Lossless Image File Formats

This was originally a two-part post on cohost.

Recently I needed to convert a large TIFF scan of a duochrome page into something reasonable, i.e. a web-supported image format that was still lossless since it seemed a shame to ruin such a nice high-definition scan with lossy compression. In terms of lossless formats, all browsers¹ support PNG, WEBP, and AVIF, while I really hope JXL support is imminent.

I therefore wanted to see which file format would perform the best in terms of file size by converting my ~183 MiB TIFF to each of them using ImageMagick. For PNG, WEBP, and JXL, there’s an effort setting: lower effort means faster compression but larger size, while higher effort means slower compression but smaller size. I used the highest three settings for these, yielding sizes from ~50 MiB to ~20 MiB. (As a treat, I’ve also converted to JPG, WEBP, AVIF, and JXL at -quality 0, i.e. lossy with the worst settings.)

What's in a GIF?

This was originally a multi-part post on cohost.

I wanted to inspect the structure of an animated GIF, so I created a 1 px × 1 px monochrome animation that switches from white to black every 1024 milliseconds in GNU IMP, exported it as an animated GIF with disposal method “combine”, and hexdumped it. Here’s the GIF below, at the center of this 1rem box so you can see it.

Thulium is Four Years Old!

Thulium, my personal server, turned four this year! Its official birthday was a few months ago on 15 April. A few more things have changed since I last posted about it, so I thought I’d update with what’s new.

LaTeX for Jekyll from GitHub Pages to GitLab Pages

About a year ago I posted about using $\text{K}\text{A}\text{T}\text{E}\text{X}$ in a Jekyll site for GitHub Pages. This had been an unsatisfying solution to me, since GH Pages restricts Jekyll plugins to their allowlist, meaning that if I didn’t want to manually add precompiled HTML pages, LaTeX rendering would have to be done client-side using JavaScript. Furthermore, I found out that kramdown, the Markdown compiler that GH Pages uses, has built-in support for KaTeX without needing to explicitly include additional Liquid tags, but GH Pages, too, has overridden configurations needed to enable using KaTeX as well!

It's not all it's cracked up to be

Friday, 22 October 2021, 10:30 am. Cold, rainy, wet. From inside Joyce–Collingwood station I spotted the R4, just as it was closing its back doors. My first mistake was hope: The front door was not yet closed. My second mistake was hubris: I will make it to the bus if I run. And so I ran, but my normally-grippy sneakers slipped on the sidewalk slick with rainwater, and I ended up landing hard on my ass right in front of the bus driver.

It was a miracle I ended up mostly physically unscathed. I instinctively shot out my arms underneath me and I could have broken a wrist or two. I could’ve landed on my tailbone wrong and broken that too. But it seemed the only damage was a light bruise on my sacrum (had to look up the word for that) and to my ego. Not even a scratch on my palms! Then I sat down, took out my laptop, opened it, and discovered the large crack from the bottom left corner, reaching longingly to conquer the entirety of the screen.

Adding LaTeX to your Jekyll Site

As it turns out, adding support to render LaTeX in a Jekyll blog isn’t all that hard, because other people have done most of the heavy lifting. There are two main ways to do this:

• Client-side rendering: After the page loads, a JS script is run to transform LaTeXy parts of the page to lovely, styled HTML.
• Build-time rendering: After Markdown files are compiled to HTML, a Jekyll plugin further transforms those LaTeXy parts to HTML as well. Here’s how you do either using $\KaTeX$.

Thulium: Disk Failure

On 24 December 2020, my home server Thulium went down. Usually the cause of downtime is my home’s public IP address changing, and I need to update the DDNS record with my domain name provider. This time it wasn’t; when I tried to SSH in through the domain, I reached something, but it wouldn’t let me in. I managed to SSH in through the local IP address and tried to reboot, but I got a segmentation fault, of all things. In the end, I rebooted the server manually by walking over to the other room and holding down the power button. I could then SSH in, my Docker containers were up, all was well.

On 27 December 2020, it happened all over again. This time, I could SSH in again, but everything was painfully slow. I checked htop: CPU and memory were doing fine. I checked my internet connection: that was fine too. It must be, then, a disk issue (obviously, since that’s the title of this post).

Thulium: A One-Year Retrospective

A few months ago, on the 15th of April, was the one-year anniversary of ert.space and the Thulium server, still running happily in its desktop tower, now with an extra 2 GB of RAM. Even if I didn’t have the Thulium posts to remind me, I would always have the timely bill for the domain name. Over the past year, a multitude of services and Docker containers have risen and fallen, having been replaced or abandoned or, rarely, taken up a more permanent post. In 2018, I began with the following:

Designing ShareVitalSigns for iOS

For usage notes, see the LNhealth wiki page on SVS for iOS. This post is cross-posted to the LNhealth wiki at Designing ShareVitalSigns for iOS.

Thulium Part 3: Ghost, monitoring, backups, and a summary

This is part 3 of the Thulium series. Go back to part 2 or jump back to part 1.

Exam season has ended, and so too must this story. There are a lot more things I could self-host, but I’ve come to a point where I’m comfortable with the services I’ve set up for myself, and other ideas have larger scales and likely would deserve their own posts (setting up a mail server, for instance).

Thulium Part 2: Nextcloud (formerly Syncthing) and Gitea

This is part 2 of the Thulium series. Visit part 3 or go back to part 1.

We are now in the middle of the exam season. What better time than now to set up file syncing and a personal Git host?

Thulim Part 1: SSH and Web Server

This is part 1 of the Thulium series. Go to part 2 or jump to part 3.

Exam season is coming up now, so naturally I’ve decided to spend my time setting up a home server. I’m hoping to eventually be able to replace Google Drive with a self-hosted instance of perhaps NextCloud or SyncThing, but we’ll start small first. I’ve installed Ubuntu Server 16.04.4 LTS (Xenial Xerus), which was sufficiently straightforward that I won’t elaborate on it except to say that using an LVM caused me to be unable to boot into the OS, so don’t do that.

Making Swagger play nice with ProtoBufs

My previous workplace’s frontend is mostly in TypeScript and the backend mostly in Scala, and to share data back and forth, DTOs written as ProtoBufs were implemented some time ago. There’s a script that generates from these ProtoBuf files Java classes using protobuf-java and TypeScript classes using protobufjs. The Java classes can then be used directly in Scala code.

From Mercurial to Git

A few months ago I had to figure out how to migrate a 4 GB repository from Mercurial to Git, and trim the size down along the way. Luckily, I wasn’t the first one to have to do that, so there were a number of resources I could reference, namely these two. But of course, every specific case has its own specific problems.

BunsenLabs on VirtualBox on Windows 10 on a Laptop

Why: Because.

How: With great effort and time.

I’ve gone through so, so many iterations of this installation process because of various things that have gone irreversibly wrong. Luckily, this has all been on a VM, so nothing is truly irreversible (save for the overall entropy of the universe), but many mistakes were made, then remade (“testing”, they call it) to be sure of their causes. To note: