cc::LayerTreeHostImpl (Input Handler & Scroll Logic)
Blink28623 Sep 2025

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 scroll state of all scroll nodes (via the ScrollTree) and determines when a scroll has hit the extent of an element. Currently, this is where overscroll is detected and reported – but only for the root/viewport. For example, the InputHandler sets did_overscroll_root in the scroll result when the root scroll node reaches its boundary , triggering the elastic effect on the root. To support elastic overscroll on non-root elements, this logic in LayerTreeHostImpl (and its ScrollTree/ScrollNode handling) needs to be generalized: it must detect overscroll on any scrollable node and initiate the overscroll animation (via the helper/controller) for that node instead of chaining upward. Understanding LayerTreeHostImpl and how it yields overscroll information (e.g. populating InputHandlerScrollResult.unused_scroll_delta, accumulated overscroll, and overscroll_behavior flags ) is key, as changes here will route overscroll into the ElasticOverscrollController for the right element rather than exclusively the root.

Episoder(391)

Blink Rendering: Background Paint Location in Overflow Scrolling boxes

Blink Rendering: Background Paint Location in Overflow Scrolling boxes

The provided text explains the technical inner workings of LayoutBox::ComputeBackgroundPaintLocation, a specific C++ function within Google’s Blink rendering engine. This function acts as a decision-m...

21 Jan 29min

The Popover API and Blink Implementation Deep Dive

The Popover API and Blink Implementation Deep Dive

The provided text explains the Popover API, a standardized web feature that allows developers to create top-layer overlays like menus and tooltips using a global HTML attribute. It details three disti...

21 Jan 26min

Blink Rendering Engine: ScrollableAxes System Architecture

Blink Rendering Engine: ScrollableAxes System Architecture

Blink’s ScrollableAxes system is the architectural framework within the Chromium rendering engine that manages how web content moves along horizontal and vertical paths. This system coordinates a vari...

21 Jan 32min

Blink's Unsplittable Scrolling Overflow: A Layout Deep Dive

Blink's Unsplittable Scrolling Overflow: A Layout Deep Dive

The provided text explains Blink’s LayoutBox::HasUnsplittableScrollingOverflow, a specialized method within Google Chrome’s rendering engine that manages how elements are divided across pages or colum...

21 Jan 25min

Blink DOM Tree Architecture and Implementation Deep Dive

Blink DOM Tree Architecture and Implementation Deep Dive

This technical deep dive explores the C++ architecture and implementation of the Document Object Model (DOM) within Blink, Chromium’s rendering engine. It details how the DOM is represented as a hiera...

21 Jan 33min

DrawScrollingContentsOp: Accelerated Scrolling via Raster-Inducing Display Lists

DrawScrollingContentsOp: Accelerated Scrolling via Raster-Inducing Display Lists

The provided text describes DrawScrollingContentsOp, a specialized paint operation within Chromium’s rendering engine that enhances scrolling performance for non-composited content. By utilizing the R...

21 Jan 30min

Chromium Compositor Synced Properties: Deep Dive

Chromium Compositor Synced Properties: Deep Dive

Chromium uses synced properties as a specialized coordination system to maintain consistency between the main thread and the compositor thread. These properties manage essential values that change fre...

21 Jan 27min

Mastering CSS Background Attachment: A Technical Guide

Mastering CSS Background Attachment: A Technical Guide

The provided text offers a technical examination of the background-attachment CSS property, detailing how it dictates whether images remain static or move during scrolling. It identifies three primary...

20 Jan 24min

Populært innen Teknologi

romkapsel
tomprat-med-gunnar-tjomlid
rss-avskiltet
teknisk-sett
nasjonal-sikkerhetsmyndighet-nsm
energi-og-klima
shifter
lydartikler-fra-aftenposten
elektropodden
rss-impressions-2
fornybaren
hans-petter-og-co
rss-alt-vi-kan
rss-ki-praten
pedagogisk-intelligens
smart-forklart
rss-fish-ships
rss-trippel-bunnlinje
rss-alt-som-gar-pa-strom
rss-ai-forklart