cc::LayerImpl: Compositor Layer Deep Dive
Blink2861 Marras 2025

cc::LayerImpl: Compositor Layer Deep Dive

The sources provide an exhaustive technical explanation of the cc::LayerImpl class, which is the core representation of a visual element within Chromium's multi-threaded rendering pipeline. These layers exist exclusively on the compositor thread and are created or updated during the commit process from the main thread, operating in a layer list mode that leverages four types of property trees (Transform, Clip, Effect, Scroll) to manage hierarchical relationships and properties instead of traditional parent-child pointers. The layer objects are crucial for the performance optimization of drawing frames, as they store geometry, manage input regions for hit testing, and are instrumental in the asynchronous tiling and rasterization system (especially through PictureLayerImpl) and the three-tree model (Active, Pending, Recycle) used for frame staging and reuse. Ultimately, each layer's state is used in the quad generation step to produce a viz::CompositorFrame for the display compositor.


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B5: Platform View Architecture

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B4: Render Host Layer: RVH and RWH

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The technical documentation provides an extensive overview of two crucial browser-side components in Chromium's multi-process architecture: the RenderViewHost (RVH) and the RenderWidgetHost(RWH). The ...

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B3: RenderFrameHost: Core Document Lifeline

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The source documentation provides a detailed analysis of the RenderFrameHost (RFH) and its implementing class, RenderFrameHostImpl, which constitute the essential browser-side representation of every ...

28 Marras 202534min

B2: Frame Tree Navigation and Process Management

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This document details the Chromium browser's Layer 2 architecture, which is responsible for coordinating the structure and navigation of complex webpages across multiple renderer processes. The core o...

27 Marras 202544min

B1: WebContents: The Foundation of Chromium Tabs

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The text thoroughly analyzes the foundational structure of Chromium's architecture, which controls the browser window and tab strip elements. This system relies on a central Browser class acting as th...

27 Marras 202547min

B0: Governing Browser Windows and Tabs

B0: Governing Browser Windows and Tabs

The text thoroughly analyzes the foundational structure of Chromium's architecture, which controls the browser window and tab strip elements. This system relies on a central Browser class acting as th...

27 Marras 202535min

CSS Anchor Positioning in LayoutNG

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The sources provide a comprehensive specification deep dive into CSS Anchor Positioning, a modern layout module designed to position elements like tooltips and popovers relative to an anchor without r...

27 Marras 202545min

Layer Invalidation to Partial Swap

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The source details Chromium's damage tracking architecture, a critical mechanism within the cc compositor that identifies regions of the screen requiring redrawing to ensure rendering efficiency. This...

27 Marras 202535min