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Comment by bsimpson | Hacker News Reader

Flutter renders the whole UI, like a game engine. In the past, this has meant that if there isn't a Flutter implemention of a component (like a video player or map), you couldn't add it to your app. I don't know if that's still true.

[edit]: It looks like this has been addressed with the PlatformView widget: https://developers.googleblog.com/2018/12/flutter-10-googles...

[edit]: Sorry, bluetidepro - this was supposed to be a reply to you.

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That's modern development for you. Shipping a copy of Skia so you can render exact facsimiles of Android widgets to a Vulkan context and avoid having Android render Android widgets with Skia to a Vulkan context.

A full Chrome copy for your desktop app is whatever, we have the resources, but on smartphones this is actively harmful. It bypasses the hardware compositors. Displaying a video, they have to render that to a graphics texture; on many smartphones, the IP that is doing hardware video decoding has nothing to do with the GPU and they might very well not use the same formats, requiring CPU conversion (if it's at all possible).

For bonus points you've probably broken accessibility on many platforms as the way that a11y works is intrinsic to the native widgets used by a platform.

I wouldn't assume that. It's literally the number one thing people bring up with custom UI components, I'd be very surprised if Flutter ignored the issue.

https://flutter.io/docs/development/accessibility-and-locali...

Oh I'm sure they didn't ignore is, just that you're constrained to platforms that allow a side-channel mechanism to expose a11y and handle focus+navigation.

I haven't looked deeply at the HTML5 APIs but if you wanted to say port Flutter to HTML5 Canvas you may run into problems where you can't expose rich enough a11y primitives on something that was just meant to be a bitmap.

Seems like some research and benchmarking into this potential issue is in order.

They just addressed this in today's announcement:

As for new Flutter features, Google today announced ‘Add to App,’ a new feature that makes it easier for developers to slowly add Flutter code to existing apps. In its early days, Flutter’s focus was squarely on building new apps from scratch, but as it has grown in popularity, developers now want to use it for parts of their existing applications as they modernize them.

They recently added "PlatformView" which allows you to embed any native (Android/iOS) component in the app. Sample: https://medium.com/flutter-community/flutter-platformview-ho...

I hated this about CoronaSDK (how the framework would render everything like a game engine to one canvas). It was so much harder to debug things if the only way you can debug components is only within the scope of the framework, and you don't have any of the benefits of using the native views/containers. This means you can't effectively use Appium or UIAutomator or anything nice like that. If Flutter does render everything like a canvas, then that will pretty negatively affect my impression of it.

There's a demo of running native tests that also test flutter on iOS here: https://github.com/flutter/ios_add2app

> like a game engine

In this aspect it's very similar to Flash or QT.

or canvas or kodi (which has been improved now to not refresh the entire screen.)

you mean this Kodi https://kodi.tv/ ?

Correct. The XBMC/Kodi UI was developed with game engine tools for the xbox, and the way the UI worked the screen redrew at 60fps, or whatever, whether the content on the screen changed or not.

That will always be Flutter's weakness.

You also don't get to use the wealth of libraries that target native development.

Cross platform always has trade-offs.

There's definitely been work on this as another commenter mentioned, and a first-party Google Maps plugin

How does interactive debugging and inspection work? This is the true power of the web as a platform.

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