Align region filtering with rotated-page coordinate rewrites, switch region text assembly to the shared line-grouping pipeline, and retain edge-overlap text to avoid false empty regions that incorrectly trigger OCR fallback. Also make Python region inputs fail fast with clear ValueError messages for malformed boxes.
Made-with: Cursor
* fix sort panics on NaN values from bogus PDF font metrics
Replace all `partial_cmp(...).unwrap_or(Ordering::Equal)` and bare
`partial_cmp(...).unwrap()` with `total_cmp()` across the codebase.
`partial_cmp` returns `None` for NaN, and mapping that to `Equal`
violates total ordering: `a == NaN` and `NaN == b` but `a != b`.
Rust 1.81+ detects this and panics in sort_by. `total_cmp` handles
NaN deterministically (sorts to end) and guarantees total ordering.
The critical crash was in `extract_text_in_regions` (lib.rs:478)
where PDFs with bogus font ascent/descent values produced NaN in
text item coordinates, causing process abort via NAPI.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
* fix missed partial_cmp in layout.rs and restore napi exports
- Convert two remaining b.y.partial_cmp(&a.y) calls to total_cmp
in group_single_column and column layout sorting
- Restore missing napi exports: detectPdf, extractText,
extractTextWithPositions, processPdf
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
---------
Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Add `extract_text_in_regions_mem` that takes layout-detected bounding
boxes (top-left origin, PDF points) and returns text within each region
in reading order. Designed for pipelines where a layout model detects
regions and text-based pages can skip GPU OCR by extracting text from
the PDF structure directly.
Also add `classify_pdf_mem` for lightweight PDF type classification
returning 0-indexed pages_needing_ocr.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
* fix(extractor): strip PDF comments that break lopdf content stream parsing
Some PDF generators (notably PD4ML used by school districts) embed
comments (% to end of line) in content streams. lopdf's Content::decode
parser fails to parse operators that follow comments, silently dropping
ET (end text) and Q (restore graphics state) operators. This caused
entire pages to produce 0 text items despite having valid text.
Fix: pre-process content streams to strip comments before parsing.
Comments inside string literals (parentheses) and hex strings are
preserved. The comment is replaced with a space to maintain token
separation.
Impact: fixes 13+ school district PDFs and similar PD4ML-generated
documents that were producing near-empty output (454 → 31,955 chars
for a 22-page school improvement plan).
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
* fix(detect): flag sparse-extraction pages as needing OCR
When a TEXT-BASED PDF produces <50 chars/page average with <500 total
chars, flag all pages as needing OCR. This catches PDFs where the
extractable text is minimal (form templates, image-heavy layouts)
and the bulk of content requires OCR to access.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
* fix(detect): improve CID mojibake detection for Japanese/CJK PDFs
Extend is_cid_garbage to detect CID-as-Latin-1 mojibake: when ≥40%
of characters are high Latin-1 (U+00A0-00FF) and <33% are ASCII
letters, the text is likely CID values misinterpreted as Latin-1
characters (common in Japanese/CJK PDFs with broken ToUnicode CMaps).
Also add sparse-extraction OCR flagging: TEXT-BASED PDFs with
<50 chars/page and <500 total chars get all pages flagged for OCR.
Impact: Softbank Japanese PDFs now produce empty output with
pages_needing_ocr=all instead of mojibake garbage. Korean PDFs
with valid extraction (nexo-price-en) remain unaffected.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
* fix(detect): sparse extraction check only when markdown is generated
The sparse-extraction OCR check was triggering in Analyze mode where
markdown is not generated (md_len=0), causing false OCR flags on
every PDF processed via detect-pdf --analyze.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
---------
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>
---------
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
* fix: skip page extraction when operation count exceeds 1M
Vector-heavy architectural PDFs can have 10-26M path operators per page,
causing ~60 GB allocation during per-op processing. The decode itself is
tolerable but the subsequent loop amplifies memory 2-5x with text items,
rects, paths, and state tracking.
Check operation count after Content::decode() and return empty extraction
for pages exceeding the limit, with a warning log.
* test: add unit test for excessive operations guard
Constructs a synthetic PDF with 1.1M path operators to verify
that pages exceeding the operation limit return empty extraction.
* 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>
---------
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
PDFs that embed landscape content in portrait pages via a rotated text
matrix (e.g. [0, b, -b, 0, tx, ty] for 90° CCW) produced garbled output
because the layout engine assumed x=horizontal, y=vertical.
Track the dominant text direction from combined matrices during extraction.
When ≥67% of text operators are rotated, swap x↔y coordinates (with
y-negation for correct reading order) for all text items, rects, and lines.
Also estimate text widths from char count × font size since scale_x ≈ 0
for rotated text.
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>
---------
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
lopdf's decompressed_content() fails on Form XObjects without a /Filter
entry (uncompressed streams). This caused all body text to be lost in PDFs
generated by pdfrw and similar tools that wrap page content in uncompressed
Form XObjects (e.g. Cambridge University Press excerpts).
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
lopdf's decompressed_content() fails with DictKey("Filter") when a
ToUnicode stream has no /Filter entry (uncompressed raw text). Now
falls back to the raw stream.content when decompression fails.
Fixes Identity-H fonts with valid uncompressed ToUnicode CMaps
producing empty text (e.g. neoenergia tabela PDF).
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>
Fonts using raw glyph ID names (gidNNNNN) in their Differences
encoding cannot be decoded to Unicode without the original font's
cmap table. Detect this pattern during font parsing and add
affected pages to pages_needing_ocr so downstream consumers
know to use OCR instead.
Fixes text extraction on PDFs like Tezukuri_Food-Menu.pdf where
the main body font (AcuminVariableConcept) uses gid-encoded
glyphs — even PyMuPDF and ODL fail on these.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Scanned PDFs with OCR text layers use rendering mode 3 (invisible text)
positioned behind page images. Previously we skipped all Tr=3 text.
Now for Mixed/template PDFs, if normal extraction produces garbage or
empty output, we retry with invisible text included. This unlocks text
from OCR-generated PDFs without requiring external OCR.
Also adds Windows Unicode BMP (3,1) subtable support to the TrueType
cmap fallback, and allows TrueType fonts with explicit encoding to
extract their embedded cmap (OCR fonts often lie about encoding).
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Multi-item lines (titles, section headers) that span across detected
columns were being split into individual column buckets, corrupting
newspaper detection and reading order. Add identify_spanning_lines()
that groups items by Y-proximity and marks lines wider than 1.3x the
widest column that have no gap at a detected gutter boundary.
Uses column-aware thresholds and gutter-interval gap detection for
precision — only fires on pages with detected columns, preserves
original item order via boolean mask.
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>
Narrow annotation columns beside wide body columns were being
Y-interleaved with body text, producing garbled reading order.
Add sidebar detection with width ratio, line balance, and sparse
density guards to correctly trigger sequential column reading.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Canva-generated PDFs render text character-by-character with CSS-style
letter-spacing (~0.5-0.9× font_size). The hardcoded 0.10 threshold
caused every character to get a space inserted ("K a r i b i b").
Detect Canva pages via fix_letterspaced_items (≥50% items match "a b c"
pattern), compute an IQR-based threshold (median × 1.55) on the gap
distribution BEFORE space removal, then propagate per-page thresholds
through PageThresholds → group_into_lines_with_thresholds → TextLine
→ should_join_items.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Subset fonts number GIDs by document encounter order, not sorted order.
The sequential remap scrambled character mappings, losing 2,532+ CJK
characters. Now promotes TrueType cmap fallback when it has more entries
than the primary ToUnicode CMap. Also adds CJK scoring to score_text()
as defense-in-depth.
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>
Pages using nested Form XObject chains (page → wrapper Form → text Form)
were returning 0 text items because extract_form_xobject_text() didn't
handle the Do operator. Add Do/q/Q/cm handling with recursive descent
(max depth 5) and proper CTM tracking through the nesting.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
PDFs like fare1011.pdf draw table row stripes and borders using
m/l/h/f* filled paths instead of `re` operators. Extract axis-aligned
rectangles from these filled subpaths as a third-priority rect source
(after `re` rects and clip-path rects).
Key changes:
- Track completed subpaths in `h` handler for f/f* rect extraction
- Update W/W* handler to read from pending_subpaths when pending_lines
is empty (after h clears them)
- Add row-stripe fallback in detect_rects when clustering produces no
large clusters (non-overlapping row stripes), with ≥15 rects and
≥10 rows required to prevent decorative fill false positives
- Revert body-font upper bound to 1.05x (no longer needed at 1.10x)
fare1011.pdf: 12-col heuristic table → 14-col rect-based table with
all fare values correctly captured.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Extract axis-aligned rectangles from W/W* clip operators in content
streams — many PDFs define table cells as clipping paths instead of
stroked rects. Add merged-cluster fallback in detect_tables_from_rects()
that merges all cluster rects when per-cluster detection fails or only
produces narrow false-positives (≤3 columns). Uses rect Y-edges for
rows and text X-clustering for columns.
Also updates lopdf to firecrawl fork (fix-leading-whitespace branch).
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.
PDFs that set fill color via `sc`/`scn` (named color space operators)
instead of `g`/`rg`/`k` were incorrectly keeping fill_is_white=true
from earlier page background fills, causing all text to be skipped.
Infer color model from operand count: 3=RGB, 4=CMYK, other=non-white.
Fixes extraction of tension_chart PDF (D'Addario string specifications)
which previously output only glyph names.
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>
- Remove `process_mode` from `MarkdownOptions` (it controlled the
pipeline, not markdown formatting)
- Remove dead `text` field from `PdfProcessResult`
- Add `PdfOptions` builder consolidating mode, detection, markdown,
and page filter configuration
- Add convenience functions: `detect_pdf()`, `detect_pdf_mem()`,
`process_pdf_with_options()`, `process_pdf_mem_with_options()`
- Eliminate double document parsing: load once, share between
detection and extraction via internal `pub(crate)` helpers
- Deprecate old `process_pdf_with_config*` functions (kept as shims)
- Update binaries to use new API
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Soft hyphens, zero-width spaces, BOM, ZWNJ/ZWJ, and word joiners now get
stripped in expand_ligatures(). Also call expand_ligatures() on the ActualText
code path which was the only TextItem creation site missing it.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Map lopdf's Unimplemented("encrypted...") error to PdfError::Encrypted
instead of falling through to PdfError::Parse. Retry all Document::load
calls with an empty password when encryption is detected, so
owner-password-only PDFs can be opened. If the retry also fails, the
user now sees a clear "PDF is encrypted" message.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Symbol/Wingdings fonts often map codes to PUA (U+F000-F0FF) via ToUnicode
CMaps, producing invisible/tofu characters in markdown output. Add
clean_symbol_pua() post-processing to extract_text_from_operand() that
converts these to standard Unicode: bullets to U+2022, checkmark to U+2713,
and ASCII/Latin-1 range by stripping the F000 offset.
Eliminates 1,405 PUA characters across 25+ eval PDFs.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
- Add pdf.js binary CMap (bcmap) parser for Japan1/GB1/CNS1 CID fonts
- Support inline ToUnicode streams (not just object references)
- Add CMapDecisionCache for heuristic primary vs remapped CMap selection
- Build fallback CMaps from embedded font data and CIDSystemInfo
- Handle simple fonts without ToUnicode via embedded font cmap
- Add Symbol/Wingdings/ZapfDingbats font decoding fallback
- Support usecmap chaining in both text and binary CMap formats
- Scan XObject Forms for text operators in detector
- Change default detection strategy from EarlyExit to Sample(8)
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Introduces a ProcessMode enum that controls how far the PDF pipeline
runs, enabling fast document triage without paying extraction or
markdown conversion costs. Exposed via --detect-only and --analyze
flags in both pdf2md and detect-pdf CLIs.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Add LayoutComplexity struct to PdfProcessResult so callers can detect
when a PDF has complex layout (tables or multi-column text) and decide
whether to use the extracted markdown or fall back to OCR.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Merge CMap and Differences encoding at the byte level for single-byte
fonts, fixing garbled output when partial ToUnicode CMaps caused Latin-1
fallback to block the Differences path. Add Adobe-Korea1 CID-to-Unicode
predefined mapping for Identity-H CID fonts without ToUnicode streams,
and support TrueType cmap extraction via ttf-parser for embedded fonts.
Also handle suffixed glyph names (e.g. zero.tf, a.ss01) per Adobe spec.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Eliminates double-parsing of PDFs by using the lopdf document model exclusively
for ToUnicode CMap extraction. The old raw byte scanner parsed PDFs separately
from lopdf and only handled FlateDecode, while lopdf handles FlateDecode + LZW +
ASCII85. The new approach walks page fonts and Form XObject fonts via the document
API, yielding ~7x speedup on text-heavy PDFs and ~1.2x overall.
- Add FontCMaps::from_doc() with recursive Form XObject font walking
- Remove ~270 lines of raw byte scanning code (from_pdf_bytes, extract_stream_from_raw_pdf, etc.)
- Remove flate2 dependency (lopdf handles decompression internally)
- Remove dead CMap lookup fallback branches (by_name, get_with_obj, base_font_name)
- Remove unused font_base_names parameter from extract_text_from_operand
- Skip U+FFFD replacement characters in CMap decode (PDF notdef glyph markers)
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
