Struct PresenceLayer 

pub struct PresenceLayer { /* private fields */ }

The presence a window paints over its widgets, kept from frame to frame so the next frame damages only what changed. Retains draw caches only.

Per frame: Self::widgets_need_full_repaint for the presence the widgets were drawn from, then Self::record the layer, append Self::scene over the widgets and add Self::damage; once the frame is submitted, Self::presented.

Implementations

impl PresenceLayer

pub fn new() -> PresenceLayer

pub fn widgets_need_full_repaint( &mut self, presence: &PresenceCtx, now: Instant, ) -> bool

Whether the widgets’ presence differs from the last submitted frame’s, or is animating. Widgets do not report damage for the carets, selections and marks they paint, so the window must repaint.

pub fn widgets_place_content_marks(&self) -> bool

Whether this frame’s widgets paint marks placed from their content (WidgetPresence::marks_follow_content). true until Self::widgets_need_full_repaint has seen the frame.

pub fn record(&mut self, draw: impl FnOnce(&mut Scene))

Record this frame’s layer. draw paints into an empty scene and must put every command in a scene_parts::part with honest bounds, the same parts in the same order every frame.

pub fn scene(&self) -> &Scene

This frame’s layer, to append over the widgets.

pub fn paints(&self) -> bool

Whether the layer on screen or this frame’s paints anything over the widgets.

pub fn damage(&self) -> Option<Vec<Rect>>

Damage, in the layer’s scene coordinates, between the layer on screen and this frame’s: the old and new bounds of every part that changed. None when that cannot be proven (no frame shown yet, a part left unbounded, commands outside every part), and the window must repaint.

pub fn marks(&self, bounds: &mut DrawBounds) -> Option<LayerMarks>

Where the layer on screen and this frame’s paint, in the layer’s scene coordinates: what a scroll copy must not carry with the content beneath (crate::scroll_copy::marks_over_copies). None when either cannot be bounded (a part without bounds, commands outside every part that bounds cannot bound), and the content beneath must repaint instead of copying.

pub fn presented(&mut self)

The frame recorded since the last call was submitted: it is what the next frame’s damage is measured against.

Trait Implementations

impl Default for PresenceLayer

fn default() -> PresenceLayer

Returns the “default value” for a type.