Struct VirtualViewCallbackInfo 

pub struct VirtualViewCallbackInfo {
    pub reason: VirtualViewCallbackReason,
    pub system_fonts: *const FcFontCache,
    pub image_cache: *const ImageCache,
    pub window_theme: WindowTheme,
    pub bounds: HidpiAdjustedBounds,
    pub scroll_size: LogicalSize,
    pub scroll_offset: LogicalPosition,
    pub virtual_scroll_size: LogicalSize,
    pub virtual_scroll_offset: LogicalPosition,
    /* private fields */
}

Fields

reason: VirtualViewCallbackReason

system_fonts: *const FcFontCache

image_cache: *const ImageCache

window_theme: WindowTheme

bounds: HidpiAdjustedBounds

scroll_size: LogicalSize

scroll_offset: LogicalPosition

virtual_scroll_size: LogicalSize

virtual_scroll_offset: LogicalPosition

Implementations

impl VirtualViewCallbackInfo

pub const fn new<'a>( reason: VirtualViewCallbackReason, system_fonts: &'a FcFontCache, image_cache: &'a ImageCache, window_theme: WindowTheme, bounds: HidpiAdjustedBounds, scroll_size: LogicalSize, scroll_offset: LogicalPosition, virtual_scroll_size: LogicalSize, virtual_scroll_offset: LogicalPosition, ) -> Self

pub const fn set_callable_ptr(&mut self, callable: &OptionRefAny)

Set the callable pointer for FFI language bindings

pub fn set_measure_dom_fn(&mut self, f: MeasureDomFn, ctx: *mut c_void)

Inject the headless-measure trampoline (called by the layout crate right before the user callback is invoked).

pub fn measure_dom(&self, dom: Dom, available: LogicalSize) -> LogicalSize

Measure a DOM headlessly: style + lay it out against available constraints using the host window’s fonts and system style, without touching the live layout. Returns the union of all node bounds.

Use a very tall available.height (e.g. 1_000_000.0) to obtain a DOM’s natural height at a fixed width - the building block for virtual-scroll sizing: measure one (or a few) item template(s), then virtual_scroll_size.height = item_height * item_count and render only the visible window of items. Each call is a full cold layout pass, so cache measured sizes per item template.

Returns LogicalSize::zero() when no measure hook was injected.

pub fn get_ctx(&self) -> OptionRefAny

Get the callable for FFI language bindings (Python, etc.)

pub const fn get_bounds(&self) -> HidpiAdjustedBounds

Trait Implementations

impl Clone for VirtualViewCallbackInfo

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for VirtualViewCallbackInfo

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

Formats the value using the given formatter.