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use std::collections::HashSet;
use rustc_hash::{
FxHashMap,
FxHashSet,
};
use crate::{
EmmitableEvent,
EventsMeasurer,
NameOfEvent,
NodeKey,
PotentialEvent,
SourceEvent,
};
/// [`NodesState`] stores the nodes states given incoming events.
pub struct NodesState<Key: NodeKey> {
pressed_nodes: FxHashSet<Key>,
hovered_nodes: FxHashSet<Key>,
}
impl<Key: NodeKey> Default for NodesState<Key> {
fn default() -> Self {
Self {
pressed_nodes: FxHashSet::default(),
hovered_nodes: FxHashSet::default(),
}
}
}
pub type PotentialEvents<Key, Name, Source> =
FxHashMap<Name, Vec<PotentialEvent<Key, Name, Source>>>;
impl<Key: NodeKey> NodesState<Key> {
/// Retain or not the states of the nodes given the [EmmitableEvent]s and based on the sideffects of these removals
/// a set of [PotentialEvent]s are returned.
pub(crate) fn retain_states<
Emmitable: EmmitableEvent<Key = Key, Name = Name>,
Name: NameOfEvent,
Source: SourceEvent,
>(
&mut self,
events_measurer: &impl EventsMeasurer<
Key = Key,
Name = Name,
Emmitable = Emmitable,
Source = Source,
>,
emmitable_events: &[Emmitable],
source_events: &[Source],
) -> Vec<Emmitable> {
let mut collateral_emmitable_events = Vec::default();
// Any press event at all
let source_press_event = source_events.iter().any(|e| e.is_pressed());
// Pressed Nodes
#[allow(unused_variables)]
self.pressed_nodes.retain(|node_key| {
// Check if a Tree event that presses this Node will get emitted
let emmitable_press_event = emmitable_events
.iter()
.any(|event| event.name().is_pressed() && &event.key() == node_key);
// If there has been a mouse press but a Tree event was not emitted to this node, then we safely assume
// the user does no longer want to press this Node
if !emmitable_press_event && source_press_event {
#[cfg(debug_assertions)]
tracing::info!("Unmarked as pressed {:?}", node_key);
// Remove the node from the list of pressed nodes
return false;
}
true
});
// Any movement event at all
let source_movement_event = source_events.iter().find(|e| e.is_moved());
// Hovered Nodes
self.hovered_nodes.retain(|node_key| {
// Check if a Tree event that moves the cursor in this Node will get emitted
let emmitable_movement_event = emmitable_events.iter().any(|event| {
(event.name().is_moved() || event.name().is_enter()) && &event.key() == node_key
});
if !emmitable_movement_event {
// If there has been a mouse movement but a Tree event was not emitted to this node, then we safely assume
// the user does no longer want to hover this Node
if let Some(source_event) = source_movement_event {
if let Some(area) = events_measurer.try_area_of(node_key) {
// Emit a leave event as the cursor was moved outside the Node bounds
let event = Name::new_leave();
for derived_event in event.get_derived_events() {
let is_node_listening =
events_measurer.is_listening_to(node_key, &derived_event);
if is_node_listening {
collateral_emmitable_events.push(
events_measurer.new_emmitable_event(
*node_key,
derived_event,
source_event.clone(),
Some(area),
),
);
}
}
#[cfg(debug_assertions)]
tracing::info!("Unmarked as hovered {:?}", node_key);
}
// Remove the node from the list of hovered nodes
return false;
}
}
true
});
collateral_emmitable_events
}
pub(crate) fn filter_emmitable_events<
Emmitable: EmmitableEvent<Key = Key, Name = Name>,
Name: NameOfEvent,
>(
&self,
emmitable_events: &mut Vec<Emmitable>,
) {
emmitable_events.retain(|ev| {
match ev.name() {
// Only let through enter events when the node was not hovered
_ if ev.name().is_enter() => !self.hovered_nodes.contains(&ev.key()),
// Only let through release events when the node was already pressed
_ if ev.name().is_released() => self.pressed_nodes.contains(&ev.key()),
_ => true,
}
});
}
/// Create the nodes states given the [PotentialEvent]s.
pub fn create_update<
Emmitable: EmmitableEvent<Key = Key, Name = Name>,
Name: NameOfEvent,
Source: SourceEvent,
>(
&self,
events_measurer: &impl EventsMeasurer<Key = Key, Name = Name>,
potential_events: &PotentialEvents<Key, Name, Source>,
) -> NodesStatesUpdate<Key> {
let mut hovered_nodes = FxHashSet::default();
let mut pressed_nodes = FxHashSet::default();
// Update the state of the nodes given the new events.
for events in potential_events.values() {
let mut child_node: Option<Key> = None;
for PotentialEvent { node_key, name, .. } in events.iter().rev() {
if let Some(child_node) = child_node
&& !events_measurer.is_node_parent_of(&child_node, *node_key)
{
continue;
}
if !events_measurer.is_node_transparent(node_key) && !name.does_go_through_solid() {
// If the background isn't transparent,
// we must make sure that next nodes are parent of it
// This only matters for events that bubble up (e.g. cursor click events)
child_node = Some(*node_key);
}
match name {
// Update hovered nodes state
name if name.is_moved() => {
// Mark the Node as hovered if it wasn't already
hovered_nodes.insert(*node_key);
#[cfg(debug_assertions)]
tracing::info!("Marked as hovered {:?}", node_key);
}
// Update pressed nodes state
name if name.is_pressed() => {
// Mark the Node as pressed if it wasn't already
pressed_nodes.insert(*node_key);
#[cfg(debug_assertions)]
tracing::info!("Marked as pressed {:?}", node_key);
}
_ => {}
}
}
}
NodesStatesUpdate {
pressed_nodes,
hovered_nodes,
}
}
/// Apply the given [NodesStatesUpdate] in a way so that only newly hovered/pressed nodes are cached.
/// Any discard of nodes in the [NodesStatesUpdate] wont matter here.
pub fn apply_update(&mut self, update: NodesStatesUpdate<Key>) {
self.hovered_nodes.extend(update.hovered_nodes);
self.pressed_nodes.extend(update.pressed_nodes);
}
pub fn is_hovered(&self, key: Key) -> bool {
self.hovered_nodes.contains(&key)
}
pub fn is_pressed(&self, key: Key) -> bool {
self.pressed_nodes.contains(&key)
}
}
#[derive(Clone, Debug, PartialEq)]
pub struct NodesStatesUpdate<Key: NodeKey> {
pressed_nodes: FxHashSet<Key>,
hovered_nodes: FxHashSet<Key>,
}
impl<Key: NodeKey> Default for NodesStatesUpdate<Key> {
fn default() -> Self {
Self {
pressed_nodes: HashSet::default(),
hovered_nodes: HashSet::default(),
}
}
}
impl<Key: NodeKey> NodesStatesUpdate<Key> {
/// Discard the state of a given [NodeKey] and a [NameOfEvent] in this [NodesStatesUpdate].
pub fn discard<Name: NameOfEvent>(&mut self, name: &Name, node_key: &Key) {
match name {
// Just like a movement makes the node hover, a discard movement also unhovers it
_ if name.is_moved() => {
self.hovered_nodes.remove(node_key);
}
_ if name.is_pressed() => {
self.pressed_nodes.remove(node_key);
}
_ => {}
}
}
}