History

What has happened to this document, as a list of dated lines.

What a line holds

When it happened, what happened, and a note about it: three things you write, and can edit. The list shows those three as columns, and two more you cannot edit: Who did it, and Details, for whatever else a machine wrote.

Anything a machine wrote alongside, such as page counts, a recogniser's confidence or a source path, is carried with the line and left untouched. The file has to survive readers older and newer than whatever wrote it, so nothing is discarded for being unfamiliar.

Dates are shown year-first and fixed-width, in your local time, so a column of them sorts by eye the way it sorts by clock.

What gets recorded, and what does not

The history records what happened to the document: pages added, removed, reordered, cropped, made permanent.

Marking does not write a line. A highlight, an underline or a note is content on the page. It does not become history, any more than typing into a form field does. What does write a line is talking: the first words typed into a mark's card, and every reply after them, each add an entry. A document you have read and marked heavily can still have a short history. That is correct, not a gap.

Where it lives

Inside the PDF itself, in its XMP metadata, under a namespace of CaseLeaf's own.

That was chosen by measurement rather than preference: of five places a marker can be put in a PDF, XMP and the Keywords field are the only two that survive a full rewrite by Preview. Custom entries in the Info dictionary and embedded file attachments are both destroyed, and extended attributes do not survive a copy to a network volume.

Writing it does not re-render or recompress anything. The original bytes are left exactly as they are, and a new version of the metadata is appended with a small cross-reference section pointing at it. That is also why a failed write cannot corrupt the document: a reader that stops at the first end-of-file marker still sees a valid, older version.

The paper trail travels with the file. Send the PDF to somebody else and the history goes with it. There is no database on this machine holding it.

To edit a line, click a cell and then click it again: the ordinary table gesture, not a double-click. It becomes a field you can type into.

The date is different. Click it once and a small calendar opens, because committing a date re-sorts the history, and a row that moves while it is being edited takes the cursor with it.

Double-clicking a line opens its note in a bigger editor, for a note too long to read in one row.

A document opened into an existing window keeps its own records, and they can be edited there like any other. The list only refuses when there is no document in front at all, such as a handbook tab or an empty area, and the status bar then says "There is no document in front to change the records of."

See also

• What is written into the file

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