如何在flutter中将SVG转换为PNG

Question

我希望将 SVG 从 asset 转换为 png 并将其写入文件。

我已成功将 SVG 写入文件，但我想将图像作为 PNG 写入文件

将 SVG 写入文件的代码：

 final bytes = await rootBundle.load('assets/images/example.svg');
  final String tempPath = (await getTemporaryDirectory()).path;
  final File file = File('$tempPath/profile.svg');
  await file.writeAsBytes(
      bytes.buffer.asUint8List(bytes.offsetInBytes, bytes.lengthInBytes));
  return file;
}

Answer 1

我在另一个答案中找到了解决您问题的方法。

您将需要添加flutter_svg为项目的依赖项。

这几乎是引用答案中给出的代码的副本：

Future<Uint8List> svgToPng(BuildContext context, String svgString,
    {int svgWidth, int svgHeight}) async {
  DrawableRoot svgDrawableRoot = await svg.fromSvgString(svgString, null);

  // to have a nice rendering it is important to have the exact original height and width,
  // the easier way to retrieve it is directly from the svg string
  // but be careful, this is an ugly fix for a flutter_svg problem that works
  // with my images
  String temp = svgString.substring(svgString.indexOf('height="') + 8);
  int originalHeight =
      svgHeight ?? int.parse(temp.substring(0, temp.indexOf('p')));
  temp = svgString.substring(svgString.indexOf('width="') + 7);
  int originalWidth =
      svgWidth ?? int.parse(temp.substring(0, temp.indexOf('p')));

  // toPicture() and toImage() don't seem to be pixel ratio aware, so we calculate the actual sizes here
  double devicePixelRatio = MediaQuery.of(context).devicePixelRatio;

  double width = originalHeight *
      devicePixelRatio; // where 32 is your SVG's original width
  double height = originalWidth * devicePixelRatio; // same thing

  // Convert to ui.Picture
  final picture = svgDrawableRoot.toPicture(size: Size(width, height));

  // Convert to ui.Image. toImage() takes width and height as parameters
  // you need to find the best size to suit your needs and take into account the screen DPI
  final image = await picture.toImage(width.toInt(), height.toInt());
  ByteData bytes = await image.toByteData(format: ImageByteFormat.png);

  return bytes.buffer.asUint8List();
}