PDF file compression is a common challenge. While many online services upload your documents to remote servers to compress them, I EDIT PDF handles everything directly inside your browser RAM. In this guide, we explore the difference between two advanced client-side compression methods: Canvas Rasterization and Ghostscript WebAssembly.
1. The Canvas Rasterization Method
This approach flattens the pages of your PDF into high-quality JPEG images. It is excellent for scanned documents or image-heavy PDFs because it reduces the resolution scale to save up to 90% of file size. However, it strips the text selection layer, rendering the text as flat graphics.
2. The Ghostscript WebAssembly Engine
For professional-grade compression, the Ghostscript WASM engine runs a compiled C/C++ engine locally. This preserves vector fonts, hyperlinks, text layers, and annotations while downsampling embedded images, keeping the PDF editable.
By using the compression range slider from 5% to 95%, you can balance quality and document size.