excel_plus 1.0.0

Fast, low-memory Excel (.xlsx) library for Dart and Flutter to read, create, edit, and style spreadsheets. A drop-in replacement for the excel package.

1.0.0

First major release. A broad set of worksheet features built on the performance-focused engine (SAX streaming, lazy per-sheet loading, byte-for-byte archive reuse), with a single, contained breaking change. excel_plus remains a source-compatible drop-in for the excel package.

Breaking changes

• CellValue is now sealed and gains a CellErrorValue member. The only code affected is an exhaustive switch over a CellValue (it must now handle CellErrorValue). No other public type, method, or signature changed.

Migration

• Most projects need no changes. Cell read/write, styling, number formats, layout, and every existing colour API are source-compatible — recompile and go.
• If you switch exhaustively over a CellValue, add a CellErrorValue case, or replace the switch with value.isError / value.asError. Error cells that previously surfaced as text are now this typed value.
• Colour authoring is additive. Existing literal colours (ExcelColor.fromHexString, named constants, fromInt) behave exactly as before; theme/indexed authoring is opt-in via the new ExcelColor.theme / ExcelColor.indexed. CellStyle and Border now hold an ExcelColor internally rather than a hex string, but their constructors, getters, and setters are unchanged.
• Generated styles.xml is now more canonical for styled workbooks (theme/ indexed references where you author them, plus applyFont/applyFill/ applyBorder flags). Files open identically in Excel/Sheets; only update byte-exact snapshots of the output if you keep any.

Added

• Theme colour reading — <color theme="N" tint="X"/> references in font, fill, and border colours resolve to real ARGB from xl/theme/theme1.xml (with Excel's light/dark index swap and HSL tint) instead of falling back to black. The theme part round-trips on save.
• Indexed (palette) colour reading — legacy <color indexed="N"/> references resolve via the standard 64-colour palette, honouring a workbook's <indexedColors> override when present; the automatic system indices (64/65) fall back to the default colour.
• Theme & indexed colour authoring — ExcelColor.theme(ThemeColor.accentN, tint: x) and ExcelColor.indexed(n) write real <color theme="N" tint="X"/> / <color indexed="N"/> references for font, fill, and border colours, so authored colours stay linked to the document theme instead of baking in literal RGB. They resolve against the standard Office palette for display (colorHex), compare distinctly from a literal of the same ARGB, and round-trip.
• Hyperlinks (read + write) — external URLs / mailto: (Hyperlink.url, Hyperlink.email) and internal 'Sheet'!A1 jumps (Hyperlink.location), each with optional display text and tooltip. Set via sheet.setHyperlink(cell, link) or cell.hyperlink = …. External links manage the worksheet _rels automatically (allocating rIds and preserving any existing relationships).
• Data validation (read + write) — dropdown lists (DataValidation.list / .listFromRange), numeric and length bounds (DataValidation.wholeNumber, .decimal, .textLength with an operator), and custom-formula rules (DataValidation.custom), each with an optional input prompt and error message. Apply to a cell or range via sheet.setDataValidation(start, rule, end:) or cell.dataValidation = ….
• Sheet-view settings (read + write) — freeze panes (sheet.freezePanes(rows:, columns:) / unfreezePanes), gridline and row/column-header visibility (sheet.showGridLines, sheet.showRowColHeaders), and zoom (sheet.zoom). These now also survive a round-trip instead of being dropped on save.
• Autofilter (read + write) — sheet.setAutoFilter(from, to) adds header filter dropdowns over a range, sheet.removeAutoFilter() clears it, and sheet.autoFilter reads the range. Files opened with applied filter criteria keep them on save.
• Sheet protection (read + write) — sheet.protect(password:, allow:) locks editing while permitting the actions you list (SheetProtectionOption), sheet.unprotect() removes it, and sheet.isProtected / sheet.protectionAllowed read the state. Passwords use Excel's legacy hash (deters edits, not strong encryption); an opened file's existing hash is preserved on save.
• Sheet tab colour and visibility (read + write) — sheet.tabColor (an ExcelColor, resolving rgb/theme/indexed on read) and sheet.visibility (SheetVisibility.visible / hidden / veryHidden). An untouched theme/indexed tab colour round-trips as a reference rather than being down-converted.
• Sheet reordering — excel.moveSheet(name, toIndex:) reorders the worksheet tabs, and excel.sheetOrder reads the current order.
• Defined names / named ranges (read + write) — excel.setDefinedName(name, refersTo, localSheetId:) (global or sheet-scoped), excel.removeDefinedName(...), and excel.definedNames. Names can be used by FormulaCellValue.
• Conditional formatting (authoring) — sheet.addConditionalFormat(start, end, rule) with ConditionalFormat.greaterThan / .lessThan / .equalTo / .between / .formula (each applying a CellStyle via an auto-managed <dxf>), plus .colorScale (2/3-colour) and .dataBar. Rules already present in an opened file are preserved on save.
• CellErrorValue — error cells (#DIV/0!, #N/A, #REF!, #VALUE!, #NAME?, #NUM!, #NULL!) read from t="e" cells as a typed value and written back, instead of being coerced to text. Detect with CellValue.isError / CellValue.asError. (This is the source of the breaking change above.)
• FormulaCellValue.cachedValue — a formula's last cached result (<v>) is preserved on read and re-emitted on save (fixing the previously empty <v>), so formula cells keep a value until the app recalculates. Equality still compares the formula only.
• CellStyle.indent — alignment-side cell padding (OOXML <alignment indent="N">), with full read/write round-trip; negative values clamp to zero.

Fixed

• Rich-text write preservation — multi-run cells built with TextCellValue.span (bold/italic/underline/colour/size/font per run) are now written as <r> runs instead of being flattened to plain text, so in-cell formatting survives a read → save round-trip. Two runs with identical plain text but different styling also stay distinct.
• Authored styles that reuse an existing record — an authored style whose font/fill/border already exists in the opened file no longer reverts to the default (the appended <xf> resolves to the correct record), and applyFont/applyFill/applyBorder are emitted when the part is non-default.
• Illegal XML 1.0 control characters in cell text are stripped on save, so files no longer open as "corrupt" in Excel.
• Excel.findAndReplace returns the actual replacement count and accepts non-String targets without throwing.
• On the web, save() triggers the browser download under wasm builds (flutter build web --wasm), not only the JS compiler — the conditional import uses dart.library.js_interop, and the download Blob is constructed correctly for dart:js_interop.
• Underline styles read single vs double correctly, and bold/italic honour val="0" (explicitly-off) instead of always reading as enabled.
• The parser no longer crashes on out-of-range shared-string or style indexes, ISO-8601 (t="d") date cells, or namespace-prefixed worksheet XML (x:row, x:c).
• Cells without an explicit r reference are positioned by column order, and inline strings made of multiple runs keep all of their text.
• getColumnWidth / getRowHeight return Excel's defaults instead of throwing when a sheet defines no defaults.
• headerFooter is written in the schema-correct position (before drawing), so Excel no longer prompts to repair the file.

Improved

• More robust style parsing — malformed numFmt/border entries degrade gracefully instead of failing.

0.0.4

• Upgraded the xml dependency to ^7.0.1 and updated internal XML name handling for compatibility.
• Reworked the example app into a real workbook demo with import, inline editing, styling, sheet tools, and export flows.
• Added a dedicated Validation Lab screen, bundled workbook sample, and safer temp-directory fallback when platform storage plugins are unavailable.
• Improved the example web bootstrap so debug runs use a compatible renderer while wasm builds still opt into skwasm.

0.0.3

• Organized API docs into 5 categories: Core, Cell Values, Styling, Number Formats, Layout.
• Hidden internal APIs (Parser, ExcelWriter, FastList, etc.) from public documentation.
• Improved dartdoc comments across all public classes and methods.
• Cleaned up Excel class method docs with proper one-line summaries.

0.0.2

• Removed collection and equatable dependencies — reduced to 3 deps (archive, xml, web).
• Codebase cleanup: removed dead code, duplicate utilities, and redundant comments.
• Consolidated XML escaping into a single shared utility.
• Extracted common date/time fraction calculation helper.
• Fixed minimum xml constraint to ^6.3.0 for downgrade compatibility.

0.0.1

• Initial release.
• Performance-optimized fork of excel v5.0.0.
• SAX-based streaming parser replaces full DOM parsing for cell data and shared strings.
• Lazy sheet loading — sheets are parsed on first access, not at file open.
• O(1) cell style lookup via cached reverse index.
• Smart archive cloning — reuses unmodified ZIP entries instead of copying.
• Fixed-point span correction algorithm with early termination.
• 100% API compatible — drop-in replacement for the excel package.
• 76 unit tests + 13 integration tests on Android emulator.