Enum ScrollCacheExtent 

pub enum ScrollCacheExtent {
    Pixels(f64),
    Viewport(f64),
}

The amount of additional content to display and lay out around the viewport.

The cache area is used to lay out slivers before they are visible on screen. Items that fall in this cache area are laid out even though they are not visible on screen. This allows the viewport to render them ahead of time, enabling a smoother scrolling experience.

This type encapsulates both the value and the style of the cache extent. It allows the cache extent to be defined either as a fixed number of logical pixels using ScrollCacheExtent::Pixels or as a multiplier of the viewport’s main axis extent using ScrollCacheExtent::Viewport.

Variants

Pixels(f64)

A cache extent in logical pixels.

Viewport(f64)

A cache extent as a multiplier of the viewport’s main axis extent.

The main axis extent is the size of the viewport in its main axis. For example, for a vertically scrolling list, the main axis extent is the height of the viewport. If the viewport is 600 logical pixels tall, then ScrollCacheExtent::Viewport(2.0) results in a cache extent of 1200 logical pixels.

Implementations

impl ScrollCacheExtent

pub fn style(self) -> CacheExtentStyle

Returns the style of the cache extent.

pub fn value(self) -> f64

Returns the raw value of the cache extent.

If style is CacheExtentStyle::Pixel, this is the number of pixels to cache. If it is CacheExtentStyle::Viewport, this is the multiplier of the viewport’s main axis extent to cache.

Trait Implementations

impl Clone for ScrollCacheExtent

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for ScrollCacheExtent

impl Debug for ScrollCacheExtent

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl PartialEq for ScrollCacheExtent

fn eq(&self, other: &Self) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for ScrollCacheExtent