Next: Constructors
Up: Displayable
Previous: Displayable
The Displayable base class is the parent class for all items which need
to be drawn to a DisplayDevice. For example, the set of axes which
appear in the corner of the VMD display screen are maintained as a
Displayable, and each Molecule is one as well. The Scene
(section 6.3.7) object maintains a list of all the Displayable's
that are to be drawn to the screen. Each Displayable consists of the
following components:
- A transformation matrix which describes how the graphical object
represented by the Displayable is transformed (via translations,
rotations, and scaling).
- A display list which contains a set of drawing tokens, in a
device-independent format. The display list is used by a DisplayDevice
to actually draw the object.
- A parent Displayable, which acts as an `owner';
transformations applied to the parent are also applied to its children. If
an object does not have a parent, it is a top-level Displayable.
- A set of child Displayable objects.
The Displayable class is the fundamental building block for all items
which want to draw something to the screen. Consequently, it is a rather
complicated beast.
Justin Gullingsrud
Tue Apr 6 09:26:48 CDT 1999