Placeable [Layout Library (Eve)]

Detailed Description

A model of the Placeable concept is an item that can be measured and placed within a visual space.

Refinement Of:

Associated Types:

Extents Type	typename placeable_extents_type<Placeable>::type	Models adobe::extents_t. Used by the Placeable to relate the minimum visual extents it requires in order to be placed correctly.
Placement Data Type	typename placement_data_type<Placeable>::type	Models adobe::place_data_t. Contains the derived information necessary for the Placeable to position itself within the visual space

Todo:

Need concepts for extents and placement data

Notation:

T	A type that is a model of Placeable
t	Object of type T
e	Object of type Placeable::extents_type
p	Object of type Placeable::placement_data_type

Definitions:

Valid Expressions:

Name	Expression	Type requirements	Return type
Measure	measure(t, e);	e is a reference parameter that on return must contain the calculated horizontal and vertical extents of t within the visual space	void
Place	place(t, p);	p contains the calculated horizontal and vertical extents of t within the visual space	void

Expression Semantics:

Name	Expression	Precondition	Semantics	Postcondition
Place	place(t, p);	p must not be less than the minimum extents specified by measure	Places t within the visual space according to p	t is properly placed within the visual space

Complexity Guarantees:

Invariants:

Type(s) Modeling this Concept:

• Most user interface elements are Placeable, in that they need to be measured before they can be placed appropriately within the dialog to which they belong.

Notes:

See Also:

concept_placeable, measure, place

Example:

    Placeable_t             p;

    adobe::extents_t h;
    measure(p, h);

    adobe::place_data_t(/*initialized with h and actual placement location*/);

    place(p, d);