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(392)

FragmentBuilder: Architecture and Role

FragmentBuilder: Architecture and Role

In Blink’s LayoutNG engine, the FragmentBuilder class serves as a vital instrument for generating immutable fragment trees, which represent the final geometric output of the layout process. This syste...

2 Tammi 37min

ObjectPaintProperties: Linking Layout and Painting in Blink Engine

ObjectPaintProperties: Linking Layout and Painting in Blink Engine

In the Blink rendering engine, the ObjectPaintProperties structure serves as a vital bridge between the layout and painting phases. It functions by organizing specific visual property nodes—such as tr...

2 Tammi 33min

BoxFragmentBuilder and Layout Architecture in Blink's LayoutNG

BoxFragmentBuilder and Layout Architecture in Blink's LayoutNG

The provided text details the BoxFragmentBuilder, a vital component within the Blink LayoutNG engine that constructs physical representations of layout elements. It acts as a transitional bridge, taki...

2 Tammi 39min

Pseudo-Elements in Blink's Layout Tree

Pseudo-Elements in Blink's Layout Tree

In the Blink rendering engine, CSS pseudo-elements are managed through specialized C++ classes and internal structures that link them to their originating DOM elements. These entities are dynamically ...

2 Tammi 42min

Clip Nodes in the Blink and Chromium Compositor

Clip Nodes in the Blink and Chromium Compositor

The provided text explains how Chromium’s Blink engine and the compositor utilize clip nodes within property trees to manage page geometry and visual masking. These nodes define specific regions where...

2 Tammi 35min

Blink Runtime-Enabled Features in Chromium

Blink Runtime-Enabled Features in Chromium

Blink runtime-enabled features serve as internal configuration flags that allow Chromium developers to manage new web platform capabilities without rebuilding the browser. These flags facilitate safel...

1 Tammi 41min

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...

31 Joulu 202528min

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...

30 Joulu 202530min