{"id":484,"date":"2014-08-01T13:10:57","date_gmt":"2014-08-01T11:10:57","guid":{"rendered":"http:\/\/blogs.igalia.com\/jaragunde\/?p=484"},"modified":"2014-08-01T13:10:58","modified_gmt":"2014-08-01T11:10:58","slug":"tales-of-libreoffice-interoperability-the-missing-files","status":"publish","type":"post","link":"https:\/\/blogs.igalia.com\/jaragunde\/2014\/08\/tales-of-libreoffice-interoperability-the-missing-files\/","title":{"rendered":"Tales of LibreOffice interoperability: the missing files"},"content":{"rendered":"

I’m welcoming the release of LibreOffice 4.3.0<\/a> in the name of Igalia<\/a> with the last post in this series<\/a>. This time we will talk about the preservation of embeddings in OOXML text documents, and devote some lines to the support of Standard Document Tags.<\/p>\n

Embedded content in documents<\/h4>\n

Our goal this time was the preservation of embedded content in OOXML text documents, as a first step towards full support like we did with other features. The insertion of new embeddings in .docx documents or the edition of existing ones will have to come later in the future.<\/p>\n

An embedded document usually consists of two files; one of them is a preview picture to be shown in the parent document, and the other one is the actual embedded document. For the case of a spreadsheet embedded in a text document, the most common case, you will find these two files in the document:<\/p>\n

[code]
\n\/word\/media\/image1.emf
\n\/word\/embeddings\/Microsoft_Excel_Worksheet1.xlsx
\n[\/code]<\/p>\n

With the corresponding entries in the relations file:<\/p>\n

[code language=”xml”]
\n<Relationship Id="rId2"
\n Type="http:\/\/schemas.openxmlformats.org\/officeDocument\/2006\/relationships\/package"
\n Target="embeddings\/oleObject1.xlsx" \/>
\n <Relationship Id="rId3"
\n Type="http:\/\/schemas.openxmlformats.org\/officeDocument\/2006\/relationships\/image"
\n Target="media\/image1.emf" \/>
\n[\/code]<\/p>\n

The relevant bits in the document.xml<\/em> file are below. Notice a w:object<\/em> consists of one shape, which is filled with data from an image file, and the OLE object itself, linked to the embedded spreadsheet. Also notice the attribute ProgID<\/em>, which defines the program, document type and version:<\/p>\n

[code language=”xml”]
\n<w:object>
\n <v:shape id="ole_rId2"
\n style="width:362.25pt;height:146.25pt" o:ole="">
\n <v:imagedata r:id="rId3" o:title="" \/>
\n <\/v:shape>
\n <o:OLEObject Type="Embed" ProgID="Excel.Sheet.12"
\n ShapeID="ole_rId2" DrawAspect="Content"
\n ObjectID="_570182397" r:id="rId2" \/>
\n<\/w:object>
\n[\/code]<\/p>\n

There is one more element that allows the embedded file to be properly detected by Word, it’s a content type definition in the content types file:<\/p>\n

[code language=”xml”]
\n<Override PartName="\/word\/embeddings\/oleObject1.xlsx"
\nContentType="application\/vnd.openxmlformats-officedocument.spreadsheetml.sheet" \/>
\n[\/code]<\/p>\n

As you can see there are three elements that determine the kind of embedding we are dealing with, and Word requires the right combination of the three of them: <\/p>\n