Files
pdf-inspector/src/markdown.rs
T
Abimael MartellandClaude Opus 4.6 d8f341bafc fix(columns): Skip table detection on wide multi-column text pages
Multi-column text layouts (e.g., creditor matrices with 3 address columns)
were incorrectly claimed by body-font table detection. Now runs column
detection before table detection and skips tables on pages where all
detected columns are wider than 150pt, letting group_into_lines handle
the column-by-column reading order correctly.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
2026-02-16 09:52:58 -08:00

1705 lines
56 KiB
Rust

//! Markdown conversion with structure detection
//!
//! This module converts extracted text to markdown, detecting:
//! - Headers (by font size)
//! - Lists (bullet points, numbered lists)
//! - Code blocks (monospace fonts, indentation)
//! - Paragraphs
use crate::extractor::{group_into_lines, TextItem, TextLine};
use std::collections::{HashMap, HashSet};
use regex::Regex;
/// Options for markdown conversion
#[derive(Debug, Clone)]
pub struct MarkdownOptions {
/// Detect headers by font size
pub detect_headers: bool,
/// Detect list items
pub detect_lists: bool,
/// Detect code blocks
pub detect_code: bool,
/// Base font size for comparison
pub base_font_size: Option<f32>,
/// Remove standalone page numbers
pub remove_page_numbers: bool,
/// Convert URLs to markdown links
pub format_urls: bool,
/// Fix hyphenation (broken words across lines)
pub fix_hyphenation: bool,
/// Detect and format bold text from font names
pub detect_bold: bool,
/// Detect and format italic text from font names
pub detect_italic: bool,
/// Include image placeholders in output
pub include_images: bool,
/// Include extracted hyperlinks
pub include_links: bool,
}
impl Default for MarkdownOptions {
fn default() -> Self {
Self {
detect_headers: true,
detect_lists: true,
detect_code: true,
base_font_size: None,
remove_page_numbers: true,
format_urls: true,
fix_hyphenation: true,
detect_bold: true,
detect_italic: true,
include_images: true,
include_links: true,
}
}
}
/// Convert plain text to markdown (basic conversion)
pub fn to_markdown(text: &str, options: MarkdownOptions) -> String {
let mut output = String::new();
let mut in_list = false;
let mut in_code_block = false;
for line in text.lines() {
let trimmed = line.trim();
if trimmed.is_empty() {
if in_list {
in_list = false;
}
if in_code_block {
output.push_str("```\n");
in_code_block = false;
}
output.push('\n');
continue;
}
// Detect list items
if options.detect_lists && is_list_item(trimmed) {
let formatted = format_list_item(trimmed);
output.push_str(&formatted);
output.push('\n');
in_list = true;
continue;
}
// Detect code blocks (indented lines)
if options.detect_code && is_code_like(trimmed) {
if !in_code_block {
output.push_str("```\n");
in_code_block = true;
}
output.push_str(trimmed);
output.push('\n');
continue;
} else if in_code_block {
output.push_str("```\n");
in_code_block = false;
}
// Regular paragraph text
output.push_str(trimmed);
output.push('\n');
}
if in_code_block {
output.push_str("```\n");
}
output
}
/// Convert positioned text items to markdown with structure detection
pub fn to_markdown_from_items(items: Vec<TextItem>, options: MarkdownOptions) -> String {
use crate::extractor::ItemType;
use crate::tables::{detect_tables, table_to_markdown};
use std::collections::HashSet;
if items.is_empty() {
return String::new();
}
// Separate images and links from text items
let mut images: Vec<TextItem> = Vec::new();
let mut links: Vec<TextItem> = Vec::new();
let mut text_items: Vec<TextItem> = Vec::new();
for item in items {
match &item.item_type {
ItemType::Image => {
if options.include_images {
images.push(item);
}
}
ItemType::Link(_) => {
if options.include_links {
links.push(item);
}
}
ItemType::Text => {
text_items.push(item);
}
}
}
// Calculate base font size for table detection
let font_stats = calculate_font_stats_from_items(&text_items);
let base_size = options
.base_font_size
.unwrap_or(font_stats.most_common_size);
// Detect tables on each page
let mut table_items: HashSet<usize> = HashSet::new();
let mut page_tables: std::collections::HashMap<u32, Vec<(f32, String)>> =
std::collections::HashMap::new();
// Store images by page and Y position for insertion
let mut page_images: std::collections::HashMap<u32, Vec<(f32, String)>> =
std::collections::HashMap::new();
for img in &images {
// Extract image name from "[Image: Im0]" format
let img_name = img
.text
.strip_prefix("[Image: ")
.and_then(|s| s.strip_suffix(']'))
.unwrap_or(&img.text);
let img_md = format!("![Image: {}](image)\n", img_name);
page_images
.entry(img.page)
.or_default()
.push((img.y, img_md));
}
// Pre-group items by page with their global indices (O(n) instead of O(pages*n))
let mut page_groups: HashMap<u32, Vec<(usize, &TextItem)>> = HashMap::new();
for (global_idx, item) in text_items.iter().enumerate() {
page_groups
.entry(item.page)
.or_default()
.push((global_idx, item));
}
let mut pages: Vec<u32> = page_groups.keys().copied().collect();
pages.sort();
for page in pages {
let group = page_groups.get(&page).unwrap();
let page_items: Vec<TextItem> = group.iter().map(|(_, item)| (*item).clone()).collect();
// Skip table detection on pages with clear multi-column text layout.
// Column detection in group_into_lines handles these correctly, and
// table detection would incorrectly claim columnar text as table rows.
// Only skip when all detected columns are wide (>150pt ~ 2 inches),
// indicating true text columns rather than narrow table columns.
let columns = crate::extractor::detect_columns(&page_items, page);
if columns.len() >= 2 {
let min_col_width = columns
.iter()
.map(|c| c.x_max - c.x_min)
.fold(f32::INFINITY, f32::min);
if min_col_width > 150.0 {
continue;
}
}
let tables = detect_tables(&page_items, base_size);
for table in tables {
// Mark items as belonging to a table using pre-computed global indices
for &idx in &table.item_indices {
if let Some(&(global_idx, _)) = group.get(idx) {
table_items.insert(global_idx);
}
}
// Get Y position for table insertion (use highest Y in table)
let table_y = table.rows.first().copied().unwrap_or(0.0);
let table_md = table_to_markdown(&table);
page_tables
.entry(page)
.or_default()
.push((table_y, table_md));
}
}
// Filter out table items and process the rest
let non_table_items: Vec<TextItem> = text_items
.into_iter()
.enumerate()
.filter(|(idx, _)| !table_items.contains(idx))
.map(|(_, item)| item)
.collect();
// Find pages that are table-only (no remaining non-table text)
let table_only_pages: HashSet<u32> = {
let pages_with_text: HashSet<u32> = non_table_items.iter().map(|i| i.page).collect();
page_tables
.keys()
.filter(|p| !pages_with_text.contains(p))
.copied()
.collect()
};
// Merge continuation tables across page breaks, but only for table-only pages
merge_continuation_tables(&mut page_tables, &table_only_pages);
let lines = group_into_lines(non_table_items);
// Convert to markdown, inserting tables and images at appropriate positions
to_markdown_from_lines_with_tables_and_images(lines, options, page_tables, page_images)
}
/// Calculate font stats directly from items (before grouping into lines)
fn calculate_font_stats_from_items(items: &[TextItem]) -> FontStats {
let mut size_counts: HashMap<i32, usize> = HashMap::new();
for item in items {
if item.font_size >= 9.0 {
let size_key = (item.font_size * 10.0) as i32;
*size_counts.entry(size_key).or_insert(0) += 1;
}
}
let most_common_size = size_counts
.iter()
.max_by_key(|(_, count)| *count)
.map(|(size, _)| *size as f32 / 10.0)
.unwrap_or(12.0);
FontStats { most_common_size }
}
/// Merge continuation tables that span across page breaks.
///
/// When consecutive pages each have exactly one table with the same number of columns
/// AND both pages are table-only (no non-table text), treat them as a single table.
/// We strip their header+separator rows and append their data rows to the first page's
/// table, then remove them from later pages.
fn merge_continuation_tables(
page_tables: &mut std::collections::HashMap<u32, Vec<(f32, String)>>,
table_only_pages: &HashSet<u32>,
) {
let mut sorted_pages: Vec<u32> = page_tables.keys().copied().collect();
sorted_pages.sort();
if sorted_pages.len() < 2 {
return;
}
// Find runs of consecutive pages that each have exactly one table with matching columns
let mut i = 0;
while i < sorted_pages.len() {
let first_page = sorted_pages[i];
let first_tables = match page_tables.get(&first_page) {
Some(t) if t.len() == 1 => t,
_ => {
i += 1;
continue;
}
};
// First page must be table-only to start a merge chain
if !table_only_pages.contains(&first_page) {
i += 1;
continue;
}
let first_col_count = count_table_columns(&first_tables[0].1);
if first_col_count == 0 {
i += 1;
continue;
}
// Collect continuation pages (must also be table-only)
let mut continuation_pages = Vec::new();
let mut j = i + 1;
while j < sorted_pages.len() {
let next_page = sorted_pages[j];
// Must be consecutive page numbers
let prev_page = if continuation_pages.is_empty() {
first_page
} else {
*continuation_pages.last().unwrap()
};
if next_page != prev_page + 1 {
break;
}
// Continuation page must be table-only
if !table_only_pages.contains(&next_page) {
break;
}
let next_tables = match page_tables.get(&next_page) {
Some(t) if t.len() == 1 => t,
_ => break,
};
let next_col_count = count_table_columns(&next_tables[0].1);
if next_col_count != first_col_count {
break;
}
continuation_pages.push(next_page);
j += 1;
}
if !continuation_pages.is_empty() {
// Collect data rows from continuation pages
let mut extra_rows = String::new();
for &cont_page in &continuation_pages {
if let Some(tables) = page_tables.get(&cont_page) {
let table_md = &tables[0].1;
// Skip header row (line 1) and separator row (line 2), keep the rest
for (line_idx, line) in table_md.lines().enumerate() {
if line_idx >= 2 {
extra_rows.push_str(line);
extra_rows.push('\n');
}
}
}
}
// Append continuation rows to the first page's table
if let Some(tables) = page_tables.get_mut(&first_page) {
tables[0].1.push_str(&extra_rows);
}
// Remove continuation pages from the map
for &cont_page in &continuation_pages {
page_tables.remove(&cont_page);
}
// Skip past the merged pages
i = j;
} else {
i += 1;
}
}
}
/// Count the number of columns in a markdown table by counting `|` in the separator row.
fn count_table_columns(table_md: &str) -> usize {
// The separator row is the second line, containing "| --- | --- |"
if let Some(sep_line) = table_md.lines().nth(1) {
if sep_line.contains("---") {
// Count cells: number of | minus 1 (leading |), but handle edge cases
let pipes = sep_line.chars().filter(|&c| c == '|').count();
return if pipes >= 2 { pipes - 1 } else { 0 };
}
}
0
}
/// Flush any remaining tables and images for a given page
fn flush_page_tables_and_images(
page: u32,
page_tables: &std::collections::HashMap<u32, Vec<(f32, String)>>,
page_images: &std::collections::HashMap<u32, Vec<(f32, String)>>,
inserted_tables: &mut HashSet<(u32, usize)>,
inserted_images: &mut HashSet<(u32, usize)>,
output: &mut String,
in_paragraph: &mut bool,
) {
if let Some(tables) = page_tables.get(&page) {
for (idx, (_, table_md)) in tables.iter().enumerate() {
if !inserted_tables.contains(&(page, idx)) {
if *in_paragraph {
output.push_str("\n\n");
*in_paragraph = false;
}
output.push('\n');
output.push_str(table_md);
output.push('\n');
inserted_tables.insert((page, idx));
}
}
}
if let Some(images) = page_images.get(&page) {
for (idx, (_, image_md)) in images.iter().enumerate() {
if !inserted_images.contains(&(page, idx)) {
if *in_paragraph {
output.push_str("\n\n");
*in_paragraph = false;
}
output.push('\n');
output.push_str(image_md);
output.push('\n');
inserted_images.insert((page, idx));
}
}
}
}
/// Convert text lines to markdown, inserting tables and images at appropriate Y positions
fn to_markdown_from_lines_with_tables_and_images(
lines: Vec<TextLine>,
options: MarkdownOptions,
page_tables: std::collections::HashMap<u32, Vec<(f32, String)>>,
page_images: std::collections::HashMap<u32, Vec<(f32, String)>>,
) -> String {
if lines.is_empty() && page_tables.is_empty() && page_images.is_empty() {
return String::new();
}
// Calculate font statistics
let font_stats = calculate_font_stats(&lines);
let base_size = options
.base_font_size
.unwrap_or(font_stats.most_common_size);
// Merge drop caps with following text
let lines = merge_drop_caps(lines, base_size);
// Discover heading tiers for this document
let heading_tiers = compute_heading_tiers(&lines, base_size);
// Merge consecutive heading lines at the same level (e.g., wrapped titles)
let lines = merge_heading_lines(lines, base_size, &heading_tiers);
// Compute the typical line spacing for paragraph break detection.
// For double-spaced documents (like legal/government PDFs), the normal
// line spacing can be 2.3x base_size, which would exceed a fixed 1.8x
// threshold and cause every line to be treated as a paragraph break.
let para_threshold = compute_paragraph_threshold(&lines, base_size);
let mut output = String::new();
let mut current_page = 0u32;
let mut prev_y = f32::MAX;
let mut in_list = false;
let mut in_paragraph = false;
let mut last_list_x: Option<f32> = None;
let mut inserted_tables: HashSet<(u32, usize)> = HashSet::new();
let mut inserted_images: HashSet<(u32, usize)> = HashSet::new();
// Collect all pages that have tables or images (including image-only pages)
let mut all_content_pages: Vec<u32> = page_tables
.keys()
.chain(page_images.keys())
.copied()
.collect();
all_content_pages.sort();
all_content_pages.dedup();
for line in lines {
// Page break
if line.page != current_page {
// Flush current page's remaining tables and images
if current_page > 0 {
flush_page_tables_and_images(
current_page,
&page_tables,
&page_images,
&mut inserted_tables,
&mut inserted_images,
&mut output,
&mut in_paragraph,
);
if in_paragraph {
output.push_str("\n\n");
in_paragraph = false;
}
output.push_str("\n\n");
}
// Flush any intermediate pages (image-only or table-only) between
// current_page and line.page that have no text lines
for &p in &all_content_pages {
if p <= current_page {
continue;
}
if p >= line.page {
break;
}
flush_page_tables_and_images(
p,
&page_tables,
&page_images,
&mut inserted_tables,
&mut inserted_images,
&mut output,
&mut in_paragraph,
);
if in_paragraph {
output.push_str("\n\n");
in_paragraph = false;
}
output.push_str("\n\n");
}
current_page = line.page;
prev_y = f32::MAX;
}
// Check if we should insert a table before this line
if let Some(tables) = page_tables.get(&current_page) {
for (idx, (table_y, table_md)) in tables.iter().enumerate() {
// Insert table when we pass its Y position
if *table_y > line.y && !inserted_tables.contains(&(current_page, idx)) {
if in_paragraph {
output.push_str("\n\n");
in_paragraph = false;
}
output.push('\n');
output.push_str(table_md);
output.push('\n');
inserted_tables.insert((current_page, idx));
}
}
}
// Check if we should insert an image before this line
if let Some(images) = page_images.get(&current_page) {
for (idx, (image_y, image_md)) in images.iter().enumerate() {
// Insert image when we pass its Y position
if *image_y > line.y && !inserted_images.contains(&(current_page, idx)) {
if in_paragraph {
output.push_str("\n\n");
in_paragraph = false;
}
output.push('\n');
output.push_str(image_md);
output.push('\n');
inserted_images.insert((current_page, idx));
}
}
}
// Paragraph break (large Y gap relative to document's typical line spacing)
let y_gap = prev_y - line.y;
let is_para_break = y_gap > para_threshold;
if is_para_break && in_paragraph {
output.push_str("\n\n");
in_paragraph = false;
}
// Don't immediately end list on paragraph break
// Let the continuation check below decide if we're still in a list
prev_y = line.y;
// Get text with optional bold/italic formatting
let text = line.text_with_formatting(options.detect_bold, options.detect_italic);
let trimmed = text.trim();
// Also get plain text for pattern matching (list detection, captions, etc.)
let plain_text = line.text();
let plain_trimmed = plain_text.trim();
if trimmed.is_empty() {
continue;
}
// Detect figure/table captions and source citations
// These should be on their own line followed by a paragraph break
if is_caption_line(plain_trimmed) {
if in_paragraph {
output.push_str("\n\n");
in_paragraph = false;
}
output.push_str(trimmed);
output.push_str("\n\n");
continue;
}
// Detect headers by font size
// Note: Headers typically shouldn't have bold markers since they're already emphasized
// Skip very short text (drop caps/labels) and very long text (body paragraphs)
if options.detect_headers
&& plain_trimmed.len() > 3
&& plain_trimmed.split_whitespace().count() <= 15
{
let line_font_size = line.items.first().map(|i| i.font_size).unwrap_or(base_size);
if let Some(header_level) =
detect_header_level(line_font_size, base_size, &heading_tiers)
{
if in_paragraph {
output.push_str("\n\n");
in_paragraph = false;
}
let prefix = "#".repeat(header_level);
// Use plain text for headers to avoid redundant formatting
output.push_str(&format!("{} {}\n\n", prefix, plain_trimmed));
in_list = false;
continue;
}
}
// Detect list items
if options.detect_lists && is_list_item(plain_trimmed) {
if in_paragraph {
output.push_str("\n\n");
in_paragraph = false;
}
let formatted = format_list_item(trimmed);
output.push_str(&formatted);
output.push('\n');
in_list = true;
last_list_x = line.items.first().map(|i| i.x);
continue;
} else if in_list {
// Check if this line is a continuation of the previous list item
// Continuations have similar X position and reasonable Y gap
let line_x = line.items.first().map(|i| i.x);
let is_continuation = if let (Some(list_x), Some(curr_x)) = (last_list_x, line_x) {
// Continuation criteria:
// 1. X is at or past the list text position
// 2. Y gap is not too large (max ~5 line heights)
// 3. Not a new list item
let x_ok = curr_x >= list_x - 5.0 && curr_x <= list_x + 50.0;
let y_ok = y_gap < base_size * 7.0;
x_ok && y_ok && !is_list_item(plain_trimmed)
} else {
false
};
if is_continuation {
// Append to previous list item with a space
if output.ends_with('\n') {
output.pop();
output.push(' ');
}
output.push_str(trimmed);
output.push('\n');
continue;
} else {
in_list = false;
last_list_x = None;
}
}
// Detect code blocks by font
if options.detect_code {
let is_mono = line.items.iter().any(|i| is_monospace_font(&i.font));
if is_mono {
if in_paragraph {
output.push_str("\n\n");
in_paragraph = false;
}
// Use plain text for code blocks
output.push_str(&format!("```\n{}\n```\n", plain_trimmed));
continue;
}
}
// Regular text - join lines within same paragraph with space
if in_paragraph {
output.push(' ');
}
output.push_str(trimmed);
in_paragraph = true;
}
// Flush current page and any remaining pages with tables/images
// (handles table-only pages after the last text line, and trailing image-only pages)
flush_page_tables_and_images(
current_page,
&page_tables,
&page_images,
&mut inserted_tables,
&mut inserted_images,
&mut output,
&mut in_paragraph,
);
for &p in &all_content_pages {
if p <= current_page {
continue;
}
flush_page_tables_and_images(
p,
&page_tables,
&page_images,
&mut inserted_tables,
&mut inserted_images,
&mut output,
&mut in_paragraph,
);
}
// Close final paragraph
if in_paragraph {
output.push('\n');
}
// Clean up and post-process
clean_markdown(output, &options)
}
/// Convert text lines to markdown
pub fn to_markdown_from_lines(lines: Vec<TextLine>, options: MarkdownOptions) -> String {
if lines.is_empty() {
return String::new();
}
// Calculate font statistics
let font_stats = calculate_font_stats(&lines);
let base_size = options
.base_font_size
.unwrap_or(font_stats.most_common_size);
// Merge drop caps with following text
let lines = merge_drop_caps(lines, base_size);
// Discover heading tiers for this document
let heading_tiers = compute_heading_tiers(&lines, base_size);
// Merge consecutive heading lines at the same level (e.g., wrapped titles)
let lines = merge_heading_lines(lines, base_size, &heading_tiers);
// Compute the typical line spacing for paragraph break detection
let para_threshold = compute_paragraph_threshold(&lines, base_size);
let mut output = String::new();
let mut current_page = 0u32;
let mut prev_y = f32::MAX;
let mut in_list = false;
let mut in_paragraph = false;
let mut last_list_x: Option<f32> = None;
for line in lines {
// Page break
if line.page != current_page {
if current_page > 0 {
if in_paragraph {
output.push_str("\n\n");
in_paragraph = false;
}
output.push_str("\n\n");
}
current_page = line.page;
prev_y = f32::MAX;
in_list = false;
last_list_x = None;
}
// Paragraph break (large Y gap relative to document's typical line spacing)
let y_gap = prev_y - line.y;
let is_para_break = y_gap > para_threshold;
if is_para_break && in_paragraph {
output.push_str("\n\n");
in_paragraph = false;
}
// Don't immediately end list on paragraph break
// Let the continuation check below decide if we're still in a list
prev_y = line.y;
// Get text with optional bold/italic formatting
let text = line.text_with_formatting(options.detect_bold, options.detect_italic);
let trimmed = text.trim();
// Also get plain text for pattern matching
let plain_text = line.text();
let plain_trimmed = plain_text.trim();
if trimmed.is_empty() {
continue;
}
// Detect figure/table captions and source citations
// These should be on their own line followed by a paragraph break
if is_caption_line(plain_trimmed) {
if in_paragraph {
output.push_str("\n\n");
in_paragraph = false;
}
output.push_str(trimmed);
output.push_str("\n\n");
continue;
}
// Detect headers by font size
// Skip very short text (drop caps/labels) and very long text (body paragraphs)
if options.detect_headers
&& plain_trimmed.len() > 3
&& plain_trimmed.split_whitespace().count() <= 15
{
let line_font_size = line.items.first().map(|i| i.font_size).unwrap_or(base_size);
if let Some(header_level) =
detect_header_level(line_font_size, base_size, &heading_tiers)
{
if in_paragraph {
output.push_str("\n\n");
in_paragraph = false;
}
let prefix = "#".repeat(header_level);
// Use plain text for headers to avoid redundant formatting
output.push_str(&format!("{} {}\n\n", prefix, plain_trimmed));
in_list = false;
continue;
}
}
// Detect list items
if options.detect_lists && is_list_item(plain_trimmed) {
if in_paragraph {
output.push_str("\n\n");
in_paragraph = false;
}
let formatted = format_list_item(trimmed);
output.push_str(&formatted);
output.push('\n');
in_list = true;
last_list_x = line.items.first().map(|i| i.x);
continue;
} else if in_list {
// Check if this line is a continuation of the previous list item
let line_x = line.items.first().map(|i| i.x);
let is_continuation = if let (Some(list_x), Some(curr_x)) = (last_list_x, line_x) {
// Continuation criteria:
// 1. X is at or past the list text position
// 2. Y gap is not too large (max ~5 line heights)
// 3. Not a new list item
let x_ok = curr_x >= list_x - 5.0 && curr_x <= list_x + 50.0;
let y_ok = y_gap < base_size * 7.0;
x_ok && y_ok && !is_list_item(plain_trimmed)
} else {
false
};
if is_continuation {
// Append to previous list item with a space
if output.ends_with('\n') {
output.pop();
output.push(' ');
}
output.push_str(trimmed);
output.push('\n');
continue;
} else {
in_list = false;
last_list_x = None;
}
}
// Detect code blocks by font
if options.detect_code {
let is_mono = line.items.iter().any(|i| is_monospace_font(&i.font));
if is_mono {
if in_paragraph {
output.push_str("\n\n");
in_paragraph = false;
}
// Use plain text for code blocks
output.push_str(&format!("```\n{}\n```\n", plain_trimmed));
continue;
}
}
// Regular text - join lines within same paragraph with space
if in_paragraph {
output.push(' ');
}
output.push_str(trimmed);
in_paragraph = true;
}
// Close final paragraph
if in_paragraph {
output.push('\n');
}
// Clean up and post-process
clean_markdown(output, &options)
}
/// Merge drop caps with the appropriate line
/// A drop cap is a single large letter at the start of a paragraph
/// Due to PDF coordinate sorting, the drop cap may appear AFTER the line it belongs to
/// Merge consecutive heading lines at the same level into a single line.
///
/// When a heading wraps across multiple text lines (e.g., "About Glenair, the Mission-Critical"
/// and "Interconnect Company"), each fragment becomes a separate `# Header` in the output.
/// This function detects consecutive lines at the same heading tier on the same page
/// with a small Y gap and merges them into one line.
fn merge_heading_lines(
lines: Vec<TextLine>,
base_size: f32,
heading_tiers: &[f32],
) -> Vec<TextLine> {
if lines.is_empty() {
return lines;
}
let mut result: Vec<TextLine> = Vec::with_capacity(lines.len());
for line in lines {
let line_font = line.items.first().map(|i| i.font_size).unwrap_or(base_size);
let line_level = detect_header_level(line_font, base_size, heading_tiers);
// Check if the previous line is a heading at the same level on the same page
let should_merge = if let (Some(prev), Some(curr_level)) = (result.last(), line_level) {
let prev_font = prev.items.first().map(|i| i.font_size).unwrap_or(base_size);
let prev_level = detect_header_level(prev_font, base_size, heading_tiers);
let same_page = prev.page == line.page;
let same_level = prev_level == Some(curr_level);
let y_gap = prev.y - line.y;
// Merge if gap is within ~2x the font size (normal line wrap spacing)
let close_enough = y_gap > 0.0 && y_gap < line_font * 2.0;
same_page && same_level && close_enough
} else {
false
};
if should_merge {
// Append this line's items to the previous line
let prev = result.last_mut().unwrap();
// Add a space-bearing TextItem to separate the merged text
if let Some(first_item) = line.items.first() {
let mut space_item = first_item.clone();
space_item.text = format!(" {}", space_item.text.trim_start());
prev.items.push(space_item);
}
for item in line.items.into_iter().skip(1) {
prev.items.push(item);
}
} else {
result.push(line);
}
}
result
}
fn merge_drop_caps(lines: Vec<TextLine>, base_size: f32) -> Vec<TextLine> {
let mut result: Vec<TextLine> = Vec::with_capacity(lines.len());
for line in &lines {
let text = line.text();
let trimmed = text.trim();
// Check if this looks like a drop cap:
// 1. Single character (or single char + space)
// 2. Much larger than base font (3x or more)
// 3. The character is uppercase
let is_drop_cap = trimmed.len() <= 2
&& line.items.first().map(|i| i.font_size).unwrap_or(0.0) >= base_size * 2.5
&& trimmed
.chars()
.next()
.map(|c| c.is_uppercase())
.unwrap_or(false);
if is_drop_cap {
let drop_char = trimmed.chars().next().unwrap();
// Find the first line that starts with lowercase and is at the START of a paragraph
// (i.e., preceded by a header or non-lowercase-starting line)
let mut target_idx: Option<usize> = None;
for (idx, prev_line) in result.iter().enumerate() {
if prev_line.page != line.page {
continue;
}
let prev_text = prev_line.text();
let prev_trimmed = prev_text.trim();
// Check if this line starts with lowercase
if prev_trimmed
.chars()
.next()
.map(|c| c.is_lowercase())
.unwrap_or(false)
{
// Check if previous line exists and doesn't start with lowercase
// (meaning this is the start of a paragraph)
let is_para_start = if idx == 0 {
true
} else {
let before = result[idx - 1].text();
let before_trimmed = before.trim();
!before_trimmed
.chars()
.next()
.map(|c| c.is_lowercase())
.unwrap_or(true)
};
if is_para_start {
target_idx = Some(idx);
break;
}
}
}
// Merge with the target line
if let Some(idx) = target_idx {
if let Some(first_item) = result[idx].items.first_mut() {
let prev_text = first_item.text.trim().to_string();
first_item.text = format!("{}{}", drop_char, prev_text);
}
}
// Don't add the drop cap line itself
continue;
}
result.push(line.clone());
}
result
}
/// Font statistics for a document
struct FontStats {
most_common_size: f32,
}
fn calculate_font_stats(lines: &[TextLine]) -> FontStats {
let mut size_counts: HashMap<i32, usize> = HashMap::new();
for line in lines {
// Count once per line (first item) to give each line equal weight
// Prevents small captions/footnotes from skewing the base
if let Some(first) = line.items.first() {
if first.font_size >= 9.0 {
let size_key = (first.font_size * 10.0) as i32;
*size_counts.entry(size_key).or_insert(0) += 1;
}
}
}
let most_common_size = size_counts
.iter()
.max_by_key(|(_, count)| *count)
.map(|(size, _)| *size as f32 / 10.0)
.unwrap_or(12.0);
FontStats { most_common_size }
}
/// Compute the Y-gap threshold for paragraph break detection.
///
/// Instead of using a fixed multiple of base_size (which fails for double-spaced
/// documents), we compute the document's typical (median) line spacing and use
/// a multiplier on that. A gap significantly larger than typical indicates a
/// paragraph break.
///
/// Fallback: if we can't compute typical spacing, use base_size * 1.8.
fn compute_paragraph_threshold(lines: &[TextLine], base_size: f32) -> f32 {
let fallback = base_size * 1.8;
// Collect Y gaps between consecutive lines on the same page
let mut gaps: Vec<f32> = Vec::new();
let mut prev_y: Option<(u32, f32)> = None;
for line in lines {
if let Some((prev_page, py)) = prev_y {
if line.page == prev_page {
let gap = py - line.y;
// Only consider positive gaps within a reasonable range
// (skip huge gaps from page headers/footers)
if gap > 0.0 && gap < base_size * 10.0 {
gaps.push(gap);
}
}
}
prev_y = Some((line.page, line.y));
}
if gaps.len() < 5 {
return fallback;
}
gaps.sort_by(|a, b| a.partial_cmp(b).unwrap_or(std::cmp::Ordering::Equal));
let median = gaps[gaps.len() / 2];
// The paragraph threshold should be larger than the typical line spacing.
// Use 1.3x the median gap. This means:
// - Single-spaced (median ~14pt for 12pt font): threshold = 18.2pt
// - Double-spaced (median ~28pt for 12pt font): threshold = 36.4pt
// Also ensure it's at least base_size * 1.5 to avoid false paragraph breaks
// in tightly-spaced documents.
(median * 1.3).max(base_size * 1.5)
}
/// Discover distinct heading font-size tiers in the document.
/// Returns tiers sorted largest-first (tier 0 = H1, tier 1 = H2, …).
/// Sizes within 0.5pt are clustered into the same tier. Capped at 4 tiers.
fn compute_heading_tiers(lines: &[TextLine], base_size: f32) -> Vec<f32> {
let mut heading_sizes: Vec<f32> = Vec::new();
for line in lines {
if let Some(first) = line.items.first() {
if first.font_size / base_size >= 1.2 {
heading_sizes.push(first.font_size);
}
}
}
// Sort descending
heading_sizes.sort_by(|a, b| b.partial_cmp(a).unwrap_or(std::cmp::Ordering::Equal));
// Cluster sizes within 0.5pt into same tier (use first value as representative)
let mut tiers: Vec<f32> = Vec::new();
for size in heading_sizes {
let already_in_tier = tiers.iter().any(|&t| (t - size).abs() < 0.5);
if !already_in_tier {
tiers.push(size);
}
}
// Cap at 4 tiers
tiers.truncate(4);
tiers
}
/// Detect header level from font size using document-specific heading tiers.
/// When tiers are available, maps tier 0→H1, tier 1→H2, etc.
/// Falls back to ratio-based thresholds when no tiers exist.
fn detect_header_level(font_size: f32, base_size: f32, heading_tiers: &[f32]) -> Option<usize> {
let ratio = font_size / base_size;
if ratio < 1.2 {
return None; // Regular text
}
if !heading_tiers.is_empty() {
// Match font_size to a tier (within 0.5pt tolerance)
for (i, &tier_size) in heading_tiers.iter().enumerate() {
if (font_size - tier_size).abs() < 0.5 {
return Some(i + 1); // tier 0 → H1, tier 1 → H2, etc.
}
}
// No tier match but large ratio — assign level after last tier
if ratio >= 1.5 {
let level = (heading_tiers.len() + 1).min(4);
return Some(level);
}
// No tier match and small ratio — not a heading
return None;
}
// Fallback: original ratio-based thresholds (no tiers discovered)
if ratio >= 2.0 {
Some(1)
} else if ratio >= 1.5 {
Some(2)
} else if ratio >= 1.25 {
Some(3)
} else {
Some(4)
}
}
/// Check if text is a figure/table caption or source citation
fn is_caption_line(text: &str) -> bool {
let trimmed = text.trim();
// Common caption prefixes in multiple languages
let caption_prefixes = [
"Figure ",
"Figura ",
"Fig. ",
"Fig ",
"Table ",
"Tabela ",
"Source:",
"Fonte:",
"Source ",
"Fonte ",
"Note:",
"Nota:",
"Chart ",
"Gráfico ",
"Graph ",
"Diagram ",
"Image ",
"Imagem ",
"Photo ",
"Foto ",
];
// Check if line starts with a caption prefix
for prefix in &caption_prefixes {
if trimmed.starts_with(prefix) {
return true;
}
}
// Check case-insensitive patterns
let lower = trimmed.to_lowercase();
if lower.starts_with("figure ") || lower.starts_with("table ") || lower.starts_with("source:") {
return true;
}
false
}
/// Check if text looks like a list item
fn is_list_item(text: &str) -> bool {
let trimmed = text.trim_start();
// Bullet patterns
if trimmed.starts_with("• ")
|| trimmed.starts_with("- ")
|| trimmed.starts_with("* ")
|| trimmed.starts_with("○ ")
|| trimmed.starts_with("● ")
|| trimmed.starts_with("◦ ")
{
return true;
}
// Numbered list patterns: "1.", "1)", "(1)", "a.", "a)"
let first_chars: String = trimmed.chars().take(5).collect();
if first_chars.contains(|c: char| c.is_ascii_digit()) {
// Check for "1.", "1)", "10."
if let Some(idx) = first_chars.find(['.', ')']) {
let prefix = &first_chars[..idx];
if prefix.chars().all(|c| c.is_ascii_digit()) {
return true;
}
}
}
// Letter list: "a.", "a)", "(a)"
let mut chars = trimmed.chars();
if let (Some(first), Some(second)) = (chars.next(), chars.next()) {
if first.is_ascii_alphabetic() && (second == '.' || second == ')') {
return true;
}
if first == '(' && chars.next() == Some(')') {
return true;
}
}
false
}
/// Format list item to markdown
fn format_list_item(text: &str) -> String {
let trimmed = text.trim_start();
// Convert various bullet styles to markdown
// Note: bullet characters like • are multi-byte in UTF-8, use char indices
for bullet in &['•', '○', '●', '◦'] {
if let Some(rest) = trimmed.strip_prefix(*bullet) {
return format!("- {}", rest.trim_start());
}
}
if trimmed.starts_with("- ") || trimmed.starts_with("* ") {
return trimmed.to_string();
}
// Keep numbered lists as-is (markdown supports them)
trimmed.to_string()
}
/// Check if text looks like code
fn is_code_like(text: &str) -> bool {
let trimmed = text.trim();
// Code patterns
let code_patterns = [
// Language keywords
"import ",
"export ",
"from ",
"const ",
"let ",
"var ",
"function ",
"class ",
"def ",
"pub fn ",
"fn ",
"async fn ",
"impl ",
// Syntax patterns
"=> ",
"-> ",
":: ",
":= ",
// Common code endings
];
for pattern in &code_patterns {
if trimmed.starts_with(pattern) {
return true;
}
}
// Check for code-like syntax
let special_chars: usize = trimmed
.chars()
.filter(|c| matches!(c, '{' | '}' | '(' | ')' | '[' | ']' | ';' | '=' | '<' | '>'))
.count();
if special_chars >= 3 && trimmed.len() < 200 {
return true;
}
// Ends with semicolon or braces
if trimmed.ends_with(';') || trimmed.ends_with('{') || trimmed.ends_with('}') {
return true;
}
false
}
/// Check if font name indicates monospace
fn is_monospace_font(font_name: &str) -> bool {
let lower = font_name.to_lowercase();
let patterns = [
"courier",
"consolas",
"monaco",
"menlo",
"mono",
"fixed",
"terminal",
"typewriter",
"source code",
"fira code",
"jetbrains",
"inconsolata",
"dejavu sans mono",
"liberation mono",
];
patterns.iter().any(|p| lower.contains(p))
}
/// Clean up markdown output with post-processing
fn clean_markdown(mut text: String, options: &MarkdownOptions) -> String {
// Collapse dot leaders (e.g. TOC entries: "Introduction...............................1")
text = collapse_dot_leaders(&text);
// Fix hyphenation first (before other processing)
if options.fix_hyphenation {
text = fix_hyphenation(&text);
}
// Remove standalone page numbers
if options.remove_page_numbers {
text = remove_page_numbers(&text);
}
// Format URLs as markdown links
if options.format_urls {
text = format_urls(&text);
}
// Remove excessive newlines (more than 2 in a row)
while text.contains("\n\n\n") {
text = text.replace("\n\n\n", "\n\n");
}
// Trim leading and trailing whitespace, ensure ends with single newline
text = text.trim().to_string();
text.push('\n');
text
}
/// Collapse dot leaders (runs of 4+ dots) into " ... "
/// Common in tables of contents: "Introduction...............................1" -> "Introduction ... 1"
fn collapse_dot_leaders(text: &str) -> String {
use once_cell::sync::Lazy;
static DOT_LEADER_RE: Lazy<Regex> = Lazy::new(|| Regex::new(r"\.{4,}").unwrap());
DOT_LEADER_RE.replace_all(text, " ... ").to_string()
}
/// Fix words broken across lines with spaces before the continuation
/// e.g., "Limoeiro do Nort e" -> "Limoeiro do Norte"
fn fix_hyphenation(text: &str) -> String {
use once_cell::sync::Lazy;
// Fix "word - word" patterns that should be "word-word" (compound words)
// But be careful not to break list items (which start with "- ")
static SPACED_HYPHEN_RE: Lazy<Regex> = Lazy::new(|| {
Regex::new(r"([a-zA-ZáàâãéèêíïóôõöúçñÁÀÂÃÉÈÊÍÏÓÔÕÖÚÇÑ]) - ([a-zA-ZáàâãéèêíïóôõöúçñÁÀÂÃÉÈÊÍÏÓÔÕÖÚÇÑ])").unwrap()
});
let result = SPACED_HYPHEN_RE
.replace_all(text, |caps: &regex::Captures| {
format!("{}-{}", &caps[1], &caps[2])
})
.to_string();
result
}
/// Remove standalone page numbers (lines that are just 1-4 digit numbers)
fn remove_page_numbers(text: &str) -> String {
let mut result = Vec::new();
let lines: Vec<&str> = text.lines().collect();
for (i, line) in lines.iter().enumerate() {
let trimmed = line.trim();
// Check for page number patterns
if is_page_number_line(trimmed) {
// Check context to determine if this is isolated
let prev_is_break = i > 0 && lines[i - 1].trim() == "---";
let next_is_break = i + 1 < lines.len() && lines[i + 1].trim() == "---";
let prev_is_empty = i > 0 && lines[i - 1].trim().is_empty();
let next_is_empty = i + 1 < lines.len() && lines[i + 1].trim().is_empty();
// Check if it's on its own line (surrounded by empty lines or page breaks)
let is_isolated = (prev_is_break || prev_is_empty || i == 0)
&& (next_is_break || next_is_empty || i + 1 == lines.len());
// Also remove numbers that appear right before a page break
let before_break = i + 1 < lines.len()
&& (lines[i + 1].trim() == "---"
|| (i + 2 < lines.len()
&& lines[i + 1].trim().is_empty()
&& lines[i + 2].trim() == "---"));
if is_isolated || before_break {
continue;
}
}
result.push(*line);
}
result.join("\n")
}
/// Check if a line looks like a page number
fn is_page_number_line(trimmed: &str) -> bool {
// Empty lines are not page numbers
if trimmed.is_empty() {
return false;
}
// Pattern 1: Just a number (1-4 digits)
if trimmed.len() <= 4 && trimmed.chars().all(|c| c.is_ascii_digit()) {
return true;
}
// Pattern 2: "Page X of Y" or "Page X" or "Page of" (placeholder)
let lower = trimmed.to_lowercase();
if let Some(rest) = lower.strip_prefix("page") {
let rest = rest.trim();
// "Page of" (empty page numbers)
if rest == "of" || rest.starts_with("of ") {
return true;
}
// "Page X" or "Page X of Y"
if rest
.chars()
.next()
.map(|c| c.is_ascii_digit())
.unwrap_or(false)
{
return true;
}
// Just "Page" followed by whitespace and maybe "of"
if rest.is_empty()
|| rest
.split_whitespace()
.all(|w| w == "of" || w.chars().all(|c| c.is_ascii_digit()))
{
return true;
}
}
// Pattern 3: "X of Y" where X and Y are numbers
if let Some(of_idx) = trimmed.find(" of ") {
let before = trimmed[..of_idx].trim();
let after = trimmed[of_idx + 4..].trim();
if before.chars().all(|c| c.is_ascii_digit())
&& after.chars().all(|c| c.is_ascii_digit())
&& !before.is_empty()
&& !after.is_empty()
{
return true;
}
}
// Pattern 4: "- X -" centered page number
if trimmed.len() >= 3 && trimmed.starts_with('-') && trimmed.ends_with('-') {
let inner = trimmed[1..trimmed.len() - 1].trim();
if inner.chars().all(|c| c.is_ascii_digit()) && !inner.is_empty() {
return true;
}
}
false
}
/// Convert URLs to markdown links
fn format_urls(text: &str) -> String {
use once_cell::sync::Lazy;
// Match URLs - we'll check context manually to avoid formatting already-linked URLs
static URL_RE: Lazy<Regex> =
Lazy::new(|| Regex::new(r"https?://[^\s<>\)\]]+[^\s<>\)\]\.\,;]").unwrap());
let mut result = String::with_capacity(text.len());
let mut last_end = 0;
for mat in URL_RE.find_iter(text) {
let start = mat.start();
let url = mat.as_str();
// Check if this URL is already in a markdown link by looking at preceding chars
// Use safe character boundary checking for multi-byte UTF-8
let before = {
let mut check_start = start.saturating_sub(2);
// Find a valid character boundary
while check_start > 0 && !text.is_char_boundary(check_start) {
check_start -= 1;
}
if check_start < start && text.is_char_boundary(start) {
&text[check_start..start]
} else {
""
}
};
let already_linked = before.ends_with("](") || before.ends_with("](");
// Also check if it's inside square brackets (link text)
// Ensure we're slicing at a valid char boundary
let prefix = if text.is_char_boundary(start) {
&text[..start]
} else {
// Find the nearest valid boundary before start
let mut safe_start = start;
while safe_start > 0 && !text.is_char_boundary(safe_start) {
safe_start -= 1;
}
&text[..safe_start]
};
let open_brackets = prefix.matches('[').count();
let close_brackets = prefix.matches(']').count();
let inside_link_text = open_brackets > close_brackets;
// Ensure mat boundaries are valid char boundaries
let safe_last_end = if text.is_char_boundary(last_end) {
last_end
} else {
let mut pos = last_end;
while pos < text.len() && !text.is_char_boundary(pos) {
pos += 1;
}
pos
};
let safe_start = if text.is_char_boundary(start) {
start
} else {
let mut pos = start;
while pos < text.len() && !text.is_char_boundary(pos) {
pos += 1;
}
pos
};
let safe_end = if text.is_char_boundary(mat.end()) {
mat.end()
} else {
let mut pos = mat.end();
while pos < text.len() && !text.is_char_boundary(pos) {
pos += 1;
}
pos
};
if already_linked || inside_link_text {
// Already formatted, keep as-is
if safe_last_end <= safe_end {
result.push_str(&text[safe_last_end..safe_end]);
}
} else {
// Add text before this URL
if safe_last_end <= safe_start {
result.push_str(&text[safe_last_end..safe_start]);
}
// Format as markdown link
result.push_str(&format!("[{}]({})", url, url));
}
last_end = safe_end;
}
// Add remaining text (ensure valid char boundary)
let safe_last_end = if text.is_char_boundary(last_end) {
last_end
} else {
let mut pos = last_end;
while pos < text.len() && !text.is_char_boundary(pos) {
pos += 1;
}
pos
};
if safe_last_end < text.len() {
result.push_str(&text[safe_last_end..]);
}
result
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_is_list_item() {
assert!(is_list_item("• Item one"));
assert!(is_list_item("- Item two"));
assert!(is_list_item("* Item three"));
assert!(is_list_item("1. First"));
assert!(is_list_item("2) Second"));
assert!(is_list_item("a. Letter item"));
assert!(!is_list_item("Regular text"));
}
#[test]
fn test_format_list_item() {
assert_eq!(format_list_item("• Item"), "- Item");
assert_eq!(format_list_item("- Item"), "- Item");
assert_eq!(format_list_item("1. First"), "1. First");
}
#[test]
fn test_is_code_like() {
assert!(is_code_like("const x = 5;"));
assert!(is_code_like("function foo() {"));
assert!(is_code_like("import React from 'react'"));
assert!(!is_code_like("This is regular text."));
}
#[test]
fn test_detect_header_level() {
// With three tiers: 24→H1, 18→H2, 15→H3, 12→None
let tiers = vec![24.0, 18.0, 15.0];
assert_eq!(detect_header_level(24.0, 12.0, &tiers), Some(1));
assert_eq!(detect_header_level(18.0, 12.0, &tiers), Some(2));
assert_eq!(detect_header_level(15.0, 12.0, &tiers), Some(3));
assert_eq!(detect_header_level(12.0, 12.0, &tiers), None);
// Single tier: 15→H1 (ratio 1.25 ≥ 1.2), 14→None (ratio 1.17 < 1.2)
let tiers = vec![15.0];
assert_eq!(detect_header_level(15.0, 12.0, &tiers), Some(1));
assert_eq!(detect_header_level(14.0, 12.0, &tiers), None);
assert_eq!(detect_header_level(12.0, 12.0, &tiers), None);
// No tiers (empty): falls back to ratio thresholds
let tiers: Vec<f32> = vec![];
assert_eq!(detect_header_level(24.0, 12.0, &tiers), Some(1));
assert_eq!(detect_header_level(18.0, 12.0, &tiers), Some(2));
assert_eq!(detect_header_level(15.0, 12.0, &tiers), Some(3));
assert_eq!(detect_header_level(14.5, 12.0, &tiers), Some(4));
assert_eq!(detect_header_level(14.0, 12.0, &tiers), None);
assert_eq!(detect_header_level(12.0, 12.0, &tiers), None);
// Body text excluded when tiers exist: 13pt (ratio 1.08) → None
let tiers = vec![20.0];
assert_eq!(detect_header_level(13.0, 12.0, &tiers), None);
}
#[test]
fn test_to_markdown() {
let text = "• First item\n• Second item\n\nRegular paragraph.";
let md = to_markdown(text, MarkdownOptions::default());
assert!(md.contains("- First item"));
assert!(md.contains("- Second item"));
}
}