CID to AFM Converter

AFM (Adobe Font Metrics) is a plain-text metadata file format developed by Adobe Systems as a companion to PostScript Type 1 font outlines. Introduced alongside the PostScript language in 1984, AFM files provide the glyph-level metrics that applications need for text layout — individual character widths, bounding boxes, kerning pair adjustments, ligature substitutions, and global font dimensions like ascender height and cap height. The file is structured as a series of human-readable keyword-value pairs, making it easy to inspect and parse with simple text processing tools. AFM data is essential for accurate typesetting: without it, a layout engine knows the shapes of the glyphs but not how much space to allocate for each character or how to tighten spacing between specific letter combinations. One advantage is format transparency — because AFM is plain ASCII text, metric data can be audited, compared, and version-controlled without specialized software. The separation of metrics from outlines is another architectural strength, allowing a single AFM file to serve multiple rendering environments (screen, print, PDF) without duplicating glyph data. The current specification, Version 4.1 published in 1998, extended the format with composite character definitions and writing direction support. While modern OpenType fonts bundle metrics internally, AFM remains relevant in PostScript workflows, PDF generation pipelines, and legacy publishing systems that depend on Type 1 fonts.