Not implemented

PhpSpreadsheet APIs the polyfill does not provide. Found by running real PhpSpreadsheet code against it (data/public/index.php is one such probe); COMPAT.md documents what is supported and where supported behavior intentionally diverges. Calling anything below fails loudly (class not found / clear exception) ? never with a silently different file.

An implementation plan for closing these gaps exists: PLAN.md §13 "Phase 4 ? compat completion" orders everything below into four ROI waves with verified excelize APIs and effort estimates. Items land there and get deleted here.

Found by the ERP report probe (data/public/index.php)

Closed by wave 4.4 (2026-06-13): rich-text cell values with per-run fonts, GD MemoryDrawing, the PhpSpreadsheet Chart\* object model (Worksheet::addChart), and auto-filter column rules (getAutoFilter()->getColumn()). This completes Phase 4 ? MISSING.md now lists only items that stay out by design.

Closed by wave 4.3 (2026-06-13): insert/remove rows and columns, createSheet($index), sheet copy (Spreadsheet::copySheet extra), sheet views (gridlines/zoom/RTL/tab color), headers/footers, page margins ? plus a correctness fix: post-save mutations were silently dropped by excelize on stream-flushed sheets; they now reopen first (COMPAT.md §21).

Closed by wave 4.2 (2026-06-13): getDefaultStyle(), row/column iterators, IReadFilter, style read-back from loaded files + duplicateStyle, validation/conditional/defined-name/auto-filter getters.

Closed by wave 4.1 (2026-06-13): custom value binders, document properties (getProperties(); setManager is kept PHP-side only ? excelize has no field for it), print titles + print area, the getConditionalStyles() getter, workbook encryption (writer/reader setPassword(), easy-excel extras), gradient fills, diagonal borders, unmergeCells + merge getter, and calculation-cache no-ops.

Known gaps (by area)

Reading / introspection - getCellCollection() / existing-cells-only iteration flags - Auto-filter column rule introspection (range getter landed in 4.2)

Structure editing - removeConditionalStyles - clone $sheet / Spreadsheet::addExternalSheet (use Spreadsheet::copySheet instead)

Content types - Vertical/horizontal borders (conditional-formatting-only border sides) - Header/footer images, cell background images (file & memory drawings anchored to cells are supported)

Formats & security - Readers/writers: Ods, Xls, Html, Pdf, Slk, Gnumeric ? install the real phpoffice/phpspreadsheet alongside (the alias bootstrap stays dormant and defers to it) or convert externally - 63 of PhpSpreadsheet's 529 calculation functions (list in FORMULAS.md)

Misc - Calculation array-formula toggles (the cache controls are accepted no-ops since wave 4.1) ? calculation is delegated to excelize - Auto-filter does not hide non-matching rows (column rules are recorded; Excel re-applies on open ? COMPAT.md §23) - Pre-computed formula cache ? formula cells are written without a cached <v> result, so spreadsheet apps that don't auto-recalculate on open (some headless readers) show them blank until recalculated. Excel, LibreOffice and getCalculatedValue() evaluate them correctly. PhpSpreadsheet pre-calculates and stores the value; excelize has no recalculate-and-cache step (COMPAT.md §24).

Verified against PhpSpreadsheet

data/public/index.php is a self-verifying probe: it generates the ERP report through the PhpOffice\PhpSpreadsheet\* aliases, reloads it, and diffs the data table against data/public/phpspreadsheet.xlsx (the same report from real PhpSpreadsheet). Run it over HTTP (see http-verify.sh):

docker run -d -e SERVER_NAME=":80" -v $PWD/data:/app \
  -v $PWD/php:/opt/easy-excel/php -p 8085:80 frankenphp-easy-excel
curl http://localhost:8085/        # ? REPORT TEST PASS

Want one of these? Open an issue at xiidea/easy-excel ? gaps get prioritized by real-world usage, and this file shrinks as they land.