bcell 1.1.3

A Flutter data-grid widget with a pluto_grid-shaped API and spreadsheet features: a formula engine, multi-sheet workbooks, charts, pivot tables, and CSV/XLSX/PDF import-export.

1.1.3

Tier-3 release on top of 1.1.2 — advanced formula, what-if, and import features, all additive.

• Formula engine — LAMBDA(params, calc) produces a callable value; call it directly (=LAMBDA(x, x+1)(5)) or bind it with LET (=LET(f, LAMBDA(a,b, a*b), f(6,7))). BYROW(array, lambda) and MAP(array, lambda) apply a lambda over an array's rows / elements and spill. (Self-application is depth- capped to #CIRC!; no BYCOL/REDUCE/SCAN yet.)
• Solver — stateManager.solve({targetCell, targetValue, byChanging: [...]}) (bcell_solver.dart): a multi-cell what-if solver (coordinate descent over the Goal Seek bisection) that drives several input cells until a target formula cell reaches a value; restores all inputs on failure. Unconstrained / target-value only.
• Scenario Manager — stateManager.saveScenario(name, cells) / applyScenario(name) / scenarios / removeScenario(name) (bcell_scenario.dart): save and restore named sets of input-cell values.
• Import transforms — BCellImportTransform(rows) (bcell_import_transform.dart): a chainable, non-mutating pipeline over List<Map> — rename/select/drop/where/mapColumn/addColumn/distinct/sortBy — to reshape a JSON payload to the grid's columns before importJson (Power-Query "lite").
• Performance — incremental formula recalc: a single-cell edit now invalidates only the cached formula results whose reference set covers the edited cell (plus transitive dependents), instead of clearing the whole formula cache. Structural changes (sort/filter/paging/row+column ops), edits under an active filter, and volatile formulas (TODAY/NOW) still full-clear — correctness first, over-invalidate never under. No API change; the 10k-row tripwire stays green.
• Widgetbook — a use-case for every feature above.

1.1.2

Excel-parity Tier-2 release on top of 1.1.1. Additive except for the removal of the this-row structured reference (see the Removed note below).

• Table object — stateManager.defineTable({name, totals, bandRows}) (bcell_table.dart): registers the grid as an Excel table and unlocks the [#Headers] / [#Totals] structured references (headers resolve to the column titles, totals to the computed per-column aggregate). bandRows (default true) paints the Excel zebra stripe automatically when the widget leaves oddRowColor null. table / removeTable.
• Conditional-formatting rules — BCellConditionalFormat.duplicates(), .topN(n, {bottom}), and .formulaRule(formula, style) (the formula engine evaluates the rule per row), alongside the existing color-scale / data-bar / icon-set.
• Slicers — BCellSlicer(stateManager, field:) companion widget: a chip bar of the field's distinct values, multi-select filters the grid (sibling of BCellPagination / BCellAutoSum).
• Per-cell lock — BCellValue.locked (default true, Excel semantics): a protected (readOnly) grid still edits cells explicitly marked locked: false; unprotected grids ignore it.
• Pivot advanced — pivot() gains multi-level row/column fields (List<String> keys), a percentOfTotal value mode (BCellPivotValueMode), and an optional key comparator, keeping the single-String call path.
• Goal Seek — stateManager.goalSeek(targetCell:, targetValue:, byChanging:) (bcell_goal_seek.dart): bisection solver that drives one input cell until a target formula cell hits a value.
• Formula engine — array-reshape functions TAKE, DROP, HSTACK, VSTACK, TOCOL, TOROW over the existing dynamic-array (spill) values.
• Widgetbook — a use-case for every feature above.
• Removed: the this-row structured reference. Structured references now name a whole column only ([Sales] → the column's data range); use plain relative A1 refs (=B1-C1) for per-row math. [#Headers]/[#Totals] (via defineTable) are unaffected.

1.1.1

Excel-parity feature release on top of 1.1.0 — all additive, no breaking API changes.

• Cell display — per-column formatter (BCellColumnValueFormatter) and per-cell BCellValue.formatter override, wrapText (soft-wrap in the fixed row height), and textAlign (BCellColumnTextAlign auto/left/center/right, cells and header).
• Select column — BCellColumnType.select([...]) edits via an inline dropdown of fixed options (Excel data-validation list), mirroring pluto_grid.
• Number format — multi-section codes (positive;negative;zero;text, with accounting-style (1,234) negatives), scientific notation (0.00E+00), and [Red]/[Blue] colour tokens parsed-and-stripped.
• Data validation — BCellValidation.number/date/time/list/formula prebuilt validator helpers (bcell_data_validation.dart).
• Freeze rows — setFrozenRowCount(n) pins the top N rows below the header while the rest scroll (freeze panes; composes with frozen columns).
• Find & Replace — replaceAll(query, replacement) (case-insensitive, routes through the edit path so validator/undo apply; skips formula/non-text cells).
• AutoFilter — BCellAutoFilter controller + BCellColumnFilterButton (Excel column funnel; multiple columns AND together), backed by distinctValues(field) / filterByValues(map) on the state manager.
• AutoSum — BCellAutoSum status-bar widget (live Count / Sum / Average of the selection).
• Cell comments — setNote/noteFor now render a corner marker plus a hover tooltip.
• Per-cell styling — BCellValue.style (a BCellStyle override that wins over the column cellStyle resolver) and per-side cell borders via BCellStyle.border (Flutter Border).
• Sparklines — BCellSparkline.line/.bar in-cell mini charts via .toRenderer() (bcell_sparkline.dart).
• Charts — BCellChartType gains area and stackedBar (line/bar/pie/area/ scatter/radar/stackedBar).
• Formula engine — $A$1 absolute-ref markers parse (bcell treats all refs as fixed); XLOOKUP; LET(name, value, …, calc); A1# spill-range refs; array broadcasting at operator combine points (scalar⊗array and same-shape array⊗array). Dynamic-array spill (FILTER/SORT/UNIQUE/SEQUENCE) and SUMPRODUCT/TEXTJOIN remain. First-class function values (LAMBDA) stay out of scope.
• XLSX fidelity — toXlsx({styled, formulas, merged}): bold header, per-column alignment, and cellStyle fill/font colour (default on); =… cells as real Excel formulas (opt-in); colspan/rowspan as Excel merges with value round-trip (default on).
• Widgetbook — a use-case for every feature above, plus more composite custom knobs (EdgeInsets / TextStyle / BorderSide / Size).

1.1.0

Feature release: charts, pivot tables, workbook security, and styling options on top of 1.0.0 — all additive, no breaking API changes.

• Charts — BCellChart companion widget (line / bar / pie via fl_chart) that plots the grid's filtered rows through evaluated formula values and redraws live on edits, sorts, and filters.
• Pivot tables — bcell_pivot.dart aggregation plugin with a toGrid() helper that renders the pivot result as a regular BCellGrid.
• Shared workbook — bcell_workbook_share.dart collaboration plumbing.
• Workbook file encryption — toEncryptedBytes / decryptWorkbook / loadEncryptedBytes (AES-256-GCM, PBKDF2-HMAC-SHA256 with hardened iteration bounds). Wrong passwords and tampered files fail with BCellDecryptException, never garbage data.
• Version history — saveVersion / versions / restoreVersion / removeVersion snapshots on the workbook (in-memory, JSON-based).
• Sheet-protection password — SHA-256 hashed, persisted in workbook JSON.
• Number-format codes now persist through the workbook JSON round-trip.
• Styling — BCellGridStyleConfig gains cell padding, header sort-icon, and fill-handle (fillHandleSize / fillHandleColor / fillHandleBorderColor) options, all theme-resolved like the existing style fields.
• Docs — live Widgetbook demo linked from the README; pluto_grid LICENSE attribution added.
• Performance — profile-mode scroll baselines re-verified on the expanded feature set (all three render paths stay well under the 8 ms frame-build budget); layout regression guard added for auto-size, frozen, colspan, rowspan, and hidden-column sizing.
• Dependency: pointycastle ^4.0.0.

1.0.0

First stable release. BCell grows from the minimal 0.0.1 data grid into a spreadsheet-capable widget: a formula engine, a multi-sheet workbook, a full import/export surface, and a large set of Excel-style cell, column, and selection features — all still built on the flat BCellGridStateManager and virtualized rendering, guarded by a 10k-row performance regression test.

Column types & formatting

• Date columns — BCellColumnType.date({format}) hold a DateTime, display yyyy-MM-dd (or a custom formatter), edit via a native date picker, and coerce ISO strings / Excel date serials on import and paste.
• Number format codes — BCellColumnType.number(format: '#,##0.00' | '0%' | '$#,##0.00' | '000') apply display grouping/decimals/percent/prefix while cells stay raw numbers, so sort and export are unaffected.
• Custom cell renderer — BCellColumn(renderer:) draws any widget in place of the default cell text.
• Conditional formatting — BCellColumn(cellStyle:) colors a cell by its value, plus BCellConditionalFormat.colorScale/dataBar/iconSet(...) renderers for color scales, data bars, and threshold icon sets.
• Rich text — a cell can hold a BCellRichText([BCellTextRun(...)]) with bold/italic/underline/color runs (via BCellRichText.column().toRenderer()); exports flatten to plain text automatically.
• Hyperlink cells — BCellHyperlink.column(onTap:).toRenderer() renders styled, tappable, accessible link text (no launcher dependency).
• Cell notes — setNote/noteFor/hasNote/clearNotes.
• Merge cells — BCellValue(colspan:, rowspan:) (display-only; colspan stays on the virtualized path, rowspan switches to a non-virtualized body).
• Banded rows — BCellGridStyleConfig(oddRowColor:) zebra striping.
• More style knobs — BCellGridStyleConfig gains defaultColumnTitlePadding, defaultCellPadding, iconSize, iconColor (pluto_grid names), and fillHandleSize/fillHandleColor/fillHandleBorderColor for the drag-fill handle; defaults are unchanged (the handle outline now theme-resolves to colorScheme.surface instead of hardcoded white).
• Per-row height — BCellRow(height:) with virtualization preserved.

Columns & selection

• Freeze columns — BCellColumn(frozen: BCellColumnFrozen.start | .end) pins a column left/right with synced vertical scroll across sections.
• Column reorder — moveColumn(from, to) plus header drag-to-reorder and accessible "Move left/right" actions.
• Range/multi selection — anchor+focus range with Shift+click/arrow, extendSelectionTo/isInRange/selectedCells/rangeAsTsv, range copy / clear / fill, and a drag-fill handle.
• Fill — fillDown (Ctrl+D), fillRight (Ctrl+R), fillSeriesDown() (series/ auto fill), flashFillDown() (flash fill by inferred transform).
• Checkbox row selection — setRowChecked/toggleRowChecked/ setAllRowsChecked/checkedRows/isAllChecked/isAnyChecked.
• Clipboard — copySelectionToClipboard/cutSelectionToClipboard/ pasteFromClipboard (TSV block paste, anchored and clipped).
• Data validation — BCellColumn(validator:) enforced centrally in changeCellValue (also guards paste/fill), with an onInvalid callback.
• Undo/redo (undo/redo/canUndo/canRedo), find (find('q')), and go-to (goToCell/goToRow).
• Read-only mode — BCellGrid(mode: BCellGridMode.readOnly) / setGridMode(...) blocks every edit and structural row change.

Formula engine

• = formulas evaluate on display, sort, and export, with error results (#DIV/0!/#NAME?/#CIRC!/#NUM!/#REF!/#VALUE!/#N/A) and a cycle guard; results memoized per notification. Formula cells never leak a live =... into CSV.
• A1 refs and A1:B2 ranges; arithmetic, comparison, & concat, string literals.
• Function library: Math/Trig, Statistical, Financial (PMT/FV/PV/NPV/IRR), Lookup (VLOOKUP/HLOOKUP/INDEX/MATCH), Date & Time, Information, Logical, and Text categories.
• Named ranges — defineName/removeName/clearNames/namedRange/ definedNames.
• Structured references — enableStructuredRefs() for [Column] and decorative Table[Column] whole-column refs, live over displayed rows.

Import / export

• Exports — CSV, TSV, HTML, XML, Markdown, JSON, PDF (toPdf, dep: pdf; selectionOnly print area), and XLSX (toXlsx, dep: excel). Markup exports escape every cell value and title.
• Imports — importTsv/importCsv (RFC 4180)/importHtml/importMarkdown/ importJson/importXlsx, mapping onto visible columns and coercing to each column type.

Workbook & infrastructure

• Multi-sheet workbook — BCellWorkbook (ordered BCellSheets + active sheet) with add/remove/rename/select/move, per-sheet tab color, protect, and hidden flags; BCellSheetTabBar (tab strip with drag-to-reorder and accessible move actions) and BCellWorkbookView.
• Sheet-protection password — optional password: on BCellWorkbook.setProtected; unprotecting a password-protected sheet requires the matching password. Only a SHA-256 hash is stored and persisted in the workbook JSON, never the plaintext.
• Workbook persistence — BCellWorkbook.toJson() / BCellWorkbook.fromJson() round-trip sheets, flags, column definitions (incl. number-format codes), and row data; loadJson() loads a map into an existing workbook in place.
• Version history — saveVersion() / versions / restoreVersion() / removeVersion() / clearVersions(): in-memory named, timestamped workbook snapshots built on the JSON persistence, restorable in place.
• Encrypted workbook file — toEncryptedBytes(password) seals the workbook JSON into an authenticated AES-256-GCM blob (PBKDF2-HMAC-SHA256 key derivation, random per-file salt and nonce); decryptWorkbook() / loadEncryptedBytes() open it, throwing BCellDecryptException on a wrong password or tampered bytes. Backed by pointycastle.
• Shared-workbook merge — mergeChanges(base:, theirs:) folds another copy's edits into the workbook via a three-way, cell-level merge over toJson() snapshots; cells both copies changed differently keep the local value and are reported as BCellMergeConflicts. BCellWorkbookView now rebuilds its grid after any in-place load (loadJson/restoreVersion/ loadEncryptedBytes/mergeChanges), fixing stale rows when the active index was unchanged.
• Event bus — BCellGridEventManager (addEvent/listener/stream) on a broadcast stream, allocated lazily.
• Font scope — BCellFontController + BCellFontScope (InheritedNotifier) re-font every BCell widget under one controller live.
• Charts — BCellChart(stateManager, type: BCellChartType.line/.bar/.pie, categoryField:, valueFields:), a companion widget that plots the grid's filtered rows (formula-evaluated) and re-draws live. Backed by fl_chart.
• Pivot tables — stateManager.pivot(rowField:, columnField:, valueField:, aggregate: BCellPivotAgg.sum/count/average/min/max) aggregates the filtered rows into a rows × columns matrix (value/rowTotal/columnTotal/ grandTotal); totals re-aggregate the raw numbers. toGrid() renders the result into BCellGrid columns+rows. Single row/column field.

0.0.1

Initial release — a minimal data grid with a pluto_grid-shaped API.

• BCellGrid widget: columns, rows, onLoaded, onChanged, onSelected, onSorted, configuration.
• Models: BCellColumn (width, minWidth, readOnly, suppressedAutoSize), BCellColumnType.text()/.number(), BCellRow, BCellValue.
• BCellGridStateManager (ChangeNotifier): cell editing (changeCellValue), selection (setCurrentCell/setEditing on a dedicated selection ValueNotifier, currentRow/currentRowIdx), sort cycle (toggleSortColumn, type-aware, restores insertion order), column resize (normal/pushAndPull/none), row ops (insertRows/prependRows/appendRows/removeRows/removeCurrentRow), column hiding (hideColumn/visibleColumns), row filtering (setFilter, sourceRows), paging (setPageSize/setPage/totalPage), keyboard navigation core (moveCurrentCell with BCellMoveDirection).
• Keyboard support in BCellGrid: arrows/Tab move the selection, Enter/F2 edits, Escape cancels an edit without committing.
• BCellPagination plugin widget: ready-made pager driven by the state manager (same shape as pluto_grid's PlutoPagination).
• Inline tap-to-edit cells; number columns validate input.
• Responsive column auto-sizing: BCellAutoSizeMode.equal/.scale, per-column opt-out.
• CSV export (toCsv) with RFC 4180 quoting and opt-in formula-injection sanitizing.
• Material 3 theme-aware styling; all colors/text styles overridable via BCellGridStyleConfig.
• Performance: virtualized rows, cached list views, cell position lookup via back-references, selection changes rebuild only cells; guarded by a 10k-row regression test.