PDF Compress Tool

Performs actual PDF compression, supporting both target size and percentage modes. Unlike existing solutions that only provide guidance, this tool compresses files directly.

Features

• - Two compression modes: target size (--target-size 2MB) / percentage (--reduce 30)
• Three-stage compression pipeline: pikepdf structural optimization → Ghostscript progressive compression → QPDF secondary optimization
• Quality floor protection: three levels (high / medium / low) to prevent excessive compression from damaging image quality
• Batch processing: compress all PDFs in a directory at once
• Auto dependency detection: detects available tools at runtime and adapts compression strategy accordingly

Usage

Compress to target size

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Compress by percentage

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Specify output path and quality

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Batch processing

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Compression Strategy

Stage 1: pikepdf structural optimization

Removes redundant objects, compresses streams, and packs object streams. Lossless operation that preserves maximum image quality.

Stage 2: Ghostscript progressive compression

Tries prepress → printer → ebook → screen progressively, checking at each level and stopping as soon as the target is met.
Also supports custom DPI downsampling (100 → 72 → 50 → 36 dpi), subject to quality floor protection.

Stage 3: QPDF secondary optimization

Object stream generation and stream recompression, saving an additional 5-15%. Requires qpdf installation (optional).

Quality floor protection

Dependencies

• - python3 (required)
• ghostscript (recommended): core compression engine
• qpdf (optional): secondary structural optimization, additional 5-15% compression
• pikepdf (auto-installed via pip): Python PDF library, fallback when Ghostscript is unavailable

Install by platform

The script auto-detects your platform and shows the correct install command when a dependency is missing.