Blink Engine LayoutBox Rectangles and Overflow Flags

The provided text examines the geometry and overflow management systems within Chromium’s Blink Engine, focusing specifically on the LayoutBox class and its associated rectangles. It details how the engine distinguishes between physical and logical coordinates to handle complex tasks like text direction, scrolling, and hit-testing. Key structures such as OverflowClipRect and VisualRect are explained to show how the browser determines which content is visible, scrollable, or interactive. Additionally, the source describes several boolean flags, such as HasScrollableOverflow and HasNonVisibleOverflow, which optimize performance by indicating if an element exceeds its boundaries. The text also covers specialized scenarios like sticky positioning and fragmented layouts in multi-column designs. Ultimately, these technical definitions and states work together to ensure that painting, compositing, and user interactions align correctly with CSS specifications.