Scene(3I) InterViews Reference Manual Scene(3I)
Scene, MonoScene - composite interactors
Scene is the base class for all interactors that are defined in terms of one or more instances of other interactors. MonoScene is a sub-
class for scenes that contain a single instance. A monoscene's shape is copied from its component and the component's canvas is given the
same size and location as the monoscene's canvas.
When a scene is deleted, it should delete all its component interactors. A monoscene deletes its existing component if a new component is
void Insert(Interactor*, Coord x, Coord y, Alignment = BottomLeft)
virtual Interactor* Wrap(Interactor*)
virtual void DoInsert(Interactor*, boolean, Coord& x, Coord& y, Shape*)
Add an interactor to the scene, optionally aligned with respect to a specific position relative to the lower-left corner of the
scene. Valid alignment types are TopLeft, TopCenter, TopRight, CenterLeft, Center, CenterRight, BottomLeft, BottomCenter, Bottom-
Right, Left, Right, Top, Bottom, HorizCenter, and VertCenter. The scene uses the interactor's desired shape, if it has non-zero
width, to size the interactor. The base scene class always calls Wrap and DoInsert from Insert; thus subclasses only implement
DoInsert (and Wrap if they want to wrap additional interactors around the inserted interactor) and users only call Insert. In the
case of a monoscene, the current interior interactor, if not nil, is deleted and replaced by the given interactor. If an interactor
is inserted into a scene that is already mapped, the interactor and its descendants will be configured before DoInsert is called.
virtual void DoChange(Interactor*, Shape*)
Change notifies a scene that a given interactor has changed its desired shape. If the propagate flag associated with the scene is
true, Change will call DoChange and then Change(this) on the scene's parent. If the propagate flag is false, Resize will be called
instead. The propagate flag is true by default and can be set with the Propagate operation.
void Move(Interactor*, Coord x, Coord y, Alignment = BottomLeft)
virtual void DoMove(Interactor*, Coord& x, Coord& y)
Request that an interactor be moved to the given coordinates using the given alignment. As with Insert and Change, users call Move
and subclasses implement DoMove.
virtual void DoRemove(Interactor*)
Remove an interactor from a scene. Users call Remove and subclasses implement DoRemove.
virtual void DoLower(Interactor*)
Put the interactor's canvas below all others in the scene, potentially obscuring it. Users call Lower and subclasses implement
virtual void DoRaise(Interactor*)
Put the interactor's canvas above all others in the scene, making it fully visible. Users call Raise and subclasses implement
Construct a new scene or monoscene. Scenes and monoscenes are abstract classes; thus, the constructors should only be called
implicitly by subclass constructors.
void Place(Interactor*, Coord x1, Coord y1, Coord x2, Coord y2, boolean = true)
Assign an interactor's canvas to be a given region of the scene's canvas. Unless the optional sixth parameter is false, the inter-
actor will be mapped. If the interactor is already assigned the given position and size, then this operation will have no effect.
This optimization means that a scene can place all of its elements in response to a Change and be assured that only those elements
that have really changed will be redrawn.
void Map(Interactor*, boolean = true)
Make the interactor visible on the display if and when the scene is visible. Unless the optional second parameter is false, the
interactor will be raised to the top of the scene.
Make the interactor not be visible on the display if and when the scene is visible.
void UserPlace(Interactor*, int w, int h)
Let the user interact with the window manager to specify the size and location of the interactor's canvas, whose default width and
height must also be supplied by the program.
Canvas(3I), Interactor(3I), Shape(3I)
InterViews 7 Mar 1989 Scene(3I)