BUG: BackdropFilter not applied over web view content in iOS

[zhushenwudi]

issue bind #114740
@AlexDochioiu
I'm sure this bug still exists so far

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I am only tested on iOS.
i use a we_slide library, it has a suspended layer with backdropfilter container. And I write a stack in the suspended layer, main view contain a webview with flutter_inappwebview. When the suspended layer opened, there is a webview rect area will without blur effect

[zhushenwudi]

webview container area:

When the floating suspended layer is displayed on the non-webview, the effect is as follows

When the floating suspended layer is above WebView, the effect is as follows

[moffatman]

I think it would be fixed with my change here: flutter/engine#39244. Do you have an example program I can run to try it?

[zhushenwudi]

flutter/engine#39244

Ok, I'll make a demo for testing

[zhushenwudi]

I think it would be fixed with my change here: flutter/engine#39244. Do you have an example program I can run to try it?

hello again, i make a demo for testing:

https://github.com/zhushenwudi/BackdropFilterDemo

[zhushenwudi]

This bug effect is very interesting

527394667d1a72aadfe2eaf701f566b8.mp4

[moffatman]

Ok, so your demo isn't affected by my bug fix. This is some separate problem.

It looks like there is some limitation in the platform view blur implementation where we can't blur easily across the edges of the webview. You can see it easily by reducing sigmaY, the affected area shrinks.

I found this related article, but I couldn't find a way to implement the advice (not an expert of UIKit).

It seems like a hard issue to get right. Tag @cyanglaz for opinion.

[exaby73]

I can reproduce this issue with the sample you provided. @zhushenwudi is it possible for you to modify the code sample to exclude any 3rd party libraries, eg: we_slide and using webview_flutter instead of webview_flutter_plus?

[zhushenwudi]

webview_flutter

I have tested webview_flutter, it does not support WebView with params
and, I also tested flutter_inappwebview, it can open webview with params, but it has the same effect with flutter_webview_plus, due to this library is very heavy, last I only choose webview_flutter_plus

[zhushenwudi]

if you know how to open an local asset resouce webview with params, please write it, i will test, thx

[exaby73]

Is it reproducible with loading a URL, like https://flutter.dev for example?

[zhushenwudi]

No, it can't be loaded because it doesn't meet the ios specification by directly splicing the URL