[Bug]: iPadOS 26.1 – Apple Pencil: severe drawing latency in editor

[alialim]

Package Version

11.15.5

Flutter Version

3.38.6

Platforms

iOS

How to reproduce?

Hi Alex,

we’re seeing an issue on iPadOS 26.1 (tested on iPad Pro 1st–3rd gen and the new iPad 7th gen):

When drawing with the Apple Pencil in the image editor, strokes are rendered noticeably delayed—lines “catch up” after the user has already finished.

This causes a laggy, offset experience and makes precise work difficult.

On Android, the behavior is much better / barely noticeable.

Questions:
Are there known causes/workarounds (e.g., pointer events, requestAnimationFrame, coalesced events, pressure/tilt handling, canvas batching)?
Would a screen recording and device/browser details help you reproduce?

Thanks in advance,
Ali

Logs (optional)

Example code (optional)

Device Model (optional)

iPad Pro iOS version 26.1

[hm21]

Because I don't have much time, I've asked Copilot to search for a solution. Could you test PR #753 to see if it fixes the issue for you? If so, I will merge it.

[alialim]

Hi Alex,

thanks for your quick reply. I’m just not 100% sure how you want me to test PR #753 on my side.

Do I need to change anything in my Flutter view / source code, or copy parts of the PR into my project manually? Or is this already included in a version so I can simply update the package and test?

If you could briefly share the exact steps (branch/commit/version), that would be great.

Best regards

Ali

`import 'dart:io';
import 'package:flutter/material.dart';
import 'package:pro_image_editor/pro_image_editor.dart';

import 'package:esass_mobile/src/helpers/mvvm.dart' as mvvm;
import 'package:esass_mobile/src/download/editoren/bild_editor_controller.dart';
import 'package:esass_mobile/src/localization/app_localizations.dart';

class BildEditorView extends mvvm.View {

BildEditorView({super.key}) : super(viewModelBuilder: () => BildEditorController());

static const routeName = '/bild_editor';

@OverRide
Widget build(BuildContext context) {

final l10n = AppLocalizations.of(context)!;

return ValueListenableBuilder<String>(
  valueListenable: controller.pfadOriginal,
  builder: (context, pfad, _) {
    if (pfad.isEmpty) {
      return Scaffold(
        body: SafeArea(
          child: Center(child: Text(l10n.downloadBildEditorFehlerKeinBild)), // Kein Bild gefunden
        ),
      );
    }

    return ProImageEditor.file(
      File(pfad),
      callbacks: ProImageEditorCallbacks(
        onImageEditingComplete: (bytes) async {

          final navigator = Navigator.of(context);
          final neuerPfad = await controller.speichereBearbeitetesBild(bytes);

          if (!navigator.mounted) return;
          
          if (neuerPfad != null) {
            navigator.pop({'neuerPfad': neuerPfad});
          } else {
            navigator.pop();
          }
        },
        
      ),
      configs: ProImageEditorConfigs(
        imageGeneration: const ImageGenerationConfigs(
          maxOutputSize: Size.infinite,
          jpegQuality: 90,
          jpegChroma: JpegChroma.yuv444,
          outputFormat: OutputFormat.jpg,
          enableUseOriginalBytes: true,
        ),
        mainEditor: MainEditorConfigs(
          enableZoom: true,
          enableDoubleTapZoom: true,
          enableCloseButton: false,
          widgets: MainEditorWidgets(
            appBar: (editor, rebuildStream) => ReactiveAppbar(
              stream: rebuildStream,
              builder: (_) => AppBar(
                automaticallyImplyLeading: false,
                leading: IconButton(
                  tooltip: l10n.downloadBildEditorButtonSchliessen, // Schließen
                  icon: const Icon(Icons.close),
                  onPressed: editor.closeEditor,
                ),
                titleSpacing: 0,
                title: Padding(
                  padding: const EdgeInsets.only(left: 8),
                  child: TextButton(
                    onPressed: editor.doneEditing,
                    style: TextButton.styleFrom(
                      backgroundColor: Colors.green,
                      foregroundColor: Colors.white,
                      padding: const EdgeInsets.symmetric(
                        horizontal: 16,
                        vertical: 8,
                      ),
                      shape: RoundedRectangleBorder(
                        borderRadius: BorderRadius.circular(6),
                      ),
                    ),
                    child: Text(
                      l10n.downloadBildEditorButtonSpeichern, // Speichern
                      style: const TextStyle(fontSize: 14),
                    ),
                  ),
                ),
              ),
            ),
          ),
        ),
        emojiEditor: const EmojiEditorConfigs(enabled: false),
        filterEditor: const FilterEditorConfigs(enabled: false),
        tuneEditor: const TuneEditorConfigs(enabled: false),
        blurEditor: const BlurEditorConfigs(enabled: false),
        paintEditor: const PaintEditorConfigs(
          enableModePixelate: false,
          enableModeBlur: false,
          enableZoom: true,
          enableDoubleTapZoom: true,
        ),
      ),
    );
  },

);

}
}
`

[alialim]

Hi Alex,

thanks for your help — no need to explain the Git/PR setup anymore. I’ve already integrated the PR version into my project and I’m testing it now. I’ll get back to you shortly with feedback on whether it resolves the Apple Pencil latency.

Best regards,
Ali