captureScreenshot method

Future<Uint8List?> captureScreenshot({ double pixelRatio = 1.0, Rect? area, })

Capture the boundary to PNG bytes. Full window when area is null; otherwise crops to area (logical coordinates) via a PictureRecorder pass. Returns null when the boundary is not yet attached / sized.

Implementation

Future<Uint8List?> captureScreenshot({
  double pixelRatio = 1.0,
  Rect? area,
}) async {
  final ro = captureKey.currentContext?.findRenderObject();
  if (ro is! RenderRepaintBoundary) return null;
  if (!ro.attached || !ro.hasSize) return null;
  try {
    final fullImage = await ro.toImage(pixelRatio: pixelRatio);
    if (area == null) {
      final byteData =
          await fullImage.toByteData(format: ui.ImageByteFormat.png);
      return byteData?.buffer.asUint8List();
    }
    final recorder = ui.PictureRecorder();
    final canvas = ui.Canvas(recorder);
    final src = Rect.fromLTWH(
      area.left * pixelRatio,
      area.top * pixelRatio,
      area.width * pixelRatio,
      area.height * pixelRatio,
    );
    final dst = Rect.fromLTWH(0, 0, area.width, area.height);
    canvas.drawImageRect(fullImage, src, dst, ui.Paint());
    final picture = recorder.endRecording();
    final cropped = await picture.toImage(
      area.width.toInt(),
      area.height.toInt(),
    );
    final byteData =
        await cropped.toByteData(format: ui.ImageByteFormat.png);
    return byteData?.buffer.asUint8List();
  } catch (_) {
    return null;
  }
}