MacOS provides a few different ways to do screen captures. My personal favorite is Grab, which is found in the Applications/Utilities folder. It lets me capture a selection, a window, or the whole screen without having to remember any magic key combinations. I keep it in the Dock for quick access.
Grab has one deficiency, though. It can save screenshots only as TIFF files. If Apple had to pick just one format, that’s hardly the most useful one. But there’s an easy workaround.
After you’ve got your screen shot, press Command-C or choose “Copy” from the Edit menu. Open the Preview application. Press Command-N or select “New from clipboard” from the File menu. You now have the screenshot in Preview.
In Preview, press Command-S or choose “Save…” from the File menu. You’ll get a dialog to save the file, with a choice of formats: JPEG, JPEG2000, OpenEXR, PDF, PNG, or TIFF. Pick whichever one you like. If you’re going to put the image into a Web page, PNG is usually the best choice. Preview will remember your choice for next time. Then save the file.
If you prefer, you can do the equivalent in Photoshop, Gimp, or any other image-processing application, but Preview has the advantage of launching quickly and keeping the process simple.
That’s it. You can now use Grab to save screenshots to a Web-friendly format.
The Washington Post reports that some police departments are dropping body camera programs because of the expense. I’ll admit that my first gut reaction on seeing the story was that it’s just an excuse. In some cases it probably is. But it’s a fact that while the cameras are cheap, storing and managing large amounts of video data isn’t. The question needs objective examination.
The array of sneaky tricks to get past Internet users’ veil of privacy is astonishing. At least it would be, if we weren’t all past the capacity for astonishment. One which has been around for years is Canvas fingerprinting. It lets servers narrow your profile down to a small number of clients. Combined with other measures, it can uniquely identify you.
How Canvas works
Canvas wasn’t designed to spy on you. It’s a way to draw graphics very efficiently in a browser. It supports animation and interaction. In order to get fast performance, it allows hardware acceleration and doesn’t mandate the exact set of pixels to be drawn. The server can then get those pixels back using getImageData() or toDataURL() in the Canvas API.
A tweet led me to a pair of articles about a new file format called FUIF. That stands for “Free Universal Image Format.” Jon Sneyers describes it in a series of articles which so far include a Part 1 and Part 2.
It’s “responsive by design”; a single image file can be truncated at various offsets to produce different resolutions. Sneyers says FUIF meets JPEG’s criteria for a new format that provides “efficient coding of images with text and graphics” and “very low file size image coding.”
Of all the issues in file formats, the pronunciation of “GIF” is surely close to the bottom in importance. When an issue is that minor, you can be sure everyone has strong opinions on it and will defend them on the barricades. It’s like the way political movements work: the closer together they are in their beliefs, the more ferociously they’ll vilify each other over little differences.
Personally, I always pronounce it my mind with a hard “G,” as in “give” rather than “giraffe.” I’m glad to see some support for this view in “A Linguist’s Guide to Pronouncing ‘GIF’.” One of its arguments matches the main reason in my mind: the “G” stands for “graphics,” which is pronounced with a hard “G.”
Case closed. Now can we agree that “PNG” is pronounced “Pee-Enn-Gee,” and not “Ping”?
Posted in commentary
JHOVE is still alive and active! The Open Preservation Foundation is holding a workshop on “Getting Started with JHOVE” on January 25, 2019 in the Hague, Netherlands. The announcement says, “This workshop is aimed at beginners, or anyone who is new to JHOVE.”
OPF members get priority for registration.
Sometimes when you click on a link to a PDF, it comes up in the browser. Other times, the browser downloads the file. Everyone must wonder why, but few have wondered enough to find out. Here’s a quick explanation.
It has nothing to do with the PDF version, the content of the file, or the link. It’s the HTTP headers that make the difference. Specifically, a header called “Content-Disposition” is the determining factor. If it’s absent, the file will open in the browser. If it’s present, the value it specifies determines how you get the file.
Posted in commentary
Tagged HTTP, PDF
Should there be songs about digital preservation? This is just a special case of the question, “Should there be songs about X?” For nearly all X, the answer is “Yes, and there probably are!” (Even — perhaps especially — if there shouldn’t be, there are.)
Someone in the Australiasian preservation community asked if AusPreserves needed a theme song. The first responses were existing popular songs, but then people started getting more creative. This led to the Digital Preservation Song Challenge!
One response was the Beyonce parody, “All the Corrupt Files” (“Put a checksum on it”). I think it’s the first song ever to mention JHOVE!
Naturally, I already have my own song on digital preservation, called Files that Last. I wrote it to promote my book of the same title, but it stands (or falls) by itself.
If it’s worth doing, it’s worth singing about, and that certainly applies to digital preservation!
The Politifact article on the White House’s video “evidence” against reporter Jim Acosta looked plausible enough to me, until I got to the explanation of GIF files. It got significant points wrong, following common misunderstandings.
The regular readers of this blog mostly know what GIF really is, but this article may be a useful reference if you need to explain to anyone. The Politifact article says:
Posted in commentary
For years I wrote most of the code for JHOVE. With each format, I wrote tests for whether a file is “well-formed” and “valid.” With most formats, I never knew exactly what these terms meant. They come from XML, where they have clear meanings. A well-formed XML file has correct syntax. Angle brackets and quote marks match. Closing tags match opening tags. A valid file is well-formed and follows its schema. A file can be well-formed but not valid, but it can’t be valid without being well-formed.
With most other formats, there’s no definition of these terms. JHOVE applies them anyway. (I wrote the code, but I didn’t design JHOVE’s architecture. Not my fault.) I approached them by treating “well-formed” as meaning syntactically correct, and “valid” as meaning semantically correct. Drawing the line wasn’t always easy. If a required date field is missing, is the file not well-formed or just not valid? What if the date is supposed to be in ISO 8601 format but isn’t? How much does it matter?