worksheet 3.9.0

High-performance Flutter spreadsheet widget supporting large datasets, 10%-400% zoom, and GPU-optimized tile-based rendering.

Changelog

All notable changes to this project will be documented in this file.

The format is based on Keep a Changelog, and this project adheres to Semantic Versioning.

3.9.0 - 2026-03-05

Added

• Widget-level tests for column/row resize and auto-fit at sub-100% zoom levels
• Verifies manual resize correctly converts screen-pixel deltas to logical units at 50% zoom
• Verifies auto-fit fires correctly at 50% zoom
• Verifies zoom changes do not trigger spurious resize callbacks

3.8.2 - 2026-03-01

Fixed

• Auto-fit now considers cell-level rich text styles (e.g. bold, large font) and CellFormat (e.g. currency) when calculating column width and row height
• Previously, cell-level styles measured as zero width and formatted text used raw values, causing columns to be too narrow

Added

• example/auto_fit.dart — demonstrates auto-fit with rich text styles, number formats, and combinations

3.8.1 - 2026-03-01

Fixed

• Applied dart format to resolve CI formatting failures
• Added format check as Step 1 in the release process

3.8.0 - 2026-02-28

Added

• Cell-level rich text styles — WorksheetData.getRichText can now return a single TextSpan with no text to apply a cell-wide style (e.g. bold + color) to the entire display value. Previously only per-character spans were supported
• EditController.isEditingFormula — convenience getter for checking if the cell being edited contains a formula
• example/formula_richtext.dart — new example demonstrating formula evaluation with rich text styling

Fixed

• Formula cell editing — double-clicking a formula cell now shows the formula string (e.g. =B2*C2) in the editor instead of the evaluated display value (e.g. 126)
• Arrow keys in formula edit mode — ArrowUp/Down no longer commit the edit and navigate away when editing a formula cell. Arrow keys move the cursor within the formula text; cell reference insertion only triggers after typing an operator (point mode)
• Operator boundary cursor trapping — arrowing through an operator character (+, *, etc.) in a formula no longer inserts a cell reference when the user is simply navigating

3.7.0 - 2026-02-27

Added

• AutocompleteController.handleKeyEvent() — keyboard dispatch helper for formula autocomplete (arrow navigation, Tab/Enter accept, Escape dismiss). Enables external formula bar implementations without duplicating keyboard wiring boilerplate
• AutocompleteController.applyAcceptedFunction() — static utility that replaces a token in any TextEditingController with the accepted function name and opening parenthesis

Changed

• CellEditorOverlay refactored to use handleKeyEvent() internally (no behaviour change)
• Applied Dart 3.10 tall style formatting across the codebase
• Consolidated tool/bootstrap.sh, tool/test.sh, tool/bench.sh into unified tool/ci.sh

Fixed

• Golden tests excluded from CI to avoid cross-platform font rendering false positives

3.6.0 - 2026-02-25

Added

• Undo/redo for column and row resize — drag resize, multi-select resize, and auto-fit operations now push undo entries. Ctrl+Z reverts column width and row height changes just like cell edits

3.5.0 - 2026-02-24

Added

• Worksheet.rawData — optional raw data source for editing. When provided, the cell editor shows values from rawData instead of data, so formula wrappers that evaluate CellValue.formula into computed results still let users edit the original formula text
• DelegatingWorksheetData — base class for writing WorksheetData wrappers with minimal boilerplate (override only the methods you need; everything else delegates to the inner data source)
• Undo/Redo — UndoManager class provides full undo/redo support for all worksheet mutations
• UndoEntry immutable model storing before/after cell snapshots, merge regions, and selection state
• UndoSnapshot helper with capture() and restore() static methods for range-scoped cell state snapshots
• Pass UndoManager to WorksheetController to enable: WorksheetController(undoManager: UndoManager())
• All 13 mutation paths automatically recorded: cell edit, paste, cut, fill handle drag, fill down/right, clear, merge/unmerge, move, rich text toggle, set style
• Keyboard shortcuts: Ctrl+Z / Cmd+Z (undo), Ctrl+Y / Ctrl+Shift+Z / Cmd+Shift+Z (redo)
• UndoIntent and RedoIntent for custom shortcut/action integration
• WorksheetController.invokeAction(Intent) — invoke any registered worksheet action from external UI (toolbars, side panels)
• WorksheetController.isActionEnabled(Intent) — check if an action is currently enabled
• undo() and redo() are now convenience wrappers around invokeAction
• WorksheetData.getFormatsInRange() for sparse format iteration
• example/undo_redo.dart — example with toolbar undo/redo buttons, invokeAction pattern, and stack depth display

3.4.0 - 2026-02-23

Added

• Frozen panes — Worksheet.freezeConfig property wires existing FreezeConfig model and FrozenLayer renderer into the widget for pinned rows and columns
• _FrozenLayerPainter renders frozen cells on top of scrolling content with opaque backgrounds, gridlines, text spillover, and separator lines at the freeze boundary
• _FrozenSelectionPainter renders selection indicators in the three frozen regions (corner, frozen rows, frozen columns) with adjusted scroll offsets
• Frozen-aware hit testing — taps in frozen regions resolve to the correct unscrolled cell
• Frozen-aware scrollToCell() — skips scrolling for frozen cells and accounts for frozen dimensions when scrolling to non-frozen cells
• Frozen headers — column/row headers for frozen panes stay pinned alongside their content cells with separator lines at the freeze boundary
• Elastic overscroll suppression on frozen axes — prevents bounce gap at the frozen boundary while preserving bottom/right bounce
• example/frozen_panes.dart — interactive example with +/- controls and presets for frozen rows and columns

3.3.0 - 2026-02-21

Added

• Formula function autocomplete — typing function names in formula mode (=SU) shows a dropdown with matching suggestions; arrow keys navigate, Tab/Enter accept (inserts FN(), Escape dismisses
• FormulaAutocompleteConfig — configurable function list, maxVisibleItems, minChars, and custom matcher (set formulaAutocompleteConfig on Worksheet; default null disables autocomplete)
• FormulaFunction — data class for function name, signature, and optional description
• AutocompleteController — manages dropdown state (visibility, matches, selection, accept/dismiss)
• AutocompleteDropdown — renders function suggestions with bold prefix highlighting and muted signatures
• FormulaFunctionTokenizer — extracts alphabetic function name token at cursor position
• FormulaFunctionMatcher — case-insensitive prefix matching with alphabetical sorting
• Worksheet.onAutocompleteAccept callback — notified when a function is accepted from the dropdown

3.2.0 - 2026-02-21

Added

• Formula cell reference editing — clicking cells during formula editing inserts A1 references, dragging inserts ranges, arrow keys insert/move references, F4 cycles absolute/relative modes (A1 → $A$1 → A$1 → $A1 → A1)
• FormulaReferenceConfig — configurable override API for formula mode detection, tokenization, and reference generation (enabled by default; set to null to disable)
• FormulaTokenizer — parses formula strings into color-coded reference tokens with character offsets
• FormulaReferenceInserter — insert/replace cell and range references at cursor position
• FormulaReferenceLayer — renders colored borders on referenced cells with marching ants animation on the active reference
• Color-coded visual feedback: each reference in the formula gets a distinct border color matching its position in the formula text

3.1.0 - 2026-02-20

Added

• FormulaReferenceAdjuster callback API — fill down (Ctrl+D), fill right (Ctrl+R), and drag-to-fill now adjust relative cell references automatically (e.g. =A1+B1 filled down becomes =A2+B2)
• Worksheet.formulaReferenceAdjuster parameter (defaults to defaultFormulaReferenceAdjuster; set to null for legacy verbatim-copy behavior)
• Cell.copyWithValue() method
• Re-exports A1, A1Range, A1Reference from the a1 package for custom adjuster implementations

Dependencies

• Added a1: ^2.2.0 for A1-style cell reference parsing

3.0.2 - 2026-02-18

Fixed

• Auto-fit column/row now considers merged cell content — measures the anchor cell's text and distributes the needed size across spanned columns/rows

3.0.1 - 2026-02-15

Added

• Font family (Google Fonts) and font size dropdowns in example/rich_text/
• example/rich_text/ is now a standalone Flutter project (was example/rich_text.dart)
• COOKBOOK.md: "Font Family with Google Fonts" section documenting setFontFamily usage with resolved font names

Fixed

• Restore editor focus and selection after toolbar actions
• Position cursor at double-tap location instead of end of text
• Recompute wrap vertical offset when toggling wrapText or verticalAlignment
• Expand tile invalidation to full merge extent for border repaints
• Clear all borders (including anchor) when merging cells
• Border conflict resolution now uses merge region edges instead of anchor coordinate, fixing incorrect neighbor lookups for merged cells
• SetCellStyleAction skips borders on non-anchor merged cells, preventing duplicate borders in the data model

3.0.0 - 2026-02-14

Breaking Changes

• CellStyle no longer contains text appearance fields — removed fontWeight, fontStyle, fontSize, fontFamily, textColor, underline, strikethrough. Text appearance is now exclusively on rich text TextSpan styles. CellStyle retains cell-level concerns: backgroundColor, textAlignment, verticalAlignment, borders, wrapText.

Added

• unmergeCellsInRange(CellRange) on WorksheetData — unmerge all merged regions within a range
• Corner cell (top-left header intersection) tap selects all cells
• Toggle formatting actions (Bold, Italic, Underline, Strikethrough) now work when not editing — modify rich text spans on all selected cells
• ClearCellsAction unmerges cells when clearing formats
• Merged cell regions preserved during drag-to-move operations
• Fill operations expand target range to complete merge tile patterns
• Text color toolbar in example/rich_text.dart

Fixed

• Fill range and smart fill now propagate rich text spans alongside value, style, and format
• FillPatternDetector preserves rich text from template cells in linearNumeric, dateSequence, and textWithNumericSuffix patterns
• Cell editor base text color uses theme default instead of first span's color, preventing color bleed into uncolored spans

Changed

• Migrated from flutter_lints to lints package

2.5.2 - 2026-02-13

Fixed

• Fill down, fill right, and smart fill now preserve merged cell regions, tiling the merge pattern from the source into the target range

2.5.1 - 2026-02-13

Fixed

• Cell editor overlay now uses full merged cell width for text alignment

2.5.0 - 2026-02-13

Added

• Trackpad pinch-to-zoom support for desktop and web

Fixed

• Drag-to-move to same location no longer deletes cell data
• Drag-to-move preview now tracks cursor grab point instead of snapping selection top-left to cursor
• Selection border no longer detectable in header-adjacent zone, preventing accidental move-drag near row/column headers

2.4.0 - 2026-02-13

Added

• Rich text formatting via Intents/Actions — ToggleBoldIntent, ToggleItalicIntent, ToggleUnderlineIntent, ToggleStrikethroughIntent with corresponding Action classes, enabled only during editing
• EditController.richTextController — exposes the active RichTextEditingController to toolbar buttons and external code during editing
• EditController convenience methods: toggleBold(), toggleItalic(), toggleUnderline(), toggleStrikethrough() for toolbar use outside the widget tree
• EditController query getters: isSelectionBold, isSelectionItalic, isSelectionUnderline, isSelectionStrikethrough, getSelectionStyle() for toolbar active-state display
• RichTextEditingController query methods: isSelectionBold, isSelectionItalic, isSelectionUnderline, isSelectionStrikethrough, getSelectionStyle(), _queryProperty() helper
• Ctrl+B/I/U and Ctrl+Shift+S shortcut bindings in DefaultWorksheetShortcuts (both control and meta variants) mapped to the new formatting intents

2.3.0 - 2026-02-12

Added

• Excel-like mouse cursors — crosshair for cells, pointer for headers, resize arrows for column/row borders, move arrow for selection border, crosshair for fill handle
• Auto-fit column/row on double-click resize handle — measures cell content to set optimal width/height; respects wrapText style for row height calculation
• Drag-to-move selection — drag the selection border to relocate cells with a dashed preview border; source cells are cleared after move
• Border double-click jump navigation — double-clicking a selection border edge jumps to the data edge in that direction (Ctrl+Arrow behavior)

Fixed

• Cell editor stuck at first character on double-click entry
• Double-click auto-fit no longer fires spurious resize-end or selects adjacent column after layout change

2.2.1 - 2026-02-11

Fixed

• Rich text type-to-edit clearing, pending format state, and cell editor alignment
• Wrap-text cell editor expansion lag for right/bottom-aligned cells
• Cell editor edge conditions for bottom overflow and right clipping
• Text selection in cell editor overlay (click-drag, double-click word select)
• Rich text formatting (bold, italic, etc.) lost when committing edit by clicking away from cell

2.2.0 - 2026-02-10

Added

• HeaderStyle.darkStyle — dark mode header colors derived from Excel dark mode
• WorksheetThemeData.darkTheme — dark mode theme preset (dark headers, white cells)
• HeaderStyle.copyWith(), operator ==, hashCode
• SelectionStyle.copyWith(), operator ==, hashCode
• Runtime theme switching — WorksheetTheme data changes now rebuild renderers and layers automatically
• example/darklight.dart — toggle between light and dark mode with a button

Fixed

• Header background rects used non-finite dimensions (double.infinity) which some renderers silently skip — now uses viewport-sized rects
• _HeaderPainter and _SelectionPainter shouldRepaint did not detect new layers after theme change

2.1.0 - 2026-02-10

Added

• DurationParser class — parses H:mm:ss and H:mm strings into Duration values
• Duration parsing in CellValue.parse() — detection order is now: empty → formula → boolean → number → duration → date → text
• NumberFormatDetector — auto-detects currency ($1,234.56), percentage (42%), and thousands-separated (1,234) formats on edit commit, returning both parsed value and format
• DurationFormatDetector — auto-detects duration formats ([h]:mm:ss, [h]:mm, [m]:ss) on edit commit via round-trip matching
• EditController.commitEdit() now detects formats for numbers and durations in addition to dates

2.0.0 - 2026-02-10

Added

• Cell merging — WorksheetData.mergeCells(CellRange) / unmergeCells(CellCoordinate) with MergedCellRegistry for merge-aware rendering. Anchor cell keeps its value; non-anchor cells are cleared. Gridlines suppressed across merge interiors. Rendering spans the full merged bounds.
• Rich text spans — Cell.text('...', richText: [TextSpan(...)]) for inline bold, italic, underline, color, and strikethrough within a single cell. WorksheetData.getRichText() / setRichText() API. Inline editing with Ctrl+B/I/U/Shift+S formatting shortcuts.
• Multi-line cell text — CellStyle.wrapText now fully supported end-to-end: TilePainter, FrozenLayer, and cell editor all respect wrapText. Alt+Enter inserts a newline during editing when wrapText is true. Editor grows vertically to fit content.
• Auto-detect date format from user input — when a date like 1/15/2024 or 15-Jan-24 is typed, the display format is preserved via round-trip matching against candidate CellFormats
• DateFormatDetector utility class for detecting which CellFormat matches a user-typed date string
• FormatLocale.dayFirst field — resolves ambiguous numeric dates (e.g., 01/02/2024 → Jan 2 in US, Feb 1 in UK)
• Worksheet.formatLocale parameter — passes locale to EditController for date format detection
• 7 new date format presets: dateShortLong (d-mmm-yyyy), dateLong (d mmmm yyyy), dateEu (d/m/yyyy), dateUsDash (m-d-yyyy), dateEuDash (d-m-yyyy), dateUsDot (m.d.yyyy), dateEuDot (d.m.yyyy)
• CellFormatResult class — rich formatting result with optional color override from format codes like [Red] or [Color3]
• CellFormat.formatRich() method — returns CellFormatResult with text and optional color (vs format() which returns plain text)
• FormatLocale class with 6 built-in locales (enUs, enGb, deDe, frFr, jaJp, zhCn) — locale-aware decimal/thousands separators, currency symbols, and month/day names
• Comprehensive Excel custom format engine: conditional sections ([>100]), color codes ([Red], [Color3]), bracket metadata ([$EUR] currency override), comma-as-scaler, * repeat fill, fractional seconds, fraction denominator constraints

Fixed

• Zero-padded date formats (e.g., 01/02/2024) and yyyy-mmm-dd patterns now detected correctly by DateFormatDetector

Changed

• onCommit callback signature now includes optional {CellFormat? detectedFormat} parameter across EditController, CellEditorOverlay, and Worksheet
• Worksheet commit handlers auto-apply detected date format via data.setFormat() when no explicit format exists
• FrozenLayer now respects CellStyle.wrapText (previously hardcoded maxLines: 1)

1.10.0 - 2026-02-09

Changed

• Rewrote date/time formatter with token-based pipeline for correct context-sensitive m/mm disambiguation
• Reworked CellEditorOverlay to use Transform.scale at base font size (matching tile painter's GPU scaling) with glyph-based cursor height
• Editor overlay now clips behind headers using a positioned Stack

Added

• mmmmm format token — first letter of month name
• A/P and a/p format tokens — abbreviated AM/PM markers
• s format token — unpadded seconds
• mmmm and dddd/ddd format tokens now handled via tokenizer (previously worked but fragile)
• Bundled full Roboto font family (Regular, Bold, Italic, BoldItalic) for bold/italic cell styling
• CellStyle.defaultFontFamily constant and WorksheetThemeData.resolveFontPackage() for correct package font resolution
• CellStyle.implicitAlignment() — Excel-like value-type alignment (numbers/dates right, text left) when no explicit alignment is set

1.9.0 - 2026-02-08

Added

• Selective cell clearing via ClearCellsIntent flags (clearValue, clearStyle, clearFormat) — clear values, styles, or formats independently while preserving the rest
• Ctrl+\ / Cmd+\ keyboard shortcut for "Clear Formatting" (removes styles and formats, keeps values)

1.8.0 - 2026-02-08

Added

• CellValueType.duration and CellValue.duration() for storing elapsed time / duration values
• Cell.duration() constructor and WorksheetDuration extension (.cell on Duration)
• CellFormatType.duration with Excel-style bracket notation format codes ([h]:mm:ss, [h]:mm, [m]:ss, [s])
• 3 duration format presets: CellFormat.duration, CellFormat.durationShort, CellFormat.durationMinSec
• Duration formatting engine supporting bracketed accumulating units and negative durations

1.7.0 - 2026-02-08

Added

• Cell border styling with line styles (solid, dotted, dashed, double) and BorderResolver for adjacent-cell conflict resolution matching Excel/Sheets rules
• BorderPainter utility for rendering all border line styles in tiles and frozen layers
• keepAnchorVisible on WorksheetController — automatically adjusts scroll when zoom changes so the selected cell stays visible and fully in view
• copyWith methods on BorderStyle and CellBorders

1.6.3 - 2026-02-08

Fixed

• Virtual keyboard now appears immediately on double-tap editing on iOS Safari — moved cell editor overlay outside gesture interceptors and added synchronous focus trigger to satisfy Safari's user-gesture requirement
• Cell editor overlay uses dedicated FocusScope to ensure autofocus fires independently of the worksheet's existing focus tree

1.6.2 - 2026-02-06

Added

• Worksheet automatically scrolls to center the editing cell vertically when virtual keyboard appears, keeping it visible above browser URL bars and other UI elements

1.6.1 - 2026-02-06

Fixed

• Keyboard navigation now works immediately after editing completes on all platforms (web, macOS, mobile)
• Focus restoration uses explicit FocusNode and post-frame callback to avoid timing conflicts with tap events
• Software keyboard reliably activates on mobile when cell editing starts

1.6.0 - 2026-02-06

Added

• CellEditorOverlay now respects per-cell styles (font size, family, weight, style, color, text alignment) to match the tile-rendered cell appearance
• autofocus: true on cell editor TextField to ensure software keyboard activates on mobile

Fixed

• Gridlines and selection borders snap to half-pixel positions (+0.5) for crisp 1px rendering on Impeller — prevents gray anti-aliased lines
• Removed devicePixelRatio strokeWidth adjustment that caused sub-pixel blending artifacts
• Cell editor overlay text now aligns precisely with cell content using measured TextPainter height
• Cursor height matches font size instead of default line height
• Double-tap to edit places cursor at end instead of selecting all text (F2 still selects all)
• Focus returns to worksheet after editing instead of previous widget (e.g., zoom slider)

Changed

• Default gridline color changed to 0xFFD4D4D4

1.5.0 - 2026-02-03

Added

• CellValue.parse() — unified static factory that detects type from text input (formula, boolean, number, date, text) with consistent behavior across editing and clipboard paste
• Worksheet.dateParser parameter — configures date format detection via AnyDate from the any_date package; supports locale-based parsing (e.g., AnyDate.fromLocale('en-US') for month/day/year)
• Date detection during editing and clipboard paste — typing 2025-01-15 or Jan 15, 2025 now commits as CellValue.date() instead of text
• Re-exported AnyDate and DateParserInfo from worksheet.dart so consumers don't need a direct any_date dependency

Changed

• EditController._parseText now delegates to CellValue.parse() for consistent type detection
• TsvClipboardSerializer._parseValue now delegates to CellValue.parse(allowFormulas: false) — clipboard paste no longer interprets = prefix as a formula, trims whitespace, and uses case-insensitive boolean detection
• TsvClipboardSerializer constructor accepts optional dateParser parameter
• Worksheet.clipboardSerializer is now nullable (defaults to TsvClipboardSerializer with the widget's dateParser)

Fixed

• Clipboard paste boolean detection was case-sensitive (true worked but TRUE did not) — now case-insensitive
• Clipboard paste did not trim whitespace — now trims consistently
• Clipboard paste used num.tryParse while editing used double.tryParse — both now use double.tryParse

1.4.0 - 2025-02-02

Added

• Flutter Shortcuts / Actions pattern for keyboard handling — enables consumers to override, extend, or remap any keyboard shortcut
• Worksheet.shortcuts parameter — custom shortcut bindings merged on top of defaults
• Worksheet.actions parameter — custom action overrides merged on top of defaults
• DefaultWorksheetShortcuts — static map of ~44 default shortcut bindings (both control: and meta: variants for cross-platform)
• 13 Intent classes (MoveSelectionIntent, GoToCellIntent, ClearCellsIntent, etc.)
• 13 Action classes with WorksheetActionContext interface for dependency injection
• WorksheetActionContext — abstract interface implemented by the widget state, avoiding 6+ constructor params per Action
• New shortcuts: Ctrl+C/X/V (copy/cut/paste), Ctrl+D (fill down), Ctrl+R (fill right), Delete/Backspace (clear cells)
• Worksheet.editController parameter for integrated cell editing — renders CellEditorOverlay internally, handles type-to-edit, commit-and-navigate, and F2/double-tap editing
• Type-to-edit: printable characters start editing the focused cell with that character as initial content
• Commit-and-navigate: Enter (down), Shift+Enter (up), Tab (right), Shift+Tab (left) commit the edit and move selection
• CellEditorOverlay.onCommitAndNavigate callback for directional commit with row/column delta
• Arrow keys commit the edit and navigate when editing (via CellEditorOverlay)
• Tap outside the editing cell commits the current edit
• EditCommitResult value class on EditController
• Backspace/Delete tests for editing vs navigation mode

Deprecated

• KeyboardHandler class — use the Shortcuts / Actions pattern instead (see worksheet_intents.dart)

Changed

• Worksheet widget now uses Shortcuts -> Actions -> Focus widget tree instead of Focus(onKeyEvent:) with KeyboardHandler
• Destructive actions (ClearCells, Cut, Paste, FillDown, FillRight) check readOnly in isEnabled() as defense-in-depth
• Cell-level actions (copy, cut, paste, clear, select-all) are disabled while the editController is editing, so Ctrl+C/X/V/A and Backspace/Delete reach the text field for in-cell editing
• CellEditorOverlay uses TextField with InputDecoration.collapsed for proper cursor rendering, text selection, and double-click word selection
• Parent double-tap handler suppressed while editing so the TextField's word-select gesture wins the gesture arena
• Pointer-down within the editing cell is passed through to the TextField for cursor repositioning instead of committing the edit
• TilePainter.editingCell field hides tile-rendered text for the cell being edited (avoids double rendering)

1.3.0 - 2025-02-02

Added

• WorksheetController.getCellScreenBounds() — returns screen-space Rect for a cell, accounting for zoom, scroll offset, and headers
• WorksheetController.ensureCellVisible() — simplified scroll-to-cell that uses the attached layout
• WorksheetController.hasLayout / layoutSolver / headerWidth / headerHeight — public read access to the widget's internal layout state
• WorksheetController.attachLayout() / detachLayout() — called by the Worksheet widget to share its internal LayoutSolver

Fixed

• Cell text disappearing on alternating rows after column resize — cell backgrounds straddling a tile boundary overflowed into adjacent tiles because PictureRecorder cullRect is only a hint; added hard clipRect to tile canvas
• Deferred TextPainter disposal until after PictureRecorder.endRecording() to prevent premature native Paragraph resource release

Changed

• Worksheet widget now attaches its LayoutSolver and header dimensions to the controller after initialization
• Simplified _ensureSelectionVisible in Worksheet to use ensureCellVisible
• Example app no longer creates a duplicate LayoutSolver; uses controller.getCellScreenBounds() instead
• Updated GETTING_STARTED.md, COOKBOOK.md, API.md, and ARCHITECTURE.md to reflect the new API

1.2.0 - 2025-01-30

Added

• CellFormat class with Excel-style format codes for cell display formatting
• 16 built-in format presets (currency, percentage, date, scientific, fraction, etc.)
• CellFormatType enum with 12 format categories
• Cell.format field for per-cell formatting
• Cell.displayValue getter — uses format when present
• Cell.copyWithFormat() method
• WorksheetData.getFormat()/setFormat() with backward-compatible defaults
• SparseWorksheetData format storage with change events and batch support
• DataChangeType.cellFormat event type

Changed

• TilePainter and FrozenLayer use CellFormat when rendering cell content
• Cell.isEmpty considers format field

Deprecated

• CellStyle.numberFormat — use CellFormat on Cell instead

1.1.0 - 2025-01-27

Added

• Built-in keyboard navigation in Worksheet widget (arrow keys, Tab, Enter, Home/End, PageUp/Down, F2, Escape, Ctrl+A)
• 18 widget-level keyboard navigation tests
• Release process checklist in CLAUDE.md

Fixed

• Selection and header layers now repaint on selection change (CustomPainter repaint listenable)

Changed

• Simplified example/main.dart by removing manual keyboard handling code
• Updated COOKBOOK.md keyboard navigation section to reflect built-in support

1.0.1 - 2025-01-25

Added

• Screenshot in README.md via golden test
• GitHub Actions CI workflow for automated testing
• Codecov integration for coverage reporting
• Roboto font bundled for consistent text rendering

Fixed

• Resolved all dart analyzer warnings in lib/ and test/
• Fixed installation instructions to use pub.dev version
• Golden tests excluded from CI (platform-dependent font rendering)

Changed

• README badges: pub.dev version, license, CI status, coverage

1.0.0 - 2025-01-25

Added

• Example application with 50,000 rows of sample sales data
• Performance benchmarks for tile rendering (< 8ms target)
• Performance benchmarks for hit testing (< 100μs target)
• Scroll performance benchmarks
• Large dataset integration tests
• Memory leak tests
• Comprehensive documentation suite:
  • ARCHITECTURE.md with rendering pipeline deep dive
  • GETTING_STARTED.md with installation and basic usage
  • COOKBOOK.md with practical recipes
  • PERFORMANCE.md optimization guide
  • THEMING.md customization guide
  • TESTING.md testing patterns
  • API.md quick reference
• Updated PLAN.md to reflect completed implementation

Changed

• Version bumped to 1.0.0 for production release

0.9.0 - 2024-01-24

Added

• WorksheetWidget - Main public StatefulWidget
• WorksheetController - Programmatic control aggregating sub-controllers
• WorksheetThemeData - Complete theming and styling support
• WorksheetTheme - InheritedWidget for theme propagation
• Complete public API exports in worksheet.dart
• Gesture handling integration
• Layer composition using Stack

0.8.0 - 2024-01-23

Added

• RenderLayer - Abstract interface for render layers
• SelectionLayer - Selection highlight painting
• SelectionRenderer - Selection visual rendering
• HeaderLayer - Row and column header layer
• HeaderRenderer - A,B,C column and 1,2,3 row labels
• FrozenLayer - Infrastructure for frozen panes (not fully wired)

0.7.0 - 2024-01-22

Added

• EditController - Cell editing orchestration with start/commit/cancel flow
• EditTrigger enum - Double-tap, keyboard, and typing triggers
• CellEditorOverlay - Floating text editor widget for cell editing

0.6.0 - 2024-01-21

Added

• SelectionController - Selection state machine with single/range/row/column modes
• HitTester - Coordinate resolution from screen to worksheet space
• HitTestResult - Types for cell, header, and resize handle hits
• GestureHandler - Unified gesture processing
• KeyboardHandler - Arrow keys and keyboard shortcuts
• ScaleHandler - Pinch-to-zoom gesture handling

0.5.0 - 2024-01-20

Added

• ZoomController - Zoom level management extending ValueNotifier
• Support for 10%-400% zoom range (0.1 to 4.0)
• zoomIn(), zoomOut(), and reset() methods
• Zoom clamping and validation

0.4.0 - 2024-01-19

Added

• ScrollAnchor - Position preservation during zoom
• WorksheetScrollPhysics - Custom scroll momentum physics
• ViewportDelegate - Interface for viewport management
• WorksheetViewport - TwoDimensionalScrollable integration
• WorksheetScrollDelegate - Child management for 2D scrolling

0.3.0 - 2024-01-18

Added

• TileCoordinate - Tile grid position representation
• TileConfig - Configuration with 256px tiles, LRU cache settings
• Tile - Single cached tile with GPU-backed ui.Picture
• TilePainter - Cell painting with level-of-detail (LOD) rendering
• TileCache - LRU eviction cache for tiles
• TileManager - Tile lifecycle orchestration

Performance

• GPU-backed tile caching for smooth scrolling
• Level-of-detail rendering based on zoom level
• LRU cache eviction to manage memory

0.2.0 - 2024-01-17

Added

• WorksheetData - Abstract interface for worksheet data access
• SparseWorksheetData - Map-based sparse storage implementation
• DataChangeEvent - Granular change events for reactive updates
• SpanList - Cumulative row/column sizes with O(log n) lookups
• LayoutSolver - Position to index conversion
• VisibleRangeCalculator - Viewport to CellRange queries
• ZoomTransformer - Zoom-aware coordinate math with ZoomBucket enum

Performance

• O(log n) binary search for position lookups
• Memory-efficient sparse data storage

0.1.0 - 2024-01-16

Added

• Initial project scaffolding
• CellCoordinate - Immutable (row, col) address with Excel notation (A1, AA100)
• CellRange - Rectangular cell selection with normalization and contains()
• CellValue - Union type supporting text, number, boolean, formula, error, date
• CellStyle - Font, color, alignment, and border styling
• FreezeConfig - Configuration for frozen panes
• Full test coverage for all core models
• CLAUDE.md development guide
• PLAN.md implementation plan

Technical

• TDD workflow with tests written before implementation
• SOLID principles applied throughout
• Immutable models with proper equality/hashCode