esc_pos_dart 1.4.1

ESC/POS thermal WiFi printer support for Dart (non-Flutter dependent).

1.4.1

• CapabilityProfile: the capabilities are now embedded in the Dart source instead of loaded from package:esc_pos_dart/resources/capabilities.json. Fixes Unsupported operation: Isolate.resolvePackageUriSync on Flutter apps (issue #10).
• Removed dependency: resource_portable.

1.4.0

• DecoderEscPos:

  • New options: lenient, textDecoding (EscPosTextDecoding.latin1/codeTable), defaultCodeTable, detectUtf8, maxBarcodeDataLength. Defaults keep the previous (strict, latin1) behavior.
  • Lenient mode never throws: unknown/invalid commands → CommandEscPosUnknown, a command truncated at the end of the data → CommandEscPosTruncated (see warnings: DecoderWarning). Ignorable control chars are dropped.
  • Streaming API: add(chunk) + close() (a command split between chunks is decoded when complete); decode is a complete block. New commands, consumedBytes, pendingBytes.
  • Bounds-checked parsing: truncated data throws a FormatException (strict) instead of a RangeError.
  • Decodes the ESC/GS/FS/DLE commands sent by POS software and by GeneratorEscPos itself (previously a FormatException): underline, reverse, turn90, upside-down, double-strike, print mode (ESC !), feed dots, raster images (GS v 0, GS ( L, GS 8 L), barcodes (GS k, both forms) and settings, QR Codes (GS ( k), cash drawer (ESC p, DLE DC4), beeper, Kanji (FS &/FS .), international charset, status requests (DLE EOT, GS r, GS a, GS I, ESC u, ESC v), and many generic/setup commands (skipped with their parameters).
  • New commands (with toJson/fromJson): CommandEscPosUnderline, CommandEscPosReverse, CommandEscPosTurn90, CommandEscPosUpsideDown, CommandEscPosDoubleStrike, CommandEscPosPrintMode, CommandEscPosFeedDots, CommandEscPosRasterImage (toImage()), CommandEscPosBarcode, CommandEscPosBarcodeSetting, CommandEscPosQRCode, CommandEscPosDrawer, CommandEscPosBeep, CommandEscPosKanji, CommandEscPosIntlCharset, CommandEscPosStatusRequest, CommandEscPosUnknown, CommandEscPosTruncated.
  • CommandEscPosBitImage.toImage(): decodes the column format (scaled to the printer resolution).
  • CommandEscPosCut: optional feed (GS V 65..104 n); GS V '0'/'1' and ESC i/ESC m decoded.
  • Fixed: GS ! with bytes >= 0x80 (crash); ESC a '2' (right); bold uses the low bit; text pending before an end of job (FF) is now emitted before end_job (was emitted after it).

• EscPosToPrinterDocument (new): converts decoded commands into PrinterDocuments (text lines with styles, HR, feeds, tabs/absolute positions, images, barcodes, QR Codes; split by cut/end of job).

• PrinterDocument:

  • New commands: PrinterCommandBarcode, PrinterCommandQRCode (PrinterCommandType.barcode/qrcode).
  • fromJson: new ignoreUnknownCommands parameter.

• Barcode.raw and BarcodeType.fromValue/name.

• getCharsetDecoder, getCharsetCodePage and CharCodeTableEscPos.decoder.

• GeneratorEscPos.imageRaster(imageFn: PosImageFn.graphics): GS ( L width (xL xH) is now in dots (was bytes).

• NetworkPrinter.ensureConnected: no Future returned inside the try block.

• New tests: test/decoder_esc_pos_test.dart (sequences, generator round-trips with pixel comparison, JSON, truncated prefixes, fuzz, streaming split at every byte, code tables, converter end-to-end).

• Fixes (review):

  • GeneratorEscPos:
    • Images: any input format (grayscale/1-channel, palette, 16-bit...) is normalized to 8-bit RGBA, with transparent pixels as white. 1-channel images used to print all white (image) or black (imageRaster), and transparent pixels black (imageRaster).
    • image (ESC *): no extra blank stripe when the height is a multiple of 24.
    • imageRaster: GS v 0 density bits fixed (horizontal/vertical were swapped); graphics data larger than 64 KB uses GS 8 L (4-byte length; was truncated).
    • _intLowHigh: correct maximum ((1 << 8n) - 1; the operator precedence allowed overflowing values).
    • row: the overflowing text of a column is printed in the next rows (was dropped); no infinite recursion when a column can't hold 1 char; mixed Chinese text: one position per column; positions encoded with _intLowHigh (removed the hex dependency).
    • Code tables: the text is encoded with the code table sent to the printer (ESC t) by reset, setGlobalCodeTable and setStyles(codeTable:) (it was encoded as latin1 after a reset, e.g. é printed as Θ in CP437); selectCharCodeTable updates globalStyles.codeTable.
    • printCodeTable: restores the previous code table (forced) and prints only the printable bytes (32..255).
    • globalStyles starts with the printer defaults: a style (width, height, font, align) is restored after a styled text/image even without a reset.
    • feed/reverseFeed: values larger than 255 are split (were dropped / overflowed).
    • hr: linesAfter is applied (GenericPrinter.hr also forwards len).
  • QRCode: data larger than 252 bytes (2-byte pL pH; the length overflowed), maximum 7089 bytes.
  • Barcode: _convertData keeps all the chars of each element (Barcode.code128(['{A', '1'])).
  • NetworkPrinter:
    • Default port 9100 (was 91000, invalid).
    • A connection closed/reset by the printer doesn't crash the process (unhandled SocketException) and isConnected becomes false.
    • connect to another host/port reconnects; disconnect before connect doesn't throw.
    • disconnect flushes and closes the socket before destroying it (pending data was discarded); new flush.
    • transmissionOfStatus: timeout parameter (waited forever), ignores previously received bytes, returns null without a reply.
  • PrinterDocument.toString with no commands (threw StateError).
  • PrinterCommandImage.fromJson: optional mimeType (PNG/JPEG detected by signature) and align; raw RGB data length is validated.
  • PrinterCommandCut.fromJson: full defaults to true.
  • CapabilityProfile: getCodePageId is case-insensitive; new getCodePageName; capabilities.json is loaded once (cached).
  • DecoderEscPos (strict): after a FormatException the decoder can be reused (the invalid/truncated data was decoded again by the next call).
  • EscPosToPrinterDocument: ESC @ resets the barcode settings; the feed of a cut (cutFeedLines, default 4, added by Generator.cut) is not converted to a feed (document -> bytes -> document is now a fixed point).
  • New codePageCharset (profile code page name -> charset).

• Tests: generator_test.dart, network_printer_test.dart (integration: a local fake printer socket), models_test.dart (round trips document -> bytes -> document and JSON -> bytes). 101 tests; coverage 93.7% (was 77.2%).

1.3.2

• PrinterDocument:

  • Added fontType field with default 'a'.
  • Updated constructor to accept fontType parameter, normalizing to lowercase and trimming.
  • Updated fromJson and toJson to include fontType.
  • Updated print method to apply fontType along with fontSize in styles and printer commands.

• Generator:

  • Updated getCharsPerLine to accept named parameters and apply font width scaling conditionally.
  • Updated getCharWidth to pass named parameter maxCharsPerLine.
  • Updated hr method to calculate line length considering font width scaling.

1.3.1

• PrinterDocument:

  • print: added optional selectCharCodeTable parameter.
  • print: pass initial PosStyles with font size to printer.reset().
  • print: ensure fontSize style is applied via printer.setStyles().

• PrinterCommandStyle:

  • Changed all fields to nullable.
  • Added const constructor and defaults constructor.
  • fromJson: no longer provide default values; fields nullable.
  • toJson: serialize only non-null fields.
  • toPosStyles: treat null booleans as false; convert nullable width/height to PosTextSize or null.
  • Removed internal getPosTextSize method.

• GenericPrinter:

  • reset method now accepts optional PosStyles parameter and passes it to generator.

• DecoderEscPos:

  • Added support for GS command 0x21 to decode font size.
  • Added CommandEscPosFontSize command with width and height size parameters.
  • Updated CommandEscPos.fromJson to support font-size command.

• enums.dart:

  • Added PosTextSize.encodeSize to encode width and height into a single int.
  • Added PosTextSize.decodeSize to decode int into width and height PosTextSize values.

• Generator:

  • reset now accepts optional PosStyles parameter.
  • Added setAlign method with optional force parameter.
  • Updated setGlobalCodeTable and setFont to accept force parameter.
  • Updated setStyles to handle nullable width and height, and encode font size using PosTextSize.encodeSize.
  • Updated getCharWidth and getCharsPerLine to handle nullable width and global styles fallback.

• GeneratorEscPos:

  • Implemented reset with optional styles parameter, applying initial styles with defaults.
  • Implemented setAlign to update alignment if changed or forced.
  • Updated setStyles to handle nullable height and width, and encode font size accordingly.

• PosStyles:

  • Made height and width nullable.

  • Added copyWithDefaults method to fill null fields from defaults or parameters.

  • Updated constructors to allow nullable height and width.

  • PosTextSize:

    • Added static method withValue(int value) to return a PosTextSize enum matching the given value or null if none matches.

1.3.0

• PrinterDocument:

  • Added fontSize field with clamped range 1 to 8.
  • Updated constructor to accept optional fontSize parameter.
    • Breaking change: The constructor now uses named parameters.
  • Updated fromJson and toJson to handle fontSize.

• Generator:

  • Updated getCharsPerLine to adjust character count based on PosStyles.width scaling.

• Dependencies:

  • Updated image to ^4.8.0.
  • Updated test to ^1.30.0.
  • Updated dependency_validator to ^5.0.4.

1.2.1

• PrinterDocument:

  • print: added optional parameter selectCharCodeTable to select character code table before printing.

• GenericPrinter:

  • Added method selectCharCodeTable({int codeTable = 0}) to send ESC/POS command to select character code table.

• Generator (abstract):

  • Added methods and properties for character code table support:
    • selectCharCodeTable({int codeTable = 0})
    • int? get selectedCharCodeTable
    • String? get selectedCharset
    • CharsetEncoder? get selectedCharsetEncoder

• GeneratorEscPos:

  • Implemented character code table selection and tracking:
    • _selectedCharCodeTable, _selectedCharset, _selectedCharsetEncoder fields.
    • selectCharCodeTable updates selected table and charset encoder.
    • reset clears selected character code table.
  • Added enum CharCodeTableEscPos mapping ESC/POS code tables to charset names and encoders.
  • Updated text encoding to use selected charset encoder if available.

• char_encoder.dart:

  • Added comprehensive charset encoder resolution via getCharsetEncoder(String? name) using charset package.
  • Updated encodeChars to accept optional CharsetEncoder or charset name and fallback to latin1 or utf8 if encoding fails.

• Dependency updates:

  • Added charset: ^2.0.1
  • Updated image to ^4.7.2
  • Updated collection to ^1.19.1
  • Updated test to ^1.29.0
  • Updated dependency_validator to ^5.0.3
  • Updated coverage to ^1.15.0

1.2.0

• Migrate to image: ^4.5.4.

• image: ^4.5.4

• test: ^1.26.2

• dependency_validator: ^5.0.2

• coverage: ^1.14.1

1.1.3

• DecoderEscPos:

  • Fix decoding of Bit Image, calculating the correct data length.

• CommandEscPosBitImage:

  • Added field lineBreak.

• coverage: ^1.13.1

1.1.2

• Generator:

  • Fix getCharsPerLine to use styles.fontType.
  • cut: change parameter to extraLines = 4.
  • hr: fix call to getMaxCharsPerLine to use styles.fontType ?? globalFont.

• GeneratorEscPos:

  • Consider character margin for max characters per line.

• PrinterCommandHR:

  • Fix JSON: add parameter style.

• PrinterCommandImage:

  • Added decodeImage.
  • Fix JSON: add parameter mimeType.

1.1.1

• Generator:
  • cut: rollback default value for extraLines to 3. Most printers need at least 3 extra lines.

1.1.0

• Converted to Dart enums:

  • PaperSize, PosTextSize, PosBeepDuration.

• PosStyles:

  • align nullable.
  • fontType nullable.

• Generator now is a base class.

  • Added fields newLine and normalizeNewLines.
  • Renamed setGlobalFont to setFont.
  • Added styledBlock.
  • cut: parameter extraLines = 2.
  • globalFont now is a getter to globalStyles.fontType ?? PosFontType.fontA.
  • Implementation: GeneratorEscPos (ESC/POS)
    • Ensure that command styles won't affect global style.

• New Decoder and DecoderEscPos.

• PrinterCommandStyle:

  • Field align now is a PosAlign.
  • Field fontType now is a PosFontType.

• PrinterDocument:

  • print:
    • Added parameters reset and endJob.
    • Send a reset command before start printing.
    • Send a endJob command at the end of printing.
  • addHR: added parameter style.

• collection: ^1.19.0

• lints: ^5.1.1

1.0.6

🚀 Refactor: Refactor NetworkPrinter into GenericPrinter class. 🚀 New BytesPrinter.

• sdk: ^3.6.0

• resource_portable: ^3.1.2

• test: ^1.25.15

• coverage: ^1.11.1

• intl: ^0.20.2

1.0.5

• New encodeChars, to avoid encoding errors.

• Optimize imports.

• image: ^3.3.0

• resource_portable: ^3.1.0

• collection: ^1.18.0

• lints: ^4.0.0

• test: ^1.25.11

• dependency_validator: ^3.2.3

• coverage: ^1.11.0

• intl: ^0.20.1

1.0.4

• Fix NetworkPrinter.disconnect delay.

1.0.3

• Added support to optional command GS r (transmission of status).
• Added end job command.
• Added NetworkPrinter.ensureConnected.

1.0.2

• Added PrinterCommand.toString.
• Fixed load of resource: package:esc_pos_dart/resources/capabilities.json.
• collection: ^1.17.2

1.0.1

• New PrinterDocument.

1.0.0

• Dart pure version:
  • Adjusted for Dart 3.
  • Removed any Flutter dependency.
  • Fixed lints.
  • Added full printing example.

Original Work

This package is based on the packages esc_pos_printer and esc_pos_utils by Andrey Ushakov (andrey-ushakov@GitHub). Both packages are Flutter dependent, which makes it impossible to use in Dart pure applications.