Module layout 

Page-Aware Layout Engine

This is the heart of Forme and the reason it exists.

The Problem With Every Other Engine

Most PDF renderers do this:

1. Lay out all content on an infinitely tall canvas
2. Slice the canvas into pages
3. Try to fix the things that broke at slice points

Step 3 is where everything falls apart. Flexbox layouts collapse because the flex algorithm ran on the pre-sliced dimensions. Table rows get split in the wrong places. Headers don’t repeat. Content gets “mashed together.”

How Forme Works

Forme never creates an infinite canvas. The layout algorithm is:

1. Open a page with known dimensions and remaining space
2. Place each child node. Before placing, ask: “does this fit?”
3. If it fits: place it, reduce remaining space
4. If it doesn’t fit and is unbreakable: start a new page, place it there
5. If it doesn’t fit and is breakable: place what fits, split the rest to a new page, and RE-RUN flex layout on both fragments
6. For tables: when splitting, clone the header rows onto the new page

The key insight in step 5: when a flex container splits across pages, BOTH fragments get their own independent flex layout pass. This is why react-pdf’s flex breaks on page wrap — it runs flex once on the whole container and then slices, so the flex calculations are wrong on both halves. We run flex AFTER splitting.

Modules

audit

Post-render content audit (opt-in, RenderOptions::audit_content).

flex

Flex Layout Utilities

grid

CSS Grid Layout

page_break

Page Break Decisions

Structs

BookmarkEntry

A bookmark entry collected during layout.

ElementInfo

Layout metadata for a single positioned element (hierarchical).

ElementStyleInfo

Serializable snapshot of ResolvedStyle for the inspector panel.

LayoutElement

A positioned element on a page.

LayoutEngine

The main layout engine.

LayoutInfo

Complete layout metadata for all pages.

LayoutPage

A fully laid-out page ready for PDF serialization.

PageInfo

Layout metadata for a single page.

PositionedGlyph

TextLine

Enums

DrawCommand

What to actually draw for this element.

FormFieldType

Configuration for an interactive PDF form field.

Constants

PAGE_NUMBER_SENTINEL

Sentinel character for {{pageNumber}} placeholder. A single char that is atomic (can’t be split by line breaking), measured as the width of “00”, and recognized by the PDF serializer for replacement.

TOTAL_PAGES_SENTINEL

Sentinel character for {{totalPages}} placeholder.