pos_flutter_printer #

A Flutter plugin to print structured receipts (with text, images, QR codes, font styles, alignment, and margins) on Bluetooth POS printers.

🚀 Features #

• Print styled text with custom font, size, and alignment
• Print base64 images with align and width options
• Print QR codes with alignment and size
• Margin control (top and bottom)
• Supports Android Bluetooth POS printers
• Fully customizable via Flutter JSON-based structure

⚠️ Note: Make sure only one Bluetooth printer is paired with your POS terminal. The plugin automatically connects to the first paired device.

📦 Installation #

Add this plugin in your pubspec.yaml:

dependencies:
  pos_flutter_printer: ^1.0.0

🛠 Usage #

1. Import the plugin #

import 'package:pos_flutter_printer/pos_flutter_printer.dart';

2. Use it in your code #

3. Bill Receipt Example #

String formatRow(String item, int qty, double rate) {
  final total = (qty * rate).toStringAsFixed(2);
  return "${item.padRight(14).substring(0, 14)}"
      "${qty.toString().padLeft(4)}"
      "${rate.toStringAsFixed(2).padLeft(6)}"
      "${total.padLeft(8)}";
}

String generateDivider(String char, {int lineLength = 32}) {
  return List.filled(lineLength, char).join();
}

String leftRightAlign(String left, String right, {int totalWidth = 32}) {
  const spacer = ' ';
  int spaceCount = totalWidth - left.length - right.length;
  if (spaceCount < 1) {
    final allowedLeft = totalWidth - right.length - 1;
    left = left.substring(0, allowedLeft.clamp(0, left.length));
    spaceCount = 1;
  }
  return '$left${spacer * spaceCount}$right';
}

final lines = [
  {
    "text": "4Brains Technologies",
    "align": "center",
    "size": 1,
    "bold": true,
    "font": "RobotoMono-Regular.ttf",
  },
  {
    "text": "T0067, Vashi, MH",
    "align": "center",
    "size": 1,
    "font": "RobotoMono-Regular.ttf",
  },
  {
    "text": generateDivider('-'),
    "align": "left",
    "font": "RobotoMono-Regular.ttf",
    "size": 1,
  },
  {
    "text": "Item".padRight(14) +
             "Qty".padLeft(4) +
             "Rate".padLeft(6) +
             "Total".padLeft(8),
    "align": "left",
    "size": 1,
    "bold": true,
    "font": "RobotoMono-Regular.ttf",
  },
  {
    "text": formatRow("Pen", 2, 10.0),
    "align": "left",
    "size": 1,
    "font": "RobotoMono-Regular.ttf",
  },
  {
    "text": formatRow("Notebook", 1, 50.0),
    "align": "left",
    "size": 1,
    "font": "RobotoMono-Regular.ttf",
  },
  {
    "text": generateDivider('-'),
    "align": "left",
    "font": "RobotoMono-Regular.ttf",
    "size": 1,
  },
  {
    "text": leftRightAlign("Total", "₹ 100"),
    "bold": false,
    "size": 2,
    "marginTop": 10,
    "align": "left",
    "font": "RobotoMono-Regular.ttf",
  },
];

final result = await PosFlutterPrinter.print(
  lines: lines,
  topMargin: 40,
  bottomMargin: 60,
);

final lines = [
  {
    "text": "THANK YOU",
    "align": "center",
    "size": 4,
    "font": "Roboto-Regular.ttf",
    "bold": true
  },
  {
    "text": "Pawan Kumar",
    "align": "center",
    "bold": false,
    "size": 3,
    "font": "Roboto-Regular.ttf",
  },
  {
    "image": "BASE64_IMAGE_STRING",
    "width": 250,
    "align": "center"
  },
  {
    "qr": "https://4brains.in",
    "width": 200,
    "align": "center"
  }
];

final result = await PosFlutterPrinter.print(
  lines: lines,
  topMargin: 30,
  bottomMargin: 60,
);

print("Result: \$result");

Fonts #

Place your font file (e.g. Roboto-Regular.ttf) in:

android/src/main/assets/fonts/

Manifest Permissions #

In your plugin's AndroidManifest.xml:

<uses-permission android:name="android.permission.BLUETOOTH" />
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
<uses-permission android:name="android.permission.BLUETOOTH_CONNECT" />

🧩 Parameters for Each Line #

📋 License #

MIT License. Created by 4Brains Technologies.