Swift QR Code Generator: EFQRCode Library for iOS and macOS

Swift QR Code Generator (iOS/macOS): EFQRCode Library

QR codes have become an integral part of modern applications — from authentication to sharing links and contacts. If you are developing for iOS or macOS in Swift, you don't need to write complex encoding algorithms from scratch. The ready-made EFQRCode library provides a convenient API for creating, reading, and customizing QR codes. In this article, we will explore its capabilities, installation, and usage examples.

What is EFQRCode?

EFQRCode is an open-source library written in Swift. It supports iOS (starting from version 9.0) and macOS (10.11+). Key features:

• Generate QR codes from strings, URLs, vCard contacts, and text.
• Customize color, background, size, and error correction level.
• Add watermarks (logos, images) to the center of the QR code.
• Create animated QR codes (GIF).
• Decode QR codes from images.

The library uses the built-in CIFilter from Core Image but adds many convenient wrappers and customizations.

Installation via Swift Package Manager

Add the EFQRCode package to your Xcode project:

// In Xcode: File → Add Packages...// Paste the repository URL:https://github.com/EFPrefix/EFQRCode.git// Select the version (recommended "Up to Next Major")

Or manually add the dependency in Package.swift:

dependencies: [    .package(url: "https://github.com/EFPrefix/EFQRCode.git", from: "6.0.0")]

Basic QR Code Generation Example

The simplest way to create a QR code from a string:

import EFQRCode

// Create a QR code from textif let image = EFQRCode.generate(    content: "https://pythonlib.ru",    size: EFIntSize(width: 300, height: 300)) {    // Use the image (CGImage) for display    // For example, in UIImageView on iOS:    let uiImage = UIImage(cgImage: image)    imageView.image = uiImage}

The result is a standard black-and-white QR code sized 300x300 pixels.

Customizing Color and Background

You can set custom foreground and background colors:

import EFQRCode

let qrImage = EFQRCode.generate(    content: "Hello, Swift!",    size: EFIntSize(width: 400, height: 400),    backgroundColor: UIColor.yellow.cgColor,    foregroundColor: UIColor.blue.cgColor,    inputCorrectionLevel: .h  // maximum error correction)

The inputCorrectionLevel parameter accepts values .l (7%), .m (15%), .q (25%), .h (30%). The higher the level, the more data can be recovered if damaged.

Adding a Logo (Watermark)

To place a logo in the center of the QR code, use the generateWithWatermark method:

import EFQRCode

let watermarkImage = UIImage(named: "logo")?.cgImagelet qrWithLogo = EFQRCode.generateWithWatermark(    content: "https://pythonlib.ru",    size: EFIntSize(width: 500, height: 500),    watermark: watermarkImage,    watermarkMode: .center)

Important: the logo should not occupy more than 30% of the area, otherwise the code may not be readable.

Creating an Animated QR Code (GIF)

EFQRCode supports generating animated QR codes. For example, you can create a GIF with changing colors:

import EFQRCode

let qrCodeGIF = EFQRCode.generateGIF(    content: "Animated QR",    size: EFIntSize(width: 200, height: 200),    data: [someData] // array of frames)

For simple animation, you can use predefined colors. See the library documentation for details.

Decoding a QR Code from an Image

To read a QR code from a photo or screenshot:

import