GEOS SDK TechDocs
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4 Using the Visible Classes
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4.2 The Visible Object Document
Visible objects are designed for flexibility and for interacting with the user. Typically, visible objects will reside in an object tree, the root of which is a VisContent or GenDocument object connected to a GenView (this section assumes the VisContent, though the GenDocument is roughly equivalent for the purposes of overview). The relationship between these objects is simple, yet it accomplishes an immense amount of work for the application.
The GenView provides a window that may be scrollable, scalable, and resizable. The view is directly connected to the VisContent object and works very closely with it to handle input and drawing events. The VisContent acts as a manager for the visible object tree; it passes input events (mouse moves and mouse clicks) on to the proper visible object directly under the mouse pointer, and it makes sure all visible objects in the tree draw themselves at the appropriate time.
The view and VisContent may be connected tightly or very loosely for sizing purposes. For example, the view may be forced to resize itself to the proper size of the VisContent; or, the view might be scrollable and resizable independent of the content's size. The VisContent can choose whether mouse events are expected or required, and the view will notify the VisContent whenever the window has been invalidated and the document needs redrawing.
GEOS SDK TechDocs
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| 4 Using the Visible Classes
| 4.2 The Visible Object Document