AFF to PGM Converter

AFF (Acorn Draw) is a vector graphics file format native to Acorn Computers' RISC OS operating system, introduced with the Draw application bundled in RISC OS 2 in April 1989. The Draw application shipped as a standard component of every RISC OS installation, providing users with a capable vector illustration tool at no additional cost. AFF files store vector objects as a sequence of tagged data blocks, each containing object type, bounding box, and type-specific data — supported objects include paths with straight lines and Bezier curves, text objects with font references, sprite (bitmap) objects, groups, and tagged objects for application-specific extensions. Path objects use cubic Bezier curves with move, line, and curve elements, supporting variable line widths, join styles, dash patterns, and flat color fills. The coordinate system uses RISC OS draw units at 1/180 inch resolution, providing precision for both screen display and print output. One advantage is the straightforward binary structure — the tagged block architecture makes AFF files simple to parse and generate programmatically. Native operating system integration is another strength: RISC OS renders Draw files natively in its desktop environment, treating vector graphics as first-class objects alongside bitmaps. While Acorn Computers ceased operations in the late 1990s, RISC OS continues under active open-source development, and AFF files remain supported through the platform's drawing applications and conversion utilities.