I TeX therefore iPad


I have a new toy. It’s an iPad. Naturally the first thing that I tried to do was install TeXLive 2011 on it. When that didn’t work, I tried to take it back. When Apple disagreed with my reason (“Not able to run the best typesetting software”), I figured I’d just have to make the best of a bad job.

Actually, that’s a complete load of rubbish. The reason why it is rubbish is quite important to what I plan on writing here, so I’ll explain more below the fold. Above the fold, let me just explain what this article is. It is an account of my early days with the iPad with particular emphasis on anything vaguely relevant to my TeX addiction. If that interests you, read on.

Views and Reviews

This is not a review. Something that I learnt early on was that reviews are useless for making decisions about iPad stuff. They are always out of date and never concentrate on the important stuff. Videos are a bit better – whilst they have the same date issues, in a video you see the whole thing working, including those bits that the reviewer doesn’t think are important. Even so, for actually deciding which application to use, the best thing to do is email the developer. If they don’t answer (in a reasonable time, don’t expect a quick answer the day before the next update of the operating system is released), don’t use the application. If they do answer, they’re the ones who know best the capabilities of the application, and if they are sufficiently intrigued by your scenario, you might just get lucky and get a free copy1.

So this isn’t a review. It’s an account.

The other thing to know before I begin is the circumstances under which I obtained this device. It was a birthday present (so no question of taking it back!). And I wasn’t expecting it. I was actually expecting a Kindle. So anything that this can do beyond reading ebooks is a bonus. And if there’s anything that it can’t do, well, I wasn’t looking for a new device so I can always just boot up the laptop.

So what do I use it for, and what would I like to use it for? Particularly with a view to my TeX addiction.


One of the first things that I discovered was that a colleague was using his iPad for his lectures, which were prepared using beamer. This was quite exciting for me. I switched to using beamer-prepared lectures a couple of years ago, but this semester, because of the lecture room that I’m in, I have to lug a large laptop around with me. The prospect of using the iPad was therefore quite interesting. However, as I’ve been using PDFs for presentations for a couple of years now, I’ve worked out a system that I’m happy with and it has certain aspects that I’d be reluctant to give up. My non-IPad system uses xournal, a program for drawing on top of PDFs. Actually, my version is ever-so slightly hacked (the source code is beautiful: I’m no programmer but figuring out a couple of little hacks was very easy). The key features of the set-up are as follows.

  • Clean, full screen display. This was actually one of my hacks. The external screen mirrors the display, so it’s important that only the absolutely necessary icons be shown.

  • Fast, clean page transitions. Because PDF presentations simulate slide transitions by whole new pages, it is important that page transitions work by simply replacing one page by the next with no fuss so that there is the illusion of new material just appearing alongside the old material. One corollary of this is that the PDF should be processed when loaded, not as each page is rendered.

  • Easy annotation, including highlighting. The ability to do this was what decided me that it was “safe” to use a projector instead of a chalkboard. It is a rare talk where I do not change my mind about what I want to say in the middle.

  • Easy postprocessing of the annotated document. This is actually another of my hacks. A minor addition to xournal makes it possible to save only the annotated pages. Since I now use a wiki for the course pages, I can upload the annotated pages straight from the computer for the students to be able to see straightaway (before, I’d save it as a new PDF and then extract the pages, but as that had to happen later, it often happened much later).

There are plenty of presentation applications for the iPad, and there are plenty of PDF annotation applications. But the right combonation of the two was difficult to track down. In the end, there are four applications that are worth mentioning. Three that are usable, and one “honourable mentions”.

  1. The one that I’ve ended up using most is iAnnotate2. The only real difficulty with this application is that it doesn’t recognise one of the projectors that I regularly use as a projector, just as an external display, and that messes up the projected display. Fortunately, the fullscreen mode works okay and is almost as good as the presentation mode. Its annotation support is excellent (surprise, surprise, given the name) and I can email myself a copy of just the annotated pages which is almost as good as being able to upload them there and then.

    Conclusion: definitely usable, nothing annoying, just needs a little polish on the display mode.

  2. Another that is definitely usable is 2screens. As the name suggests, the focus of this application is on the presentation side. Their aim (as I understand it) is to be a universal presentation application. They certainly have made the presentation aspect very nice, with good use of the dual screens. Their desire to be a universal presentation application does mean that their annotation system is somewhat … unusual – though it makes sense. Since not all presentation stuff comprises slides that can be written upon, the annotation system can be thought of as working by putting a sheet of glass in front of the screen and writing on that. The practical upshot of that is that the annotation is separate from the presentation. In particular, it is possible to change the background without changing the annotations. And once the annotations are cleared, you can’t get them back. A partial fix is to save a copy of an annotated slide before moving to the next. I’m told
    that there are plans to do this automatically, and plans to make these snapshots available to the presentation. Those will be valuable features.

    Conclusion: definately usable, best for when you don’t anticipate all that many annotations. (And practise with the annotation stuff beforehand!)

  3. GoodNotes is a great example of why reviews don’t work. When I first got the iPad I found an application called “eNote Taker” which worked as a presentation application. It then got updated, and renamed to “GoodNotes”. Unfortunately, the update introduced sliding page transitions. So I was going to give this an “honourable mention”. But while I’ve been writing this it’s been updated again and instantaeous page transitions are back (to stay, I hope – I did email the developer to say how useful they would be). So now it’s “definitely usable”.

    Although primarily a PDF annotator, its interface is neat enough that it works well as a presentation application as well. Its simplicity works in its favour as well. Indeed, when using a projector that iAnnotate doesn’t recognise as a projector then I’ll use GoodNotes rather than iAnnotate because there’s less risk of tapping on the wrong part of the screen and bringing up an unwanted menu. It is also the first one that I used for presentations because it was the first PDF annotator that I found without annoying page transitions.

  4. Explain Everything is an application that gets an honourable mention. It’s another presentation application, but it takes annotation seriously. It doesn’t make special use of a separate screen, but in presentation mode then its toolbar is very discreet. Its main focus is actually recording presentations, but you don’t have to use this bit (a Norwegian lecture is 2 hours long which is a bit much for an iPad to record). The only reason that this gets an “honourable mention” instead of “usable” is a strange bug which means that when you load in a PDF from LaTeX then it doesn’t get rendered quite right. There’s a small offset which accumulates, and by the length of one of my beamer lectures the offset is too much.

    Conclusion: if it weren’t for the offset, it would be definitely usable.

In conclusion, it is possible to use an iPad for presentations. A few minor things that can catch you out are: make sure it has a decent charge since the power cable and the VGA output use the same socket; invest in a stylus (or build your own) as it’s much easier to do serious writing with one; I don’t know of a way to have a remote for switching pages so you have to keep returning to the iPad to change slides.

Reading Articles

I have considerably less to say about reading PDFs than presenting them (remember this is not a review, just an account). This is probably because reading a PDF is a fairly normal thing to do with one so there are good applications designed just for that purpose. For reading articles (not ebooks), I mainly use one called GoodReader. Its annotation capabilities are a bit basic (writing, in particular, isn’t great) but are just fine for circling or underlining stuff. It is very easy to load documents into it, downloading from the web or via Dropbox (the unofficial iPad file system!). The fantastic feature of GoodReader is that it is possible to specify a crop for the document (with different settings for even and odd pages if desired). A standard LaTeX document is just about the right size on an iPad screen (in portrait aspect) so long as it is cropped properly.

Having GoodNotes open as the “next application” means that with iOS5 it is really easy to go between the reader and a note-taking application using the four-finger swipe3.

Reading articles on the iPad finally gives me a way to read articles in comfort without having to print large quantities of pages. I can now learn about Khovanov homology while sitting by the swimming pool waiting for my kids to finish their swimming lesson.

Writing Articles

This is perhaps the biggest surprise. It is actually possible to write a LaTeX document on an iPad. There are plenty of text editors, but technical possibility is not enough. It’s also a question of how easy it is, and whether it would get too annoying.

From one of my previous posts, you might guess that one thing that would be quite important would be the keyboard. The standard iPad keyboard is quite limited, just the letters and a couple of other keys. Getting numbers and punctuation involves swapping keyboards which is highly irritating. So the most important feature is to be able to extend and configure the keyboard. Once again it is very difficult to figure out if an application has this facility. Many text editors have extra keys, but it is not clear which have customisable extra keys.

I found an application called Fast Keyboard which adds an extra two rows above the regular keyboard and it is free (supported by adverts, which can be removed for a small fee). What is more, those two rows are completely configurable, and aren’t restricted to single characters. So as well as the obvious backslash and braces, I have a key for \begin{ and one for \end{. I can also partially simulate Emacs’s behaviour with double quotes by having keys for ‘‘ and ``.

Again, though, there is a difference between technically possible and actually being able to do it. “Touch typing” takes on a whole new meaning on a touch screen! My typing method is completely different. Because I tend to use the iPad when I’m not at a desk, I need one hand to hold the iPad so can only type one-handed. But that works. With the small keyboard (in portrait orientation), two hands get in the way of each other. Also, because the keyboard is just below the text, the necessity of typing without looking at your fingers us greatly reduced. So one-handed touch typing with watching what you are doing is actually quite possible. My error rate is a little high, but I’ve not had much pratice yet, and it isn’t excessively so.

I’ll not write a long article on it (I doubt), but a 2500 word blog post is just fine.

Other Things

The phrase “There’s an app for that” is rapidly entering the lexicon, and with good reason. The number and range of applications is quite astounding (and thanks to the amazing Project Gutenberg you can read Astounding on your iPad). Here’s a few more for TeXers to consider.

  • Detexify (the application doesn’t have a web page that I can find). Technically an iPhone application, nonetheless it works fine on the iPad and is fantastic there. If it were an iPad-specific application, I’d say it was worth getting an iPad just for this.

  • miniDraw. So far, this is the best I’ve found that allows me to draw and manipulate vector graphics with cubic beziers – just right for sketching TikZ pictures.


I have a phrase that I use to sum up my attitude to computers:

The computer should do what I want it to do, not the other way around.

It’s been a bit of a struggle, but I think that I have tamed my iPad so that it does now do what I want. I’d also say that the struggle has been worth it because in the course of taming it, I’ve found out a few things that I wasn’t expecting. In fact, adapting it to my work habits (and adapting my work habits to it) has been a lot smoother than with more “traditional” iPad acivities such as music and photos. But that’s another story.

An iPad has features that a TeX-addict can make use of. It certainly is not a replacement for a laptop, or a desktop, but as I said right at the start, I wasn’t looking for one. Rather, I’d say that it is the “missing link” between a computer and a pad of paper.

I can’t think of a better concluding statement than to say that this blog post (of about 2500 words) was written in LaTeX on the iPad, and was variously written while sitting with my feet up on my desk, by the side of the swimming pool, and lying on the sofa. I’m going to ask for a sofa in my office now so that I can make the most of it.

  1. This seems an appropriate time to mention that I got promotion codes for iAnnotate and Explain Everything. 
  2. Application links are to homepages where I can find them. iPad owners can also find them in the App Store. 
  3. If you don’t know, just let your imagination run wild. 

14 thoughts

  1. I’ve spent a few hours with my sister’s Ipad 2 and haven’t tried any of the applications mentioned.

    From the readability/presentation point of view, going with a glossy screen inches the device away from useful and towards toy. That said, my sister uses her Ipad for her gallery to give show off the work of the artists she commissions, and the device is just perfect for that. And the ability to switch between portrait and landscape is very valuable and not really feasible with non-tablet mobile devices.

    For mobile document preparation, I don’t think the Ipad can compete in terms of total efficiency with my Acer Aspire One netbook running Debian/Texlive/Emacs, and costing less than half the current price of the Ipad 2. Uncool, but it’s good at its job. Just how good can you get with this Fast Keyboard app?

    I’m curious about the experience of people who have used the Ipad with a bluetooth keyboard. It’s still going to be a big advantage to have Texlive available locally.

    1. I agree that the shiny screen is a disadvantage when it comes to using the iPad, though as far as presentations are concerned then that isn’t a factor since the presentation is on the Big Screen.

      As to document preparation, I certainly agree that having a laptop with everything present is better with all other things being equal. But over on Photography they have a saying: “The best camera is the one that you have with you.”. There are places where a laptop is just unwieldy or too much to lug around – even a netbook. If there’s no flat surface, I’d rather have an iPad than a netbook. So if I can use a laptop, I will; but if I can’t, then the iPad is a reasonable substitute. I wrote this blog post on it as an experiment, and given my low expectations, the experiment was a success.

      Then there are the areas in which I would rather have an iPad than a computer. Reading articles is the biggest of those for me. I find it very difficult to read a lengthy article on a computer screen, but don’t want to print out 50 pages just to read once. Reading them on the iPad is the best of both worlds.

  2. Great post, Andrew; thanks for sharing it with us! IMHO the first (non)review of the iPad that focuses on the important stuff 🙂

    I would really love to read another one a bit later about your longer-term experiences (when the semester is finished, maybe?)

  3. Might I also suggest AirSketch, which hosts a whiteboard-like service that is simultaneously a web server. Then, while you have to bring a laptop as well (and have the laptop and ipad on the same wireless network) you are wirelessly connected to the projector screen. Bonus: you can pinch/zoom on iPad for annotations and write in a reasonable size on iPad (very large), while the display is appropriately sized on the screen (normal). Downsides are no text boxes for annotations, and actual PDF import is functional but crummy looking. Yu can work through the PDF problem via iBooks and screenshots.

    As for LaTeX compilation, have you investigated TexTouch? It can connect to your pc/Mac (probably not Linux…) and compile .tex documents.

    1. Although being able to roam around would be nice, having to bring in the laptop as well is a serious down-side. If I have to bring in the laptop, I may as well use xournal. Then I can use a remote for switching pages and only need to go back to the desk to do any annotations. While I almost always do some annotations, I don’t do enough for that to be annoying. However, I have some friends who do more interactive things with their iPads and they might find AirSketch useful so I’ll mention it to them. Thanks.

      I took a look at TeXTouch, but not so far as installing it. I didn’t experiment with it (there’s no free version for evaluation) but from the description, I don’t see what it brings more than a generic text editor with Dropbox support and the ability to ssh into the compiling machine. But maybe it does more that I haven’t noticed.

      (In this post, I decided only to mention applications that I actually use and not ones that I’d looked at but decided not to use.)

  4. Hi Andrew

    I am one of the creators of Explain Everything. Thanks for trying out our app!

    How long are the PDF files (# of pages) you are importing from LaTex? We have sometimes noticed the offset problem with documents that are greater than a certain length.

    Great post!

    1. I’ve exchanged a few emails with one of the other developers (Piotr Śliwiński) on this. My PDFs are typically over 100 pages long (because slide transitions are completely separate pages) and the offset is clear after only a few, by 50 pages it is enough that it is unusable. From that conversation, I gathered that it depended a bit on the PDF and that some long PDFs worked fine. I’d like to experiment a bit with this as it might be possible to post-process my PDFs to correct for this, but to do that I’d need an example of a long PDF where it did work. If you could send me one, that would be great. I like having a few different apps that are usable (since I can never be 100% sure that one isn’t going to get “updated” just before a lecture!) so it would be great if a simple tweak would make EE usable. Of course, it would be best if you could fix the offset, but maybe me investigating and experimenting will help identify the problem.

      You can get copies of my lecture notes from my webpage: http://www.math.ntnu.no/~stacey/Teaching/TMA4145h2010/lectures.html

    1. I’ll consider it. Presumably you want a bit more than just “I use xournal for my presentations”. What particularly got you curious? If you give me some hints as to what you might like to read, that would make it easier to write. (Maybe the best place to discuss this is in chat.)

    2. I was mostly interested in your xournal hacks, e.g. the one that got you “Clean, full screen display” and the one that enabled you to save annotated pages, and your workflow for presentations you do with xournal, i.e. how you (technically) do a presentation (not how you make a beamer document but how you work with xournal or any other pdf viewer).

  5. Texpad developers here.

    Texpad for iOS has had a built in LaTeX typesetter, no internet connection required. Most commonly used LaTeX packages are now included, and we expand the distribution with every update (9 updates in the past three months). It is now good enough that one user edits LaTeX on his Mac and typesets on his iPhone because the distribution is leaner, simpler and faster.

    PGF drivers are underway right now and the update with local TikZ/Beamer typesetting should be ready for download in Feburary.

  6. Andrew Stacey – I am interested in the post-processing application of saving only the annotations from xournal pdfs. Can you point me in the “right” direction.

Leave a Reply

Your email address will not be published. Required fields are marked *