Browser Rendering: Calculating Draw Properties

The source provides an extensive explanation of the internal browser rendering mechanism used in Blink and Chrome, specifically focusing on the CalculateDrawProperties algorithm. This process translates high-level web features, such as CSS transforms and opacity, into low-level GPU commands. Crucially, the system relies on specialized property trees (Transform, Clip, Effect, and Scroll trees) to efficiently cache geometric and visual data, preventing repeated traversals of the layer structure. Before calculating individual layer properties, the algorithm updates global factors like page scale and elastic overscroll to ensure accurate composition. Finally, it computes the exact draw properties for visible layers and determines which layers require render surfaces for complex effects like filtering or blending, thereby generating the final list of surfaces and layers for the GPU to process.