yoga VS og-image

We still wanted to leverage a layout engine that could be performant and easy-to-use. After doing some performance testing with native UIKit, Autolayout, and a few other third-party options, we ended up bringing FlexLayout into the mix, which is a Swift implementation of Facebook’s Yoga layout engine. All RPL components utilize FlexLayout in order to lay out content fast and efficiently. While we’ve enjoyed using it, we’ve found a few touch points to be mindful of. There are some rough edges we’ve found, such as utilizing stack views with subviews that use FlexLayout, that often come at odds with both UIKit and FlexLayout’s layout engines.

We have our own test suite (orginally derived from the test suite of Meta's Yoga layout library [0]) which consists of text fixtures that are small HTML snippets [1] and a test harness [2] that turns those into runnable tests, utilising headless chrome both to parse the HTML and to generate the assertions based on the layout that Chrome renders (so we are effectively comparing our implementation against Chrome). We currently have 686 generated tests (covering both Flexbox and CSS Grid).

We would like to utilise the Web Platform Test suite [3], however these are not in a standard format and many of the tests require JavaScript so we are not currently able to do that.

[0]: https://github.com/facebook/yoga

[1]: https://github.com/DioxusLabs/taffy/tree/main/test_fixtures

[2]: https://github.com/DioxusLabs/taffy/tree/main/scripts/gentes...

[3]: https://github.com/web-platform-tests/wpt/tree/master/css/cs...

The "engine" is built on top of amazing https://www.lwjgl.org/ and https://github.com/bkaradzic/bgfx/, and UI system is baked by https://github.com/memononen/nanovg and https://github.com/facebook/yoga

React Native uses the Yoga engine under the hood, which allows you to use CSS properties to layout your React Native UI in a way that translates really well. Layout in Yoga is limited to Flexbox and absolute/relative positioning, however; there is no CSS grid and no display attribute. This keeps things simpler and more performant, but if developers are accustomed to using other layout techniques on the web, they’ll need to adjust to this new limitation.

PR #246 is super interesting to check out: by fixing the caching strategy, we were able to eliminate an exponential time (with respect to tree depth) performance penalty, and get comparable speeds for flat and deeply nested layouts (something I'd never expected to be possible). Preliminary benchmarks shows us significantly faster than yoga, Meta's C++ library for the same thing, especially on deep trees. Not too shabby for a tiny team of volunteers!

You're going to build the CLI using Ink, a React component-based library for building interactive CLIs. It uses Yoga to build Flexbox layouts in the terminal, so most CSS-like props are available in Ink as well. Ink is simply a React renderer for the terminal, so all the React features are supported. No need to learn a new syntax specific to Ink.

Interesting.

I was thinking that this was going to be a crazy amount of layout engine work, but now I look a little closer it appears the layout work is farmed out to yoga [0] (not trying to take away anything from the effort here). So this project is almost a wrapper around running yoga as a renderer and using SVG as a form of backend target?

I say "appears" because the yoga landing page doesn't do a great job of explaining what it does.

[0] https://github.com/facebook/yoga

Now here's the thing since these are part of the meta tags, and The image shown in the tags are ... well! images, making them dynamic is a bit tricky. generating images isn't a menial task that just every web server can do ... it's resource intensive, time-consuming and all the other nightmares. and making it part of your dynamic web app is another ball game altogether. So what's new? well, @vercel/og is, this library lets you build image content from HTML/React that too insanely fast, like really fast . and you can pair this with any edge network like AWS Lambda on the edge, Cloudflare workers, etc to make it even faster.

It’s not embedding. When you paste that image url a serverless function running a headless browser requests say a next app which loads up a page based on the params in the url. Then we take a snapshot and image data is sent back as response to you hence the image appears. You can check out this: with NextJS and puppeteer

The other day I was looking through a repo and stumbled across someone using Vercel’s open graph image generator (https://og-image.vercel.app/), something I had no idea existed. I was able to set it up and replace my own implementation of something similar on my blog in an evening. My implementation involved generating images at build time with Gatsby, why I ever thought that was a good idea is beyond me.

But what if the content of the page is not visual at all, and no photo really suits the contents of the page? And what if we have a lot of these pages, with dynamically generated content? Luckily we are not limited to photography, we can use text! The prime example of this is how GitHub generates previews for issue URLs: they generate an image containing enough info such that users know what they will click on. These images are generated on-demand, as storing an image for every GitHub pull request or issue would be unfeasable. Another example is Vercel, which even open sourced their Open Graph Image as a Service that they occasionally use on blog posts or announcements.

Hi, it is basically a embedded, better and easier (API-wise) version of https://github.com/vercel/og-image

Vercel has a really good simple generator if you don’t want to spend time on graphic design: https://og-image.vercel.app

After some research, I found out that Vercel made an app (https://og-image.vercel.app/) that was really good, but did not quite fit what I was looking for, so I largely cloned the idea (but with my own code).

Nice work. But I am using my custom fork of https://github.com/vercel/og-image.