How can I store widget screenshot as jpg file in flutter? - flutter

Question

I have taken a widget screenshot and I want to save it as .jpg file. I was able to save it as .png file below but I don't know how to save it as .jpg file. Here is my code:
RenderRepaintBoundary boundary = _repainkey.currentContext.findRenderObject();
ui.Image image = await boundary.toImage();
ByteData byteData = await image.toByteData(format: ui.ImageByteFormat.png);
Uint8List pngBytes = byteData.buffer.asUint8List();
final directory = (await getExternalStorageDirectory());
print(directory.path);
File imgFile = new File('${directory.path}/flutter2.png');
await imgFile.writeAsBytes(pngBytes);

Answer 1

You could use the jpeg_encode library. It would allow you to convert your ui.Image object to a jpeg without the intermediary step of converting to a png, and is thus likely to be faster.

Answer 2

You have to do a file type conversion. You can use the image package to help you do this. This answer is very similar to what you're looking for, just doing the conversion reversed from what you want.
Example from the linked answer:
import 'dart:io';
import 'package:image/image.dart';
void main() {
// Read a jpeg image from file.
Image image = decodeImage(new File('test.jpg').readAsBytesSync());
// Resize the image to a 120x? thumbnail (maintaining the aspect ratio).
Image thumbnail = copyResize(image, 120);
// Save the thumbnail as a PNG.
new File('out/thumbnail-test.png')
..writeAsBytesSync(encodePng(thumbnail));
}
import 'dart:io';
import 'package:image/image.dart';
void main() {
// Read a jpeg image from file.
Image image = decodeImage(new File('test.png').readAsBytesSync());
// Resize the image to a 120x? thumbnail (maintaining the aspect ratio).
Image thumbnail = copyResize(image, 120);
// Save the thumbnail as a PNG.
new File('out/thumbnail-test.jpg')
..writeAsBytesSync(encodeJpg(thumbnail));
}