thermal_lib 0.0.1

Lightweight Bluetooth thermal printer helper for Flutter: list devices, connect, open drawer, print/save receipts from any widget.

thermal_lib

Lightweight Flutter helper for Bluetooth thermal printers.

• List paired Bluetooth devices
• Connect / disconnect
• Open cash drawer
• Print a receipt from any Flutter widget (offstage render)
• Save a receipt image (PNG) from any widget

Install

Add to your app pubspec.yaml:

dependencies:
  thermal_lib: ^0.0.1

If using a local path while iterating:

dependencies:
  thermal_lib:
    path: ../thermal_lib

Quick start

import 'package:thermal_lib/thermal_lib.dart';

// 1) List and connect
final devices = await ThermalPrinter.instance.listPaired();
await ThermalPrinter.instance.connect(devices.first.macAdress);

// 2) Print from any widget
await ThermalPrinter.instance.printReceipt(
  context,
  SizedBox(width: 288, child: MyReceiptWidget()),
);

// 3) Open drawer
await ThermalPrinter.instance.openDrawer();

// 4) Save receipt PNG
final path = await ThermalPrinter.instance.saveReceipt(
  context,
  SizedBox(width: 288, child: MyReceiptWidget()),
  'receipt.png',
);

// 5) Disconnect
await ThermalPrinter.instance.disconnect();

MyReceiptWidget can be any widget tree. The library renders it offstage, rasterizes it, and prints it as a bitmap for high compatibility with ESC/POS printers.

Notes

• Defaults target 80mm printers (≈576 px). Adjust logicalWidth, pixelRatio, and PaperSize as needed.
• Requires print_bluetooth_thermal for I/O and esc_pos_utils for raster output.

License

MIT