H
| Description | A generic heading element used to label sections of a document. Specific heading levels (H1–H6) provide hierarchical context. |
|---|---|
| Namespace | 1.7 2.0 |
| Category | block |
Attributes
Specifies how the element is placed relative to surrounding content (e.g., block-level or inline flow).
Defines the direction of text flow (e.g., left-to-right, right-to-left, or vertical).
Sets the background color for the element’s content area.
Specifies the color of the border around the element.
Indicates the style of the border (e.g., solid, dashed, dotted).
Defines the thickness of the border line in user space units (such as points).
Determines the space between the element’s border (or boundary) and its inner content.
Applies the primary color (fill or stroke) for the text or graphic content.
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 'H' element in Well-Tagged PDF serves as a general heading element when a specific level is not defined. It groups header content without enforcing a particular hierarchy.
For Well-Tagged PDF, 'H' should be used when the heading level is either unknown or irrelevant to the document’s reuse. It must still be properly nested within the structure tree to maintain logical content grouping.
PDFUA:
In PDF/UA, precise heading levels are preferred to support accessibility. However, if a heading does not have a defined level, the generic 'H' element may be used as a fallback.
PDF/UA recommends that authors use specific heading levels (e.g., H1, H2, etc.), but if 'H' is used, it should be accompanied by additional metadata or context to ensure that assistive technologies can interpret its role within the document structure.
Use cases
Tag Relationships
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Related Matterhorn Protocol checkpoints
- One or more non-standard tag’s mapping does not terminate with a standard type. NOTE: Although PDF/UA defines the nomenclature for heading levels above H6 (Hn), these are not standard structure types (as defined in ISO 32000-1) and therefore Hn tags must (PDF/UA-1 7.1, paragraph 1) be rolemapped to a standard structure type. According to PDF/UA-1, PDF/UA-conforming processors are expected to ignore such mappings and respect the heading level.
- The mapping of one or more non-standard types is semantically inappropriate.
- Tags are not in logical reading order.
- Structure elements are nested in a semantically inappropriate manner. (e.g. a table inside a heading).
- The structure type (after applying any role-mapping as necessary) of a structure element is not semantically appropriate.
- Headings are not tagged.
- Does use numbered headings, but the first heading tag is not H1.
- Numbered heading levels in descending sequence are skipped (Example: H3 follows directly after H1).
- Numbered heading tags do not use Arabic numerals.
- A node contains more than one H tag.
- Document uses both H and H# tags. NOTE: In weakly-structured documents, headings always take the form “Hn” (e.g. H1, H2, Hn) without intervening whitespace or numerical separators.