blue_thermal_plus 0.2.0

Flutter plugin for thermal printer discovery and raw printing over BLE, Bluetooth Classic, Brother Print SDK, Honeywell PrinterSDK, and Epson ePOS.

📦 BlueThermal Plus --- Flutter Bluetooth Thermal Printer Plugin

A high-performance Flutter plugin for printing to thermal printers over Bluetooth Low Energy (BLE) and Bluetooth Classic (SPP) on Android and iOS.

Built with a clean transport-layer architecture for reliability, scalability, and production-grade stability.

✨ Features

• BLE printing with MTU-aware chunking\
• Bluetooth Classic (SPP) support\
• Automatic MTU negotiation\
• Smart data chunking & retry system\
• Auto-disconnect after print\
• Real-time device discovery events\
• Unified transport interface\
• Epson ePOS SDK transport on iOS (optional SDK install)\
• Honeywell RP2f/RP4f PrinterSDK routing on iOS (optional SDK install)\
• Brother Print SDK routing on Android and iOS (optional SDK install)\
• Production tested

📱 Supported Platforms

Platform	BLE	Classic	Brother Print SDK	Honeywell PrinterSDK	Epson ePOS
Android	✅	✅	✅	Native Classic path	❌
iOS	✅	✅ (MFi)	✅	✅	✅

🧠 Architecture

Flutter → TransportRouter → PrinterTransportManager → (BleTransport / ClassicTransport / Brother Print SDK bridge / HoneywellPrinterSDK bridge / EpsonEposTransport)

🚀 Installation

dependencies:
  blue_thermal_plus: ^0.1.3

Then run:

flutter pub get

📡 Basic Usage

import 'package:blue_thermal_plus/blue_thermal_plus.dart';

final printer = BlueThermalPlus();
await printer.startScan();
await printer.connect(deviceId: deviceId);
await printer.printRawBytes(bytes);

⚙️ BLE Config Example

await printer.configure(const PrinterConfig(
  ble: BleConfig(
    chunkSize: 200,
    chunkDelayMs: 10,
    autoDisconnectMs: 3000,
  ),
));

🧾 Epson TM-P80II on iOS

Epson printers such as TM-P80II_001379 should use the iOS Epson ePOS SDK transport instead of the Zebra BLE UUID transport:

final printer = BlueThermalPlus();

await printer.configure(PrinterProfiles.epsonTmP80II);
await printer.startScan(transport: PrinterTransport.epson);
await printer.connect(
  deviceId: device.id,
  transport: PrinterTransport.epson,
);
await printer.printRawBytes(bytes, transport: PrinterTransport.epson);

The Epson SDK binary is not bundled or published with this package. Download Epson ePOS SDK for iOS from Epson and copy libepos2.xcframework to the consuming app:

your_app/ios/Frameworks/libepos2.xcframework

If you are developing this plugin locally, you can also place it in:

blue_thermal_plus/ios/Frameworks/libepos2.xcframework

Then run pod install in the iOS app:

cd ios
pod install

If the printer uses Bluetooth Classic MFi, add Epson's external accessory protocol in the app Info.plist:

<key>UISupportedExternalAccessoryProtocols</key>
<array>
  <string>com.epson.escpos</string>
</array>

Keep com.zebra.rawport in the same array if your app also supports Zebra. For BLE Epson discovery, use EpsonPortType.bluetoothLe; for mixed discovery, the default profile uses EpsonPortType.all.

For TCP discovery/printing on iOS, your app may also need the local network privacy keys used by iOS 14+:

<key>NSLocalNetworkUsageDescription</key>
<string>This app uses the local network to discover and connect to printers.</string>

If the Epson SDK is missing, PrinterTransport.epson remains available but emits an error event explaining that libepos2.xcframework was not found.

🧾 Honeywell RP2f/RP4f on iOS

Honeywell RP2f/RP4f printers remain on PrinterTransport.classic. When the paired accessory announces com.honeywell.print and the official SDK is installed, the plugin automatically routes connect/write/disconnect through Connection_BluetoothEA. No Honeywell-specific Dart transport is required.

Use the explicit RP4f profile before scanning and connecting:

final printer = BlueThermalPlus();

await printer.configure(PrinterProfiles.honeywellRp4f);
await printer.startScan(transport: PrinterTransport.classic);
await printer.connect(
  deviceId: device.id,
  transport: PrinterTransport.classic,
);
await printer.printRawBytes(bytes, transport: PrinterTransport.classic);

The Honeywell binary is not bundled or published with this package. Copy the official HoneywellPrinterSDK.xcframework to the consuming app:

your_app/ios/Frameworks/HoneywellPrinterSDK.xcframework

Because CocoaPods requires vendored frameworks to be relative to the plugin, call the package installer after flutter_install_all_ios_pods in the app Podfile:

target 'Runner' do
  use_frameworks!
  flutter_install_all_ios_pods File.dirname(File.realpath(__FILE__))

  plugin_ios_dir = File.expand_path(
    File.join(__dir__, '.symlinks', 'plugins', 'blue_thermal_plus', 'ios')
  )
  require File.join(plugin_ios_dir, 'prepare_optional_sdks.rb')
  BlueThermalPlusSdkInstaller.prepare(
    app_ios_dir: __dir__,
    plugin_ios_dir: plugin_ios_dir,
  )
end

Add the protocol to the app Info.plist, preserving any Zebra/Epson entries:

<key>UISupportedExternalAccessoryProtocols</key>
<array>
  <string>com.zebra.rawport</string>
  <string>com.epson.escpos</string>
  <string>com.honeywell.print</string>
</array>

Honeywell PrinterSDK 3.1.109 requires iOS 15.2 or newer. Without the SDK, the plugin keeps a direct EASession fallback for com.honeywell.print.

🧾 Brother RJ-4235B

Brother printers remain on PrinterTransport.classic. Select the explicit profile so the native layer uses Brother's SDK while keeping the raw CPCL byte payload unchanged:

final printer = BlueThermalPlus();

await printer.configure(PrinterProfiles.brotherRj4235B);
await printer.startScan(transport: PrinterTransport.classic);
await printer.connect(
  deviceId: device.id,
  transport: PrinterTransport.classic,
);
await printer.printRawBytes(bytes, transport: PrinterTransport.classic);

The proprietary SDK binaries are intentionally not included in this package. Download Brother Print SDK 4.13.2 (or a compatible version accepted under Brother's license), then place the files in the consuming app:

your_app/android/Frameworks/BrotherPrintLibrary.aar
your_app/ios/Frameworks/BRLMPrinterKit.xcframework

Use the same Podfile installer shown above for iOS and add Brother's MFi protocol to the app Info.plist:

<key>UISupportedExternalAccessoryProtocols</key>
<array>
  <string>com.brother.ptcbp</string>
</array>

The Android integration loads the AAR from the host app without making the proprietary SDK a required plugin dependency. Add it to the host application's Gradle dependencies (Kotlin DSL example):

dependencies {
  implementation(files("../Frameworks/BrotherPrintLibrary.aar"))
}

On iOS, the bridge requires iOS 14 or newer and reports an explicit error when the framework is absent.

📢 Events

scanStarted, deviceFound, connected, ready, status, error, disconnected

🧪 Testing

Flutter contract tests + native core logic + real device integration.

👨‍💻 Author

Mateus Polonini Cardoso

📄 License

MIT