The aim here is to create some kind of documentation for the Area Tree XML Intermediate Format that is under development by the Apache FOP team.

This has all spawned from my frustration at requiring the information contained within the Area Tree XML that I have managed to gain access to, only to discover that there is no definitive documentation to be found. I wanted to know the dimensions of an area that I have created and could not know for sure since the attributes of the nodes were abbreviated to forms such as bpd and ipda!

The thread that relates to this page is

I am hoping that with public participation we can provide definitions for the meaning and purpose of each node and attribute in the FOP IF Tree. I would therefore like to welcome any and all contributions!

[Tom Wilcox]

[Contributors' initials are found in square brackets with a key at the bottom of the page for recognition ]

Area Tree XML Attributes

  • bpd = block-progression-dimension of the content rectangle of the area (= height for lr-tb script) [JM];

  • bpda = allocated bpd = content bpd + spaces + borders + padding [JM];

  • ipd = inline-progression-dimension of the content rectangle of the area (= width for lr-tb script) [JM];

  • ipda = allocated ipd = content ipd + spaces + borders + padding [JM];

  • prod-id = reference attribute id (e.g. <fo:block id="123">) [GD];


The Area Tree XML closely follows the description made in the XSL-FO Recommendation.

Units are millipoints (1000ths of a point) as used in most of FOP (most notably the layout engine). [JM]


[JM] = [courtesy of Jeremias Maerki]

[GD] = [courtesy of Georg Datterl]

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