Milestro

Milestro is a native text rendering plugin for Unity.

The goal of this project is to bypass Unity's built-in text rendering pipeline and render text directly with Skia. Milestro gives Unity projects a lower-level path for text layout, glyph processing, rasterization, and render target output while keeping a C# API available inside Unity.

What This Project Does

Milestro provides:

• A native C++ library built around Skia text layout and rendering.
• Unity C# bindings for the native Milestro API.
• Unity components for rendering Skia paragraphs through bitmap textures, render textures, mesh geometry, and SDF data.
• Rich text parsing helpers for converting styled markup into paragraph payloads.
• Font registration and font family access through the native layer.
• Glyph extraction utilities for paths, vertices, bounds, and custom rendering workflows.
• Unity native rendering integration for platform graphics backends.

In short: Milestro lets Unity ask Skia to shape and render text, instead of relying on Unity's normal text rendering stack.

Why

Unity's built-in text path is convenient, but it can be limiting when a project needs direct control over:

• Text shaping and paragraph layout.
• Font fallback and font registration.
• Rendering text into custom textures or render targets.
• Converting text to paths, meshes, or SDF data.

Milestro exists to make those workflows available from Unity.

Architecture

Milestro is split into a native layer and a Unity layer.

Native Layer

The native layer is written in C++ and exposes a C-compatible interface for Unity and generated bindings.

Main areas:

• src/skia/ and include/Milestro/skia/: Skia wrappers for canvas, images, fonts, typefaces, paths, SVG, vertex data, and text layout.
• src/icu/ and include/Milestro/icu/: ICU-related helpers.
• src/game/ and include/Milestro/game/: exported plugin API used by Unity/C#.
• src/unity_render/: Unity native rendering integration.

Unity Layer

The Unity layer lives under apps/unity-plugins/Milestro/.

Main areas:

• Binding/: C# bindings to the exported native API.
• Skia/: managed wrappers for native Skia objects.
• Skia/TextLayout/: paragraph, paragraph builder, paragraph style, text style, and font collection APIs.
• Components/: Unity components for rendering paragraphs.
• RichTextParser/: markup parsing into styled text payloads.
• Model/: shared text and rendering data models.
• ColorUniverse/: color conversion and parsing helpers.

Repository Layout

apps/
  cmd/                  Native CLI entry point
  unity-plugins/        Unity C# plugin code
cmake/                  CMake helper modules
docs/                   Project documentation
ext/                    Vendored third-party dependencies
include/Milestro/       Public native headers
scripts/                Release and maintenance scripts
src/                    Native implementation
tests/                  Native tests and test data

Supported Platforms

Milestro is currently in the proof-of-concept stage.

The target Unity graphics backends are:

• Metal
• Direct3D 12
• Vulkan
• OpenGL