一用於發展視覺化編輯器之可再利用程式庫的建構

Abstract

視覺化程式設計提供應用程式發展的方便性與效率。一個設計良好的視 覺化編輯器 增加了程式的可讀性與可維護性。然而，從無到有發展一視 覺化編輯器卻是項耗時 耗力的工作。本篇論文提出一用於發展視覺化編 輯器的可重用程式庫 - Visual Editor Library (VEL)。不同於其他程 式庫只支援圖形繪製的功能，藉由物件導向技術，VEL 提供一能自動對 使用者編輯行為作反應的框架。與目前其他的視覺化程式庫相較，VEL 有效減低了再利用上的負擔。VEL 類別階層的設計使得程式發展者得以透 過 Run Time Type Information (RTTI) 的協助，定義所需的物件外型 ，達到擴展類別階層的目的。 Visual programming provides convenience and efficiency for developing applications. A well-designed visual editor increases the readability and maintainability of programs. However, constructing a visual editor from scratch is time- consuming and laborious. This thesis presents a reusable library, the Visual Editor Library (VEL), which is designed for developing visual editors. Object-oriented techniques are employed to construct the VEL, which provides a framework that automatically reacts to user editing activities, rather than other libraries that support shape drawing only. Compared with current visual programming libraries, our VEL reduces the overhead of reuse. The class hierarchy of VEL is designed with care so that the developers may define their preferred object shapes through the mechanism of Run Time Type Information (RTTI), and be able to extend the hierarchy with fair cost.