android - Dart中的图像处理

Question

我创建的应用程序可以识别图片中的元素。
现在我在File类中有图像，我想将图像旋转几度，然后再次在File类中有图像。
请问有什么解决办法吗？

附言:我不想显示此图像。我必须将图像作为File对象传递给某些方法。

Answer 1

To rotate the actual file in memory use the image library and the copyRotate function.

Image copyRotate(Image src, num angle, {
   Interpolation interpolation = Interpolation.nearest
  }
);
//Returns a copy of the [src] image, rotated by [angle] degrees.

例:

import 'dart:io';
import 'package:image/image.dart';
void main() {
  // Read an image from file (webp in this case).
  // decodeImage will identify the format of the image and use the appropriate
  // decoder.
  Image image = decodeImage(File('test.webp').readAsBytesSync());

  Image thumbnail = copyRotate(image, 120);

  // Save the thumbnail as a PNG.
  File('thumbnail.png').writeAsBytesSync(encodePng(thumbnail));
}

source

To display a rotated version of the image stored, you can use a RotationTransition with an AlwaysStoppedAnimation like-

new RotatedBox(
  quarterTurns: 1,
  child: new Text("Lorem ipsum")
)

或Transform.rotate()小部件-

  Transform.rotate(angle: - math.pi / 4, child: Text("Text"),);

对于您的用例-

  Transform.rotate(angle: degrees*3.14/180, child: Image.asset("file_path"),);