cc::TransformTree
Blink2861 Marras 2025

cc::TransformTree

source provides a highly detailed technical overview of the Transform Property Tree within the Chromium compositor, which is a core component of the RenderingNG architecture responsible for all coordinate transformations and geometric calculations. This structure uses TransformNode entries to represent individual coordinate spaces, enabling the efficient computation and caching of transforms such as to_parent (local transform to the parent) and to_screen (global transform to the root viewport). Critically, the TransformTree handles complex visual features like CSS transforms, scrolling (treating offsets as translation matrices), 3D contexts and flattening, and pixel snapping to ensure visual precision, all while propagating animation status and damage tracking to minimize recalculations and allow off-main-thread updates.


Jaksot(397)

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

blink::EventHandler (Blink core input handling)

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 . I...

23 Syys 202526min

blink::ElasticOverscrollController

blink::ElasticOverscrollController

Overscroll orchestration and animation. This Blink-side controller manages the rubber-banding (elastic stretch and rebound) effect when a scrollable area is overscrolled. It observes gesture scroll ev...

23 Syys 202526min

viz::Surface / SurfaceAggregator

viz::Surface / SurfaceAggregator

Receives frames from one or more surfaces (main page and OOPIFs), aggregates them into a single display frame.

23 Syys 202535min

viz::CompositorFrameSink (client side)

viz::CompositorFrameSink (client side)

The submission interface used by cc to hand the frame to viz.

23 Syys 202531min