如何在颤动中将小部件屏幕截图存储为 jpg 文件？

Question

我已经截取了一个小部件屏幕截图，我想将其保存为 .jpg 文件。我能够将其保存为下面的 .png 文件，但我不知道如何将其保存为 .jpg 文件。这是我的代码：

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

您必须进行文件类型转换。您可以使用image package 来帮助您执行此操作。 This answer 与您要查找的内容非常相似，只是进行了与您想要的相反的转换。

来自链接答案的示例：

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));
}