Crate vello_gpu 

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.

Re-exports

pub use text::GlyphRunBuilder;

pub use util::DimensionConstraints;

Modules

filter_effects

Filter effects API based on the W3C Filter Effects specification.

geometry

Geometry utilities.

peniko

A Rust 2D graphics type library

util

A number of utility helper methods.

Structs

AtlasConfig

Configuration for multiple atlas support.

AtlasId

Unique identifier for an atlas.

AtlasLayerDiagnostics

Free-space details for one atlas texture-array layer.

AtlasTextureInfo

Current allocation state of the WebGL image/glyph atlas textures.

CellStatistics

Summary of the differences between one expected and actual probe cell.

Config

Configuration for the GPU renderer.

GpuStrip

A GPU strip instance for rendering.

ImageId

Opaque image handle

LayersConfig

Configuration for temporary textures used to render layers and effects.

Mask

A mask.

MemorySettings

Settings controlling usage of GPU memory.

PixelMetadata

Metadata about the pixels of an image.

Pixmap

A pixmap of premultiplied RGBA8 values backed by u8.

ProbeResult

Probe failure output.

RectU16

An axis-aligned rectangle with u16 coordinates, stored as two corners (x0, y0) and (x1, y1).

RenderSettings

Settings to apply to the render context.

RenderSize

Dimensions of the rendering target.

RenderState

A render state which contains the style properties for path rendering.

RenderTargetConfig

Options for the renderer

Renderer

Vello GPU’s renderer.

Resources

Persistent resources required by Vello GPU for rendering.

Scene

A render context for GPU rendering.

SizeU16

A size represented by two 16-bit unsigned integers.

TextureBindings

Runtime bindings for externally owned textures sampled by image paints.

TextureId

A handle to an external, user-provided texture.

Tint

A tint applied to image paints.

Transforms

Context for holding transforms for paths and paints.

WebGlPendingProbe

A WebGL probe whose pixel readback has been queued but not completed.

WebGlRenderer

Vello GPU’s WebGL2 renderer.

WebGlRendererInit

WebGL renderer initialization that may still be compiling shader programs.

WebGlTextureBindings

Runtime bindings for externally owned textures sampled by image paints.

WebGlTextureWithDimensions

Wrapper for WebGlTexture with known dimensions.

Enums

AllocationStrategy

Strategy for allocating images across multiple atlases.

AtlasError

Errors that can occur during atlas operations.

AtlasSpaceDiagnostics

Free-space details collected after an atlas allocation fails.

ClearSettings

Controls how the output target is cleared before drawing.

ImageSource

Bitmap source used by Image.

IncompatibleContextReason

Reasons a WebGL context can be incompatible with the renderer.

IntermediateTextureError

Errors that can occur while allocating intermediate textures.

Level

The level enum with the specific SIMD capabilities available.

Pixels

The result of attempting to extract RGB8 data from a Pixmap.

Probe

Result of running the renderer probe.

ProbeFeature

A feature exercised by the renderer probe.

RenderError

Errors that can occur during rendering.

TintMode

How tint color is applied to an image.

WebGlContextOperation

WebGL context operations.

WebGlDataTransferOperation

WebGL data-transfer operations.

WebGlError

Errors produced by the WebGL backend.

WebGlOperation

A fallible operation performed by the WebGL backend.

WebGlProbeError

Error returned while running a WebGL probe.

WebGlProbeOperation

WebGL renderer probe operations.

WebGlProbeStatus

Result of polling the WebGL probe.

WebGlRendererInitStatus

Result of polling WebGL renderer initialization.

WebGlResourceKind

Kinds of WebGL resources.

WebGlShaderInterfaceOperation

Shader interface operations.

WebGlShaderProgramOperation

Shader compilation and program linking operations.

WebGlShaderStage

WebGL shader stages.

Constants

ALL_PROBE_ELEMENTS

All elements available for use in a probe.

Traits

AtlasWriter

Trait for types that can write image data directly to the atlas texture.

WebGlAtlasWriter

Trait for types that can write image data directly to the atlas texture in WebGL.

Type Aliases

GlyphRunBuilder

A glyph run builder.

Image

An image.

PaintType

A kind of paint that can be used for filling and stroking shapes.

TargetInit

Controls whether existing target contents are preserved or cleared before drawing.