Tags: round

44

sparkline

Wednesday, April 26th, 2023

Workaround

Two weeks ago, I wrote:

I woke up today to a very annoying new bug in Firefox. The browser shits the bed in an unpredictable fashion when rounding up single pixel line widths in SVG. That’s quite a problem on The Session where all the sheet music is rendered in SVG. Those thin lines in sheet music are kind of important.

Paul Rosen, who makes abcjs, the JavaScript library that renders sheet music on The Session, managed to get a fix out pretty quickly. But I use an older version of the library and updating it would introduce some side-effects that would take me a while to work around. So that option wasn’t available to me.

In this situation, when the problem is caused by a browser bug, the correct course of action is to file a bug with the browser. That had already been done. Now all I could do was twiddle my thumbs and wait for the next release of the browser, which would hopefully ship with the fix.

But I figured I may as well try to find a temporary workaround in the meantime.

At first, I looked at diving into the internals of the JavaScript—that’s where the instructions are given for drawing the SVGs.

But then I stopped and thought, “If the problem is with the rendering of the SVG, maybe CSS can help.”

I started messing around with SVG-specific CSS properties like stroke, fill, and so on. With dev tools open, I started targeting the paths that acted as bar lines in the sheet music, playing around with widths, opacities, and fills.

It was the debugging equivalent of throwing spaghetti at the wall. Remarkably, it actually worked.

I found a solution with this nonsensical bit of CSS:

stroke: currentColor;
stroke-opacity: 0;

For some reason, rather than making all the barlines disappear, this ensured they were visible.

It’s the worst kind of hacky fix—the kind where you have no idea why it works, but it does.

So I shipped it.

And at pretty much exactly the same time, a new version of Firefox dropped …with the bug fixed.

I can’t deny that there was a certain satisfaction in being able to work around a browser bug. But there’s much more satisfaction in deleting the hacky workaround when it’s no longer needed.

Tuesday, May 3rd, 2022

City of Women London

City of Women encourages Londoners to take a second glance at places we might once have taken for granted by reimagining the iconic Underground map.

I love everything about this …except that there’s no Rosalind Franklin station.

Thursday, September 30th, 2021

Plus Equals #3, September 2021

Want to take a deep dive into tiling images? Like, a really deep dive. Rob has you covered.

Thursday, September 16th, 2021

Basic Pattern Repository

A nice little collection of very simple—and very lightweight—SVGs to use as background patterns.

Sunday, June 6th, 2021

Ancestors and Descendants – Eric’s Archived Thoughts

Eric looks back on 25 years of CSS and remarks on how our hacks and workarounds have fallen away over time, thank goodness.

But this isn’t just a message of nostalgia about how much harder things were back in my day. Eric also shows how CSS very nearly didn’t make it. I’m not exaggerating when I say that Todd Fahrner and Tantek Çelik saved the day. If Tantek hadn’t implemented doctype switching, there’s no way that CSS would’ve been viable.

Gaming the Iron Curtain

The ZX Spectrum in a time of revolution:

Gaming the Iron Curtain offers the first book-length social history of gaming and game design in 1980s Czechoslovakia, or anywhere in the Soviet bloc. It describes how Czechoslovak hobbyists imported their computers, built DIY peripherals, and discovered games as a medium, using them not only for entertainment but also as a means of self-expression.

Sunday, December 8th, 2019

2019 Firefox Flashback

Here’s an end-of-year roundup of all the data that Mozilla have gathered through their Firefox browser—very impressive!

Tuesday, October 29th, 2019

Periodic background sync

Yesterday I wrote about how much I’d like to see silent push for the web:

I’d really like silent push for the web—the ability to update a cache with fresh content as soon as it’s published; that would be nifty! At the same time, I understand the concerns. It feels more powerful than other permission-based APIs like notifications.

Today, John Holt Ripley responded on Twitter:

hi there, just read your blog post about Silent Push for acthe web, and wondering if Periodic Background Sync would cover a few of those use cases?

Periodic background sync looks very interesting indeed!

It’s not the same as silent push. As the name suggests, this is about your service worker waking up periodically and potentially fetching (and caching) fresh content from the network. So the service worker is polling rather than receiving a push. But I’ll take it! It’s definitely close enough for the kind of use-cases I’ve been thinking about.

Interestingly, periodic background sync also ties into the other part of what I was writing about: permissions. I mentioned that adding a site the home screen could be interpreted as a signal to potentially allow more permissions (or at least allow prompts for more permissions).

Well, Chromium has a document outlining metrics for attempting to gauge site engagement. There’s some good thinking in there.

Saturday, July 6th, 2019

The Hiding Place: Inside the World’s First Long-Term Storage Facility for Highly Radioactive Nuclear Waste - Pacific Standard

Robert McFarlane’s new book is an exploration of deep time. In this extract, he visits the Onkalo nuclear waste storage facility in Finland.

Sometimes we bury materials in order that they may be preserved for the future. Sometimes we bury materials in order to preserve the future from them.

Tuesday, June 11th, 2019

Mornington Crescent - Esolang

A (possibly) Turing complete language:

As the validity and the semantics of a program depend on the structure of the London underground system, which is administered by London Underground Ltd, a subsidiary of Transport for London, who are likely unaware of the existence of this programming language, its future compatibility is uncertain. Programs may become invalid or subtly wrong as the transport company expands or retires some of the network, reroutes lines or renames stations. Features may be removed with no prior consultation with the programming community. For all we know, Mornington Crescent itself may at some point be closed, at which point this programming language will cease to exist.

Wednesday, May 8th, 2019

CSS-only chat

A truly monstrous async web chat using no JS whatsoever on the frontend.

This is …I mean …yes, but …it …I …

Thursday, April 18th, 2019

Inlining SVG background images in CSS with custom properties

Here’s a tiny lesson that I picked up from Trys that I’d like to share with you…

I was working on some upcoming changes to the Clearleft site recently. One particular component needed some SVG background images. I decided I’d inline the SVGs in the CSS to avoid extra network requests. It’s pretty straightforward:

.myComponent {
    background-image: url('data:image/svg+xml;utf8,<svg> ... </svg>');
}

You can basically paste your SVG in there, although you need to a little bit of URL encoding: I found that converting # to %23 to was enough for my needs.

But here’s the thing. My component had some variations. One of the variations had multiple background images. There was a second background image in addition to the first. There’s no way in CSS to add an additional background image without writing a whole background-image declaration:

.myComponent--variant {
    background-image: url('data:image/svg+xml;utf8,<svg> ... </svg>'), url('data:image/svg+xml;utf8,<svg> ... </svg>');
}

So now I’ve got the same SVG source inlined in two places. That negates any performance benefits I was getting from inlining in the first place.

That’s where Trys comes in. He shared a nifty technique he uses in this exact situation: put the SVG source into a custom property!

:root {
    --firstSVG: url('data:image/svg+xml;utf8,<svg> ... </svg>');
    --secondSVG: url('data:image/svg+xml;utf8,<svg> ... </svg>');
}

Then you can reference those in your background-image declarations:

.myComponent {
    background-image: var(--firstSVG);
}
.myComponent--variant {
    background-image: var(--firstSVG), var(--secondSVG);
}

Brilliant! Not only does this remove any duplication of the SVG source, it also makes your CSS nice and readable: no more big blobs of SVG source code in the middle of your style sheet.

You might be wondering what will happen in older browsers that don’t support CSS custom properties (that would be Internet Explorer 11). Those browsers won’t get any background image. Which is fine. It’s a background image. Therefore it’s decoration. If it were an important image, it wouldn’t be in the background.

Progressive enhancement, innit?

Tuesday, December 18th, 2018

Remove Background from Image – remove.bg

Well, this looks like it could come in handy—no more tedious time in Photoshop trying to select turn a person into a separate layer by hand; this does it for you.

Thursday, December 6th, 2018

Introducing Background Fetch  |  Web  |  Google Developers

I’m going to have to read through this article by Jake a few times before I begin to wrap my head around this background fetch thing, but it looks like it would be perfect for something like the dConstruct Audio Archive, where fairly large files can be saved for offline listening.

Sunday, November 11th, 2018

Push without notifications

On the first day of Indie Web Camp Berlin, I led a session on going offline with service workers. This covered all the usual use-cases: pre-caching; custom offline pages; saving pages for offline reading.

But on the second day, Sebastiaan spent a fair bit of time investigating a more complex use of service workers with the Push API.

The Push API is what makes push notifications possible on the web. There are a lot of moving parts—browser, server, service worker—and, frankly, it’s way over my head. But I’m familiar with the general gist of how it works. Here’s a typical flow:

  1. A website prompts the user for permission to send push notifications.
  2. The user grants permission.
  3. A whole lot of complicated stuff happens behinds the scenes.
  4. Next time the website publishes something relevant, it fires a push message containing the details of the new URL.
  5. The user’s service worker receives the push message (even if the site isn’t open).
  6. The service worker creates a notification linking to the URL, interrupting the user, and generally adding to the weight of information overload.

Here’s what Sebastiaan wanted to investigate: what if that last step weren’t so intrusive? Here’s the alternate flow he wanted to test:

  1. A website prompts the user for permission to send push notifications.
  2. The user grants permission.
  3. A whole lot of complicated stuff happens behinds the scenes.
  4. Next time the website publishes something relevant, it fires a push message containing the details of the new URL.
  5. The user’s service worker receives the push message (even if the site isn’t open).
  6. The service worker fetches the contents of the URL provided in the push message and caches the page. Silently.

It worked.

I think this could be a real game-changer. I don’t know about you, but I’m very, very wary of granting websites the ability to send me push notifications. In fact, I don’t think I’ve ever given a website permission to interrupt me with push notifications.

You’ve seen the annoying permission dialogues, right?

In Firefox, it looks like this:

Will you allow name-of-website to send notifications?

[Not Now] [Allow Notifications]

In Chrome, it’s:

name-of-website wants to

Show notifications

[Block] [Allow]

But in actual fact, these dialogues are asking for permission to do two things:

  1. Receive messages pushed from the server.
  2. Display notifications based on those messages.

There’s no way to ask for permission just to do the first part. That’s a shame. While I’m very unwilling to grant permission to be interrupted by intrusive notifications, I’d be more than willing to grant permission to allow a website to silently cache timely content in the background. It would be a more calm technology.

Think of the use cases:

  • I grant push permission to a magazine. When the magazine publishes a new article, it’s cached on my device.
  • I grant push permission to a podcast. Whenever a new episode is published, it’s cached on my device.
  • I grant push permission to a blog. When there’s a new blog post, it’s cached on my device.

Then when I’m on a plane, or in the subway, or in any other situation without a network connection, I could still visit these websites and get content that’s fresh to me. It’s kind of like background sync in reverse.

There’s plenty of opportunity for abuse—the cache could get filled with content. But websites can already do that, and they don’t need to be granted any permissions to do so; just by visiting a website, it can add multiple files to a cache.

So it seems that the reason for the permissions dialogue is all about displaying notifications …not so much about receiving push messages from the server.

I wish there were a way to implement this background-caching pattern without requiring the user to grant permission to a dialogue that contains the word “notification.”

I wonder if the act of adding a site to the home screen could implicitly grant permission to allow use of the Push API without notifications?

In the meantime, the proposal for periodic synchronisation (using background sync) could achieve similar results, but in a less elegant way; periodically polling for new content instead of receiving a push message when new content is published. Also, it requires permission. But at least in this case, the permission dialogue should be more specific, and wouldn’t include the word “notification” anywhere.

Tuesday, July 17th, 2018

Font Playground — Play with variable fonts!

A fun way to play around with the options in variable fonts.

Thursday, January 18th, 2018

Finding Dead CSS – CSS Wizardry

Here’s a clever idea from Harry if you’re willing to play the long game in tracking down redundant CSS—add a transparent background image to the rule block and then sit back and watch your server logs for any sign of that sleeper agent ever getting activated.

If you do find entries for that particular image, you know that, somehow, the legacy feature is potentially still accessible—the number of entries should give you a clue as to how severe the problem might be.

Friday, December 29th, 2017

My favourite books (and games) about the apocalypse

Plague; zombie; nuclear …Anna’s got them all covered in her roundup of apocalyptic literature and games.

Tuesday, March 21st, 2017

Lisbon Azulejos

When I was in Porto a few weeks back, I took lots of pictures of the beautiful tiles. They reminded me of the ubiquitous repeating background images that were so popular on the early web. I was thinking about abstracting them into a collection of reusable patterns but now it looks like I’ve been beaten to it!

Tuesday, February 21st, 2017

Send messages when you’re back online with Service Workers and Background Sync – Twilio Cloud Communications Blog

This example of using background sync looks like it’s specific to Twilio, but the breakdown of steps is broad enough to apply to many situations:

On the page we need to:

  1. Register a Service Worker
  2. Intercept the “submit” event for our message form
  3. Place the message details into IndexedDB, an in browser database
  4. Register the Service Worker to receive a “sync” event

Then, in the Service Worker we need to:

  1. Listen for sync events
  2. When a sync event is received, retrieve the messages from IndexedDB
  3. For each message, send a request to our server to send the message
  4. If the message is sent successfully, then remove the message from IndexedDB

And that’s it.