GEOS SDK TechDocs
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4.3 Visible Object Abilities
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4.5 Creating a Visible Object Tree
There are four base visible classes on which the other object libraries are founded.
VisClass
is the most basic and at the root of the visible class tree. Under it are
VisCompClass
and
VisTextClass
.
VisContentClass
is a subclass of
VisCompClass
.
VisTextClass
is special in that it is rarely subclassed as it already contains nearly all the functionality an application will need from a visible text object.
The other three classes are typically subclassed by applications. None of the three can draw itself; instead, the subclass must handle
MSG_VIS_DRAW
, the message that indicates the object must draw itself. The three different classes are used as follows:
VisClass
VisClass
is the head of the visible class tree and therefore is the most broad-based in functionality.
VisClass
objects can not have children and therefore can only exist as the leaves of the object tree.
VisCompClass
VisCompClass
provides a composite
VisClass
object. Essentially, this class is the same as
VisClass
except that it can have children. It also includes several special geometry options that allow it to manage and place its children as well as set their bounds.
VisContentClass
VisContentClass
is used only as the content of a GenView. It is a subclass of
VisCompClass
and therefore can have children and manage them with the same geometry features available to VisComp. In addition, the VisContent interacts with the GenView to handle input and drawing. The content can interact with the view to determine sizing behavior as well as input behavior.GEOS SDK TechDocs
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| 4.3 Visible Object Abilities
| 4.5 Creating a Visible Object Tree