apple-text-viewport-rendering

What problem does it solve?

This skill helps developers reason about how TextKit 2 viewport layout, line fragments, and rendering work, enabling accurate predictions of fragment frames, viewport behavior, and rendering surfaces within custom text views.

Core Features & Use Cases

• Understands viewport-based layout in TextKit 2, including fragment geometry, rendering surface placement, and font substitution timing that affects visuals.
• Aids debugging of scrolling behavior, on-screen and off-screen layout estimates, and conversions between fragment coordinates and document coordinates.
• Provides a practical mental model and reference guidelines for diagnosing layout and rendering issues in TextKit 2-based components.

Quick Start

Explain how TextKit 2 viewport rendering behaves and how to interpret fragment geometry in a debugging session.