It is possible there is a better implementation of Clipboard Monitor. I will try to take a look myself and tweak some stuff to see if it is any better. Right now it re-instantiates the ClipboardService every second, which could be an issue.

class ClipboardMonitor {
  bool _canPaste = false;
  bool get canPaste => _canPaste;
  Timer? _timer;

  void monitorClipboard(bool add, void Function() listener) {
    if (kIsWeb) return;
    if (add) {
      _timer = Timer.periodic(
          const Duration(seconds: 1), (timer) => _update(listener));
    } else {
      _timer?.cancel();
    }
  }

  Future<void> _update(void Function() listener) async {
    final clipboardService = ClipboardServiceProvider.instance;
    if (await clipboardService.hasClipboardContent) {
      _canPaste = true;
      listener();
    }
  }
}

flutter_quill: ^11.0.0-dev.17

Did you encounter the issue with older versions in case you used them?

with showClipboardCut, showClipboardCopy, or showClipboardPaste set to true
Since it adds the button with Clipboard Service it causes performance issue

To clarify, the ClipboardService is used even when the clipboard toolbar buttons are disabled. The issue is likely with ClipboardMonitor.

I will disable those buttons as a breaking change in v11 since they were already not enabled and introduced as unexpected change in a minor release. Related lines.

I'm thinking about removing them since supporting them is not a priority, and it's better to support less well-done and maintained features.

Did you encounter the issue with older versions in case you used them?

I used the previous versions but cannot confirm with certainty that it was also present.

I'll be looking into Clipboard monitor and try to fix them on myself and will open a PR if I have success.

Thanks for clarifying that Clipboard service is actually being used even when the buttons are not visible, I was not aware of this and it actually reduces the scope for my investigation :)

Also, Merry Christmas 🎄

I used the previous versions but cannot confirm with certainty that it was also present

The PR #1843 could be related, disabling the clipboard toolbar buttons should fix the issue.

I was not aware of this and it actually reduces the scope for my investigation :)

It might be worth trying quill_super_clipboard since it will replace the quill_native_bridge clipboard implementation with super_clipboard to confirm whether this is an issue with the DefaultClipboardService.

for clarifying that Clipboard service is actually being used even when the buttons are not visible

It's being used when copying an image, pasting an image (when flutter_quill_extension is utilized), and pasting rich text content from the system clipboard (as HTML).

What is the use-case for clipboard actions in the toolbar, or why is it needed?

Thanks
Merry Christmas 🎄

You're welcome. I'm familiar with those parts (except #1843), so let me know if you have questions.

What is the use-case for clipboard actions in the toolbar, or why is it needed?

Just a very convenient way to use some actions (especially paste). I have no problem implementing them on my own, but I'll give it a try to fix buttons / clipboard monitor, so those actions are available for everyone using the plugin from toolbar as well.

It's being used when copying an image, pasting an image (when flutter_quill_extension is utilized), and pasting rich text content from the system clipboard (as HTML).

After a second thought, I do use them for pasting images. I'll give it a proper test and come back to it later on

I will disable those buttons as a breaking change in v11

Change introduced (7abe6d2).

I have concluded my review and can give some more details:

1. The issue is only present for "Paste" button.
2. PerfMonitor messages were complaining only about await Clipboard.getData(Clipboard.kTextPlain); function when there was a big enough content: image or a lot of text. *The function itself is Flutter's own implementation and works as intended.
   When I then checked for very small text ("Hello World") it was fine and not complaining
3. Since the timer was periodic and was checking that every 1 second, it indeed causes a lot of lag and without debouncer / optimization it seems like a very heavy check when there is big clipboard content.
   One way to optimize that would be to introduce a flag if clipboard content is already being retrieved and do not trigger the function again in that case and while it will improve the performance by a lot in some cases, it is still not enough in others and feels a little bit useless since the timer is running constantly.

I would suggest to allow the users to determine "canPaste" status on their own and take control of the button's state. Then the users can also implement their own error handling for "onPaste".
Then we don't need periodic timer and the function will only be called during the actual use of it, which seems optimal to me.

Let me know if you would agree and then I can prepare a PullRequest with changes.

, it indeed causes a lot of lag and without debouncer / optimization it seems like a very heavy check when there is big clipboard content.

One possible solution is to listen to the system clipboard changes, which involves platform-specific code and might not be available on some platforms or has some restrictions.

await Clipboard.getData(Clipboard.kTextPlain)

I was considering replacing it with platform code in quill_native_bridge to solve the image paste issue, which was fixed in #2384 by pasting the image first.

I would suggest to allow the users to determine "canPaste" status on their own and take control of the button's state. Then the users can also implement their own error handling for "onPaste".

How would they solve it? It's not possible without platform code AFAIK, and I think users prefer something that's already implemented without much configuration.

For now, we should notify users about this issue before they enable those buttons.

One possible solution is to listen to the system clipboard changes, which involves platform-specific code and might not be available on some platforms or has some restrictions.

Exactly. I was trying to see if there are available solutions but it feels like an overkill

How would they solve it? It's not possible without platform code AFAIK, and I think users prefer something that's already implemented without much configuration.

This is already implemented in flutter with the simple in-built import from "services".

import 'package:flutter/services.dart';

...

await Clipboard.getData(Clipboard.kTextPlain);

And this is exactly the same how it is used in flutter quill => clipboard_service

  /// If the Clipboard is not empty or has something to paste
  Future<bool> get hasClipboardContent async {
    final clipboardData = await Clipboard.getData(Clipboard.kTextPlain);
    return clipboardData != null;
  }

For me it also feels like that they can implement their own "canPaste" (aka isEnabled) if they really need it to avoid periodic checks.
Aka:

1. Enable "canPaste" always by default
2. Allow pasting their own state to "canPaste" flag
3. If "paste" fails or no content found, they can handle it on their own (for example display a snackbar saying "no clipboard content").

You can paste this code to dartpad to verify that it is available.

import 'package:flutter/material.dart';
import 'package:flutter/services.dart';

void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  void getClipboardContent() async {
    final ClipboardData? clipboardData =
        await Clipboard.getData(Clipboard.kTextPlain);
    final String? copiedText = clipboardData?.text;

    print("Clipboard content: ${copiedText}");
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      home: Scaffold(
        body: Center(
          child: OutlinedButton(
            onPressed: getClipboardContent,
            child: Text("Print clipboard content"),
          ),
        ),
      ),
    );
  }
}

And this is exactly the same how it is used in flutter quill => clipboard_service

BTW, the current solution needs improvement. The hasClipboardContent determines if it has copied something to the system clipboard and if the app can retrieve it. However, it will only check plain text. It's on my TODO list to improve it.

This is already implemented in flutter with the simple in-built import from "services".

The issue is how we can listen to clipboard state changes, and the current solution achieves that by running platform code every 1 second from the Dart side, which is not efficient.

For me it also feels like that they can implement their own "canPaste" (aka isEnabled) if they really need it to avoid periodic checks.

Assuming they have greater control,
how would they solve the issue? There is almost no cross-platform solution that's consistent.

I will check to see if it's possible using platform code.

I think it comes to the discussion if the "canPaste" flag is even needed for the in-built "paste" button.

For my use case I would just completely remove the canPaste flag and make it always active, and handle the exceptions/empty clipboard when I actually interact with the button