cc::ScrollTree
Blink2862 Marras 2025

cc::ScrollTree

The source text provides an exhaustive technical overview of the Scroll Property Tree (cc::ScrollTree) within the Chromium compositor architecture, which is critical for enabling smooth, off-main-thread scrolling. It explains that the ScrollTree captures the hierarchy and properties of scrollable elements, utilizing individual ScrollNodes to store geometric data (like content and container bounds) and behavioral flags (such as whether scrolling is handled on the main thread or if scroll snapping is active). Furthermore, the text details how the ScrollTree works in close coordination with the Transform Tree to apply scroll-induced translations and how it manages the entire scrolling lifecycle, from input event hit-testing and scroll latching to handling overscroll and synchronizing scroll offsets back to the main thread (Blink) via commit mechanisms. This system ensures that complex features like pinch-zoom, sticky positioning, and scroll-linked animations operate correctly and efficiently on the compositor thread.

Jaksot(396)

Clip Nodes in the Blink and Chromium Compositor

Clip Nodes in the Blink and Chromium Compositor

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Blink Runtime-Enabled Features in Chromium

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Upward Propagation Mechanisms in Blink LayoutNG

Upward Propagation Mechanisms in Blink LayoutNG

The provided text explains how Chromium’s LayoutNG engine utilizes upward propagation to transfer critical layout data from child elements to their ancestors. By aggregating information such as intrin...

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Blink Sticky Positioning: Constraint Updates and Paint Invalidation

Blink Sticky Positioning: Constraint Updates and Paint Invalidation

The provided documentation details how the Blink rendering engine manages sticky positioning through specific methods within the PaintLayerScrollableArea class. It explains that the system first calcu...

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Blink’s Scrolling Engine: The PaintLayerScrollableArea Deep Dive

Blink’s Scrolling Engine: The PaintLayerScrollableArea Deep Dive

The provided text explains the PaintLayerScrollableArea, a central component within the Blink rendering engine that manages scrolling for web elements and viewports. It describes how this object bridg...

30 Joulu 202531min

Understanding PropagatedData in Blink’s LayoutNG Fragment Tree

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In Blink’s LayoutNG engine, PropagatedData serves as a specialized, light-weight container used to carry critical layout information upward through the fragment tree. This garbage-collected object is ...

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Self-Painting Layers in Blink: Architecture and Implementation Decisions

Self-Painting Layers in Blink: Architecture and Implementation Decisions

In the Blink rendering engine, PaintLayers form a specialized hierarchy used to manage the visual assembly of a webpage, separate from the standard layout tree. These layers are created for elements r...

30 Joulu 202539min

[EXTENDED] PaintLayer Parent Hierarchies in the Blink Rendering Engine

[EXTENDED] PaintLayer Parent Hierarchies in the Blink Rendering Engine

In the Blink rendering engine, the PaintLayer system utilizes multiple hierarchical relationships to manage how web content is displayed and organized. While the structural parent defines the primary ...

30 Joulu 202536min