PDFium Backend Integration

BarePDF uses Google PDFium as its underlying PDF rendering engine due to its industry-proven rendering fidelity, performance, and security record.

Binding Layer

PDFium C++ runtime binaries are interfaced via the pdfium-render crate inside crates/barepdf-pdf.

Key Lifetime Considerations

• PDFium page instances rely on the parent FPDF_DOCUMENT lifetime.
• barepdf-pdf encapsulates PDFium pointers inside thread-safe Rust smart pointers, preventing premature deallocation or use-after-free conditions.
• A document handle remains isolated on one background actor thread. BarePDF does not parallelize access to a PDFium document across a worker pool.

Text Extraction & Font Metrics

PDFium’s text page API (FPDFText_LoadPage) is queried to extract glyph bounding boxes (PageTextGeometry, GlyphRect). This data powers BarePDF’s mouse text drag selection, double-click word selection, and multi-page text copy capabilities.