Portable Latex: Tips For Transferring Custom Styles And Classes Across Systems

The Portability Problem

LaTeX documents rely on various package files, custom style files (.sty), and document classes (.cls) to format the document output. When transferring LaTeX source files across different systems and installations, issues can arise if these supporting files are not properly transported as well.

For example, if your LaTeX document relies on a custom thesis style file that sets the page margins and heading formats, that .sty file must be present on the target system in order to compile the document without errors. Similarly, any special document classes and packages used must be available.

This article provides tips on best practices for making your LaTeX documents portable and avoiding issues when transferring files across different LaTeX installations on various operating systems.

Table of Contents

Using Relative Paths for Files

When including images, custom style files, or other external resources in your LaTeX source, it is best to use relative rather than absolute file paths. For example:

\usepackage{./styles/mycustomstyle}

Here mycustomstyle.sty is located in a subdirectory called styles within the same directory as the LaTeX source file. Using the ./ prefix indicates it is located relative to the source document location.

Compare this to an absolute file path which includes the full path from the root directory:

\usepackage{/users/myname/documents/latex/styles/mycustomstyle}

This full static path will likely break if transferred to another system where that exact directory structure does not exist.

Using relative paths allows for the entire document directory containing images, .sty files, etc. to be transferred anywhere without breaking file imports.

Standardizing Package Versions

LaTeX distributions include various LaTeX packages and these packaging systems can differ across installations. For example MiKTeX on Windows vs TeX Live on Linux will manage packages differently in the background.

Even if the same packages are available on different systems, if the versions are different it could potentially cause issues. For instance if you relied on a feature in version 2.0 of the hyperref package, but the target system only has hyperref version 1.5 available so far.

To avoid such dependency and version issues, consider specifying versions for key packages used in your document preamble. For example:

\usepackage[v1.5]{hyperref}
\usepackage[2022/01/01 v3.0]{graphicx}
\usepackage[2021/03/15 v5.3]{amsmath}

This will force the document to attempt to utilize those specific package versions, failing to compile if unavailable on the target system. Alternatively, you could bring copies of key package files (.sty) to distribute with your document directory as needed.

Exporting Custom Classes and Styles

If your LaTeX document relies on any custom .sty and .cls files created locally, these critical files must be exported alongside your main .tex files to ensure proper compilation.

An easy method of bundling these resources is to create a dedicated LaTeX project folder containing:

Main .tex source file
Referenced image files (.png, .jpg etc)
Any custom .sty files created
Any custom .cls files created

This entire folder can then be easily distributed or transferred to other systems. As long as the custom files are referenced using relative paths, the project should compile anywhere this folder structure is reproduced.

Example Export Script

Manually managing custom style and class files across systems can become burdensome for complex documents. A handy alternative is to create an export script that automatically collects these resources into a portable LaTeX project bundle.

For example the Python script below will recursively scan the source document path for all .tex references to custom .sty and .cls files, copying these resources along with image files into an export directory:

import os
import re
import shutil
import sys

# Path to main tex file 
src_dir = os.path.dirname(sys.argv[1])  

# Output directory to store bundle
bundle_dir = 'portable_package'
if not os.path.exists(bundle_dir):
  os.makedirs(bundle_dir)

# Copy source tex file
shutil.copy(sys.argv[1], bundle_dir)

# Get list of referenced style/class files
ref_files = [] 
with open(sys.argv[1]) as f:
  for line in f:
    match = re.match(r'\\(usepackage|documentclass){([^}]+)}', line)
    if match:
      ref_files.append(match.group(2))
      
# Copy custom style and class files  
for path in ref_files:
  src_path = os.path.join(src_dir, path)
  if os.path.exists(src_path) and (path.endswith('.sty') or path.endswith('.cls')): 
    shutil.copy(src_path, bundle_dir)

# Recursively copy image files  
for root, dirs, files in os.walk(src_dir):
  for filename in files:
    file_path = os.path.join(root, filename)
    if re.match('(jpg|png|jpeg)$', file_path):
      shutil.copy(file_path, bundle_dir)

Simply executing this script on the command line will automatically bundle relevant resources from a LaTeX source document into a subfolder called portable_package. This approach simplifies the task of gathering necessary support files and images for distribution across systems.

Importing Documents on New Systems

When transferring LaTeX source and resources to a new system using the tips outlined above, compiling your documents comes next. Here are some best practices to ensure smooth first-time compilation on an alternate computer:

Confirm the target system meets basic LaTeX installation requirements - e.g. LaTeX distribution present along with sufficient packages/classes. Install any missing pieces first before importing documents.
Transfer the full source document folder to maintain custom file references/paths.
Attempt to compile the main .tex file; address any missing package or dependency errors reported by inspecting the console output after a failed build.
For complex documents with significant package demands or version specificity, also transfer copies of key packages within a local texmf folder to override system defaults as needed.

Following these guidelines when moving LaTeX projects to new environments helps minimize frustrating compilation issues on first build attempts.

Recompiling Documents After Transfer

Even after successfully compiling a transferred LaTeX document on a new system, additional unexpected issues can arise requiring recompilation. Common scenarios include:

Non-portable image formats - If EPS or other graphics formats are unsupported, image placeholders or failures could result requiring new file import.
Appearance inconsistencies - Especially if standardizing package versions, visual style differences like margins or fonts may emerge requiring style file tweaks.
Output formatting issues - Custom environments, floats, or spacing reliance could behave unexpectedly on different LaTeX engines necessitating some formatting adjustments.

Thus it is often valuable to fully recompile documents from scratch at least once after transferring LaTeX projects across operating systems or distribution environments. Be prepared to fine-tune documents further to obtain desired visual consistency.

Troubleshooting Issues After Transfer

When addressing LaTeX compilation or output issues following a document transfer, there are some general troubleshooting strategies to apply:

Carefully inspect all reported errors messages and attempt to address their root cause one by one as needed.
Explicitly test importing any images that do not initially compile using a simple placeholder document.
Comment out and systematically test each imported custom package/class file to identify problematic dependencies.
Make any needed modifications to path locations, style files, custom commands/lengths and recompile in a staggered manner.
Leverage differences in LaTeX engine handling as clues to problems - e.g. via latex vs xelatex vs lualatex compilation.

Additionally, searching online documentation resources and community forums can provide clues for resolution based on specific error messages returned. With persistence, underlying transfer issues can typically be uncovered through systematic analysis.

Best Practices for Portable LaTeX

To ensure LaTeX documents remain fully portable and transferrable across systems/installations, keep these guidelines in mind:

Rely exclusively on relative file paths when importing packages, images and other custom resources.
Standardize versions for non-standard packages utilized and include copies if needed to enforce consistency.
Bundle documents as entire project folders containing .tex sources, images and all custom .sty/.cls files.
Leverage scripts to identify/copy custom files automatically when exporting documents.
Plan to recompile from scratch and perform testing for output consistency after transferring to new environments.
Apply systematic troubleshooting techniques to address any emergent compilation or visualization issues.

Planning ahead for portability and utilizing the recommendations in this article will enable smooth document compilation when needing to produce LaTeX on alternate computers and operating systems.