File extension

.ttf

TTF free source project

.ttf files are TrueType fonts: scalable outline fonts defined by quadratic Bézier curves with hinting for sharp rendering at small sizes, the mainstream font format on Windows, macOS, and beyond.

Known meanings

Formats and reference material for .ttf

TTF free source project

TTF free source project

  • windows fonts
Open link

Opentype Spec

Opentype Spec

  • windows fonts
  • Microsoft Corp.
Open link

Truetype Spec 1.66

Truetype Spec 1.66

  • windows fonts
  • Microsoft Corp.
Download

The TrueType Font File

The TrueType Font File

  • fonts
  • Apple
  • Historical
Open link

Details

Format notes

TrueType Font (TTF)

TrueType is a scalable (outline) font format developed by Apple in the late 1980s and quickly adopted by Microsoft, becoming the dominant font technology on both platforms. Rather than storing bitmaps at fixed sizes, a TrueType font defines each glyph as outlines made of straight lines and quadratic Bézier curves, so the same font renders cleanly at any size. Its distinguishing strength is a powerful “hinting” system — instructions executed by the rasterizer — that keeps text crisp and legible at small sizes and low resolutions.

A TTF file uses the SFNT table-based container: a directory at the start locates a set of named tables, such as glyf (glyph outlines), cmap (character-to-glyph mapping), head, hmtx (horizontal metrics), name, and optional hinting tables. This structure is shared with OpenType: OpenType is effectively a superset that can carry either TrueType (glyf) or PostScript/CFF outlines and adds advanced typographic features, which is why TrueType and OpenType fonts are closely related and often both use the .ttf or .otf extensions.

Preservation And Security Notes

TrueType is openly documented and universally supported, making it a safe format for storing and distributing typefaces; note that fonts carry licensing terms and embedding permissions (in the OS/2 table) that should be respected. Because a TTF contains hinting bytecode executed by the rasterizer, font engines have historically been an attack surface, so systems that load untrusted fonts should use hardened, sandboxed, up-to-date rasterizers.

Further Reading

  • OpenType specification (Microsoft): https://learn.microsoft.com/typography/opentype/spec/
  • Apple TrueType Reference Manual: https://developer.apple.com/fonts/TrueType-Reference-Manual/