## beamer developments

I’ve been looking after beamer for a few years, largely ‘by accident’ (this seems to happen quite a lot). Relatively recently, I moved the code from BitBucket to GitHub, largely because there’s a slow drift there for LaTeX projects. The advantage of that is the chance to pick up additional help.

Eagle-eyed readers will have noticed that over the last few months there have been a lot of beamer check-ins from Louis Stuart. He’s doing excellent work on tackling a lot of tricky beamer bugs, and I hope this will mean a better user experience. Of course, changing a complex product like beamer does have some risks, and so it’s also important to get the release set up working smoothly. To that end, I’ve migrated from some custom Makefile structures to using l3build (with some new features in the latter to help). That should mean a more regular release schedule.  It also means we can integrate testing into the coding: currently there is just the one test, but I’d welcome additions!

## LaTeX2e kernel development moves to GitHub

The LaTeX team have two big jobs to do: maintaining LaTeX2e and working on LaTeX3 (currently as new packages on top of LaTeX2e). For quite a while now the LaTeX3 code has been available on GitHub as a mirror of the master repository. At the same time, the core LaTeX2e code was also available publicly using Subversion (SVN) via the team website. At least in the web view, the latter has always been a bit ‘Spartan’, both in appearance and in features (only the most recent revision could be seen).

Coupled to viewing the code for any project is tracking the issues. For LaTeX2e, the team have used GNATS for over twenty years. GNATS has served the team well, but like the web view is Subversion is showing its age.

We’ve now decided that the time is right to make a change. Eagle-eyed users will already have spotted the new LaTeX2e GitHub page, which is now the master repo for the LaTeX kernel. We’ve not yet frozen the existing GNATS database, but new bugs should be reported on GitHub. (For technical reasons, the existing GNATS bugs list is unlikely to be migrated to GitHub.)

Frank Mittelbach (LaTeX team lead developer) has written a short article on the new approach, which will be appearing in TUGboat soon. As Frank says, we hope that most users don’t run into bugs in the kernel (it is pretty stable and the code has been pushed pretty hard over the years), but this new approach will make reporting that bit easier and clearer.

Accompanying the move of LaTeX2e to GitHub, the LaTeX3 Subversion repository has also been retired: the master location for this is also now on GitHub. So everything is in a sense ‘sorted’: all in one place.

Of course, the team maintain only a very small amount of the LaTeX ‘ecosystem’: there are over 5000 packages on CTAN. To help users know whether a bug should be reported to the team or not, we have created the latexbug package.  An example using it:

\RequirePackage{latexbug}

\documentclass{article}

\begin{document}

Problems here

\end{document}



will give a warning if there is any code that isn’t covered by the team (and so should be reported elsewhere). We hope this helps bugs get to the right places as easily as possible.

I handled most of the conversion from Subversion to Git, and I’d like to acknowledge SubGit from TMate Software for making the process (largely) painless. As LaTeX is an open source project, we were able to use this tool for free. We used SubGit for the ‘live’ mirroring of LaTeX3 to GitHub for several years, and it worked flawlessly. The same was true for the trickier task of moving LaTeX2e: the repo history had a few wrinkles that we slightly more difficult to map to Git, but we got there.

## l3build development picks up the pace

The LaTeX team have over the past three years created l3build, a ‘proper’ tool which takes our previous testing and release scripts and converts them into some that can be used more widely of LaTeX developers. I talked about the early work some time ago, and Frank Mittelbach and Will Robertson also wrote about it for TUGBoat.

Promoting l3build as a general tool means that new ideas come up, and we’ve been working on that (as well as other things) quite a bit. To keep developments clear, we’ve recently moved the l3build code to a new home on GitHub. This means it’s now separate from the main LaTeX3 repository, but that the history is clearer. This change has meant new ideas have come ‘out of the woodwork’, and have started accumulating in the issue tracker. It looks like an exciting time for l3build: I’m expecting more features to appear and for that to help new developers pick it up as their release technology. Hopefully the result will be more well-designed and tested LaTeX code.

## TeX Live 2017 Pretesting

Eager TeX users will have noticed that a few days ago TeX Live 2016 updates were frozen for ever. We now have the pretest available for TeX Live 2017. As always, using pre-release software is not without risk, but as you can install it in parallel with the older releases there is not a big problem. The LaTeX team will be updating a few things on CTAN to go into the new release, and I’ll probably mention some of that in future posts. A quick look over the changes tells us that there are minor (and perhaps not-so-minor) engine changes to explore: I’m particularly keen to try out the new XeTeX math mode approach, using HarfBuzz.

As I mentioned a little while ago, I’ve moved the hosting for my blog and added https access as-standard. Doing that, I of course had to take a stab at how big a hosting package to buy. I get a steady set of hits, according to WordPress’s JetPack plugin about 5000/month. So I went for a hosting package that would easily cover that.

However, it seems that somewhere there are some more visitors! I got a mail from SiteGround saying that the site’s been using too much CPU time based on what I’ve paid for. Looking over the stats, this is not anything about my setup but is one way or another ‘real’ hits. I can’t be sure if they are real people or spam-like bots, of course, but there’s only one solution: upgrade my hosting account. Hopefully this is all transparent to readers: should mean things continue to work smoothly.

## Checking over the beamer codebase

Anyone who is watching the beamer GitHub repository will notice quite a lot of checkins, starting from the beginning beamer.cls and working forward. Most of these are ‘internal’ changes, so readers might wonder what is going on.

I’ve been involved with beamer for a while, but have not really taken a good look over the code yet. Several of the entries in the issue list are quite subtle, and it’s clear that a proper tidy-up of the code is needed to sort them out. That means addressing several internal inconsistencies, but it’s also helpful for me to get the code into a form I’m used to. So there are a mix of cosmetic changes in with some real improvements in the code.

Hopefully I’ll not introduce and new issues doing this work. However, it’s not easy to avoid changing behaviour in LaTeX, especially as beamer is somewhat delicate in the first place. So if anyway is keen to help with the work, simply grabbing the development code from time to time and making sure it doesn’t break existing presentations would be very helpful!

The LaTeX Project have been making efforts over the past few years to update support in the LaTeX2e kernel for XeTeX and LuaTeX. Supporting these Unicode-enabled engines provide new features (and challenges) compared to the ‘classical’ 8-bit TeX engines (probably pdfTeX for most users). Over recent releases, the team have made the core of LaTeX ‘engine-aware’ and pulled a reasonable amount of basic Unicode data directly into the kernel. The next area we are addressing is font loading, or rather the question of what the out-of-the-box (text) font should be.

To date, the LaTeX kernel has loaded Knuth’s Computer Modern font in his original ‘OT1’ encoding for all engines. Whilst there are good reasons to load at least the T1-encoded version rather than the OT1 version, using an 8-bit engine using the OT1 version can be justified: it’s a question of stability, and nothing is actually out-and-out wrong.

Things are different with the Unicode engines: some of the basic assumptions change. In particular, there are some characters in the upper-half of the 8-bit range for T1 that are not in the same place in Unicode. That means that hyphenation will be wrong for words using some characters unless you load a Unicode font. At the same time, both LuaTeX and XeTeX have changed a lot over recent years: stability in the pdfTeX sense isn’t there. Finally, almost all ‘real’ documents using Unicode engines will be loading the excellent fontspec package to allow system font access. Under these circumstances, it’s appropriate to look again at the standard font loading.

After careful consideration, the team have therefore decided that as of the next (2017) LaTeX2e release, the standard text font loaded when XeTeX and LuaTeX are in use will be Latin Modern as a Unicode-encoded OpenType font. (This is the font chosen by fontspec so for almost all users there will no change in output.) No changes are being made to the macro interfaces for fonts, so users wanting anything other than Latin Modern will continue to be best served by loading fontspec. (Some adjustments are being made to the package to be ready for this.)

It’s important to add that no change is being made in math mode: the Unicode maths font situation is not anything like as clear as the text mode case.

There are still some details being finalised, but the general approach is clear and should make life easier for end users.

## TeX on Windows: TeX Live versus MiKTeX revisited

On Windows, users have two main choices of TeX system to install: TeX Live or MiKTeX. I’ve looked at this before a couple of times: first in 2009 then again in 2011. Over the past few years both systems have developed, so it seems like a good time to revisit this. (I know from my logs that this is one of the most popular topics I’ve covered!)

The first thing to say is that for almost all ‘end users’ (with a TeX system on their own PC just for them to use), both options are fine: they’ll probably notice no difference between the two in use. It’s also worth noting that there is a third option: W32TeX. I’ve mentioned this before: it’s popular in the far East and is where the Windows binaries for TeX Live come from. (There’s a close relationship between W32TeX and TeX Live, with W32TeX more ‘focussed’ and expecting more user decisions in installing.)

Assuming you are going for one of the ‘big two’, what is there to think about? For most people, it’s simply:

• Both MiKTeX and TeX Live include a ‘full’ set of TeX-related binaries, including the engines pdfTeX, XeTeX, LuaTeX and support programs such as BibTeX, Biber, MakeIndex and Xindy.
• The standard installer for MiKTeX installs ‘just the basics’ and uses on-the-fly installation for anything else you need; the standard install for TeX Live is ‘everything’ (about 4.5 Gb!). Which is right for you will depend on how much space you have: you can of course customise the installation of either system to include more or less of the ‘complete’ set up.
• MiKTeX has a slightly more flexibly approach to licensing than TeX Live does: there are a small number of LaTeX packages that MiKTeX includes that TeX Live does not. (Probably the most obvious example is thesis.)
• TeX Live has a Unix background so the management GUI looks slightly less ‘standard’ than the MiKTeX one.
• TeX Live has a strict once-a-year freeze,which means that to update you have to do a fresh install once a year. On the other hand, MiKTeX versions change only when there is a significant change and otherwise ‘roll onward’.

So the decision is likely to come down to whether you want auto-installation of packages. (If you do go for MiKTeX on a one-user PC, choose the ‘Just for me’ installation option: it makes life a lot simpler!)

For more advanced users there are a few more factors you probably want to consider

• TeX Live was originally developed on Unix and so is available for Linux and on the Mac (and other systems) as well as Windows; MiKTeX is a Windows system so is (more-or-less) Windows-only. So if you want exactly the same set up on Windows and other operating systems, this of course means you need to use TeX Live.
• Both systems have graphical management tools as well as command line interfaces. They have a lot in common, but they are not identical (in particular, MiKTeX tends to emulate TeX Live command line interfaces, but the reverse is not true).
• The engine binaries in TeX Live are (almost) never updated other than in the yearly freeze period, meaning that for a given release you know which version of pdfTeX, etc., you’ll have: MiKTeX is more flexible with such updates. (At different times, one or other of the systems can be more ‘up to date’: this is not necessarily predictable! The W32TeX system often has very up-to-date testing binaries.)
• The two systems differ slightly in handling how local trees are managed (places to add TeX files that are not controlled by the TeX system itself). TeX Live automatically expects <installation root>/texmf-local to hold system-wide ‘local’ additions and <user root>/texmf to hold per-user additions, whereas MiKTeX has no out-of-the box locations, but does make it easier to add and remove them from the command line. MiKTeX also makes it easy to add multiple per-user trees, whereas for TeX Live there’s more of an assumption that all user additions will be added in one place. (This makes it easier in MiKTeX to add/remove local additions by altering a setting in the TeX system rather than deleting files.)
• TeX Live has a team doing the work; MiKTeX is a one-man project. This cuts both ways: you know exactly who is doing everything in MiKTeX (Christian Schenk), and he’s very fast, but there is more ‘spread’ in TeX Live for the work.
• For people wanting to step quickly between different versions of TeX system, the fact that TeX Live freezes once a year makes life convenient (I have TeX Live 2009,2010, 2011, 2012, 2013, 2014, 2015 and 2016 installed at present, plus MiKTeX 2.9 of course!) You can switch installations by adjusting the PATH or by choosing the appropriate version from your editor, so have a ‘fall back’ if there is an issue when you update.
• TeX Live has build-in package backup during maintenance updates.

## Blog spring-cleaning

As I’ve just moved where the blog is hosted it seemed like a good opportunity to do a bit of tidying up. Regular readers will notice that the categories have been updated, hopefully making it easier to find things. Suggestions on any new arrangements are welcome. I’ve also fixed a few missing files in older posts (the odd re-install means that not 100% of the older content is right!). I’ve also revised the static pages (About, Packages and Contact) to make sure they are up to date: the package list and my PGP key are now right! At the ‘back end’, I’ve adjusted a few WordPress plugins and generally made sure everything is as organised as it should be.  I’ve also tweaked a few parts of the layout, including adding the very-commong ‘quite share’ buttons. So hopefully the blog is tuned up for the future!