如何在XSSFWorkBook中添加SVG映像

Question

FileInputStream in = new FileInputStream("testWorkbook.xlsx");
XSSFWorkbook wb = (XSSFWorkbook)WorkbookFactory.create(in);
InputStream inputStream = new FileInputStream("/home/test/test1.svg");
//Get the contents of an InputStream as a byte[].
byte[] imageData = IOUtils.toByteArray(inputStream);
// XSSFWorkbook.PICTURE_TYPE_SVG is not supported yet.
int pictureIndex = wb.addPicture(imageData, XSSFWorkbook.PICTURE_TYPE_SVG); // Preferred support

有什么方法可以将SVG映像添加到XSSFWorkbook中吗？

Answer 1

对SVG的支持是Microsoft Office 365的新功能。这就是为什么直到现在Apache poi还不完全支持它（2021年5月，Apache poi 5.0.0)。

要在Excel中实现这种支持，需要知道Excel如何插入SVG图像。为了向后兼容，它将图像转换为png。它将SVG图像和PNG图像都放入工作簿中。然后，它将png图像显示为绘图中的形状。该形状具有对SVG图像的附加引用，因此如果使用Excel 365，也可以获得SVG图像。

要在Apache POI中实现这种支持，需要以下内容：

>

SVG到PNG的转换器。那里可以使用阿帕奇蜡染代码转换器。

扩展的XSSFWorkbook，它提供单独的AddsVGPicture方法，或者在AddPicture方法中提供对SVG的支持。但是扩展xssf...类并不是那么简单，因为有些奇怪的决定将成员或方法设置为私有。

xssfrelation.image_svg，在创建图片和形状时提供创建关系。但是XSSFRelation完全不可扩展。因此，需要扩展低层POIXMLRelation。

扩展的XSSFPictureData，为新的POIXMLRelation提供对所需图片构造函数的支持。

下面的代码提供了所有这些。在需要的地方对其进行评论。

import org.apache.poi.xssf.usermodel.*;
import org.apache.poi.ss.usermodel.*;

import java.io.InputStream;
import java.io.FileInputStream;
import java.io.FileOutputStream;

class CreateExcelXSSFPictureSVG {
 
 // use org.apache.batik.transcoder to convert SVG to PNG 
 static byte[] svgToPng(InputStream svg) throws Exception {
  org.apache.batik.transcoder.image.PNGTranscoder t = new org.apache.batik.transcoder.image.PNGTranscoder();
  org.apache.batik.transcoder.TranscoderInput input = new org.apache.batik.transcoder.TranscoderInput(svg);
  
  java.io.ByteArrayOutputStream ostream = new java.io.ByteArrayOutputStream();
  org.apache.batik.transcoder.TranscoderOutput output = new org.apache.batik.transcoder.TranscoderOutput(ostream);

  t.transcode(input, output);
  ostream.flush();
  
  return ostream.toByteArray();  
 }
    
 public static void main(String[] args) throws Exception {
     
  String svgFilePath = "./Freesample.svg";
  
  MyXSSFWorkbook workbook = new MyXSSFWorkbook(); // see MyXSSFWorkbook.java

  // add SVG Image to workbook  
  FileInputStream is = new FileInputStream(svgFilePath);
  int svgPictureIdx = workbook.addSVGPicture(is);
  is.close();
  
  // add PNG image to workbook
  is = new FileInputStream(svgFilePath);
  int pngPictureIdx = workbook.addPicture(svgToPng(is), Workbook.PICTURE_TYPE_PNG);
  is.close();

  // create sheet and get drawing
  XSSFSheet sheet = workbook.createSheet("Sheet1");
  XSSFDrawing drawing = sheet.createDrawingPatriarch();
 
  // add SVG Image relation to drawing 
  XSSFPictureData pictureData = workbook.getAllPictures().get(svgPictureIdx);
  org.apache.poi.ooxml.POIXMLDocumentPart.RelationPart rp = drawing.addRelation(null, XSSFRelation.IMAGES, pictureData);
  String svgRId = rp.getRelationship().getId();

  // create anchor for picture shape
  XSSFCreationHelper helper = workbook.getCreationHelper();
  XSSFClientAnchor anchor = helper.createClientAnchor();
  anchor.setCol1(1);
  anchor.setRow1(1); 

  // create PNG picture shape
  XSSFPicture pngPicture = drawing.createPicture(anchor, pngPictureIdx);
  pngPicture.resize();
  
  // set SVG extension to PNG picture shape
  org.openxmlformats.schemas.drawingml.x2006.main.CTOfficeArtExtension ext = pngPicture.getCTPicture().getBlipFill().getBlip().addNewExtLst().addNewExt();
  ext.setUri("{96DAC541-7B7A-43D3-8B79-37D633B846F1}");
  org.apache.xmlbeans.XmlCursor cursor = ext.newCursor();
  cursor.toNextToken();
  cursor.toNextToken();
  cursor.beginElement(new javax.xml.namespace.QName("http://schemas.microsoft.com/office/drawing/2016/SVG/main", "svgBlip", "asvg"));
  cursor.insertNamespace("asvg", "http://schemas.microsoft.com/office/drawing/2016/SVG/main");
  cursor.insertAttributeWithValue(new javax.xml.namespace.QName("http://schemas.openxmlformats.org/officeDocument/2006/relationships", "embed", "r"), svgRId);
  cursor.dispose();

  FileOutputStream out = new FileOutputStream("CreateExcelXSSFPictureSVG.xlsx");
  workbook.write(out);
  out.close();
  workbook.close();

 }
}

使用的扩展类：

myxssfworkbook.java

import org.apache.poi.xssf.usermodel.XSSFWorkbook;
import org.apache.poi.xssf.usermodel.XSSFPictureData;
import org.apache.poi.xssf.usermodel.XSSFFactory;
import org.apache.poi.util.IOUtils;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.List;

import java.lang.reflect.Field;

public class MyXSSFWorkbook extends XSSFWorkbook {

 public int addSVGPicture(InputStream is) throws Exception {
  Field _xssfFactory = XSSFWorkbook.class.getDeclaredField("xssfFactory");
  _xssfFactory.setAccessible(true);
  XSSFFactory xssfFactory = (XSSFFactory)_xssfFactory.get(this);
  
  int imageNumber = getAllPictures().size() + 1;
  
  Field _pictures = XSSFWorkbook.class.getDeclaredField("pictures");
  _pictures.setAccessible(true);
  @SuppressWarnings("unchecked")
  List<XSSFPictureData> pictures = (List<XSSFPictureData>)_pictures.get(this);

  MyXSSFPictureData img = createRelationship(MyXSSFRelation.IMAGE_SVG, xssfFactory, imageNumber, true).getDocumentPart(); // see MyXSSFPictureData.java and MyXSSFRelation.java
  try (OutputStream out = img.getPackagePart().getOutputStream()) {
   IOUtils.copy(is, out);
  }
  pictures.add(img);

  return imageNumber - 1;
 }

}

import org.apache.poi.ooxml.POIXMLRelation;
import org.apache.poi.openxml4j.opc.PackageRelationshipTypes;

public final class MyXSSFRelation extends POIXMLRelation {

 public static final MyXSSFRelation IMAGE_SVG = new MyXSSFRelation(
  "image/svg",
  PackageRelationshipTypes.IMAGE_PART,
  "/xl/media/image#.svg",
  MyXSSFPictureData::new, MyXSSFPictureData::new // see MyXSSFPictureData.java
 );

 private MyXSSFRelation(String type, String rel, String defaultName,
                      NoArgConstructor noArgConstructor,
                      PackagePartConstructor packagePartConstructor) {
  super(type, rel, defaultName, noArgConstructor, packagePartConstructor, null);
 }

}

import org.apache.poi.openxml4j.opc.PackagePart;
import org.apache.poi.xssf.usermodel.XSSFPictureData; 

public class MyXSSFPictureData extends XSSFPictureData {

 protected MyXSSFPictureData() {
  super();
 }
 
 protected MyXSSFPictureData(PackagePart part) {
  super(part);
 }

}