The little-known potential of SVG

Today on Twitter I came upon an article, “SVG Has More Potential,” by Mike Riethmuller. He points out that SVG is more than just “scalable vector graphics,” and he demonstrates that its images can be responsive.
Continue reading

Figuring out the PDF version is harder than you think

In a GitHub comment, Johan van der Knijff noted how messy it is to determine the version of a PDF file. He looked at a file with the header characters “%PDF-1.8”. DROID says this isn’t a PDF file at all.

By a strict reading of the PDF specification, it isn’t. The version number has to be in the range 1.0 through 1.7. Being this strict seems like a bad idea, since it would mean format recognition software will fail to recognize any future versions of the format. (JHOVE doesn’t care what character comes after the period.)
Continue reading

Klingon vs. Emoji in Unicode

In 2001, the Unicode Consortium rejected a proposal to include the Klingon encoding. The reasons it gave were:

Lack of evidence of usage in published literature, lack of organized community interest in its standardization, no resolution of potential trademark and copyright issues, question about its status as a cipher rather than a script, and so on.

Fair enough, but don’t most of these objections apply equally to emoji?
Continue reading

A Libtiff mirror

Libtiff is still offline at remotesensing.org, but there’s a mirror of the source available on GitHub. I held off on mentioning it in this blog till Bob Friesenhahn confirmed it’s reliable.

Libtiff goes offline

The Libtiff library, which has been a reference implementation of TIFF for many years, has disappeared from the Internet. It was located at remotesensing.org, a domain whose owner apparently was willing to host it without having any close connection to the project. The domain fell into someone else’s hands, and the content changed completely, breaking all links to Libtiff material. Malice doesn’t seem to be involved; the original owner of remotesensing.org just walked away from the domain or forgot to renew it. Who owns it now is unknown, since it’s registered under a privacy shield.

Originally Libtiff was hosted on libtiff.org, but that fell into the hands of a domain owner with no interest in the project. I don’t know why. It still holds Libtiff code, but it’s many years out of date.

As I’m writing this, people on the Libtiff list are trying to figure out exactly what happened. There’s talk of trying to get libtiff.org back, though that may or may not be possible.

For the moment, there’s no primary source for Libtiff on the Web. I’ll hopefully be able to post more information later.

How big is BigTIFF?

TIFF is a very popular image format, but it can’t handle really huge files. “Really huge” means files bigger than 4 gigabytes, or more precisely, files in which any data offset can’t be represented in 32 bits. That’s not a limitation that comes up often, but some applications, such as medical scans, need enough detail to push the limit.

A dozen years ago, members of the TIFF community at AWare Systems came up with a simple idea: Create a variant of TIFF with 64-bit offsets instead of 32 bits. The result was BigTIFF.
Continue reading

The strange state of “open” format documentation

You can legally download many specs from the ISO site, including the Open Document Format (ODF) specs. ISO lets you print out a copy. However, if you photocopy or scan it, or if you make it available on your organization’s LAN, the Copyright Police will haul you away.

I’ve seen similar restrictions elsewhere. They’re variations on the idea that you can download a document for free, but you can’t share it after you download it. It’s bizarre.

Maybe they’re trying to keep people from going into competition by selling copies of their standards. Since ISO also sells what it publishes, the goal would make sense. In fact, there’s a specific and emphatic prohibition on sales. But why they should care whether copies are printed or photocopied is beyond me.

Usually the answer to questions like these is “lawyers who are disconnected from reality.” If there’s a better answer, I’d love to hear it.

The Bitcoin blockchain format

The Bitcoin cryptocurrency depends on security and confidence. If a flaw in the design broke its trust or usability, the whole system would collapse.

It’s strange, then, that Bitcoin doesn’t have a specification. This is considered a feature, not a bug:
Continue reading

When is an algorithm not an algorithm?

The only time the news media use the term “algorithm,” it seems, is for computational methods that aren’t.

Merriam-Webster defines it as “a procedure for solving a mathematical problem (as of finding the greatest common divisor) in a finite number of steps that frequently involves repetition of an operation.” Let’s forget about repetition; almost every computational procedure uses loops. The key word is “mathematical.”

An algorithm produces results that can be mathematically verified. An algorithm for calculating pi will produce the known value to the needed level of precision, or it’s wrong. A search algorithm is an algorithm when its results correspond to precise matching criteria.
Continue reading

The decline and fall of Adobe Flash

It’s been a year since I last posted about Adobe Flash’s impending demise. Like everything else on the Internet, it won’t ever vanish completely, but its decline is accelerating.
Continue reading