Libs

Shaping Libraries

HarfBuzz

• HarfBuzz .

• HarfBuzz-Odin .

• Complex shaping.

• For serious text (RTL, ligatures, etc.): FreeType  + HarfBuzz , optionally MSDF for rendering.

• HarfBuzz won't help you with bidirectionality.

• HarfBuzz won't help you with text that contains different font properties.

• HarfBuzz won't help you with line breaking, hyphenation, or justification.

Core Text

• Shaping engine.

DirectWrite

• Shaping engine.

Uniscribe

• Shaping engine.

• Uniscribe .

• Microsoft.

Segmentation Libraries

Fribidi

• Fribidi .

  • It only implements direction breaking.

ICU

• ICU .

• Is a very complex and featureful library. However, it is restricted to offering Unicode functionality, and, as we have seen, text shaping and rasterization both require OpenType functionality.

• It performs segmentation.

Rasterization Libraries

FreeType2

• FreeType .

• FreeType .

• freetype-odin .

• Written in C.

• What it is :

  • A mature, open-source library for font rendering, supporting TrueType, OpenType, PostScript, and many other font formats.

  • Advanced hinting, subpixel rendering, kerning, ligatures, and DPI-aware scaling. Used widely in professional software (e.g., Linux, Android, Godot).

  • "rasterization library".

  • FreeType is a font rendering engine , meaning it:

    • Parses font files (e.g., TTF, OTF)

    • Extracts glyph data (metrics, outlines, bitmaps)

    • Generates glyph images (rasterizes vector outlines into bitmaps or provides outline vectors for further use)

• What it does :

  • It provides bitmap glyphs (e.g., 8-bit grayscale bitmaps) or vector outlines (e.g., curves and points).

  • It lets you rasterize a glyph at a specific size and resolution into a memory buffer.

  • The output of FT_Render_Glyph  is a rasterized glyph image  stored in the glyph->bitmap  field of the FT_GlyphSlot  structure.

    • Nothing more than "bitmap data".

    • In the Odin example, bitmap_data  is a []RGBA , where RGBA :: [4]u8 , with size bitmap_data = make([]RGBA, window_width * window_height) .

• What it doesn't do :

  • It does not handle drawing to the screen (no OpenGL, DirectX, Vulkan, etc.).

  • It does not handle text layout (no kerning application, line wrapping, or shaping for complex scripts — although it provides raw kerning info).

• Use Case :

  • Production-grade applications where text quality and typographic features are critical.

  • Godot

    • Aligns with its focus on cross-platform compatibility and high-quality UI/text rendering.

stb_truetype

• A single-file, public-domain C library for rasterizing TrueType (.ttf) fonts.

• Pros :

  • Lightweight, easy to integrate, minimal dependencies.

• Cons :

  • Limited features (basic hinting, no subpixel rendering), lower quality at small sizes, and no support for OpenType (.otf) or other font formats.

  • Does not automatically handle DPI scaling, as it requires explicit input for font size.

• Use Case :

  • Ideal for small projects, prototyping, or platforms where simplicity and size matter more than typographic perfection.

  • RayLib.

    • However, RayLib itself allows developers to manually adjust font sizes based on DPI if needed.

    • "Is there a technical reason for not using freetype? I don't know much about the subject, so I'm just wandering"

      • library size, Freetype is x100 bigger than stb_truetype; build complexity, maintenance.

• "stb_truetype is more limited and lower quality than FreeType2" :

  • This is broadly true. stb_truetype  is a minimalist library focused on basic font rasterization, while FreeType2  is a full-featured, industry-standard library with advanced rendering capabilities (e.g., subpixel rendering, better hinting, and support for complex font features). For simple use cases, stb_truetype  may suffice, but FreeType2  generally produces higher-quality results, especially at small font sizes or on low-resolution displays.

Multi-Purpose Libraries

Pango

• It can do all the steps for a Modern Text Processing Pipeline.

• Pango .

• Pango-odin .

kb-text-shape

• Segmentation (through kbts_Break) and shaping (through kbts_Shape).

• JimmyLefevre/kb .

• Now part of Odin's vendor.

• The library basically does everything you need to go from UTF-8 or Unicode codepoints to a list of glyph indices + positions, ready to send to a rasterizer  like FreeType or stb_truetype.

• Features :

  • Segmentation :

    • Provides ICU-like text segmentation (i.e. breaking Unicode text by direction, line, word and grapheme).

  • Shaping :

    • It also provides HarfBuzz-like text shaping for OpenType fonts, which means it is capable of handling complex script layout and ligatures, among other things.

  • Bundling segmentation and shaping simplifies the overall implementation, because the shaper doesn't need any ad-hoc adjustments to fix bad segmentation.

  • It also reduces the binary size by a lot, because they both share the same Unicode tables!

  • It can replace fribidi, some parts of ICU and HarfBuzz, but not Pango. Pango is a higher-level library that also handles paragraph layout and rendering glyphs to bitmaps, which we don't do.

• Not-features :

  • Rasterization :

    • It does not handle rasterization.

    • It will only help you know which glyphs to display where!

• Nic Barker: "Amazing work on this".