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>
* feat(layout): relative valley column detection for justified text
Add fallback column detection using relative valley analysis for PDFs with
justified text where item widths extend past gutter boundaries. The absolute
valley detector fails on these layouts because gutter bins are at ~40% of
peak (well above the 15% noise threshold).
The relative valley detector smooths the histogram with a 5-bin moving
average, finds local minima where contrast < 0.60 of surrounding peaks,
and validates with peak balance >= 0.40. Limited to single best valley
(max 2 columns) and requires >= 100 items per page.
Tested on IRS Publication 17 (2002), a 289-page 2-column justified text
document: column detection went from ~40 pages to 165 pages.
190 passed, 0 regressions across 191 eval PDFs.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
* fix(layout): tighten relative valley thresholds to reduce false positives
Reduce PEAK_WINDOW from 40 to 25 bins (50pt) so valleys are only validated
against nearby peaks, not distant ones. Add MIN_PEAK_HEIGHT of 20 (smoothed)
to reject sparse pages where histogram peaks are too low to indicate dense
two-column text.
Previous thresholds caused 13 regressions across the eval suite by splitting
tables, TOCs, checklists, and forms. Now: 188 passed, 0 regressions (2 minor
metadata-only diffs on IRS P17 and 9978293).
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
* fix(layout): skip relative valley detection on pages with tables
Table column gaps in the histogram look identical to text column gutters
but the table pipeline already handles reading order for those pages.
Pass page_has_table flag through detect_columns to suppress the relative
valley fallback on pages where tables were detected.
This eliminates all remaining regressions from relative valley detection:
190 passed, 0 regressions across 191 eval PDFs.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
* feat(layout): prose density validation for relative valley detection
Add columns_have_prose() to validate relative valley column splits.
Checks that both sides of a proposed split contain paragraph-like
content (fill ratio >= 40%, avg items/line <= 3.5) before committing
to a column split. Combined with the table-page guard, this prevents
false column splits on financial statements, forms, and tabular
layouts where long labels or dot leaders fill the column width.
Also tightens find_relative_valleys() thresholds (PEAK_WINDOW 40->25,
MIN_PEAK_HEIGHT 5->20) to reduce false positive valley candidates.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
When rect-based, line-based, and heuristic detection all fail to find
tables on a page, try building a table directly from the layout
engine's column boundaries. Handles borderless tabular layouts like
exam/reference grids where columns are defined purely by text
alignment.
Includes header-row column refinement: when a detected column
contains multiple header items, it gets split at the gap between
them to recover the correct number of columns.
Guards against false positives: requires ≥4 columns, ≤40 rows,
>50% multi-column rows, short cells (avg ≤40 chars), no prose
content, no dominant single column, and no structural elements
(≥6 rects or ≥4 lines) on the page.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
* feat: tagged PDF structure tree support for semantic markdown generation
Parse /StructTreeRoot from tagged PDFs and use semantic roles (H1-H6, P,
LI, BlockQuote, Code, Caption) to improve markdown output. Structure tree
headings add to font-size heuristics without suppressing them. Coverage
threshold (≥50%) ensures only properly tagged PDFs activate this path.
Phase 1: Parse structure tree with role maps, MCID collection, flattening
Phase 2: Capture MCIDs from BMC/BDC operators, tag TextItems
Phase 3: Structure-aware markdown generation in convert loop
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
* fix: accumulate consecutive code lines into single fenced block
Per-line code fencing produced broken markdown for multi-line code
blocks (separate ``` open/close per line). Unify struct-tree Code
role and font-based monospace detection into a single is_code_line
check with in_code_block state for proper accumulation.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
* test: add tagged PDF fixture with Firecrawl docs content
Synthetic 7-page PDF with rich structure tree exercising H1, H2, H3,
P, Code, LI, Caption, TH, TD roles. Generated via fpdf2 script.
Integration test verifies struct tree parsing and code fence output.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
* chore: remove python PDF generator script from repo
Keep the generated fixture PDF but don't track the generator script.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
* fix: handle malformed bare-name struct types in tagged PDFs
Some PDF generators (e.g. fpdf2) write /S Code instead of /S /Code
in structure elements. lopdf silently drops these objects since bare
tokens are invalid PDF syntax. Add a pre-processor that scans for
known bare struct type names and prepends / before loading.
Unifies path and memory loading through the same fix pipeline.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
* chore: update lopdf dependency to main branch
The firecrawl/zlib-checksum-encrypted branch was merged and deleted.
Point to main which includes all previously merged fixes.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
* chore: switch lopdf to upstream repo pinned at 845cd3d
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
---------
Co-authored-by: Claude Opus 4.6 <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>
Rect-guided tables:
- Add try_build_rect_guided_table() to build tables from rect cluster
X positions as column boundaries, bypassing heuristic detection
- Split merged multi-number TextItems (e.g. "10 11 12...31") into
individual day-column cells using column-advancing boundary assignment
- Interpolate missing column boundaries for holiday/non-work days
that lack colored rects
- Strip tilde-leader noise from cells (legend text bleeding)
- Filter legend text beyond table area via max-X threshold
- Pass cluster_rects through RectHintRegion for downstream use
Extractor improvements:
- Deduplicate clip-path and fill-path rects before using as table hints
- Add font width fallback for missing glyph metrics via average width
- Improve column detection scoring to prefer balanced gutters
- Handle side-by-side layouts with hint-region derived split points
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Many IRS forms and government PDFs draw table gridlines using path
operators (m/l/S) instead of rectangle (re) operators. This adds
line-based table detection to capture these tables.
- Add PdfLine type for line segments from path operators
- Capture m/l/h/S/s/B/b/f/n path operators in content_stream.rs
- Thread Vec<PdfLine> through extraction pipeline
- New detect_lines.rs: classify lines, snap to grid, validate and
assign items with extensive false-positive filters
- Integrate in markdown pipeline: rects first, then lines as fallback
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>
