The View System

• A damage manager that automatically refreshes those parts of the display device that no longer accurately reflect the state of the view hierarchy
• A way to deliver positional events (such as mouse clicks) to the correct view hierarchy

TIP It is possible to write programs using only lower-level frameworks such as the View System. However, as you learn to use the higher-level frameworks (such as the GUI Application framework and the Presentation framework), you'll find that they often simplify the creation of non-trivial programs.

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