
3. Screenshot 3: Fine-grained Size Control
4. Screenshot 4: Local LaTeX Header Matter
5. Hint: Always redisplay images after C-c C-c
6. Enjoy!

Screenshot 1: Fancy Writing

🌹 Click to see Source!

#+PROPERTY: header-args:latex-as-png :results raw value replace
#+begin_src latex-as-png
\input GoudyIn.fd
\def\fncy#1{\fontsize{50}{60}\selectfont{\usefont{U}{GoudyIn}{xl}{n} #1}}

\hspace{0.15\textwidth}\fncy{EMACS}
\newline
\fncy{ORG}\raisebox{0.5em}{$\sim$}\fncy{MODE}
#+end_src

Note: The Goudy Initalen font exists in uppercase only.

Screenshot 2: Bubble Diagrams

🚀 Click to see Source!

#+PROPERTY: header-args:latex-as-png :results raw value replace
#+begin_src latex-as-png :file example.pdf :resolution 120
   \smartdiagram[bubble diagram]{Emacs,Org-mode, \LaTeX, Pretty Images, HTML}
#+end_src

Note: The extension given to :file does not matter, only the base name is used and a .png is produced. As such, extensions are completely optional (and discarded when provided).

Screenshot 3: Fine-grained Size Control

Instead of using :resolution as in the previous screenshot, you can get fine grained control of the size of the resulting PNG by using LaTeX's picture environment.

🌱 Click to see Source! 🗝

#+begin_src latex-as-png :file using-picture-environment
\input GoudyIn.fd \input Acorn.fd
\def\light#1{\huge \usefont{U}{Acorn}{xl}{n} #1}
\def\thick#1{\fontsize{50}{60}\selectfont \usefont{U}{GoudyIn}{xl}{n} #1}
% \fontsize{X}{Y} ⇒ Write with point size X, using Y point size between lines

\pagecolor{brown}

\begin{picture}(124,60)
\put(0,0){\thick{ORG}}
\put(18,42){\light{EMACS}}
\put(0,55){\rotatebox{-45}{\scriptsize \LaTeX}}
\put(109,43){\rotatebox{45}{\scriptsize \texttt{HTML}}}
\end{picture}
#+end_src

Screenshot 4: Local LaTeX Header Matter

You can add arbitrary LaTeX header matter —i.e., the stuff before LaTeX's \begin{document}— by using having a line with just “ % in ” to separate the header from the main PNG body.

🐺 Customisation and Global Headers 🗝

(defvar ob-latex-as-png-header '("\\usepackage{smartdiagram}")
  "The LaTeX preamble used for executing latex-as-png source blocks.

This is generally any LaTeX matter that may appear before \\begin{document}.")


(defvar ob-latex-as-png-header-separator "% in"
  "A literal expression that separates local LaTeX header matter from the body.

Everything before the separator is matter that is necessary
to produce a PNG from the primary LaTeX.")

🌱 Click to see Source! 🗝

#+begin_src latex-as-png :results replace :file neural-networks
\usepackage{neuralnetwork}
% in
\begin{neuralnetwork}[height=4]
  \newcommand{\x}[2]{$x_#2$}
  \newcommand{\y}[2]{$y_#2$}
  \newcommand{\hfirst}[2]{\small $h^{(1)}_#2$}
  \newcommand{\hsecond}[2]{\small $h^{(2)}_#2$}
  \newcommand{\mylinktext}[4] {
    % from layer=#1, from node=#2
    % to layer=#3, to node=#4
  \ifnum1=#1\relax
     \ifnum3=#4\relax $w^{#1}_{#4,#2}$ \fi
  \else \fi
  }
  % Then assign it:
  \setdefaultlinklabel{\mylinktext}
  \inputlayer[count=3, bias=false, title=Input\\layer, text=\x]
  \hiddenlayer[count=4, bias=false, title=Hidden\\layer 1, text=\hfirst] \linklayers
  \hiddenlayer[count=3, bias=false, title=Hidden\\layer 2, text=\hsecond] \linklayers
  \outputlayer[count=2, title=Output\\layer, text=\y] \linklayers
\end{neuralnetwork}
#+end_src

( Learn more about the neural networks LaTeX library here. )

Hint: Always redisplay images after C-c C-c

Place the following incantation in your init (•̀ᴗ•́)و)

;; Always redisplay images after C-c C-c (org-ctrl-c-ctrl-c)
(add-hook 'org-babel-after-execute-hook 'org-redisplay-inline-images)

Enjoy!

ob-latex-as-png's Issues

File paths containing "." cause export errors

I'm not sure that string splitting on "." here is the right move to get the file path without extension:

ob-latex-as-png/ob-latex-as-png.el

Line 107 in d21d436

(file (car (split-string file.ext "\\.")))

If I use a path like ../img/whatever.png the filename is just the empty string, which is not ideal. Locally I replaced this binding with (file-name-sans-extension file.ext) and it seems to work much better.

Files should not clutter user-emacs-directory

• Every operation that I perform creates three files
  {tex,png,pdf}, which are all stored in my ~/.emacs.d/
  directory (variable user-emacs-directory).

• I was expecting any created files to be stored elsewhere:

  • in order to avoid cluttering

  • in order to tightly associate the files to its parent org file.

• Some options that would make sense to me:

  • A dedicated subfolder of 'user-emacs-directory'. The disadvantage
    of this option is that it collects files from many parent org
    files in a single location, ie. no tight association between
    parent org file and children {tex,png,pdf} files.

  • A dedicated sub-folder at the org-file's location, possibly with a
    naming convention that includes the org-file's name. For example,
    files created for /home/alice/Documents/foo.org would be
    stored in sub-folder /home/alice/Documents/foo_org_ob_files/.

• I wasn't expecting so many files to persist, when only the png file
  is used. The other two files seem like clutter that should be
  automatically deleted.

• I'm a brand new user to your package. I think it's a great
  contribution to Emacs and org-mode. Thanks for sharing it with
  everyone.