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https://github.com/pcwalton/pathfinder

A fast, practical GPU rasterizer for fonts and vector graphics
https://github.com/pcwalton/pathfinder

Last synced: 28 days ago
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A fast, practical GPU rasterizer for fonts and vector graphics

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README 

        
[![Build Status](https://travis-ci.org/servo/pathfinder.svg?branch=master)](https://travis-ci.org/servo/pathfinder)



# Pathfinder 3



Pathfinder 3 is a fast, practical, GPU-based rasterizer for fonts and vector graphics using OpenGL

3.0+, OpenGL ES 3.0+, or Metal.



Please note that Pathfinder is under heavy development and is incomplete in various areas.



## Quick start



Pathfinder contains a library that implements a subset of the

[HTML canvas API](https://developer.mozilla.org/en-US/docs/Web/API/Canvas_API). You can quickly add

vector rendering to any Rust app with it. See the `examples/canvas_minimal` for a small example of

usage.



This example app requires SDL 2; see the "Building" section below for information on getting it up

and running.



### Demos



Demo app sources are available in [demo/](https://github.com/servo/pathfinder/tree/master/demo). A prebuilt package for Magic Leap can be found in [releases](https://github.com/servo/pathfinder/releases).



## Features



The project features:



* High quality antialiasing. Pathfinder can compute exact fractional trapezoidal area coverage on a

  per-pixel basis for the highest-quality antialiasing possible (effectively 256xAA).



* Fast CPU setup, making full use of parallelism. Pathfinder 3 uses the Rayon library to quickly

  perform a CPU tiling prepass to prepare vector scenes for the GPU. This prepass can be pipelined

  with the GPU to hide its latency.



* Fast GPU rendering, even at small pixel sizes. Even on lower-end GPUs, Pathfinder typically

  matches or exceeds the performance of the best CPU rasterizers. The difference is particularly

  pronounced at large sizes, where Pathfinder regularly achieves multi-factor speedups. All shaders

  have no loops and minimal branching.



* Advanced font rendering. Pathfinder can render fonts with slight hinting and can perform subpixel

  antialiasing on LCD screens. It can do stem darkening/font dilation like macOS and FreeType in

  order to make text easier to read at small sizes. The library also has support for gamma

  correction.



* Support for SVG. Pathfinder 3 is designed to efficiently handle workloads that consist of many

  overlapping vector paths, such as those commonly found in SVG and PDF files. It can perform

  occlusion culling, which often results in dramatic performance wins over typical software

  renderers that use the painter's algorithm. A simple loader that leverages the `resvg` library

  to render a subset of SVG is included, so it's easy to get started.



* 3D capability. Pathfinder can render fonts and vector paths in 3D environments without any loss

  in quality. This is intended to be useful for vector-graphics-based user interfaces in VR, for

  example.



* Lightweight. Unlike large vector graphics packages that mix and match many different algorithms,

  Pathfinder 3 uses a single, simple technique. It consists of a set of modular crates, so

  applications can pick and choose only the components that are necessary to minimize dependencies.



* Portability to most GPUs manufactured in the last decade, including integrated and mobile GPUs.

  Geometry, tessellation, and compute shader functionality is not required.



## Building



Pathfinder 3 is a set of modular packages, allowing you to choose which parts of the library you

need. An SVG rendering demo, written in Rust, is included, so you can try Pathfinder out right

away. It also provides an example of how to use the library. (Note that, like the rest of

Pathfinder, the demo is under heavy development and has known bugs.)



Running the demo is as simple as:



    $ cd demo/native

    $ RUSTFLAGS="-C target-cpu=native" cargo run --release



The SDL 2 library requires some additional manual installation steps. Follow the

[`rust-sdl2` installation instructions](https://github.com/Rust-SDL2/rust-sdl2#sdl20-development-libraries) to make sure the libraries are installed. Note that SDL2 is

only required to run the demo; Pathfinder itself has no dependency on the library.



## Authors



The primary author is Patrick Walton (@pcwalton), with contributions from the Servo development

community.



The logo was designed by Jay Vining.



Contributors to Pathfinder are expected to abide by the same Code of Conduct as Rust itself.



## License



Pathfinder is licensed under the same terms as Rust itself. See `LICENSE-APACHE` and `LICENSE-MIT`.



Material Design icons are copyright Google Inc. and licensed under the Apache 2.0 license.