GEOS SDK TechDocs
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4 Using VisClass
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6 Visible Layers and 32-Bit Graphics
Visible objects can not be used unless they are placed within object trees. The top object of the tree must be of a subclass of
VisContentClass
. Other objects in the tree can be of any visible object class. Keep in mind, however, that
VisClass
objects can not have children; only the composite classes (
VisCompClass
and
VisContentClass
) may have children. Therefore,
VisClass
is useful only for leaf objects.
Each visible object has a
VI_link
instance field. This field specifies the optr of that object's next sibling in the tree. Since this is a field of
VisClass
, both composites and noncomposites have it. Composite objects also have a
VCI_comp
field which contains the optr of the composite's first child. Thus, visible trees use the same format as normal object trees.
Getting Visible Tree Information
Sending Messages Through the Tree
Visible Object Window Operations
GEOS SDK TechDocs
|
|
| 4 Using VisClass
| 6 Visible Layers and 32-Bit Graphics