### Install qrlyzer via pip

Source: https://github.com/netlifeas/qrlyzer/blob/main/README.md

The standard method to install the qrlyzer package from the Python Package Index.

```bash
python -m pip install qrlyzer
```

--------------------------------

### Install qrlyzer via pip

Source: https://context7.com/netlifeas/qrlyzer/llms.txt

Command to install the qrlyzer package from the Python Package Index.

```bash
pip install qrlyzer
```

--------------------------------

### Detect and decode QR codes

Source: https://github.com/netlifeas/qrlyzer/blob/main/README.md

Demonstrates how to extract QR code content from image files or raw byte streams. Supports optional auto-resizing for improved detection performance.

```python
import qrlyzer

# From path
qr_codes = qrlyzer.detect_and_decode("my_image.jpg")
print(f"Found QR codes: {qr_codes}")

# From bytes
from PIL import Image
im = Image.open("my_image.jpg")
im = im.convert("L")
qr_codes = qrlyzer.detect_and_decode_from_bytes(im.to_bytes(), im.width, im.height)
print(f"Found QR codes: {qr_codes}")

# Auto-scaling
qrlyzer.detect_and_decode("my_image.jpg", auto_resize=True)
```

--------------------------------

### Detect and decode QR codes from file paths

Source: https://context7.com/netlifeas/qrlyzer/llms.txt

Demonstrates reading QR codes from image files. Includes basic usage, enabling auto-resize for large images, and error handling for missing files.

```python
import qrlyzer

# Basic QR code detection from file path
qr_codes = qrlyzer.detect_and_decode("image_with_qr.png")
print(f"Found QR codes: {qr_codes}")

# With auto-resize for improved detection on large images
qr_codes = qrlyzer.detect_and_decode("large_image.jpg", auto_resize=True)
print(f"Found QR codes: {qr_codes}")

# Handle case when no QR codes found
qr_codes = qrlyzer.detect_and_decode("no_qr_image.png")
if not qr_codes:
    print("No QR codes detected")

# Handle invalid file path
try:
    qrlyzer.detect_and_decode("nonexistent.png")
except OSError as e:
    print(f"Error: {e}")
```

--------------------------------

### Detect QR Codes from Bytes with Auto-Resize

Source: https://context7.com/netlifeas/qrlyzer/llms.txt

Demonstrates how to process image bytes using the detect_and_decode_from_bytes_with_bbox function with the auto_resize parameter enabled for high-resolution images.

```python
im = Image.open("poster_scan.png").convert("L")
results = qrlyzer.detect_and_decode_from_bytes_with_bbox(
    im.tobytes(),
    im.width,
    im.height,
    auto_resize=True
)
```

--------------------------------

### Define Type Aliases for QR Detection

Source: https://context7.com/netlifeas/qrlyzer/llms.txt

Defines standard type aliases for bounding boxes and decoded QR results to improve code readability and type safety.

```python
from typing import List, Tuple, TypeAlias

# Bounding box format: (x, y, width, height)
BoundingBox: TypeAlias = Tuple[int, int, int, int]

# Result with bounding box: (decoded_text, bounding_box)
DecodedQrWithBoundingBox: TypeAlias = Tuple[str, BoundingBox]
```

--------------------------------

### Detect QR codes with bounding box coordinates

Source: https://context7.com/netlifeas/qrlyzer/llms.txt

Scans images and returns both the decoded content and the (x, y, width, height) bounding box for each QR code found.

```python
import qrlyzer
from PIL import Image, ImageDraw

# Detect QR codes with bounding box coordinates
results = qrlyzer.detect_and_decode_with_bbox("document_with_qr.png")
for content, (x, y, width, height) in results:
    print(f"Content: {content}")
    print(f"Position: x={x}, y={y}, width={width}, height={height}")

# Draw bounding boxes on image for visualization
im = Image.open("document_with_qr.png")
draw = ImageDraw.Draw(im)
results = qrlyzer.detect_and_decode_with_bbox("document_with_qr.png")
for content, (x, y, w, h) in results:
    draw.rectangle([x, y, x + w, y + h], outline="red", width=3)
    draw.text((x, y - 20), content, fill="red")
im.save("annotated_output.png")
```

--------------------------------

### Extract QR codes with bounding boxes

Source: https://github.com/netlifeas/qrlyzer/blob/main/README.md

Retrieves both the decoded content and the spatial coordinates (x, y, width, height) of detected QR codes.

```python
results = qrlyzer.detect_and_decode_with_bbox("my_image.jpg")
for content, (x, y, width, height) in results:
    print(content, x, y, width, height)

results = qrlyzer.detect_and_decode_from_bytes_with_bbox(
    im.tobytes(), im.width, im.height
)
```

--------------------------------

### Detect and decode QR codes from raw bytes

Source: https://context7.com/netlifeas/qrlyzer/llms.txt

Processes raw grayscale image bytes to detect QR codes. Requires image data in 'L' mode and explicit width/height parameters.

```python
import qrlyzer
from PIL import Image

# Load image and convert to grayscale bytes
im = Image.open("qr_code.png").convert("L")
qr_codes = qrlyzer.detect_and_decode_from_bytes(
    im.tobytes(),
    im.width,
    im.height
)
print(f"Found QR codes: {qr_codes}")

# With auto-resize for difficult images
im = Image.open("large_qr_image.png").convert("L")
qr_codes = qrlyzer.detect_and_decode_from_bytes(
    im.tobytes(),
    im.width,
    im.height,
    auto_resize=True
)
print(f"Found QR codes: {qr_codes}")
```

--------------------------------

### Process and Validate QR Code Detection Results

Source: https://context7.com/netlifeas/qrlyzer/llms.txt

Iterates through detection results to display content and bounding box coordinates, and validates that detected boxes reside within image boundaries.

```python
for idx, (content, (x, y, w, h)) in enumerate(results):
    print(f"QR Code {idx + 1}:")
    print(f"  Content: {content}")
    print(f"  Bounds: ({x}, {y}) - ({x + w}, {y + h})")

for content, (x, y, w, h) in results:
    assert x >= 0 and y >= 0
    assert x + w <= im.width
    assert y + h <= im.height
    print(f"Valid QR: {content}")
```

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