IObject Class Structure

Overview

IObject is imported from org.verapdf.wcag.algorithms.entities.IObject (external verapdf-wcag-algs library).

JSON Output Types

Based on sample response analysis, OpenDataLoader produces the following element types:

Element Types

Type	JSON `type` field	Description
Paragraph	`paragraph`	Text paragraph with font info
Heading	`heading`	Section heading with level
Table	`table`	Table with rows and cells
Image	`image`	Image/figure element
List	`list`	Bulleted or numbered list

Common Fields (all types)

json

{
  "type": "paragraph",
  "id": 17,
  "page number": 1,
  "bounding box": [left, bottom, right, top]  // PDF points, origin at bottom-left
}

Paragraph Fields

json

{
  "type": "paragraph",
  "font": "ArialMT",
  "font size": 8.0,
  "text color": "[0.0, 0.0, 0.0, 0.7]",
  "content": "Text content here"
}

Heading Fields

json

{
  "type": "heading",
  "level": "1",
  "content": "Heading text"
}

Table Structure

json

{
  "type": "table",
  "level": "1",
  "number of rows": 3,
  "number of columns": 3,
  "rows": [
    {
      "type": "table row",
      "row number": 1,
      "cells": [
        {
          "type": "table cell",
          "page number": 1,
          "bounding box": [left, bottom, right, top],
          "row number": 1,
          "column number": 1,
          "row span": 1,
          "column span": 1,
          "kids": [
            {
              "type": "paragraph",
              "content": "Cell text"
            }
          ]
        }
      ]
    }
  ]
}

Bounding Box Coordinate System

OpenDataLoader: [left, bottom, right, top] in PDF points, origin at BOTTOMLEFT
Docling: {l, t, r, b} with coord_origin: "BOTTOMLEFT" or "TOPLEFT"

Conversion Notes

If docling uses TOPLEFT origin: bottom = page_height - docling_t, top = page_height - docling_b
If docling uses BOTTOMLEFT origin: direct mapping [l, b, r, t] → [left, bottom, right, top]

Key Java Classes

From the codebase:

TableBorder - Table with border-based detection
TableBorderRow - Table row
TableBorderCell - Table cell with contents, rowSpan, colSpan
BoundingBox - PDF coordinates (page, left, bottom, right, top)
Processors: TextLineProcessor, TableBorderProcessor, HeadingProcessor, ListProcessor