POI 中PPT 文件格式

Records, Containers and Atoms

 

PPT document contrains a tree of Records.

Each Record contain either other records(Act as a contanier)

  or data(act as Atoms). Record cannot contain both.

 

PowerPoint documents don't have one overall container record

There are a number of different container records to be found at the top level.

 

 

Format of Record:

1/2 byte container flag

1.5 byte option field

2 byte record type

4 byte record length

 

If the first byte of the header, BINARY_AND with 0x0f, is 0x0f, then the record is a container. Otherwise, it's an atom.

The rest of the first two bytes are used to store the "options" for the record.

Most commonly, this is used to indicate the version of the record, but the exact useage is record specific.

 

The record type is a little endian number.

PowerPoint records have a type that's normally less than 6000 (decimal). Escher records normally have a type between 0xF000 and 0xF1FF.

 

 The record length is another little endian number

For an atom, it's the size of the data part of the record

For a container, it's the size of all the records that are children of this record

 

 

A small number of records contain byte level position offsets to other records.

So if you change the position of any records in the file, then there's a good chance that you will need to update some of these special records.

 

 

 

Paragraph and Text Styling

a number of records that affect the styling of text

a smaller number that are responsible for the styling of paragraphs

By default, a given set of text will inherit paragraph and text stylings from the appropriate master sheet

Normally, powerpoint will have one text record (TextBytesAtom or TextCharsAtom) for every paragraph, with a preceeding TextHeaderAtom to describe what sort of paragraph it is.

 

TextBytesAtom

TextCharsAtom

 

 

StyleTextPropAtom

FontCollection [live inside Document.Environment.FontCollection]

FontEntityAtom