SwiftESCPOSPrinter

A Swift Package for generating image-based receipts and printing them to ESC/POS printers via TCP/IP.

Features

• Layout to Image: Convert NSAttributedString layouts to UIImage for printing.
• Image Processing: Automatically desaturates, resizes, and dithers images for thermal printing.
• ESC/POS Support: Sends standard GS v 0 raster commands compatible with most thermal printers (Epson, Star, generic).
• Network Printing: Connects directly to printers via IP address and Port.
• No External Dependencies: All necessary logic is included within the package.

Installation

Swift Package Manager

Add the following dependency to your Package.swift:

dependencies: [
    .package(url: "https://github.com/areeb111/SwiftESCPOSPrinter.git", from: "1.0.0")
]

Usage

1. Import the Package

import SwiftESCPOSPrinter
import UIKit // Required for UIImage and NSAttributedString

2. Create Receipt Content

Use NSMutableAttributedString to build your receipt layout. The package provides extensions for easy formatting.

let receipt = NSMutableAttributedString(string: "My Store\n", attributes: [.font: UIFont.boldSystemFont(ofSize: 30)])
receipt.appendCenter("123 Main St, City\n")
receipt.append("--------------------------------\n")
receipt.append("Item 1 ................. $10.00\n")
receipt.append("Item 2 ................. $20.00\n")
receipt.append("--------------------------------\n")
receipt.appendBold("Total .................. $30.00\n")
receipt.append("\n\n")

3. Print

Connect to the printer and send the data.

let printer = PrinterManager()
let printerIP = "192.168.1.100"
let printerPort: UInt16 = 9100

printer.connect(host: printerIP, port: printerPort) { success, error in
    guard success else {
        print("Connection failed: \(String(describing: error))")
        return
    }

    // Rasterize the receipt to an image (width 576 is standard for 80mm paper)
    if let image = receipt.rasterize(width: 576) {
        // Print using Raster mode (default, faster) or BitImage mode (ESC *, from Medium article)
        printer.print(image: image, mode: .raster) { error in
            if let error = error {
                print("Print failed: \(error)")
            } else {
                print("Printed successfully!")
                // Cut paper
                printer.cutPaper { _ in
                    printer.disconnect()
                }
            }
        }
    }
}

Print Modes

The print function supports two modes:

• .raster (Default): Uses GS v 0 command. Faster and recommended for modern printers.
• .bitImage: Uses ESC * command. Follows the implementation described in the Medium article. Useful for older printers or specific compatibility needs.

Requirements

• iOS 12.0+
• Swift 5.0+

License

MIT