azul_layout/managers/
hover.rs

1//! Hover state management for tracking mouse and touch hover history
2//!
3//! The HoverManager records hit test results for multiple input points
4//! (mouse, touch, pen) over multiple frames to enable gesture detection
5//! (like DragStart) that requires analyzing hover patterns over time
6//! rather than just the current frame.
7
8use std::collections::{BTreeMap, VecDeque};
9
10use crate::hit_test::FullHitTest;
11
12/// Maximum number of frames to keep in hover history
13const MAX_HOVER_HISTORY: usize = 5;
14
15/// Identifier for an input point (mouse, touch, pen, etc.)
16#[derive(Debug, Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
17pub enum InputPointId {
18    /// Mouse cursor
19    Mouse,
20    /// Touch point with unique ID (from TouchEvent.id)
21    Touch(u64),
22}
23
24/// Manages hover state history for all input points
25///
26/// Records hit test results for mouse and touch inputs over multiple frames:
27/// - DragStart detection (requires movement threshold over multiple frames)
28/// - Hover-over event detection
29/// - Multi-touch gesture detection
30/// - Input path analysis
31///
32/// The manager maintains a separate history for each active input point.
33#[derive(Debug, Clone, PartialEq)]
34pub struct HoverManager {
35    /// Hit test history for each input point
36    /// Each point has its own ring buffer of the last N frames
37    hover_histories: BTreeMap<InputPointId, VecDeque<FullHitTest>>,
38}
39
40impl HoverManager {
41    /// Create a new empty HoverManager
42    pub fn new() -> Self {
43        Self {
44            hover_histories: BTreeMap::new(),
45        }
46    }
47
48    /// Push a new hit test result for a specific input point
49    ///
50    /// The most recent result is always at index 0 for that input point.
51    /// If the history is full, the oldest frame is dropped.
52    pub fn push_hit_test(&mut self, input_id: InputPointId, hit_test: FullHitTest) {
53        let history = self
54            .hover_histories
55            .entry(input_id)
56            .or_insert_with(|| VecDeque::with_capacity(MAX_HOVER_HISTORY));
57
58        // Add to front (most recent)
59        history.push_front(hit_test);
60
61        // Remove oldest if we exceed the limit
62        if history.len() > MAX_HOVER_HISTORY {
63            history.pop_back();
64        }
65    }
66
67    /// Remove an input point's history (e.g., when touch ends)
68    pub fn remove_input_point(&mut self, input_id: &InputPointId) {
69        self.hover_histories.remove(input_id);
70    }
71
72    /// Get the most recent hit test result for an input point
73    ///
74    /// Returns None if no hit tests have been recorded for this input point.
75    pub fn get_current(&self, input_id: &InputPointId) -> Option<&FullHitTest> {
76        self.hover_histories
77            .get(input_id)
78            .and_then(|history| history.front())
79    }
80
81    /// Get the most recent mouse cursor hit test (convenience method)
82    pub fn get_current_mouse(&self) -> Option<&FullHitTest> {
83        self.get_current(&InputPointId::Mouse)
84    }
85
86    /// Get the hit test result from N frames ago for an input point
87    // (0 = current frame)
88    ///
89    /// Returns None if the requested frame is not in history.
90    pub fn get_frame(&self, input_id: &InputPointId, frames_ago: usize) -> Option<&FullHitTest> {
91        self.hover_histories
92            .get(input_id)
93            .and_then(|history| history.get(frames_ago))
94    }
95
96    /// Get the entire hover history for an input point (most recent first)
97    pub fn get_history(&self, input_id: &InputPointId) -> Option<&VecDeque<FullHitTest>> {
98        self.hover_histories.get(input_id)
99    }
100
101    /// Get all currently tracked input points
102    pub fn get_active_input_points(&self) -> Vec<InputPointId> {
103        self.hover_histories.keys().copied().collect()
104    }
105
106    /// Get the number of frames in history for an input point
107    pub fn frame_count(&self, input_id: &InputPointId) -> usize {
108        self.hover_histories
109            .get(input_id)
110            .map(|h| h.len())
111            .unwrap_or(0)
112    }
113
114    /// Clear all hover history for all input points
115    pub fn clear(&mut self) {
116        self.hover_histories.clear();
117    }
118
119    /// Clear history for a specific input point
120    pub fn clear_input_point(&mut self, input_id: &InputPointId) {
121        if let Some(history) = self.hover_histories.get_mut(input_id) {
122            history.clear();
123        }
124    }
125
126    /// Check if we have enough frames for gesture detection on an input point
127    ///
128    /// DragStart detection requires analyzing movement over multiple frames.
129    /// This returns true if we have at least 2 frames of history.
130    pub fn has_sufficient_history_for_gestures(&self, input_id: &InputPointId) -> bool {
131        self.frame_count(input_id) >= 2
132    }
133
134    /// Check if any input point has enough history for gesture detection
135    pub fn any_has_sufficient_history_for_gestures(&self) -> bool {
136        self.hover_histories
137            .iter()
138            .any(|(_, history)| history.len() >= 2)
139    }
140}
141
142impl Default for HoverManager {
143    fn default() -> Self {
144        Self::new()
145    }
146}
azul_layout/managers/hover.rs

azul_layout/managers/
hover.rs
