#lang scribble/manual
@(require (for-label racket))

@title{EZScroller}
 Show a subset of items on gui elements@section{categories}
  GUI>EZ-GUI

@section{description}

EZScroller is a vertical slider that allows displaying different subsets of a dynamically changing list of objects on a fixed number of views by scrolling.

EZScroller is used JITLib guis like link::Classes/NodeProxyEditor::, link::Classes/ProxyMixer::, link::Classes/TdefAllGui::, and link::Classes/PdefAllGui::.

@section{examples}
 

@racketblock[
(
w = Window.new("EZScroller test", Rect(100, 400,200, 100)).front;
// 5 displays
v = { |i| DragBoth.new(w, Rect(0, i * 20, 100, 20)) }.dup(5);
// 12 items
a = (1..12);

e = EZScroller(w, Rect(100,0,14,100), v.size, a.size, { |sc|
	var startIndex = sc.value.asInteger.postcs;
	v.do { |drag, i| drag.object_( a[ (startIndex) + i] ? ""); };
	e.visible_(sc.numItems > sc.maxItems); // hide when not useful
});
e.doAction;
)
// change list a, update ezscroller
a = (1..4); e.numItems_(a.size); e.doAction;

a = (1..8); e.numItems_(a.size); e.doAction;
::
]