XFA Rich Text Paragraph Geometry
Rich text draw paragraphs place inline runs of different font sizes on a common PDF text baseline whilst retaining each run's effective font, size, colour, weight, posture and recognised CSS overrides
The layout engine offsets smaller run boxes within the line and sends the run-relative baseline through the baseline entry of the draw style channel; THotPDF emits that baseline directly and restores the page's prior TopTextPosition mode after each run
The distance between adjacent paragraphs uses the greater of the preceding paragraph's spaceBelow and the following paragraph's spaceAbove, including recognised inline CSS paragraph-margin overrides; empty paragraphs contribute no line or spacing
For example, a 30 pt line step followed by spaceBelow="4pt" and spaceAbove="3pt" advances the following paragraph by 34 pt
Paragraph lineHeight cannot reduce the line step below the height required by its text, and left, centre, right or justify alignment continues to use the effective paragraph margins and indentation
Native per-instance form overrides remain independent across repeated occurrences and persist through XDP save and reload before PDF production
These rules apply to every line in the rich text wrapping pipeline; complete widget rich text editing, additional CSS declarations and complete decoration geometry continue as separate rendering targets