解释下这段代码：private static void createPicture(int format, InputStream pictureData, int width, int height, XWPFParagraph paragraph) { String blipId = null; try { blipId = paragraph.getDocument().addPictureData(pictureData, format); } catch (InvalidFormatException e) { e.printStackTrace(); } int id = paragraph.getDocument().getAllPictures().size() - 1; final int EMU = 9525; width *= EMU; height *= EMU; CTInline inline = paragraph.createRun().getCTR().addNewDrawing().addNewInline(); String picXml = "<a:graphic xmlns:a=\"http://schemas.openxmlformats.org/drawingml/2006/main\">" + " <a:graphicData uri=\"http://schemas.openxmlformats.org/drawingml/2006/picture\">" + " <pic:pic xmlns:pic=\"http://schemas.openxmlformats.org/drawingml/2006/picture\">" + " <pic:nvPicPr>" + " <pic:cNvPr id=\"" + id + "\" name=\"Generated\"/>" + " <pic:cNvPicPr/>" + " </pic:nvPicPr>" + " <pic:blipFill>" + " <a:blip r:embed=\"" + blipId + "\" xmlns:r=\"http://schemas.openxmlformats.org/officeDocument/2006/relationships\"/>" + " <a:stretch>" + " <a:fillRect/>" + " </a:stretch>" + " </pic:blipFill>" + " <pic:spPr>" + " <a:xfrm>" + " <a:off x=\"0\" y=\"0\"/>" + " <a:ext cx=\"" + width + "\" cy=\"" + height + "\"/>" + " </a:xfrm>" + " <a:prstGeom prst=\"rect\">" + " <a:avLst/>" + " </a:prstGeom>" + " </pic:spPr>" + " </pic:pic>" + " </a:graphicData>" + "</a:graphic>"; inline.addNewGraphic().addNewGraphicData(); XmlToken xmlToken = null; try { xmlToken = XmlToken.Factory.parse(picXml); } catch (XmlException xe) { xe.printStackTrace(); } inline.set(xmlToken); inline.setDistT(0); inline.setDistB(0); inline.setDistL(0); inline.setDistR(0); CTPositiveSize2D extent = inline.addNewExtent(); extent.setCx(width); extent.setCy(height); CTNonVisualDrawingProps docPr = inline.addNewDocPr(); docPr.setId(id); docPr.setName("img" + id); docPr.setDescr("word" + id); }

这段代码是用来在一个 Word 文档的段落中插入一张图片。具体来说，它会从一个输入流中读取图片数据，然后将其添加到 Word 文档的图片集合中，并为图片生成一个唯一的标识符。然后，它会创建一个新的行，将图片插入其中，并设置图片的大小和位置。最后，它会为图片设置一些元数据，如 ID、名称和描述。这样，我们就可以在 Word 文档中插入图片了。