Crate webrender_api

The webrender_api crate contains an assortment types and functions used by WebRender consumers as well as, in many cases, WebRender itself.

This separation allows Servo to parallelize compilation across webrender and other crates that depend on webrender_api. So in practice, we put things in this crate when Servo needs to use them. Firefox depends on the webrender crate directly, and so this distinction is not really relevant there.

Re-exports

• pub extern crate crossbeam_channel;
• pub extern crate euclid;

Modules

• channel
• color 🔒
• display_item 🔒
• display_item_cache 🔒
• display_list 🔒
• font 🔒
• gradient_builder 🔒
• image 🔒
• precise_time_ns 🔒
• tile_pool 🔒
• units
  A collection of coordinate spaces and their corresponding Point, Size and Rect types.

Structs

• AuxIter
• BackdropFilterDisplayItem
  Renders a filtered region of its backdrop
• BlendPrimitive
• BlobImageDescriptor
  Metadata (but not storage) for a blob image.
• BlobImageKey
  An opaque identifier describing a blob image registered with WebRender. This is used as a handle to reference blob images, and can be used as an image in display items.
• BlobImageParams
  Input parameters for the BlobImageRasterizer.
• BlobImageRequest
  A key identifying blob image rasterization work requested from the blob image rasterizer.
• BlobTilePool
  A pool of blob tile buffers to mitigate the overhead of allocating and deallocating blob tiles.
• BlurPrimitive
• BorderDisplayItem
• BorderRadius
• BorderSide
• BoxShadowDisplayItem
• BuiltDisplayList
  A display list.
• BuiltDisplayListDescriptor
  Describes the memory layout of a display list.
• BuiltDisplayListIter
• ClearRectangleDisplayItem
  Clears all colors from the area, making it possible to cut holes in the window. (useful for things like the macos frosted-glass effect).
• ClipChainId
• ClipChainItem
  Just an abstraction for bundling up a bunch of clips into a “super clip”.
• ClipId
  A reference to a clipping node defining how an item is clipped.
• ColorF
  Represents RGBA screen colors with floating point numbers.
• ColorMatrixPrimitive
  cbindgen:derive-eq=false
• ColorU
  Represents RGBA screen colors with one byte per channel.
• CommonItemProperties
  A grouping of fields a lot of display items need, just to avoid repeating these over and over in this file.
• ComplexClipRegion
• ComponentTransferPrimitive
• CompositePrimitive
• ConicGradient
• ConicGradientDisplayItem
• CrashAnnotatorGuard
  Guard to add a crash annotation at creation, and clear it at destruction.
• DebugFlags
  Flags to enable/disable various builtin debugging tools.
• DisplayItemCache
• DisplayItemRef
• DisplayListBuilder
• DisplayListPayload
• DisplayListWithCache
• DocumentId
  A key uniquely identifying a WebRender document.
• DropShadowPrimitive
• DynamicProperties
  When using generate_frame(), a list of PropertyValue structures can optionally be supplied to provide the current value of any animated properties.
• Epoch
  An epoch identifies the state of a pipeline in time.
• ExternalEvent
  An opaque pointer-sized value.
• ExternalImage
  The data that an external client should provide about an external image. For instance, if providing video frames, the application could call wr.render() whenever a new video frame is ready. Note that the UV coords are either normalized or unnormalized depending on the value of normalized_uvs in the corresponding ExternalImageData.
• ExternalImageData
  Descriptor for external image resources. See ImageData.
• ExternalImageId
  An arbitrary identifier for an external image provided by the application. It must be a unique identifier for each external image.
• ExternalScrollId
  An external identifier that uniquely identifies a scroll frame independent of its ClipId, which may change from frame to frame. This should be unique within a pipeline. WebRender makes no attempt to ensure uniqueness. The zero value is reserved for use by the root scroll node of every pipeline, which always has an external id.
• FilterData
• FilterOpGraphNode
• FilterOpGraphPictureReference
• FilterPrimitive
  SVG Filter Primitive. See: https://github.com/eqrion/cbindgen/issues/9 cbindgen:derive-eq=false
• FloodPrimitive
• FontInstanceData
  Data corresponding to an instantiation of a font, with size and other options specified.
• FontInstanceFlags
• FontInstanceKey
• FontInstanceOptions
• FontInstancePlatformOptions
• FontKey
• FontSize
  Hashable floating-point storage for font size.
• FontVariation
• FramePublishId
• GlyphDimensionRequest
• GlyphDimensions
• GlyphIndexRequest
• GlyphInstance
• GlyphOptions
• Gradient
• GradientBuilder
  Construct a gradient to be used in display lists.
• GradientDisplayItem
  The area
• GradientStop
• HitTestDisplayItem
  A minimal hit-testable item for the parent browser’s convenience, and is slimmer than a RectangleDisplayItem (no color). The existence of this as a distinct item also makes it easier to inspect/debug display items.
• HitTestFlags
• HitTestResult
  Returned by RenderApi::hit_test.
• HitTestResultItem
  Describe an item that matched a hit-test query.
• HitTesterRequest
  A hit tester requested to the render backend thread but not necessarily ready yet.
• IdNamespace
  ID namespaces uniquely identify different users of WebRender’s API.
• IdentityPrimitive
• IframeDisplayItem
• ImageDescriptor
  Metadata (but not storage) describing an image In WebRender.
• ImageDescriptorFlags
  Various flags that are part of an image descriptor.
• ImageDisplayItem
  This describes an image that fills the specified area. It stretches or shrinks the image as necessary. While RepeatingImageDisplayItem could otherwise provide a superset of the functionality, it has been problematic inferring the desired repetition properties when snapping changes the size of the primitive.
• ImageKey
  An opaque identifier describing an image registered with WebRender. This is used as a handle to reference images, and is used as the hash map key for the actual image storage in the ResourceCache.
• ImageMask
• ImageMaskClipDisplayItem
• ItemRange
• ItemStats
  Stats for an individual item
• LineDisplayItem
• MinimapData
• MutableTileBuffer
• NativeFontHandle
• NinePatchBorder
• NormalBorder
• NotificationRequest
  A request to notify a handler when the transaction reaches certain stages of the rendering pipeline.
• OffsetPrimitive
• OpacityPrimitive
• PipelineId
  From the point of view of WR, PipelineId is completely opaque and generic as long as it’s clonable, serializable, comparable, and hashable.
• PremultipliedColorF
  Represents pre-multiplied RGBA colors with floating point numbers.
• PrimitiveFlags
• PropertyBindingId
  A key to identify an animated property binding.
• PropertyBindingKey
  A unique key that is used for connecting animated property values to bindings in the display list.
• PropertyValue
  The current value of an animated property. This is supplied by the calling code.
• PushShadowDisplayItem
• PushStackingContextDisplayItem
• QualitySettings
  Various settings that the caller can select based on desired tradeoffs between rendering quality and performance / power usage.
• RadialGradient
• RadialGradientDisplayItem
• RasterizedBlobImage
  Representation of a rasterized blob image. This is obtained by passing BlobImageData to the embedding via the rasterization callback.
• RectClipDisplayItem
• RectangleDisplayItem
  A solid or an animating color to draw (may not actually be a rectangle due to complex clips)
• ReferenceFrame
• ReferenceFrameDescriptor
• ReferenceFrameDisplayListItem
• ReferenceFrameMapper
  Maps from stacking context layout coordinates into reference frame relative coordinates.
• RenderReasons
  Flags to track why we are rendering.
• RepeatingImageDisplayItem
  This describes a background-image and its tiling. It repeats in a grid to fill the specified area.
• RoundedRectClipDisplayItem
• SampledScrollOffset
• SaveState
• ScrollFrameDescriptor
• Shadow
• SnapshotImageKey
  An opaque identifier describing a snapshot image registered with WebRender. This is used as a handle to reference snapshot images, and can be used as an image in display items.
• SnapshotInfo
  If passed in a stacking context display item, inform WebRender that the contents of the stacking context should be retained into a texture and associated to an image key.
• SpaceAndClipInfo
  Per-primitive information about the nodes in the clip tree and the spatial tree that the primitive belongs to.
• SpatialId
  A reference to a spatial node defining item positioning.
• SpatialTreeItemKey
  Defines a caller provided key that is unique for a given spatial node, and is stable across display lists. WR uses this to determine which spatial nodes are added / removed for a new display list. The content itself is arbitrary and opaque to WR, the only thing that matters is that it’s unique and stable between display lists.
• StackingContext
• StackingContextFlags
• StickyFrameDescriptor
• StickyOffsetBounds
  The minimum and maximum allowable offset for a sticky frame in a single dimension.
• SyntheticItalics
• TempFilterData
• TextDisplayItem
• YuvImageDisplayItem

Enums

• AlphaType
• BlobImageError
  Error code for when blob rasterization failed.
• BoolParameter
  Boolean configuration option.
• BorderDetails
• BorderRadiusKind
• BorderStyle
• BoxShadowClipMode
• Checkpoint
  A stage of the rendering pipeline.
• ClipMode
• ColorDepth
  Specifies the color depth of an image. Currently only used for YUV images.
• ColorRange
• ColorSpace
• ComponentTransferFuncType
• CompositeOperator
  Available composite operoations for the composite filter primitive
• CrashAnnotation
  Crash annotations included in crash reports.
• DebugDisplayItem
  This is a “complete” version of the DisplayItem, with all implicit trailing arrays included, for debug serialization (captures).
• DirtyRect
  The possible states of a Dirty rect.
• DisplayItem
• DisplayListSection
  DisplayListSection determines the target buffer for the display items.
• ExtendMode
• ExternalImageSource
  The source for an external image.
• ExternalImageType
  Storage format identifier for externally-managed images.
• FillRule
• FilterOp
• FilterOpGraphPictureBufferId
• FilterPrimitiveInput
  An input to a SVG filter primitive.
• FilterPrimitiveKind
  See: https://github.com/eqrion/cbindgen/issues/9 cbindgen:derive-eq=false
• FloatParameter
  Floating point configuration option.
• FontHinting
• FontLCDFilter
• FontRenderMode
• FontTemplate
  Container for the raw data describing a font. This might be a stream of bytes corresponding to a downloaded font, or a handle to a native font from the operating system.
• GeckoDisplayListType
• HasScrollLinkedEffect
  A flag in each scrollable frame to represent whether the owner of the frame document has any scroll-linked effect. See https://firefox-source-docs.mozilla.org/performance/scroll-linked_effects.html for a definition of scroll-linked effect.
• ImageBufferKind
  Specifies the type of texture target in driver terms.
• ImageData
  Represents the backing store of an arbitrary series of pixels for display by WebRender. This storage can take several forms.
• ImageFormat
  Specifies the format of a series of pixels, in driver terms.
• ImageRendering
• IntParameter
  Integer configuration option.
• LineOrientation
• LineStyle
• MixBlendMode
• NinePatchBorderSource
• Parameter
  A configuration option that can be changed at runtime.
• PrimitiveKeyKind
  Information specific to a primitive type that uniquely identifies a primitive template by key.
• PropertyBinding
  A binding property can either be a specific value (the normal, non-animated case) or point to a binding location to fetch the current value from. Note that Binding has also a non-animated value, the value is used for the case where the animation is still in-delay phase (i.e. the animation doesn’t produce any animation values).
• RasterSpace
  Configure whether the contents of a stacking context should be rasterized in local space or screen space. Local space rasterized pictures are typically used when we want to cache the output, and performance is important. Note that this is a performance hint only, which WR may choose to ignore.
• ReferenceFrameKind
• ReferenceTransformBinding
• RepeatMode
• Rotation
• ScrollLocation
• SpatialTreeItem
• TransformStyle
• YuvColorSpace
• YuvData
• YuvFormat
• YuvRangedColorSpace

Constants

• DEFAULT_TILE_SIZE
  The default tile size for blob images and regular images larger than the maximum texture size.
• MAX_RENDER_TASK_SIZE
  Defined here for cbindgen
• MAX_TEXT_RUN_LENGTH
• POLYGON_CLIP_VERTEX_MAX
• SVGFE_GRAPH_MAX
  Maximum number of SVGFE filters in one graph, this is constant size to avoid allocating anything, and the SVG spec allows us to drop all filters on an item if the graph is excessively complex - a graph this large will never be a good user experience, performance-wise.

Traits

• ApiHitTester
  An object that can perform hit-testing without doing synchronous queries to the RenderBackendThread.
• AsyncBlobImageRasterizer
  A group of rasterization requests to execute synchronously on the scene builder thread.
• BlobImageHandler
  A handler on the render backend that can create rasterizer objects which will be sent to the scene builder thread to execute the rasterization.
• BlobImageResources
  The resources exposed by the resource cache available for use by the blob rasterizer.
• CrashAnnotator
  Handler to expose support for annotating crash reports.
• ExternalImageHandler
  The interfaces that an application can implement to support providing external image buffers. When the application passes an external image to WR, it should keep that external image life time. People could check the epoch id in RenderNotifier at the client side to make sure that the external image is not used by WR. Then, do the clean up for that external image.
• NotificationHandler
  A handler to notify when a transaction reaches certain stages of the rendering pipeline.
• RenderNotifier
  A handler to integrate WebRender with the thread that contains the Renderer.

Functions

• precise_time_ns

Type Aliases

• APZScrollGeneration
• BlobImageData
  Backing store for blob image command streams.
• BlobImageResult
  Result type for blob raserization.
• GlyphIndex
• ItemKey
  An identifier used to refer to previously sent display items. Currently it refers to individual display items, but this may change later.
• ItemTag
  A tag that can be used to identify items during hit testing. If the tag is missing then the item doesn’t take part in hit testing at all. This is composed of two numbers. In Servo, the first is an identifier while the second is used to select the cursor that should be used during mouse movement. In Gecko, the first is a scrollframe identifier, while the second is used to store various flags that APZ needs to properly process input events.
• PipelineSourceId
  This type carries no valuable semantics for WR. However, it reflects the fact that clients (Servo) may generate pipelines by different semi-independent sources. These pipelines still belong to the same IdNamespace and the same DocumentId. Having this extra Id field enables them to generate PipelineId without collision.
• TileSize
  Width and height in device pixels of image tiles.
• VoidPtrToSizeFn
  A C function that takes a pointer to a heap allocation and returns its size.