Compression Overview

Overview

HotPDF uses several compression and decompression paths depending on whether it is generating new PDF content or reading existing streams and images from external files.

Main Compression Paths

• FlateDecode: Used for generated PDF streams through THotPDF.Compression and backed by zlib-ng in zlib-compatible mode, with 64-bit runtime SIMD dispatch where available
• LZWDecode: Supported for legacy PDF and TIFF-style data through HPDFLZW.pas
• DCT/JPEG: Used for standard JPEG image workflows handled by HotPDF image support and backed by libjpeg-turbo 3.1.90 with NASM SIMD acceleration objects
• JBIG2 and JPEG2000: Available for specialized image workflows where the source format already uses those codecs

Related Units

• HPDFZLib.pas for FlateDecode and predictor-aware inflate helpers
• HPDFLZW.pas for LZW decompression
• HPDFJBIG2.pas for JBIG2 decoding support
• HPDFJpeg2000.pas and HPDFOpenJpeg.pas for JPEG2000-related workflows

See Also

• THotPDF.Compression Property
• Enhanced ZLib Support
• LZW Compression Support
• JBIG2 Compression Support
• PDF Filter Support