cc Transform and Scroll Trees
Blink28628 Syys 2025

cc Transform and Scroll Trees

The source text details the architecture of Chromium's compositor, focusing on the tandem operation of two critical data structures: the Transform Tree and the Scroll Tree. The Transform Tree manages visual coordinate space transformations, including CSS transforms and scroll offsets, with each TransformNode calculating its final position relative to its parent using local matrices and the scroll translation. In parallel, the Scroll Tree, composed of ScrollNodes, handles the logical state of scrollable elements, defining constraints like scrollable bounds, allowed directions, and scroll chaining behavior. Crucially, the sources explain that the two trees are linked via a shared ElementId and that while the Scroll Tree determines how a scroll should happen (bounds and policy), the Transform Tree executes the change by holding and applying the live scroll_offset to visually move the layer content, enabling smooth, composite-threaded scrolling.

Jaksot(417)

cc::CommitState

cc::CommitState

The provided source offers an extensive architectural analysis of Chromium’s cc::CommitState struct, detailing its critical function as the intermediary data structure that facilitates communication b...

25 Syys 202540min

Blink and Compositor Stacking Contexts

Blink and Compositor Stacking Contexts

These sources provide an extensive technical explanation of how CSS stacking contexts are implemented within the Chromium rendering engine, focusing on the collaboration between the Blink renderer and...

25 Syys 202538min

Chromium Architecture: Input, Synchronization, and Animation Pipelines

Chromium Architecture: Input, Synchronization, and Animation Pipelines

These sources provide an extensive architectural overview of the core C++ classes that implement Chromium's input handling, synchronization, and animation systems. The documents detail the multi-proce...

25 Syys 202540min

CSS View Transition Pseudo-elements Explained

CSS View Transition Pseudo-elements Explained

These sources provide a detailed, technical explanation of the View Transition API implementation within the Chromium web browser, focusing on how CSS pseudo-elements enable smooth animations. The fir...

24 Syys 202538min

gpu::SkiaOutputSurfaceImplOnGpu / gpu::CommandBuffer

gpu::SkiaOutputSurfaceImplOnGpu / gpu::CommandBuffer

Bridges Skia’s recorded commands to the GPU command buffer; submits and SwapBuffers to present. (Backend: GL/Vulkan/Metal via GPU process.)

23 Syys 202532min

viz::SkiaRenderer

viz::SkiaRenderer

Renderer that turns quads into Skia operations (recording DDLs / drawing to the output surface).

23 Syys 202552min

viz::Display

viz::Display

The display compositor that walks the aggregated render passes and issues draw commands for the final output.

23 Syys 202538min

cc::LayerTreeHostImpl (Input Handler & Scroll Logic)

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...

23 Syys 202527min