Module tile_cache 

Tile cache types and descriptors

This module contains the core tile caching infrastructure including:

• Tile identification and coordinate types
• Tile descriptors that track primitive dependencies
• Comparison results for invalidation tracking

Re-exports

pub use self::slice_builder::TileCacheBuilder;

pub use self::slice_builder::TileCacheConfig;

pub use self::slice_builder::PictureCacheDebugInfo;

pub use self::slice_builder::SliceDebugInfo;

pub use self::slice_builder::DirtyTileDebugInfo;

pub use self::slice_builder::TileDebugInfo;

pub use self::slice_builder::CompositorClipDebugInfo;

Modules

slice_builder

Structs

BackdropInfo

Stores information about the calculated opaque backdrop of this slice.

BackdropSurface

CompositorSurface

Wrapper struct around an external surface descriptor with a little more information that the picture caching code needs.

DeferredDirtyTest

In some cases, we need to know the dirty rect of all tiles in order to correctly invalidate a primitive.

ExternalNativeSurface

Information about a native compositor surface cached between frames.

ExternalNativeSurfaceKey

Hash key for an external native compositor surface

NativeSurface

Represents the native surfaces created for a picture cache, if using a native compositor. An opaque and alpha surface is always created, but tiles are added to a surface based on current opacity. If the calculated opacity of a tile changes, the tile is invalidated and attached to a different native surface. This means that we don’t need to invalidate the entire surface if only some tiles are changing opacity. It also means we can take advantage of opaque tiles on cache slices where only some of the tiles are opaque. There is an assumption that creating a native surface is cheap, and only when a tile is added to a surface is there a significant cost. This assumption holds true for the current native compositor implementations on Windows and Mac.

SliceId

The key that identifies a tile cache instance. For now, it’s simple the index of the slice as it was created during scene building.

SubSlice

A SubSlice represents a potentially overlapping set of tiles within a picture cache. Most picture cache instances will have only a single sub-slice. The exception to this is when a picture cache has compositor surfaces, in which case sub slices are used to interleave content under or order the compositor surface(s).

SubSliceIndex

Defines which sub-slice (effectively a z-index) a primitive exists on within a picture cache instance.

Tile

Information about a cached tile.

TileCacheInstance

Represents a cache of tiles that make up a picture primitives.

TileCacheParams

Information that is required to reuse or create a new tile cache. Created during scene building and passed to the render backend / frame builder.

TileId

A unique identifier for a tile. These are stable across display lists and scenes.

TileKey

Uniquely identifies a tile within a picture cache slice

TilePostUpdateContext 🔒

TilePostUpdateState 🔒

TilePreUpdateContext 🔒

Enums

BackdropKind

SurfacePromotionFailure 🔒

TileSurface

The backing surface for this tile.

Constants

MAX_COMPOSITOR_SURFACES

The maximum number of compositor surfaces that are allowed per picture cache. This is an arbitrary number that should be enough for common cases, but low enough to prevent performance and memory usage drastically degrading in pathological cases.

MAX_SURFACE_SIZE

The maximum size per axis of a surface, in DevicePixel coordinates. Render tasks larger than this size are scaled down to fit, which may cause some blurriness.

TILE_SIZE_DEFAULT

The size in device pixels of a normal cached tile.

TILE_SIZE_SCROLLBAR_HORIZONTAL

The size in device pixels of a tile for horizontal scroll bars

TILE_SIZE_SCROLLBAR_VERTICAL

The size in device pixels of a tile for vertical scroll bars

Statics

NEXT_TILE_ID 🔒

Used to get unique tile IDs, even when the tile cache is destroyed between display lists / scenes.

Type Aliases

TileOffset

TileRect