cc::EffectTree
Blink2862 Marras 2025

cc::EffectTree

The source provides an extensive technical explanation of the Effect Property Tree within the Chromium compositor, which is crucial for managing how visual effects are applied to web content. This tree structure, composed of EffectNodes, decouples effects (such as opacity, filters, and blending modes) from the traditional layer hierarchy to centralize calculations, improving rendering performance. A primary function of the effect tree is determining when content must be rendered into a separate RenderSurface (an offscreen texture) for correct compositing, flagged by the render_surface_reason field for complex needs like filters or non-standard blend modes. The document details the structure of an EffectNode, including fields that track cumulative properties like screen_space_opacity and visibility flags like is_drawn, and explains how the effect tree seamlessly interacts with the Transform and Clip property trees to ensure correct coordinate spaces and boundaries are maintained during effect application. Finally, it addresses the tree's role in facilitating performant CSS animations by allowing real-time property updates on the compositor thread and ensuring stability through element identification.

Jaksot(397)

gpu::SkiaOutputSurfaceImplOnGpu / gpu::CommandBuffer

gpu::SkiaOutputSurfaceImplOnGpu / gpu::CommandBuffer

Bridges Skia’s recorded commands to the GPU command buffer; submits and SwapBuffers to present. (Backend: GL/Vulkan/Metal via GPU process.)

23 Syys 202532min

viz::SkiaRenderer

viz::SkiaRenderer

Renderer that turns quads into Skia operations (recording DDLs / drawing to the output surface).

23 Syys 202552min

viz::Display

viz::Display

The display compositor that walks the aggregated render passes and issues draw commands for the final output.

23 Syys 202538min

cc::LayerTreeHostImpl (Input Handler & Scroll Logic)

cc::LayerTreeHostImpl (Input Handler & Scroll Logic)

Scroll processing and overscroll detection in the compositor. The LayerTreeHostImpl in cc implements the compositor-thread InputHandler that processes gesture scroll updates and flings. It manages the...

23 Syys 202527min

blink::EventHandler (Blink core input handling)

blink::EventHandler (Blink core input handling)

Scroll chain builder and overscroll chaining logic. Blink’s EventHandler is responsible for building the scroll chain (the sequence of nested scrollable ancestors) when the user scrolls an element . I...

23 Syys 202526min

blink::ElasticOverscrollController

blink::ElasticOverscrollController

Overscroll orchestration and animation. This Blink-side controller manages the rubber-banding (elastic stretch and rebound) effect when a scrollable area is overscrolled. It observes gesture scroll ev...

23 Syys 202526min

viz::Surface / SurfaceAggregator

viz::Surface / SurfaceAggregator

Receives frames from one or more surfaces (main page and OOPIFs), aggregates them into a single display frame.

23 Syys 202535min

viz::CompositorFrameSink (client side)

viz::CompositorFrameSink (client side)

The submission interface used by cc to hand the frame to viz.

23 Syys 202531min