Function maybe_submit_hover_request

src/plot_widget.rs:1280–1331

(
    widget: &PlotWidget,
    state: &mut PlotState,
    effects: &mut UpdateEffects,
)

struct UpdateEffects {
    needs_redraw: bool,
    hover_pick: Option<HoverPickEvent>,
    drag_event: Option<DragEvent>,
    cursor_ui: Option<CursorPositionUiPayload>,
    clear_cursor_position: bool,
    /// Request publishing `camera_bounds` even when ticks didn't change.
    /// This keeps overlays in sync when tick producers are disabled.
    publish_camera_bounds: bool,
}

#[derive(Default, Debug)]
struct CanvasInvalidation {
    static_layer: bool,
    overlay_layer: bool,
}

impl CanvasInvalidation {
    fn static_layer(&mut self) {
        self.static_layer = true;
    }

    fn overlay_layer(&mut self) {
        self.overlay_layer = true;
    }

    fn all(&mut self) {
        self.static_layer = true;
        self.overlay_layer = true;
    }

    fn apply(self, widget: &PlotWidget) {
        if self.static_layer {
            invalidate_static_canvas(widget);
        }
        if self.overlay_layer {
            invalidate_overlay_canvas(widget);
        }
    }
}

fn widget_has_any_tooltips(widget: &PlotWidget) -> bool {
    widget
        .hovered_points
        .values()
        .chain(widget.picked_points.values())
        .any(|(_, tooltip)| tooltip.is_some())
}

fn widget_needs_camera_bounds(widget: &PlotWidget) -> bool {
    widget_has_any_tooltips(widget) || widget.shape_overlays_enabled.load(Ordering::Relaxed)
}

fn clear_hover_effect(widget: &PlotWidget, state: &mut PlotState, effects: &mut UpdateEffects) {
    let should_clear_hover =
        state.picking.last_hover_cache.is_some() || !widget.hovered_points.is_empty();