custom_qr Library

The custom_qr library enables the generation and customization of QR codes with various options.

Installation

1. Install the library:

pip install custom_qr

2. Verify Installation:

pip list

Note: It is recommended to use a virtual environment.

Usage

1. Import the library:

from custom_qr import QrCode
from custom_qr import (
    ERROR_CORRECTION_LEVEL_H,
    ERROR_CORRECTION_LEVEL_Q,
    ERROR_CORRECTION_LEVEL_M,
    ERROR_CORRECTION_LEVEL_L
)

Note: Error correction level constants are optional. 2. Create a QR Code:

qr = QrCode()
matrix, version = qr.generate("https://www.qrcode.com/")

To specify a version and/or error correction level:

qr = QrCode()
matrix, version = qr.generate("https://www.qrcode.com/", version=6, error_correction=ERROR_CORRECTION_LEVEL_Q)

• Default Error Correction Level: Q (recovers 25% of data).
  • Default Version: Automatically calculated based on data size.

3. Print on Console:

qr.print_qr_console(matrix)

Note: Console output is not scannable. 4. Get Image Version:

img = qr.create_qr_image(matrix)

5. Display On Screen:

qr.display_qr(img)

6. Save Image:

qr.create_image_file(img, filename="qr.png")

Note: Default filename is "qr.png".

Custom QR Code Features

Color Usage in QR Codes

• Adding Text: Be cautious, as text may cover modules and hinder scannability.
• Contrast: Ensure sufficient contrast between blocks, background, and fixed patterns.
• Complexity: Avoid overly complex color schemes to maintain scanner compatibility.

Test QR codes with various devices to ensure scannability.

Customization Options

1. Background Color: Default is white.

background = (255, 255, 255)
qr.create_qr_image(matrix, background)

2. Block/Modules Style Options: Default size is 10, type square, and color black. Example:

block_style = {
    "size": 10,
    "type": 0,
    "color": [(0, 0, 0), (255, 0, 0)]  # Black and Red
}
qr.create_qr_image(matrix, block_style)

• size: Size of each module in pixels.
  • type: Shape of modules:
    • 0: Square blocks.
    • 1: Circular blocks.
  • color: List of RGB tuples for module colors.

3. Custom Circular Modules:

block_style = {
    "size": 10,
    "type": 1,  # Circular
    "color": [(0, 0, 0), (255, 0, 0)]  # Black and Red
}
qr.create_qr_image(matrix, block_style)

Finder and Alignment Pattern Colors

• Finder Pattern: Default color is the same of modules first color.

finder_style = {"color": (0, 0, 0)}
qr.create_qr_image(matrix, finder_style)

• Alignment Pattern: Defaults to the finder pattern's color if not specified.

alignment_style = {"color": (0, 0, 0)}
qr.create_qr_image(matrix, alignment_style)

Adding Custom Text

Overlay custom text on the QR code, but be mindful of potential readability issues:

• Text Style Options:
  • color: RGB tuple for text color.
  • size: Font size (currently only "small" is enabled).
  • bot: Bottom margin in blocks.
  • left: Left margin in blocks.
  • orientation:
    • 0: Write text from left.
    • 1: Write text from right.

Example:

text_style = {
    "color": (6, 123, 194),
    "size": "small",
    "bot": 10,
    "left": 3,
    "orientation": 0
}
text = "CUSTOM"
img = qr.create_qr_image(matrix)
qr.write_text(img, text, text_style, background, block_style["size"])

Write from Right:

text_style = {
    "color": (6, 123, 194),
    "size": "small",
    "bot": 10,
    "left": 30, # Left margin has to be greater than text width
    "orientation": 1  # Adjusted to write from right
}
text = "CUSTOM"
img = qr.create_qr_image(matrix)
qr.write_text(img, text, text_style, background, block_style["size"])

Note: Use higher versions and error correction levels to maintain validity when adding text. If the text is too large, write_text() will return None.