📚 Automatic Mangas CBZ Spread Fuser

A Python script to automatically detect and merge double-page spreads in .cbz manga files, enhancing the reading experience.

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🚀 Features

• 📂 Automatic Extraction: Unzips .cbz files into a temporary folder.
• 🧠 Smart Spread Detection: Analyzes the left and right borders of images to detect spreads.
  • Skips merging if either edge is completely black (commonly used for flashbacks or transitions).
• 🖼️ Image Merging: Combines two consecutive pages side by side if they qualify as a spread.
• 📦 CBZ Repackaging: Generates a new .cbz file with the suffix _fused containing the merged pages.

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🔧 Requirements

• Python 3.x
• Pillow (PIL fork)

Install Dependencies

pip install pillow

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🛠️ Usage

1. Process a single .cbz file:

python spread_fuse.py /path/to/file.cbz

2. Process a folder containing multiple .cbz files:

python spread_fuse.py /path/to/folder

The script automatically detects whether the input is a file or a folder. All .cbz files in the folder will be processed.

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📁 Output Structure

For each .cbz file:

• Pages are extracted into a temporary folder.
• Consecutive images forming a spread are merged.
• A new .cbz file is created: original_name_fused.cbz.

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🧪 How It Works

1. Images are extracted and sorted alphabetically.
2. Each image is analyzed:
   • If both current and next image have visible (non-white) borders and are not mostly black → they are merged.
3. Merged images replace the original pair, and a new .cbz file is created with the updated content.

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⚙️ Technical Notes

• Spread detection is based on:
  • The percentage of black pixels on each border (default threshold: 45%).
  • Presence of at least one non-white pixel on both edges.
• Border size and thresholds can be adjusted directly in the script.

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🧼 Temporary File Cleanup

Temporary folders are not automatically deleted by default.
You can uncomment the shutil.rmtree(...) lines in the script to enable cleanup after processing.

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🧩 Potential Future Features

• GUI support for drag-and-drop usage.
• Command-line arguments to adjust thresholds.
• Support for .cbr and .rar files.

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📜 License

This script is open source. Feel free to use or modify it for personal projects, scanlation teams, or manga reading tools.