Struct StyleReason 

pub struct StyleReason {
    pub flags: StyleReasonFlags,
    pub selectors: Option<StyleSelectors>,
    pub classes_changed: Option<SmallVec<[StyleClassRef; 4]>>,
    pub targets: Vec<(ElementId, StyleReason)>,
}

Describes why a view has been marked style-dirty. Combines a cheap bitmap of reason categories with optional payloads for the reasons that carry associated data.

The flags are the primary signal used to decide how much work style_view needs to do. The payload fields provide the details needed to actually do that work.

Invariants:

• selectors.is_some() iff flags.contains(SELECTOR)
• targets.is_empty() iff !flags.contains(TARGET)

Fields

flags: StyleReasonFlags

selectors: Option<StyleSelectors>

The selector set that caused this view to be dirty. Present when SELECTOR is set. Stored so that the style pass can skip resolve_nested_maps if the selectors that changed don’t actually affect any properties (e.g. a :hover selector exists but none of the now-hovered selectors match any style rules on this view).

classes_changed: Option<SmallVec<[StyleClassRef; 4]>>

targets: Vec<(ElementId, StyleReason)>

Sub-element rectangles owned by this view that need targeted restyling. Each entry is (element_id, reason) where element_id identifies a specific box-tree rectangle (e.g. the vertical scrollbar of a scroll view) and reason describes why that rectangle is dirty (typically SELECTOR due to hover/press state change on that specific hit region).

Present when TARGET is set. SmallVec<2> because most views with sub-elements have only a small fixed number of them (e.g. scroll view has 3 total, rarely more than 2 dirty simultaneously).

Implementations

impl StyleReason

pub fn empty() -> Self

pub fn with_selectors(selectors: StyleSelectors) -> Self

pub fn with_selector(selector: StyleSelector) -> Self

pub fn is_empty(&self) -> bool

pub fn set_inherited(&mut self)

pub fn set_class_cx(&mut self)

pub fn set_animation(&mut self)

pub fn set_transition(&mut self)

pub fn set_style_pass(&mut self)

pub fn set_view_style(&mut self)

pub fn set_visibility(&mut self)

pub fn set_selectors(&mut self, selectors: StyleSelectors)

pub fn add_target(&mut self, id: ElementId, reason: StyleReason)

pub fn animation() -> Self

pub fn style_pass() -> Self

pub fn view_style() -> Self

pub fn visibility() -> Self

pub fn transition() -> Self

pub fn inherited() -> Self

pub fn class_cx(classes: SmallVec<[StyleClassRef; 4]>) -> Self

pub fn needs_resolve_nested_maps(&self) -> bool

Returns true if this reason set requires a full cascade recomputation (i.e. resolve_nested_maps must run). False means only animation/transition stepping is needed and the cached combined_style can be reused.

pub fn needs_animation(&self) -> bool

pub fn needs_property_extraction(&self) -> bool

pub fn has_animation(&self) -> bool

pub fn has_visiblity(&self) -> bool

pub fn has_transition(&self) -> bool

pub fn has_selector(&self) -> bool

pub fn has_target(&self) -> bool

pub fn has_target_id(&self, id: ElementId) -> bool

pub fn target_reason(&self, id: ElementId) -> Option<&StyleReason>

pub fn merge(&mut self, other: StyleReason)

Merge another set into self, unioning all reasons.

pub fn filter(&self, flags: StyleReasonFlags) -> StyleReason

Returns a new set containing only the reasons that match the given flags.

pub fn clear_flag(&mut self, flag: StyleReasonFlags)

Remove a specific flag and its associated data.

pub fn clear_target(&mut self, id: ElementId)

pub fn for_children(&self) -> StyleReason

pub fn with_target(element_id: ElementId, reason: StyleReason) -> Self

pub fn with_selectors_and_target( element_id: ElementId, selectors: StyleSelectors, ) -> Self

pub fn full_recalc() -> Self

All flags set — forces a full recalc with no fast paths possible. Use as a fallback when the specific reason is unknown.

Trait Implementations

impl Clone for StyleReason

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 StyleReason

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

Formats the value using the given formatter.