Scroll View

YauiScrollView scrolls a content element inside a viewport element by dragging, with the scroll wheel, and with scrollbars, like uGUI's ScrollRect.

The scroll view moves the content with its render transform (YauiElement.Translate). Scrolling never runs the layout again.

Setup

The content keeps its own layout. A typical setup for vertical scrolling:

ScrollView        YauiElement (ClipChildren), YauiScrollView
└─ Content        YauiElement (Position Absolute, Inset Left 0 / Top 0, Width 100%)
   ├─ Item
   ├─ Item
   └─ ...

• The viewport clips its children (ClipChildren). The viewport is the scroll view's own element unless Viewport is set.
• The content is an absolutely positioned child of the viewport, at the top-left. For vertical scrolling, its width is 100% of the viewport and its height is Auto, so that its children decide it. For horizontal scrolling, swap the width and the height.

Properties

Member	Description
Content, Viewport	The scrolled element, and the element that shows it
Horizontal, Vertical	The axes that scroll
MovementType	Elastic (pulls past the edges and springs back), Clamped (stops at the edges) or Unrestricted
Elasticity	Elastic: roughly the time in seconds to spring back
Inertia, DecelerationRate	Whether the content keeps moving after a drag, and the fraction of the velocity left after a second
ScrollSensitivity	Canvas units per step of the scroll wheel
HorizontalScrollbar, VerticalScrollbar	Scrollbars driven by the scroll view. The vertical one uses the direction TopToBottom.
OnValueChanged	Invoked with the normalized position when it changes

Scrolling from scripts

Member	Description
ScrollPosition	How far the content is scrolled from its place, in canvas units (positive toward its end)
ScrollRange	How far the content can scroll on each axis
NormalizedPosition	The scroll position as a fraction of the range (0 at the top-left)
Velocity	The current velocity
StopMovement()	Stops the inertia
ScrollIntoView(element)	Scrolls as little as needed to show a descendant of the content

Nested scroll views

A scroll view passes drags on the axes it cannot scroll, and scroll wheel events when its content fits, to the scroll view above it. A vertical list inside a horizontal pager works without extra code.

The scroll view does not virtualize its items. See Performance.