Generating revision bars

If you use Antenna House Formatter or RenderX XEP, you can generate revision bars in your PDF output by using the @changebar attribute of the DITAVAL <revprop> element.

Note: FOP 1.1 does not support the XSL fo:change-bar formatting object.
The DITA specification for @changebar simply says:
When flag has been set, specify a changebar color, style, or character, according to the changebar support of the target output format. If flag has not been set, this attribute is ignored.

The syntax for @changebar is a sequence of name and value pairs that are delimited by semicolons, for example:

<revprop action="flag" val="rev01"

To produce a revision bar, you must specify a value for style and should specify a value for width so you get a visible rule.

Each name and value pair corresponds to an attribute of the XSL-FO fo:change-bar-begin element. The following attributes and values are available:

The style to use for the line, as for other XSL-FO rules (@change-bar-style). The value solid produces a solid rule; the default value is none.
Any color value recognized by XSL-FO, including the usual color names or a hex color value. The default value is black.
The space to offset the revision bar from the edge of the text column. You can use points (pt) or millimeters (mm).
The side of the text column on which to place the revision bar. The allowed values are start (left side for left-to-right languages) and end (right side for left-to-right languages). The default value is start.
The width of the rule as a measurement value. Typical values are 1pt and 0.5pt, which renders a hairline rule.

XSL-FO 1.1 does not provide for revision bars that are not rules, so there is no way to get text revision indicators instead of rules, for example, using a number in place of a rule. Antenna House Formatter provides a proprietary extension to enable this, but the DITA-OT PDF transformation does not take advantage of it.