This repository is a production-grade, canvas-based WYSIWYG rich text document editor published as the npm package `@hufe921/canvas-editor`. It is a monolithic library that provides a fully self-contained document editing experience, rendering text, tables, images, LaTeX, and form controls entirely on an HTML `<canvas>` element. The architecture is a well-structured layered design featuring a Command pattern facade (`Command`/`CommandAdapt`), a custom particle-based rendering engine (`Draw`), a pub/sub event system (`EventBus`), and a plugin system. The editor supports a wide array of features including pagination, headers/footers, watermarks, change tracking (trace mode), macros, spell checking, accessibility, multi-column layouts, and a sophisticated cascade expression engine for dynamic form control behavior. It is specifically designed for high-fidelity document editing in domains like Electronic Medical Records (EMR), contracts, and official documents, as evidenced by the mock data and feature set. The codebase demonstrates strong engineering craftsmanship. Several components are genuinely reusable, including a custom Myers O(ND) diff algorithm, a standalone LaTeX-to-SVG renderer using Hershey fonts, a fully featured DSL expression evaluator for control cascading, and a clean event bus implementation. The project is actively maintained with a comprehensive test suite (Cypress E2E, Vitest unit tests), modern tooling (Vite, TypeScript), and a rich plugin ecosystem. While some core files like `Draw.ts` and `CommandAdapt.ts` are large and exhibit tight coupling, the overall architecture, separation of concerns, and quality of the reusable components are well above average.