InterViews Reference Manual -- Perspective
NAME
Perspective - visible portion of an interactor
SYNOPSIS
#include <InterViews/perspective.h>
DESCRIPTION
A perspective object describes which part of an interactor's total display area
is visible in the interactor's canvas. The main use of perspectives is for
scrolling, panning, and zooming interactors. The member variables
(x0, y0) define the origin of the interactor's display area;
width and height define the total height of the area. The
member variables (curx, cury) define the lower-left corner of
the interactor's canvas relative to the total area; curwidth and
curheight define how much of the total area is displayed in the
canvas.
The member variables sx, sy, lx, and ly
specify small and large increments in each dimension. These increments are
used by a scroller to implement line and page scrolling.
PUBLIC OPERATIONS
Perspective()
Define a new perspective with all member variables initialized to zero.
void Attach(Interactor*)
Add to the list of interactors that are interested in updates to the
perspective. These interactors reflect the perspective visually; examples
include scrollers and sliders.
void Detach(Interactor*)
Remove an interactor from the list of those interested in updates. This
operation should be called from the interactor's destructor.
void Init(Coord x0, Coord y0, Coord width, Coord height)
Initialize the perspective display area.
void Update()
Notify all the interactors interested in the perspective that it has changed.
The perspective's interactor should call Update after modifying its
perspective.
SEE ALSO
Adjuster , Interactor , Panner , Scroller
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