When a PDF has a well-formed structure tree with /Table > /TR > /TD|TH
elements linked to MCIDs, build tables directly from the semantic
hierarchy. Runs as highest-priority detection (step 0) before rect-based,
line-based, and heuristic strategies.
- Add StructTree::extract_tables() to walk the tree and collect table
descriptors with row/cell/MCID info
- Add detect_tables_from_struct_tree() to match MCIDs to TextItems
- Reject tables with <30% MCID cell coverage (stale structure trees)
- Update 2013-app2 snapshot (struct-tree gives valid but different
column ordering)
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
* fix(text): handle Tc/Tw character and word spacing in text width computation
PDFs using Tc (character spacing) and Tw (word spacing) operators for text
justification had words incorrectly split across TextItems. The computed
advance width didn't account for these spacing parameters, causing spurious
spaces mid-word (e.g. "deve lopers" instead of "developers").
- Add Tc/Tw operator handling and graphics state save/restore
- Incorporate char_spacing and word_spacing into compute_string_width_ts
- Add adaptive merge threshold: tighter for lowercase→lowercase junctions,
wider before joining punctuation
- Add unit tests for Tc/Tw width computation and merge behavior
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
* test(fonts): add large Tc width computation test
Verifies that large character spacing values are applied in full
without any artificial cap, matching PDF spec behavior.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
* fix(text): guard against Tc/Tw-inflated widths in merge and join paths
Two targeted fixes to prevent character-spacing (Tc) and word-spacing
(Tw) inflation from causing data quality regressions:
1. should_join_items: reject large negative gaps (< -font_size) that
arise when Tc/Tw inflate item widths past adjacent items. Fixes
FY_2015 merged numbers (e.g. "239.696.0" → "239.69 6.0").
2. merge_text_items: cap effective width for gap computation when Tw
inflates space-containing items beyond 0.85× font_size per char.
Prevents column-level gaps from collapsing into merge range,
recovering table detection for Baldwin-Edwards and similar PDFs.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
* fix(fonts): CID-as-Unicode passthrough and subscript/superscript merging
Add smart CID-as-Unicode passthrough for Identity-H fonts without
ToUnicode maps. Uses /W array median CID heuristic to distinguish
Unicode-CID PDFs (Chromium-generated) from GID-based subsets.
Add merge_subscript_items() pass that merges small-font items (<75%
of dominant font size, ≤4 chars, tightly adjacent) into parent items.
Fixes chemical formulas (NH3, H2O, KClO3), footnote references, and
subscript notation (vf, Hfg, m3/kg) that were previously orphaned
as separate text items.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
* fix(subscripts): restrict merge to purely numeric text only
Tighten subscript merging to only merge items containing ASCII digits
(0-9). This avoids false positives with ordinal indicators (º), letter
subscripts (sol, vf), and small bullet characters (▶) that caused
table restructuring regressions.
Numeric-only keeps the primary wins: chemical formulas (NH3, H2O),
footnote references, and unit notation (m2, m3).
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
* fix(subscripts): restrict merge to parent text ending with a letter
Only merge numeric subscripts when the parent item's text ends with
an alphabetic character. Prevents false merges like "33" + "1" in
fractions (33 1/3%), table credit numbers after spaces, and footnote
refs after punctuation (land.1 → land. 1). Chemical formulas (NH3,
H2O, KClO3) still merge correctly since parent ends with a letter.
Reduces pdf-eval regressions from 13 to 2 (both are correct reversions
of over-aggressive footnote merging from the prior commit).
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
Document titles, column headers, and newsletter mastheads that repeat
on every page were being fully stripped by strip_repeated_lines. Now
the first page's occurrence is preserved so the content appears once.
Fixes missing titles like "VOICE OF SOUTH MARION" in tax certificate
PDFs and column headers in IRS forms.
OCR text layers and some PDF producers emit trailing spaces on each
text item, which combine with gap-based joining to produce double
spaces ("Vice President"). Now collapses runs of 2+ spaces to single
space within lines, preserving leading indentation.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Drop column-width padding from table output. Saves ~37% bytes on
table-heavy PDFs. Markdown renders identically — padding was purely
cosmetic. Optimizes token efficiency for AI agent consumers.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Tables with very wide cells (e.g. 230+ chars from merged schedule columns)
caused massive whitespace padding in every row. Capping alignment at 40
characters reduces output size significantly (franklin: 77KB→24KB,
Closed-Business: 571KB→502KB) without affecting content.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Only skip text with rendering mode 3 (truly invisible). Removes
fill color tracking that was incorrectly hiding white-on-dark text
in presentations and brochures.
Strip leading/trailing digit sequences (page numbers) before frequency
comparison so headers like "Page 5" and "Page 6" are treated as identical.
Group TextLines at the same Y position into Y-bands and propagate removal
to all siblings when any member is stripped. Increase EDGE_LINE_COUNT from
4 to 5 to cover 5-row form column headers (e.g., IRS p1244).
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Bumps EDGE_LINE_COUNT from 3 to 4 to strip repeated form column headers
that sit just inside the page margin (4th-from-edge Y position).
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Add strip_repeated_lines() preprocessing step that removes running
headers and footers before markdown conversion. Uses multiple guard
rails to avoid false positives:
- Edge-line detection: only considers lines among the first/last 3
distinct Y positions on each page (not percentage-based margins)
- Y-position consistency: requires low variance across pages (stddev
< 5% of page span) to distinguish headers from scattered table content
- Position-aware removal: only strips instances at page edges, preserving
body content that happens to match a header/footer text
- Skips structural lines (headings, list items), short lines (<10 chars),
and decorative separators (repeated single characters)
- Frequency threshold: >= max(3, page_count * 30%) distinct pages
New strip_headers_footers option on MarkdownOptions (default: true).
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Unit test verifying short sub-header rows (e.g. month names) are not
merged as continuation rows in table formatting. Snapshot test for
2013_app2.pdf pinning the full row-stripe table output.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
When a PDF page has a graph directly above a table (e.g. Figure 2 above
Table II in real-estate-pricing.pdf), the heuristic table detector would
merge graph axis labels and legend items into the table, producing a
corrupted result.
Add rect hint regions: when a small cluster of cell-border rects (4-6)
fails full grid validation (e.g. only row borders, no column dividers),
extract their Y bounding box as a "hint region". The heuristic detector
then runs separately on items inside vs outside hint regions, preventing
unrelated content from being merged into tables.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Rects spanning multiple grid rows (e.g. classification labels) now have
their text consolidated into the first sub-row via propagate_merged_cells().
Also prevent continuation-row merge from folding body data into the header.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Add 5 stripped public-domain PDF fixtures and golden markdown snapshots
for CI regression testing. Fix non-deterministic output caused by
HashMap iteration order in font stats, table heuristics, and rect
clustering by adding deterministic tie-breaking.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
