Failed assertion: line 3379 pos 12: '!debugNeedsPaint': is not true. I get an error?

Question

Future<ui.Image> toImage({ double pixelRatio = 1.0 }) {
    assert(!debugNeedsPaint);
    final OffsetLayer offsetLayer = layer! as OffsetLayer;
    return offsetLayer.toImage(Offset.zero & size, pixelRatio: pixelRatio);
  }

I get an error? This is the error in the console package:flutter/src/rendering/proxy_box.dart': Failed assertion: line 3379 pos 12: '!debugNeedsPaint': is not true.

I've tried various things but it doesn't work.

Answer 1

You can try this way to do it. The problem with your code is that it is unable to re-render the Image with extension .toImage(). I hope this would work.

Future<void> _capturePng() {
  return new Future.delayed(const Duration(milliseconds: 20), () async {
    RenderRepaintBoundary boundary =
      globalKey.currentContext.findRenderObject();
    ui.Image image = await boundary.toImage();
    ByteData byteData =
      await image.toByteData(format: ui.ImageByteFormat.png);
    Uint8List pngBytes = byteData.buffer.asUint8List();
    print(pngBytes);
  });
}