蜡染-如何从SVGGraphics2D多次导出Svg

Question

我想要

1. 处理svg文档，然后将其导出到svg文件
2. 然后再次处理现有的svg文档，并将其第二次导出到svg文件，依此类推...

我注意到，在使用svgGenerator.stream(streamWriter, useCss)方法将svg文档导出到svg文件svgGenerator.stream(streamWriter, useCss) svg文档变为空。

有人可以给我一个提示，我的代码有什么问题吗？

public void svgExportExample() {

  final SVGGraphics2D svgGenerator = createSvgGenerator();

  drawRectangle(svgGenerator);

  drawText(svgGenerator);

  final String xml1 = toXml(svgGenerator);

  final String xml2 = toXml(svgGenerator);

  assertEquals("xml document was not changed and should be the same",
    xml1, xml2);

}

private SVGGraphics2D createSvgGenerator() {
  final Document document = initNewDocument();

  final SVGGraphics2D svgGenerator = new SVGGraphics2D(document);
  return svgGenerator;
}

private Document initNewDocument() {
  // Get a DOMImplementation.
  final DOMImplementation domImpl = GenericDOMImplementation
    .getDOMImplementation();

  // Create an instance of org.w3c.dom.Document.
  final String svgNS = "http://www.w3.org/2000/svg";
  return domImpl.createDocument(svgNS, "svg", null);
}

private String toXml(final SVGGraphics2D svgGenerator) {

  try (ByteArrayOutputStream os = new ByteArrayOutputStream(); OutputStreamWriter streamWriter = new OutputStreamWriter(os)) {

    final boolean useCss = true;
    // this method clears the content of the xnl-document
    svgGenerator.stream(streamWriter, useCss);

    return os.toString(StandardCharsets.UTF_8.name());

  } catch (final IOException e) {
    throw new IllegalStateException(
      "a proble during printing to svg file was occured", e);
  }

}

private void drawText(final Graphics2D g) {
  final String text = "My Text inside Svg";
  final int fontSize = 10;
  final int width = 10;
  final int height = 10;
  final Graphics g1 = new BufferedImage(width, height,
    BufferedImage.TYPE_INT_RGB).getGraphics();
  final int style = 0;
  final Font font = new Font(g1.getFont().toString(), style, fontSize);
  g1.dispose();

  g.setFont(font);

  g.setColor(Color.GREEN);

  g.drawString(text, 50, 100);
}

private void drawRectangle(final Graphics2D g) {
  g.setColor(Color.RED);
  final int width = 500;
  final int height = 300;
  g.fillRect(0, 0, width, height);
}

Answer 1

您的代码没有错。 通常， stream清空svgGenerator 。

如果要将其导出到文件中然后再进行处理，建议您

1. 定义文档的工作副本
2. 在...上下功夫
3. 将您的工作副本复制到temp svg文档
4. 将临时svg文档导出到文件
5. 重复步骤2.-4。

---

这是我进行编辑的方法（非常简单）：

private String toXml(final SVGGraphics2D svgGenerator) {

  try (ByteArrayOutputStream os = new ByteArrayOutputStream(); OutputStreamWriter streamWriter = new OutputStreamWriter(os)) {

    final boolean useCss = true;

    // create new temp SVGGraphics2D
    SVGGraphics2D svgToExport = (SVGGraphics2D) svgGenerator.create();
    // use it to export (and empty) it
    svgToExport.stream(streamWriter, useCss);

    return os.toString(StandardCharsets.UTF_8.name());

  } catch (final IOException e) {
    throw new IllegalStateException(
      "a problem during printing to svg file occured", e);
  }
}