README.md - external/github.com/linebender/vello - Git at Google


            
            <div align="center">


            # Vello


            **High-performance 2D renderers written in Rust**


            [![Linebender Zulip](https://img.shields.io/badge/Linebender-%23vello-blue?logo=Zulip)](https://xi.zulipchat.com/#narrow/channel/197075-vello)

            
            [![dependency status](https://deps.rs/repo/github/linebender/vello/status.svg)](https://deps.rs/repo/github/linebender/vello)

            
            [![Apache 2.0 or MIT license.](https://img.shields.io/badge/license-Apache--2.0_OR_MIT-blue.svg)](#license)

            
            [![Build status](https://github.com/linebender/vello/workflows/CI/badge.svg)](https://github.com/linebender/vello/actions)


            </div>


            Vello is a project for high-performance 2D vector rendering. It contains three

            
            renderer implementations with different hardware requirements and maturity

            
            profiles.


            ## Choose a renderer


            ### Vello CPU


            [`vello_cpu`](vello_cpu) is a CPU-only renderer optimized for multithreading and

            
            SIMD. It is the most mature choice when predictable CPU rendering, software

            
            rendering, or support for devices without a suitable GPU is required.


            ### Vello GPU


            [`vello_gpu`](vello_gpu) is a renderer that preprocesses paths on the CPU and

            
            uses the GPU for rasterization and compositing. It supports a native WebGL2

            
            backend and a wgpu backend without requiring compute shaders. Choose it when GPU

            
            acceleration and broad GPU compatibility are important. Vello GPU is intended

            
            to become the primary renderer for production GPU use cases as it matures; Vello

            
            CPU is currently overall more mature.


            ### Vello compute renderer


            The [`vello`](research/vello_research) crate is the original compute-centric

            
            renderer. It performs most rendering work in GPU compute shaders and remains an

            
            experimental implementation for compute-capable GPUs. Its source and supporting

            
            crates live under [`research/`](research/README.md).


            Vello CPU and Vello GPU share the Sparse Strips architecture and common

            
            infrastructure in [`vello_common`](vello_common). See

            
            [ARCHITECTURE.md](ARCHITECTURE.md) for how the renderer families differ.


            ## Quick start


            Run the windowed example for the renderer you want to try:


            ```shell

            
            # Vello CPU

            
            cargo run -p vello_cpu_winit --release


            # Vello GPU

            
            cargo run -p vello_gpu_winit --release


            # Compute-centric research renderer

            
            cargo run -p with_winit --release

            
            ```


            Package-specific setup and API examples are in the

            
            [`vello_cpu`](vello_cpu), [`vello_gpu`](vello_gpu), and

            
            [`vello`](research/vello_research) READMEs.


            ## Repository layout


            - [`vello_cpu/`](vello_cpu) and [`vello_gpu/`](vello_gpu) contain the

            
              user-facing Sparse Strips renderers.

            
            - [`vello_common/`](vello_common) and

            
              [`vello_gpu_shaders/`](vello_gpu_shaders) support those renderers.

            
            - [`glifo/`](glifo) provides text and glyph-run support shared by both Sparse

            
              Strips renderers.

            
            - [`vello_tests/`](vello_tests) contains their shared development tests,

            
              snapshots, scenes, and browser tooling.

            
            - [`research/`](research/README.md) contains the compute-centric renderer, its

            
              encoding and shader crates, examples, tests, historical design documents, and

            
              changelog.

            
            - [`vello_bench/`](vello_bench) contains Sparse Strips benchmarks.


            Release histories are maintained in the

            
            [`vello` changelog](research/CHANGELOG.md),

            
            [`vello_cpu` changelog](vello_cpu/CHANGELOG.md),

            
            [`vello_gpu` changelog](vello_gpu/CHANGELOG.md), and

            
            [`vello_common` changelog](vello_common/CHANGELOG.md).


            ## Motivation


            Vello is intended to fill the same place in the graphics stack as vector

            
            renderers such as [Skia](https://skia.org/),

            
            [Cairo](https://www.cairographics.org/), and its predecessor project

            
            [Piet](https://github.com/linebender/piet). Its renderers draw shapes, images,

            
            gradients, and text using a PostScript-inspired imaging model like those behind

            
            SVG and the browser [`<canvas>` element][canvas].


            The implementations explore complementary ways to use SIMD, multithreading,

            
            and GPUs while sharing the same broader rendering goals.


            ## Minimum supported Rust Version (MSRV)


            This version of Vello has been verified to compile with **Rust 1.89** and later.


            Future versions of Vello might increase the Rust version requirement. It will

            
            not be treated as a breaking change and as such can even happen with small

            
            patch releases.


            <details>

            
            <summary>Click here if compiling fails.</summary>


            As time has passed, some of Vello's dependencies could have released versions

            
            with a higher Rust requirement. If you encounter a compilation issue due to a

            
            dependency and don't want to upgrade your Rust toolchain, then you could

            
            downgrade the dependency.


            ```sh

            
            # Use the problematic dependency's name and version

            
            cargo update -p package_name --precise 0.1.1

            
            ```


            </details>


            ## Community


            Discussion of Vello development happens in the

            
            [Linebender Zulip](https://xi.zulipchat.com/), specifically the

            
            [#vello channel](https://xi.zulipchat.com/#narrow/channel/197075-vello). All

            
            public content can be read without logging in.


            Contributions are welcome by pull request. The [Rust code of conduct] applies.


            Unless you explicitly state otherwise, any contribution intentionally submitted

            
            for inclusion in the work by you, as defined in the Apache 2.0 license, shall be

            
            licensed as noted in the [License](#license) section, without any additional

            
            terms or conditions.


            ## License


            Licensed under either of


            - Apache License, Version 2.0 ([LICENSE-APACHE](LICENSE-APACHE) or

            
              <http://www.apache.org/licenses/LICENSE-2.0>)

            
            - MIT license ([LICENSE-MIT](LICENSE-MIT) or

            
              <http://opensource.org/licenses/MIT>)


            at your option.


            In addition, all files in the

            
            [`research/vello_shaders/shader`][vello-shaders-dir] and

            
            [`research/vello_shaders/src/cpu`][vello-shaders-cpu-dir] directories and

            
            subdirectories thereof are alternatively licensed under the Unlicense

            
            ([research/vello_shaders/shader/UNLICENSE][shader-unlicense] or

            
            <http://unlicense.org/>). For clarity, these files are also licensed under

            
            either of the above licenses. The intent is for this research to be used in as

            
            broad a context as possible.


            The files in subdirectories of the [`assets`][assets] directory are licensed

            
            solely under their respective licenses, available in the `LICENSE` file in

            
            their directories.


            [Rust code of conduct]: https://www.rust-lang.org/policies/code-of-conduct

            
            [assets]: https://github.com/linebender/vello/tree/main/assets

            
            [canvas]: https://developer.mozilla.org/en-US/docs/Web/API/CanvasRenderingContext2D

            
            [shader-unlicense]: https://github.com/linebender/vello/blob/main/research/vello_shaders/shader/UNLICENSE

            
            [vello-shaders-cpu-dir]: https://github.com/linebender/vello/tree/main/research/vello_shaders/src/cpu

            
            [vello-shaders-dir]: https://github.com/linebender/vello/tree/main/research/vello_shaders/shader
	<div align="center">

	# Vello

	High-performance 2D renderers written in Rust

	[![Linebender Zulip](https://img.shields.io/badge/Linebender-%23vello-blue?logo=Zulip)](https://xi.zulipchat.com/#narrow/channel/197075-vello)
	[![dependency status](https://deps.rs/repo/github/linebender/vello/status.svg)](https://deps.rs/repo/github/linebender/vello)
	[![Apache 2.0 or MIT license.](https://img.shields.io/badge/license-Apache--2.0_OR_MIT-blue.svg)](#license)
	[![Build status](https://github.com/linebender/vello/workflows/CI/badge.svg)](https://github.com/linebender/vello/actions)

	</div>

	Vello is a project for high-performance 2D vector rendering. It contains three
	renderer implementations with different hardware requirements and maturity
	profiles.

	## Choose a renderer

	### Vello CPU

	[`vello_cpu`](vello_cpu) is a CPU-only renderer optimized for multithreading and
	SIMD. It is the most mature choice when predictable CPU rendering, software
	rendering, or support for devices without a suitable GPU is required.

	### Vello GPU

	[`vello_gpu`](vello_gpu) is a renderer that preprocesses paths on the CPU and
	uses the GPU for rasterization and compositing. It supports a native WebGL2
	backend and a wgpu backend without requiring compute shaders. Choose it when GPU
	acceleration and broad GPU compatibility are important. Vello GPU is intended
	to become the primary renderer for production GPU use cases as it matures; Vello
	CPU is currently overall more mature.

	### Vello compute renderer

	The [`vello`](research/vello_research) crate is the original compute-centric
	renderer. It performs most rendering work in GPU compute shaders and remains an
	experimental implementation for compute-capable GPUs. Its source and supporting
	crates live under [`research/`](research/README.md).

	Vello CPU and Vello GPU share the Sparse Strips architecture and common
	infrastructure in [`vello_common`](vello_common). See
	[ARCHITECTURE.md](ARCHITECTURE.md) for how the renderer families differ.

	## Quick start

	Run the windowed example for the renderer you want to try:

	```shell
	# Vello CPU
	cargo run -p vello_cpu_winit --release

	# Vello GPU
	cargo run -p vello_gpu_winit --release

	# Compute-centric research renderer
	cargo run -p with_winit --release
	```

	Package-specific setup and API examples are in the
	[`vello_cpu`](vello_cpu), [`vello_gpu`](vello_gpu), and
	[`vello`](research/vello_research) READMEs.

	## Repository layout

	- [`vello_cpu/`](vello_cpu) and [`vello_gpu/`](vello_gpu) contain the
	user-facing Sparse Strips renderers.
	- [`vello_common/`](vello_common) and
	[`vello_gpu_shaders/`](vello_gpu_shaders) support those renderers.
	- [`glifo/`](glifo) provides text and glyph-run support shared by both Sparse
	Strips renderers.
	- [`vello_tests/`](vello_tests) contains their shared development tests,
	snapshots, scenes, and browser tooling.
	- [`research/`](research/README.md) contains the compute-centric renderer, its
	encoding and shader crates, examples, tests, historical design documents, and
	changelog.
	- [`vello_bench/`](vello_bench) contains Sparse Strips benchmarks.

	Release histories are maintained in the
	[`vello` changelog](research/CHANGELOG.md),
	[`vello_cpu` changelog](vello_cpu/CHANGELOG.md),
	[`vello_gpu` changelog](vello_gpu/CHANGELOG.md), and
	[`vello_common` changelog](vello_common/CHANGELOG.md).

	## Motivation

	Vello is intended to fill the same place in the graphics stack as vector
	renderers such as [Skia](https://skia.org/),
	[Cairo](https://www.cairographics.org/), and its predecessor project
	[Piet](https://github.com/linebender/piet). Its renderers draw shapes, images,
	gradients, and text using a PostScript-inspired imaging model like those behind
	SVG and the browser [`<canvas>` element][canvas].

	The implementations explore complementary ways to use SIMD, multithreading,
	and GPUs while sharing the same broader rendering goals.

	## Minimum supported Rust Version (MSRV)

	This version of Vello has been verified to compile with Rust 1.89 and later.

	Future versions of Vello might increase the Rust version requirement. It will
	not be treated as a breaking change and as such can even happen with small
	patch releases.

	<details>
	<summary>Click here if compiling fails.</summary>

	As time has passed, some of Vello's dependencies could have released versions
	with a higher Rust requirement. If you encounter a compilation issue due to a
	dependency and don't want to upgrade your Rust toolchain, then you could
	downgrade the dependency.

	```sh
	# Use the problematic dependency's name and version
	cargo update -p package_name --precise 0.1.1
	```

	</details>

	## Community

	Discussion of Vello development happens in the
	[Linebender Zulip](https://xi.zulipchat.com/), specifically the
	[#vello channel](https://xi.zulipchat.com/#narrow/channel/197075-vello). All
	public content can be read without logging in.

	Contributions are welcome by pull request. The [Rust code of conduct] applies.

	Unless you explicitly state otherwise, any contribution intentionally submitted
	for inclusion in the work by you, as defined in the Apache 2.0 license, shall be
	licensed as noted in the [License](#license) section, without any additional
	terms or conditions.

	## License

	Licensed under either of

	- Apache License, Version 2.0 ([LICENSE-APACHE](LICENSE-APACHE) or
	<http://www.apache.org/licenses/LICENSE-2.0>)
	- MIT license ([LICENSE-MIT](LICENSE-MIT) or
	<http://opensource.org/licenses/MIT>)

	at your option.

	In addition, all files in the
	[`research/vello_shaders/shader`][vello-shaders-dir] and
	[`research/vello_shaders/src/cpu`][vello-shaders-cpu-dir] directories and
	subdirectories thereof are alternatively licensed under the Unlicense
	([research/vello_shaders/shader/UNLICENSE][shader-unlicense] or
	<http://unlicense.org/>). For clarity, these files are also licensed under
	either of the above licenses. The intent is for this research to be used in as
	broad a context as possible.

	The files in subdirectories of the [`assets`][assets] directory are licensed
	solely under their respective licenses, available in the `LICENSE` file in
	their directories.

	[Rust code of conduct]: https://www.rust-lang.org/policies/code-of-conduct
	[assets]: https://github.com/linebender/vello/tree/main/assets
	[canvas]: https://developer.mozilla.org/en-US/docs/Web/API/CanvasRenderingContext2D
	[shader-unlicense]: https://github.com/linebender/vello/blob/main/research/vello_shaders/shader/UNLICENSE
	[vello-shaders-cpu-dir]: https://github.com/linebender/vello/tree/main/research/vello_shaders/src/cpu
	[vello-shaders-dir]: https://github.com/linebender/vello/tree/main/research/vello_shaders/shader