Lightweight QR Code Generator

Overview

Create a utility that generates QR codes without requiring the Pillow/PIL image library. The tool should output standard PNG files that can be viewed and scanned on any device.

Requirements

Your implementation must:

1. Generate QR codes as PNG files without using PIL/Pillow
2. Accept text data as input and encode it into a QR code
3. Support configurable QR code size and border width
4. Handle medium error correction level
5. Save the output to a specified file path

Constraints

• Must not depend on PIL/Pillow for image generation
• Output must be valid PNG files
• QR codes must be scannable by standard QR readers
• Use greyscale 1-bit format for the output

Dependencies { .dependencies }

qrcode { .dependency }

Python QR code generation library with multiple output format support.

pypng { .dependency }

Pure Python PNG encoder and decoder library.

Test Cases

Test Case 1: Basic QR Code Generation { @test }

File: test_qr_generator.py

Description: Generate a QR code with default settings

Input:

• Data: "Hello, World!"
• Output file: "test_output.png"

Expected Behavior:

• A PNG file is created at the specified path
• The file can be opened as a valid PNG image
• The QR code encodes the text "Hello, World!"
• No PIL/Pillow libraries are used in the process

Test Case 2: Custom Size and Border { @test }

File: test_qr_generator.py

Description: Generate a QR code with custom dimensions

Input:

• Data: "https://example.com"
• Output file: "custom_qr.png"
• Box size: 15 pixels per module
• Border: 2 modules

Expected Behavior:

• A PNG file is created with larger modules (15 pixels each)
• The border is 2 modules wide instead of the default
• The QR code correctly encodes the URL
• File is a valid PNG that can be scanned

Test Case 3: Longer Data { @test }

File: test_qr_generator.py

Description: Generate a QR code with more complex data

Input:

• Data: "The quick brown fox jumps over the lazy dog. Pack my box with five dozen liquor jugs."
• Output file: "long_data_qr.png"

Expected Behavior:

• The QR code automatically adjusts to accommodate the longer text
• Output is a valid, scannable PNG file
• No errors occur due to data length