vello_gpu 0.3.0

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# Vello GPU

**GPU renderer with CPU-side preprocessing**

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[`Resources`]: https://docs.rs/vello_gpu/latest/vello_gpu/struct.Resources.html
[`Scene::glyph_run`]:
  https://docs.rs/vello_gpu/latest/vello_gpu/struct.Scene.html#method.glyph_run

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A GPU renderer for 2D vector graphics with CPU-side preprocessing.

Vello GPU uses the Sparse Strips architecture to divide work between CPU
preprocessing and GPU rendering:

- The CPU processes paths, tiles, and schedules sparse strips.
- The GPU rasterizes those strips and performs compositing.
- The compact strip representation limits data transfer between them.

### Key Features

- Efficient path rendering with CPU-side processing
- GPU-accelerated compositing and blending
- Support for both windowed and headless rendering

### Feature Flags

- `wgpu` (enabled by default): Enables the GPU rendering backend via wgpu and
  includes the required Vello GPU shaders.
- `wgpu_default` (enabled by default): Enables wgpu with its default hardware
  backends (such as Vulkan, Metal, and DX12).
- `text` (enabled by default): Enables glyph rendering ([`Scene::glyph_run`]).
- `webgl`: Enables the WebGL rendering backend for browser support, using GLSL
  shaders for compatibility.

If you need to customize the set of enabled wgpu features, disable this crate's
default features then enable its `wgpu` feature. You can then depend on wgpu
directly, setting the specific features you require. Don't forget to also
disable wgpu's default features.

### Architecture

The renderer is split into several key components:

- `Scene`: Manages the render context and path processing on the CPU
- `Renderer` or `WebGlRenderer`: Handles GPU resource management and executes
  draw operations

See the individual module documentation for more details on usage and
implementation.

### Current state

Vello GPU is a solid GPU-accelerated 2D renderer with broad, reliable feature
support. Although it does not match the compute-centric `vello` renderer's raw
performance on dynamic and vector-heavy workloads, it provides excellent
performance on workloads that benefit from GPU acceleration, such as images,
gradients, and filters. Overall, we still consider it to be slightly less mature
than its CPU-only counterpart Vello CPU.

Vello GPU remains under active development. Known limitations include:

- The following features are not yet supported and will panic: Mask layers,
  complex filter graphs as well as certain blend modes for non-isolated
  blending.
- Parts of the API and its documentation are still suboptimal, for example the
  lifecycle and ownership of external resources through [`Resources`][].
- Some exposed features remain experimental and are not recommended for use,
  including glyph caching. Experimental APIs are identified in their method
  documentation.
- Parts of the rendering pipeline are not yet fully optimized, particularly the
  wgpu backend, but also other aspects.
- Some failures panic instead of being reported through a user-facing error.

With that said, we are continuously improving Vello GPU and will address these
and other limitations in future releases.

### Package rename

This package was previously named `vello_hybrid`. New dependencies and Rust
imports should use `vello_gpu`; no compatibility re-export package is provided
in this repository. Existing crates.io releases under `vello_hybrid` remain
available, and publication under the new name may lag behind the repository
rename.

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## Minimum supported Rust Version (MSRV)

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

Future versions of Vello GPU 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 GPU'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 GPU 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.

## 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.

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