blink::EventHandler (Blink core input handling)
Blink28623 Syys 2025

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 . It determines how scroll events propagate up through parent containers and when to terminate the chain. Crucially, it respects the CSS overscroll-behavior of each element to decide if overscroll should propagate or stop at that element. For example, if an inner element is scrolled to its boundary, by default the scroll chains to its parent – but if that element’s style has overscroll-behavior: contain or none, the chain is broken and the overscroll is handled locally . To implement non-root elastic overscroll, one must modify how EventHandler (and associated scroll logic) interprets these style flags and sends overscroll events: instead of always bubbling to the root, it should allow an overscroll at the element itself when appropriate. In short, EventHandler is where the blink style system meets input: it ensures the scroll chain and overscroll-behavior rules are applied, so the developer must understand it to route overscroll to non-root scrollers.

Jaksot(396)

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The source provides an extensive technical overview of Chrome’s Compositor-Thread Scrolling architecture, explaining how modern web rendering achieves smooth, low-latency scrolling by handling most sc...

11 Marras 202545min

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The source provides an extensive technical overview of how the Blink rendering engine handles scrolling, particularly focusing on the main-thread scrolling lifecycle. It explains that while modern bro...

10 Marras 202545min

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The source provides an extensive overview of the Chrome browser's scrolling architecture, detailing the division of labor between the Blink rendering engine (main thread) and the Chromium Compositor (...

10 Marras 202526min