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PDF Oxide

Conversão para Markdown

O PDF Oxide converte páginas PDF em Markdown limpo e legível. O pipeline de conversão extrai spans de texto, os agrupa em linhas, consulta /StructTreeRoot para obter títulos e papéis de lista em PDFs marcados, detecta gutters de múltiplas colunas e quebras com ordem de leitura reversa em x, agrupa parágrafos e emite a sintaxe Markdown.

A partir da v0.3.36, para PDFs marcados o conversor lê StructRole(Heading(1..6) | ListItem | ListItemLabel | ListItemBody) diretamente de /StructTreeRoot em vez de rederivar os níveis de título a partir do tamanho da fonte. A informação de papel é propagada através de MCRs aninhadas (H1 → Span → MCR, LI → LBody → Span → MCR). Para documentos sem tags, vale o fallback geométrico: negrito + aumento de 5 % no tamanho promove a H4, e is_ordered_list_marker reconhece 1. / 12. / a) / iv. / A. ao mesmo tempo em que rejeita legendas de figura e anos.

Múltiplas colunas: spans na mesma baseline separados por > max(3 × font_size, 30 pt) são tratados como cross-column. Quebras de ordem de leitura com x decrescente (último span da col 1 → primeiro span da col 2) quebram parágrafos em vez de unir tudo em tokens sem sentido.

RTL: o reorder bidi fica desligado por padrão — o reorder incondicional visual→lógico anterior quebrava PDFs já em ordem lógica (o nome hebraico בנימין estava sendo invertido). Marcadores **bold** espúrios ao redor de glifos árabes contextuais são removidos. Chamadores cuja entrada esteja em ordem visual podem invocar text::bidi::reorder_visual_to_logical manualmente (Rust).

Imagens inline têm payload base64 limitado a 200 KB (adicionado na v0.3.36). Imagens acima do limite emitem um comentário HTML informando o tamanho original; use image_output_dir para gravá-las em disco.

Quick Example

Python

from pdf_oxide import PdfDocument

doc = PdfDocument("paper.pdf")
md = doc.to_markdown(0, detect_headings=True)
print(md)

Node.js

const { PdfDocument } = require("pdf-oxide");

const doc = new PdfDocument("paper.pdf");
const md = doc.toMarkdown(0, { detectHeadings: true });
console.log(md);
doc.close();

Go

import pdfoxide "github.com/yfedoseev/pdf_oxide/go"

doc, _ := pdfoxide.Open("paper.pdf")
defer doc.Close()
md, _ := doc.ToMarkdown(0)
fmt.Println(md)

C#

using PdfOxide.Core;

using var doc = PdfDocument.Open("paper.pdf");
var md = doc.ToMarkdown(0);
Console.WriteLine(md);

WASM

const doc = new WasmPdfDocument(bytes);
const md = doc.toMarkdown(0, true);
console.log(md);

Rust

use pdf_oxide::PdfDocument;
use pdf_oxide::converters::ConversionOptions;

let mut doc = PdfDocument::open("paper.pdf")?;
let options = ConversionOptions { detect_headings: true, ..Default::default() };
let md = doc.to_markdown(0, &options)?;
println!("{}", md);

API Reference

to_markdown(page_index, ...) -> str

Convert a single page to Markdown.

Python Signature

doc.to_markdown(
    page: int,
    preserve_layout: bool = False,
    detect_headings: bool = True,
    include_images: bool = True,
    image_output_dir: str | None = None,
    embed_images: bool = True,
) -> str

JavaScript Signature

doc.toMarkdown(pageIndex, detectHeadings?, includeImages?, includeFormFields?) -> string

Rust Signature

pub fn to_markdown(
    &mut self,
    page_index: usize,
    options: &ConversionOptions,
) -> Result<String>
Parameter Type Default Description
page_index int / usize / number – Zero-based page index
preserve_layout bool false Preserve visual layout positioning
detect_headings bool true Detect headings based on font size and weight
include_images bool true Include images in output
image_output_dir str / None None Directory to save extracted images (Python/Rust only). Unaffected by the 200 KB inline cap.
embed_images bool true Embed images as base64 data URIs (Python/Rust only). Payloads over 200 KB emit a placeholder HTML comment noting the original size (v0.3.36).
include_form_fields bool true Include form field values (Python/JS)

Returns: Markdown string for the page.

to_markdown_all(...) -> str

Convert all pages to Markdown, separated by horizontal rules (---).

Python Signature

doc.to_markdown_all(
    preserve_layout: bool = False,
    detect_headings: bool = True,
    include_images: bool = True,
    image_output_dir: str | None = None,
    embed_images: bool = True,
) -> str

JavaScript Signature

doc.toMarkdownAll(detectHeadings?, includeImages?, includeFormFields?) -> string

Rust Signature

pub fn to_markdown_all(
    &mut self,
    options: &ConversionOptions,
) -> Result<String>
Parameter Type Default Description
preserve_layout bool false Preserve visual layout
detect_headings bool true Detect headings
include_images bool true Include images
image_output_dir str / None None Image output directory
embed_images bool true Embed images as base64

Returns: Markdown string for all pages joined with --- separators.

to_markdown_with_ocr(page_index, model_path, options) -> str

Convert a page to Markdown with OCR fallback for scanned pages. When the page has little or no extractable text, OCR is used to recognize text from the rendered page image. Requires the ocr feature.

Parameter Type Description
page_index usize Zero-based page index
model_path &str Path to the OCR model files
options &ConversionOptions Conversion options

Rust

let mut doc = PdfDocument::open("scanned.pdf")?;
let options = ConversionOptions { detect_headings: true, ..Default::default() };
let md = doc.to_markdown_with_ocr(0, "/path/to/models", &options)?;
println!("{}", md);

ConversionOptions

The ConversionOptions struct controls all conversion behavior.

Field Type Default Description
preserve_layout bool false Preserve visual layout with positioning
detect_headings bool true Auto-detect headings from font size clusters
extract_tables bool false Extract tables (experimental)
include_images bool true Include images in output
image_output_dir Option<String> None Save images to this directory
embed_images bool true Embed images as base64 data URIs
reading_order_mode ReadingOrderMode Auto How to determine reading order
bold_marker_behavior BoldMarkerBehavior Conservative Bold marker application strategy

How It Works

The Markdown conversion pipeline operates in several stages:

  1. Text Extraction – Extracts TextSpan objects from the page content stream, capturing text, position, font, size, weight, and color.

  2. Character Clustering – Groups characters into words based on inter-character gaps, then words into lines based on vertical proximity.

  3. Reading Order – Determines reading order using either the Tagged PDF structure tree (preferred) or a graph-based spatial analysis of text block positions.

  4. Heading Detection – When detect_headings is enabled, clusters font sizes across the page to identify heading levels. Larger and bolder text is mapped to #, ##, ### headings.

  5. Formatting – Applies bold (**text**) and italic (*text*) markers based on font weight and style metadata.

  6. Table Detection – Identifies tabular layouts using spatial analysis of aligned text blocks and emits GFM-style Markdown tables.

  7. Whitespace Cleanup – Normalizes spacing, removes redundant blank lines, and ensures consistent paragraph breaks.

Advanced Examples

Convert entire PDF to a Markdown file

Python

from pdf_oxide import PdfDocument

doc = PdfDocument("book.pdf")
md = doc.to_markdown_all(detect_headings=True)

with open("book.md", "w", encoding="utf-8") as f:
    f.write(md)

Node.js

const fs = require("node:fs");

const doc = new PdfDocument("book.pdf");
const md = doc.toMarkdownAll();
fs.writeFileSync("book.md", md);
doc.close();

Go

doc, _ := pdfoxide.Open("book.pdf")
defer doc.Close()
md, _ := doc.ToMarkdownAll()
os.WriteFile("book.md", []byte(md), 0644)

C#

using var doc = PdfDocument.Open("book.pdf");
var md = doc.ToMarkdownAll();
File.WriteAllText("book.md", md);

WASM

const doc = new WasmPdfDocument(bytes);
const md = doc.toMarkdownAll(true);
writeFileSync("book.md", md);
doc.free();

Convert with images saved to a directory

use pdf_oxide::PdfDocument;
use pdf_oxide::converters::ConversionOptions;

let mut doc = PdfDocument::open("report.pdf")?;
let options = ConversionOptions {
    detect_headings: true,
    include_images: true,
    embed_images: false,
    image_output_dir: Some("output/images".to_string()),
    ..Default::default()
};

let md = doc.to_markdown_all(&options)?;
std::fs::write("output/report.md", &md)?;

Page-by-page conversion with progress

from pdf_oxide import PdfDocument

doc = PdfDocument("report.pdf")
pages = doc.page_count()

parts = []
for i in range(pages):
    md = doc.to_markdown(i, detect_headings=True)
    parts.append(md)
    print(f"Converted page {i + 1}/{pages}")

full_md = "\n\n---\n\n".join(parts)
with open("report.md", "w") as f:
    f.write(full_md)

Disable heading detection for flat text

doc = PdfDocument("form.pdf")
md = doc.to_markdown(0, detect_headings=False)
# All text rendered as paragraphs, no # headings

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