RP

Description	Provides fallback punctuation or parentheses for ruby annotations when the ruby text cannot be rendered.
Namespace	1.7 2.0
Category	inline

Attributes

Placement

Specifies how the element is placed relative to surrounding content (e.g., block-level or inline flow).

WritingMode

Defines the direction of text flow (e.g., left-to-right, right-to-left, or vertical).

BackgroundColor

Sets the background color for the element’s content area.

BorderColor

Specifies the color of the border around the element.

BorderStyle

Indicates the style of the border (e.g., solid, dashed, dotted).

BorderThickness

Defines the thickness of the border line in user space units (such as points).

Padding

Determines the space between the element’s border (or boundary) and its inner content.

Color

Applies the primary color (fill or stroke) for the text or graphic content.

role

Main indicator of type. This semantic association allows tools to present and support interaction with the object in a manner that is consistent with user expectations about other objects of that type.

Differences

Well tagged PDF:

The 'RP' (Ruby Parenthesis) element in Well-Tagged PDF is used to enclose fallback characters (such as parentheses) that may be rendered if the ruby text is not displayed.

It should be used in conjunction with Ruby annotations to indicate grouping of fallback punctuation, ensuring visual consistency during content extraction.

PDFUA:

In PDF/UA, the 'RP' element supports accessibility by providing fallback cues for ruby annotations, ensuring that the relationship between base text and annotation is maintained.

The 'RP' element must be tagged with appropriate alternative text if needed, so that assistive technologies can convey its function when ruby annotations are not directly rendered.