GitHub Repository: quarto-dev/quarto-cli
Path: blob/main/llm-docs/ensure-pdf-text-positions.md
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ensurePdfTextPositions Test API

A test predicate for verifying the spatial layout of text in rendered PDFs. Use this to assert that elements appear in the correct positions relative to each other.

Requirements

Tagged PDFs only: This API requires PDFs with PDF 1.4+ structure tree support (MCIDs linking text to semantic elements)
Typst: Works out of the box (Typst produces tagged PDFs by default)
LaTeX: Not currently supported (requires \DocumentMetadata{} before \documentclass)

Basic Usage

Add assertions to your .qmd file's YAML front matter:

_quarto:
  tests:
    typst:
      ensurePdfTextPositions:
        - # First array: positive assertions (these must be true)
          - subject: "Chapter 1"
            relation: above
            object: "Introduction text"
          - subject: "Margin note"
            relation: rightOf
            object: "Body paragraph"
        - [] # Second array: negative assertions (these must NOT be true)
      noErrors: default

Text Selectors

A selector identifies text in the PDF. It can be a simple string or an object with options.

Simple String Selector

subject: "Hello World"

Searches for text containing "Hello World". The text must appear exactly once in the PDF.

Object Selector

subject:
  text: "Hello World"
  role: "H1"
  page: 1
  edge: left
  granularity: "Div"

Field	Description
`text`	Text to search for (required unless `role: "Page"`)
`role`	Expected PDF structure role (see Roles below)
`page`	Page number, 1-indexed (required for `role: "Page"`)
`edge`	Override which edge to use: `left`, `right`, `top`, `bottom`
`granularity`	Aggregate bounding box to ancestor with this role

Roles

Standard PDF structure roles: P, H1, H2, H3, Figure, Table, Span, Div, etc.

Special Roles

Decoration - For untagged page elements like headers, footers, and page numbers:

subject:
  text: "Page 1"
  role: "Decoration"

Uses raw text item bounds (no structure tree lookup)
Allows multiple matches (uses first match)

Page - Represents the entire page area:

subject:
  role: "Page"
  page: 2

The text field is ignored
Useful for negative assertions (e.g., "this text should NOT be on page 1")

Relations

Directional Relations

Assert spatial ordering between elements.

Relation	Meaning	Default Edges
`above`	Subject is above object	subject.bottom < object.top
`below`	Subject is below object	subject.top > object.bottom
`leftOf`	Subject is left of object	subject.right < object.left
`rightOf`	Subject is right of object	subject.left > object.right

Distance constraints (optional):

- subject: "Title"
  relation: above
  object: "Subtitle"
  byMin: 10    # At least 10pt gap
  byMax: 50    # At most 50pt gap

Alignment Relations

Assert that edges are aligned (within tolerance).

Relation	Meaning
`topAligned`	Top edges match
`bottomAligned`	Bottom edges match
`leftAligned`	Left edges match
`rightAligned`	Right edges match

- subject: "Column A"
  relation: leftAligned
  object: "Column B"
  tolerance: 5  # Allow 5pt difference (default: 2pt)

Tag-Only Assertions

Validate that text exists with a specific role (no position comparison):

- subject:
    text: "Important"
    role: "H1"

Edge Overrides

Override which edge is used for comparison:

- subject:
    text: "Left column"
    edge: right        # Use right edge of subject
  relation: leftOf
  object:
    text: "Right column"
    edge: left         # Use left edge of object

Default edges per relation:

Relation	Subject Edge	Object Edge
`leftOf`	right	left
`rightOf`	left	right
`above`	bottom	top
`below`	top	bottom
`leftAligned`	left	left
`rightAligned`	right	right
`topAligned`	top	top
`bottomAligned`	bottom	bottom

Granularity

Aggregate the bounding box to an ancestor element:

- subject:
    text: "cell content"
    granularity: "Table"  # Use entire table's bbox, not just the cell
  relation: below
  object: "Heading"

This walks up the structure tree to find an ancestor with the specified role and computes the bounding box from all its descendant content.

Negative Assertions

The second array contains assertions that must NOT be true:

_quarto:
  tests:
    typst:
      ensurePdfTextPositions:
        - # Positive (must be true)
          - subject: "Content"
            relation: below
            object: "Title"
        - # Negative (must NOT be true)
          - subject: "Margin note"
            relation: leftOf
            object: "Body text"

Negative assertions pass if:

The elements are on different pages
The spatial relation does not hold
Either element is not found

Coordinate System

Origin: top-left corner of page
X: increases rightward
Y: increases downward

Error Messages

"Cannot compare positions: X is on page 1, Y is on page 2"

The two elements are on different pages. This is an error, not a pass or fail. If you expect elements to potentially be on different pages, use negative assertions.

"Text X is ambiguous - found N matches"

The search text appears multiple times. Use a more specific string, or use role: "Decoration" if this is expected (e.g., repeated headers).

"Text not found in PDF: X"

The search text doesn't exist in the PDF.

"Text X has no MCID - PDF may not be tagged"

The text exists but isn't linked to the structure tree. Use role: "Decoration" for untagged elements.

Examples

Verify heading hierarchy

ensurePdfTextPositions:
  - - subject: "Chapter 1"
      relation: above
      object: "Section 1.1"
    - subject: "Section 1.1"
      relation: above
      object: "Section 1.2"
  - []

Verify margin layout

ensurePdfTextPositions:
  - - subject: "Margin note text"
      relation: rightOf
      object: "Body paragraph"
    - subject: "Margin note text"
      relation: topAligned
      object: "Body paragraph"
  - []

Verify header/footer positioning

ensurePdfTextPositions:
  - - subject:
        text: "HEADER_TEXT"
        role: "Decoration"
      relation: above
      object: "Page content"
    - subject: "Page content"
      relation: above
      object:
        text: "FOOTER_TEXT"
        role: "Decoration"
  - []

Verify elements are NOT on a specific page

ensurePdfTextPositions:
  - []  # No positive assertions
  - # Negative: "Secret" should NOT be anywhere on page 1
    - subject: "Secret content"
      relation: above
      object:
        role: "Page"
        page: 1

Verify minimum spacing

ensurePdfTextPositions:
  - - subject: "Figure 1"
      relation: above
      object: "Figure 1 caption"
      byMin: 5   # At least 5pt gap
      byMax: 20  # At most 20pt gap
  - []

Verify column alignment

ensurePdfTextPositions:
  - - subject: "Row 1 Col A"
      relation: leftAligned
      object: "Row 2 Col A"
      tolerance: 1
    - subject: "Row 1 Col B"
      relation: leftAligned
      object: "Row 2 Col B"
      tolerance: 1
  - []