lardbucket: general

12/25/2016

Merry Christmas, Once Again

Filed under: General — Andy @ 12:00 am

It seems these days I’m basically only doing Christmas updates on my blog, which is probably a shame. Unfortunately, I don’t have anything all too public to update on. Work is going well, but is of course almost entirely NDA’d and so I can’t really say much about it, and what I can say isn’t worth a blog post.

More generally this year, however, it seems as though a number of people have been discouraged by political, economic, or other changes over the year. I can generally agree with some of them, as it seems as though a number of US (and potentially, world) policies are likely to change for the worse over the course of the next year. However, it’s also worth pointing out that a number of good things have happened (or become noticeable) this year:

* USB C became popular (though it was approved in 2014)
* Apple (semi-)successfully refused to provide assistance unlocking a targeted iPhone 5C (and, according to them, does not have the ability to provide such assistance on newer devices)
* The United States has begun to normalize its relationship with Cuba
* The Dow Jones Industrial Average has hit yet another all-time high

And of course there were many other “regular” good events. I’m sure I’m forgetting many major events, too.

Despite this, things could always be better. My plan for the coming year – and I’d encourage others to do similarly – is to find more areas where I can help make positive changes, and push to make those changes. Be they individuals or organizations who simply need a bit of support, or entirely new projects, the coming year promises to be one where many important things will be decided (as with every year, of course), and it’s important to remember that simply sitting on the side (or Twitter, or Facebook, or etc.) and wishing for things to be better is insufficient.

And with that, I’ll leave you with a link to the seasonal Darlene Love cover of A Marshmallow World.

Merry Christmas, everyone!
Andy Schmitz

12/25/2015

Merry Christmas, 2015

Filed under: General — Andy @ 12:00 am

And so we’re about to round out 2015. I haven’t done much public of note (other than what’s already documented on this blog), but hopefully everyone has had a productive and enjoyable year. Here’s to a 2016 that’s even better.

5/31/2015

Sunsets

Filed under: General — Andy @ 8:27 pm

sunset

If you’re a U.S. citizen under 27 years old, the sunsetting of the USAPATRIOT Act’s Section 215 provision at midnight tonight will mark the first time since before you were a teenager that the U.S. government will not have legal cover to collect data on every phone call you make. (Barring yet more secret interpretations of existing laws.)

Reasonable people can have reasonable debates about what surveillance should be allowed. For example, it’s reasonable to allow police to follow a murder suspect. However, these debates must be had, must be had in public, and must include the public. The USAPATRIOT Act had none of these qualities, and it is high time that some of its sections have now “sunsetted”.

While several portions of the act will likely be reauthorized in the coming days, potentially with some reforms, it is important to not simply accept minor changes as the only possibility. We can – and should – continue to protect privacy as an important civil liberty.

11/30/2014

2012 Book Archive: Now With PDFs

Filed under: General — Andy @ 10:58 am

Almost two years ago, I launched (what became) my 2012 book archive. There’s a bit of background on that project on that page. While there have been a few minor developments since then, none of them have been noteworthy enough to document here. Recently, however, I decided that I would try to make PDF copies of the books. I wanted these to be good-quality PDFs, as although a number of PDFs of the books had circulated from other groups in the past, they weren’t particularly visually appealing: they were essentially what you would get by quickly printing each of the HTML files from the publisher.

My guess was that a simple HTML file with all of the book content could be combined with a quick print CSS style and get good-quality output without too much effort. I figured that with a decent number of iterations on the book CSS and test runs, the project might take a week or so. Over two months later, I’m finally set to release the PDFs. I’ve made a few notes of the things that I did along the way, in case anybody finds them useful in the future.

If you just want the PDFs, you can visit the 2012 book archive and download them there. There are a few ways to download each book: you can download a whole-book PDF file, or a PDF for each chapter. Both are accessible from a book’s table of contents, and the whole-book PDFs can be downloaded from the archive’s book list as well.

Getting a PDF

It’s worth noting that the content I have from the books is already in an HTML format, not necessarily the raw input to a book creator. I decided early on to try to work with HTML and CSS, because although the HTML I have is structured and could probably be parsed into a different format, doing that correctly for over a hundred books would be iffy. With that said, the HTML was well-structured, and lent itself to easy use of CSS to style specific things.

If you’ve been following CSS development, there are a lot of features in CSS that are supposed to allow styling of printed content. Unfortunately, support for some of these in browsers is spotty, and they don’t necessarily provide all of the features that you’d like when styling a book. (In particular, footnotes, page-relative positioning, page numbering, and PDF bookmarks are all difficult. There are likely other features I’ve forgotten about as well.)

At first, I was hoping to be able to use something like wkhtmltopdf, which wraps WebKit and converts an input file to a PDF. This gave me a number of problems, and didn’t seem to support the concept of pages as natively as would be desirable. (It’s still impressive that they managed to get the project to work as well as it does, but it doesn’t produce nice-looking books yet.) After that, I decided that perhaps Firefox’s support for printing would work for me: it works pretty well with many of the CSS printing features, and I can probably script Firefox to output PDFs if I want. Unfortunately, I again ran in to bugs with the rendering. I don’t recall the details at the moment, but I believe that content had a tendency to not wrap between pages in the right spots. Either way, this sent me in search of a high-quality PDF rendering solution.

If you look online for advice about generating PDFs from HTML, you will inevitably run upon many people suggesting PrinceXML (or, as it seems to be rebranding itself, Prince). They’re probably right. It is a commercial piece of software in a case where I had hoped to use free software, but it is still the best solution I have found by far, both in ease of use and functionality.

Princely Things

Prince itself is not cheap. A personal license is $495 at the time of writing, and even that may not cover what I intend to do in terms of converting books automatically. (To be clear, it might be covered, but only just barely if it is. I haven’t asked, for reasons I’ll explain shortly) If you are doing anything serious with Prince, you’re probably looking at a $3800 license per server generating PDFs, or a $1900 one if you’re only doing academic things. Upgrades are available for an additional annual cost. To be clear, if you’re generating revenue from the PDFs (or even just saving yourself loads of time), Prince is almost certainly worth every penny, but it’s prohibitive for side projects.

For non-commercial projects, Prince offers a free version with the requirement that you allow it to add a logo and link to the corner of your document’s first page, link to their website wherever you have Prince PDFs for download, and link to their website on a sponsors/partners page. This is mostly unintrusive (although a tad confusing at first: I’ve considered trying to style in a little “Made with” above the logo to explain why it’s there), and very nice of Prince to allow. (To get the “Non-commercial” license, just download the software: you don’t need a special license key or anything.)

In fact, I had a question about their licensing (“The books are licensed under a Creative Commons license that doesn’t allow me to add restrictions to them, so is it required for people who receive the PDFs from me to keep the Prince logo on them? If so, I can’t use the noncommercial license.”), emailed them, and got an email back quite quickly from Håkon Wium Lie, Prince’s Director (not to mention CTO at Opera and founding member of the Pirate Party of Norway). He’s definitely on top of things, and was quite happy to help. (The answer is no, other people can do whatever they want to the PDFs. In my case, they’re still subject to the Creative Commons license they always were, but that’s not because of Prince.) Later, I had a question about how to get something to render correctly (a somewhat minor, obscure layout bug), and quickly received a comment from Mike Day, the CEO, noting that they were looking into the issue. When I followed up, the bug hadn’t yet been fixed (it undoubtedly has tricky interactions with their page layout code), but I quickly received an alternative suggestion complete with example code. Definitely a pleasant experience all the way around.

If you’re looking for a cheaper option to start with, you’ll probably run into DocRaptor as well. DocRaptor started out as Prince-as-a-service, providing an API to allow people to generate PDFs using Prince. It now appears to support Excel files, although I haven’t looked in to those features. For many people, the benefits of being able to rely on DocRaptor to scale up as your workloads do (they claim “thousands of documents a second”) and the lower initial costs are probably a great benefit. They also provide well-supported libraries for a number of languages, where Prince usage is largely done by command line (although Prince has a PHP API as well). Overall, DocRaptor almost certainly provides benefits for many people. However, their plans aren’t super cheap either, and they’re targeted at recurring use, not one-shot uses like mine. I generated over 2500 PDFs in my final output (one per book, plus one per chapter), which would probably have cost me $149 in a month, assuming I didn’t want to tweak them later. Still far cheaper than the cheapest Prince license, but pricey for a personal side project like mine.

DocRaptor does have a 7-day free trial, which probably would have allowed me to generate whatever I wanted during that time, but that’s not exactly ideal, either. (Nor do I mind paying something for the service, but over a hundred dollars a shot is high for my purposes.) I emailed the DocRaptor folks about a pay-as-you-go plan (so I wasn’t paying monthly fees when I wasn’t using the service), because I had found references to such a plan elsewhere. I got a very nice response from Matt Gordon, the “lead vocalist” for the group running DocRaptor. Unfortunately, they no longer offer that plan, because they found that disproportionately more of their support costs (and they do provide good support) were going to users who didn’t spend much on the service anyway. We had a nice conversation about the possibility of plans that might support alternative uses such as mine, but it doesn’t sound like there’s anything planned in the immediate future. (I can’t blame them, as they need to make money and do what makes sense for their business to continue existing.) They did make a very nice offer (I won’t disclose the details) that I turned down for unrelated reasons, but they’re definitely nice folks too.

My conclusion is that you pretty much can’t go wrong with Prince or DocRaptor. Both have very nice and responsive folks behind them, and seem to be quite well done.

Tables of Contents and Bookmarks

One of the things relatively unique to printed books is cross-references with page numbers. Most of the book content doesn’t include these. This is primarily because any existing cross references are links to a specific section, and I didn’t think it necessary to include a page number along with the section number. However, the table of contents for the book definitely benefits from page numbers. Pulling a table of contents together in Prince is relatively easy. It could possibly be done automatically with JavaScript, but I chose to create taables of contents in a Ruby preprocessor as I was assembling whole-book files anyway. Prince makes it easy to include page numbers for links to given anchors, so I only needed to pull out the anchor for each section. (Luckily for me, I already had the anchors in a database.)

Secondly, I wanted to make sure that chapters and sections were listed in the PDF list of bookmarks. This list is sometimes useful when navigating a book in a PDF viewer, although some viewers don’t show it. Prince again makes this quite easy, simply requiring a CSS annotation for the items you wish to be bookmark headings. (In fact, by default it uses h1-h6 tags, but I disabled that default because it picked up way too many bookmarks.)

Optimization

In creating the full-book files, I noticed that some books created particularly large files. In general, this appeared to be because they embedded the full source images, rather than resampling them. While an option to resample the images inside Prince would be great, it doesn’t exist at this time. Some of the source images were quite large, and clearly intended to be printed at >= 300 dpi, while most users of the PDFs wouldn’t benefit from such images. My first attempt at reducing file size was to use Ghostscript to resample the images. Ghostscript has some features that work similarly to the now-unavailable Acrobat Distiller, and seemed likely to do the job. Unfortunately, after getting Ghostscript working (Ubuntu 14.04’s version appears to crash on larger documents, but 14.10’s works), I found that it removed page numbering information and bookmarks. The next step was to try to export this metadata using PDFtk before using Ghostscript, and then import it again afterward. Unfortunately, while PDFtk will output page numbering details, it won’t import them into a PDF, and there doesn’t appear to be any easily-available way to do so.

So, I temporarily abandoned the option to resample the images using Ghostscript. (It also may or may not have been worth it in the first place: some Ghostscript-generated files were larger than the Prince originals, so I had to handle both cases.) It may be worth patching Ghostscript in the future to keep the metadata around, but that seems likely to be quite involved. In many cases, you may get some benefit out of using Ghostscript with appropriate options (“gs -q -sDEVICE=pdfwrite -dPDFSETTINGS=/printer -dBATCH -dNOPAUSE -sOutputFile=[outfile] [inputfile]” seems to work well besides the additional metadata), but it was unfortunately unsuitable for my purposes at this time.

Chapter Files

Following up on the “whole book PDFs can be pretty big” issue, and after trying to open some such books and experiencing slow loading times, I decided that it may be appropriate to create one PDF per chapter as well as the whole-book PDF. My first pass at creating these PDFs was to use PDFtk to pull out just the pages from a given chapter. This posed a few problems: first, I had to figure out which pages belonged to which chapter. Luckily, the bookmarks inserted by Prince, combined with PDFtk’s metadata output, gave me the starting page for each chapter (although for a few minor reasons, this link was a bit iffy: the generated bookmark title did not always match the section name I had in my database), and I could assume that a chapter ended just before the next one began. Unfortunately, this ran into the same problem I had before: I would lose the page numbering and bookmarks. (Not to mention the fact that I would need to separately render a new first page to describe the licensing and get the Prince logo back on the first page.) Finally, I decided to simply depend on Prince once again.

I got Prince to log the page number and ID for each chapter heading by using a ::before psuedo-class with a content property of “prince-script(log, counter(page), attr(id))”, and a small “log” function in the JavaScript on each page. This allowed me to use the IDs to match up with my database, and easily identify where each chapter started. Because I already had whole-chapter HTML files, I could then use those HTML files to render the chapter in Prince, and everything would still be in sync, without having to try to render and merge together separate front pages for each chapter. (I still needed to get the page numbers to Prince for rendering purposes, but for this, I simply placed the page number in a CSS block in the HTML file.)

This solution appears to have worked surprisingly well, with the page numbers matching up where expected. Because the files were rendered separately, there is the possibility of some unforeseen issue (I certainly didn’t inspect the thousands of files by hand), but it seems unlikely.

Math

Finally, when reviewing one of the math textbooks in the collection, I noticed that Prince’s MathML rendering wasn’t particularly great. It is definitely better than nothing, but the rendering quality did leave something to be desired. Unfortunately, the most common web-based solution here, MathJax, doesn’t work very well with Prince. (This is a noted todo item on Prince’s release notes, but it’s not available yet.) After stumbling through a number of other options to try, I ended up using PhantomJS together with MathJax to prerender the math to MathJax’s “HTML-CSS” output (the SVG output didn’t look very good and produced a very large PDF file after the required fixes to make Prince display the SVG output). I forced MathJax to use the STIX fonts (which I installed on my computer), and after the math was rendered, I output the document’s HTML form again (after removing the MathJax wrapper divs). This produced files with reasonably good-looking math, the way they were intended to look. The prerendering code hasn’t been published yet because I haven’t taken the time to clean it up, but if someone is interested, I can definitely post it.

Prerendering with MathJax is a step that seems to have very poor asymptotic time complexity. I haven’t formally benchmarked it, but a chapter’s sections took about two minutes to prerender in total, while the whole chapter itself took roughly twelve minutes to prerender. The whole book took roughly four days to prerender. It’s not clear why this occurred, but the prerendering did eventually succeed. It’s also not clear if this is a bug in MathJax, or simply some inefficiency in PhantomJS, so I have yet to report it as a bug to either project (and may never report it – it’s unlikely to come up in common use).

Fin

So, to summarize, getting PDFs of a quality I’m comfortable with took quite a bit of effort. In the end, Prince does most of the work, and I rarely had problems with Prince itself. I think it was worth the effort, at least for a personal learning experience. Hopefully the books will be useful to other people as well. Once again, they’re all available at http://2012books.lardbucket.org. Please feel free to copy or redistribute them as you see fit, pursuant to the terms of the associated Creative Commons by-nc-sa license.

Andy Schmitz

P.S. If you’re interested in any of the print-specific (or Prince-specific) things I did to make the books look decent when printed, it’s all left in the book’s CSS file toward the bottom, under the “prince” @media type. Feel free to reuse any of that styling for any purpose you see fit, in any situation. I do not believe it is covered under the Creative Commons license: you may consider it to be public domain.

12/25/2012

Merry Christmas, Again

Filed under: General — Andy @ 12:00 am

Another year has passed, and with just one [other] published post here. I’m slowly starting to have more discretionary time, and to get some projects closer to completion. Barring any major surprises, I should have at least one or two things to release next year. (The problem, of course, with long-running projects is that there are few of them, and if I should decide for whatever reason to not release them, they tend to disappear entirely.)

In the arbitrary milestones department, GraphSketch passed 1.5 million graphs delivered a while back, and I should really pay attention for the 2 million milestone that’ll be coming up sooner or later. I’ve also obtained a full-time job, which surprisingly seems to take less time than school did at times. It seems to be pretty nice, although, as with many things, I haven’t yet taken the time to step back and thoroughly examine how it’s going. There will probably be more comments on the job in the future, but for the moment, allow me to disclaim everything posted here and say that unless an exception is clearly noted in a post, the posts on this blog represent only my own views (if that), and have never been, and will never be intended to represent the opinions of my employer, school, friends, colleagues, or anyone else.

So, this makes for a particularly lackluster sometimes-annual update, but it’s about everything I have to say. Have a Merry Christmas if that’s your thing, and have a great new year when that rolls around. With any luck, I’ll have something new to post in January.

Until then,
Andy Schmitz

4/4/2011

Portrait: Linux System Management Tool

Filed under: General — Andy @ 3:13 pm

So, over the past year or so, I’ve been working on a project I’m calling Portrait. It’s [going to be] a piece of open-source software system administrators can use to manage Linux computers. Unfortunately, there’s still a fair amount of work to be done on Portrait, because my free time is pretty sparse. I’d also like to launch a hosted version of Portrait, which people can use if they don’t want to deal with setting up and maintaining a copy of the software. To help get both of those things moving, I’ve set up a Kickstarter project, titled simply Portrait: Linux System Management Tool to raise funds to let me work on Portrait over the summer and set up a hosted version that people can use.

Most of my readers won’t personally have any use for a Linux system management tool, but if you happen to know anyone you think might find it useful, I’ll ask you to please pass the Kickstarter project along to them. If you’re interested yourself, please head on over to the Kickstarter project page, where I’ve put much more information on exactly what Portrait will do.

Andy Schmitz

2/11/2011

Testing Help?

Filed under: General — Andy @ 11:30 am

I’m working on a program that will let users of TI-84+ or TI-89 Titanium calculators see their calculators on the computer screen, and take screenshots. (If you have a TI calculator that has a USB port and  isn’t an Nspire, you’ve probably got one of these.)

Right now, it runs on the Mac only (although that will hopefully change in a while). It works on my Mac, and at least one other, but I’m looking for one or two more test cases. If you have a TI-84+ or TI-89 Titanium, a USB cable that will plug into it and your computer, and one of the following computer setups, please give me an email at andy.schmitz@gmail.com so I can send you a copy and see if it works. The whole process of testing it out should only take a minute or so.

I’m looking for:

  • Mac OS X 10.5 (Leopard) on a PowerPC processor

If you’re not sure what operating system or processor you have, just click on the Apple menu in the upper-right corner of your screen, and click “About This Mac.” Your version of OS X will be displayed (I’m looking for anything that begins with 10.5), and your processor will be shown as well. Please let me know which version and processor you have when you email me, so I know which one you’re testing.

Thanks!

Andy Schmitz

12/27/2009

WordPress 2.9 Image/Media Upload Problems

Filed under: General — Andy @ 4:45 pm

So, as I just spent a half hour fixing friends’ blogs after the upgrade to WordPress 2.9, perhaps this will help someone else if it gets indexed by the search engines:

We were having problems with WordPress thinking that it was accepting uploads of images and trying to display them, but the files didn’t actually exist where they should have, throwing a file not found in the browser. It was a bit weird, because the only errors in the server log were that the browser couldn’t find the file, but the AJAX image editor in WordPress seemed to work. It turns out that somehow the settings got changed. If you’re having the same problem, follow these steps:

(more…)

12/25/2009

For All the People Back on Earth

Filed under: General — Andy @ 12:01 am

If you’re old enough (well, not that old), odds are that you watched this live, or at some point. In what, as far as I can tell, was the first human non-terrestrial Christmas greeting, Frank Borman, Jim Lovell, and William Anders, after noting the lonely view below, read off Genesis 1:1-10, then,

“And from the crew of Apollo 8, we close with good night, good luck, a Merry Christmas, and God bless all of you – all of you on the good Earth.”

And, of course, for anyone who has been persuaded otherwise, just under three hours later, after performing the Trans-Earth Injection on the far side of the moon, Lovell reported back, “Please be informed, there is a Santa Claus.” (Houston / Mattingly accepted the information, saying, “That’s affirmative. You’re the best ones to know.”)

11/20/2009

MIPS and spimbot

Filed under: General — Andy @ 2:38 pm

So, the CS232 spimbot competition was today. My partner (Connor Simmons) and I made a robot (actually just a piece of code) that came in second out of 37 (or 38?). It was a rather interesting competition. The page on it that I’ve set up (complete with MIT-licensed source code) is right here.

I remain impressed by the only team to beat us (and their come-from-behind win), whose inventive approach used an attack on the time-based seed of the random number generator to find where the tokens could be placed within the 50 minutes the competition was run. The one-second resolution used as a seed for the random number generator gave a small enough number of possible locations for tokens that they were able to accurately predict where all the tokens would be given just one token’s location. This strategy meant they lost a number of matches (I assume to slow calculations, but I may be wrong), including to our robot, but in the end, they were able to win more often (or by more tokens), so congratulations to them.

Andy Schmitz

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