egui/
widget_rect.rs

1use ahash::HashMap;
2
3use crate::*;
4
5/// Used to store each widget's [Id], [Rect] and [Sense] each frame.
6///
7/// Used to check which widget gets input when a user clicks somewhere.
8#[derive(Clone, Copy, Debug, PartialEq, Eq)]
9pub struct WidgetRect {
10    /// The globally unique widget id.
11    ///
12    /// For interactive widgets, this better be globally unique.
13    /// If not there will be weird bugs,
14    /// and also big red warning test on the screen in debug builds
15    /// (see [`Options::warn_on_id_clash`]).
16    ///
17    /// You can ensure globally unique ids using [`Ui::push_id`].
18    pub id: Id,
19
20    /// What layer the widget is on.
21    pub layer_id: LayerId,
22
23    /// The full widget rectangle.
24    pub rect: Rect,
25
26    /// Where the widget is.
27    ///
28    /// This is after clipping with the parent ui clip rect.
29    pub interact_rect: Rect,
30
31    /// How the widget responds to interaction.
32    ///
33    /// Note: if [`Self::enabled`] is `false`, then
34    /// the widget _effectively_ doesn't sense anything,
35    /// but can still have the same `Sense`.
36    /// This is because the sense informs the styling of the widget,
37    /// but we don't want to change the style when a widget is disabled
38    /// (that is handled by the `Painter` directly).
39    pub sense: Sense,
40
41    /// Is the widget enabled?
42    pub enabled: bool,
43}
44
45/// Stores the [`WidgetRect`]s of all widgets generated during a single egui update/frame.
46///
47/// All [`Ui`]s have a [`WidgetRects`], but whether or not their rects are correct
48/// depends on if [`Ui::interact_bg`] was ever called.
49#[derive(Default, Clone)]
50pub struct WidgetRects {
51    /// All widgets, in painting order.
52    by_layer: HashMap<LayerId, Vec<WidgetRect>>,
53
54    /// All widgets, by id, and their order in their respective layer
55    by_id: IdMap<(usize, WidgetRect)>,
56
57    /// Info about some widgets.
58    ///
59    /// Only filled in if the widget is interacted with,
60    /// or if this is a debug build.
61    infos: IdMap<WidgetInfo>,
62}
63
64impl PartialEq for WidgetRects {
65    fn eq(&self, other: &Self) -> bool {
66        self.by_layer == other.by_layer
67    }
68}
69
70impl WidgetRects {
71    /// All known layers with widgets.
72    pub fn layer_ids(&self) -> impl ExactSizeIterator<Item = LayerId> + '_ {
73        self.by_layer.keys().copied()
74    }
75
76    pub fn layers(&self) -> impl Iterator<Item = (&LayerId, &[WidgetRect])> + '_ {
77        self.by_layer
78            .iter()
79            .map(|(layer_id, rects)| (layer_id, &rects[..]))
80    }
81
82    #[inline]
83    pub fn get(&self, id: Id) -> Option<&WidgetRect> {
84        self.by_id.get(&id).map(|(_, w)| w)
85    }
86
87    /// In which layer, and in which order in that layer?
88    pub fn order(&self, id: Id) -> Option<(LayerId, usize)> {
89        self.by_id.get(&id).map(|(idx, w)| (w.layer_id, *idx))
90    }
91
92    #[inline]
93    pub fn contains(&self, id: Id) -> bool {
94        self.by_id.contains_key(&id)
95    }
96
97    /// All widgets in this layer, sorted back-to-front.
98    #[inline]
99    pub fn get_layer(&self, layer_id: LayerId) -> impl Iterator<Item = &WidgetRect> + '_ {
100        self.by_layer.get(&layer_id).into_iter().flatten()
101    }
102
103    /// Clear the contents while retaining allocated memory.
104    pub fn clear(&mut self) {
105        let Self {
106            by_layer,
107            by_id,
108            infos,
109        } = self;
110
111        for rects in by_layer.values_mut() {
112            rects.clear();
113        }
114
115        by_id.clear();
116
117        infos.clear();
118    }
119
120    /// Insert the given widget rect in the given layer.
121    pub fn insert(&mut self, layer_id: LayerId, widget_rect: WidgetRect) {
122        let Self {
123            by_layer,
124            by_id,
125            infos: _,
126        } = self;
127
128        let layer_widgets = by_layer.entry(layer_id).or_default();
129
130        match by_id.entry(widget_rect.id) {
131            std::collections::hash_map::Entry::Vacant(entry) => {
132                // A new widget
133                let idx_in_layer = layer_widgets.len();
134                entry.insert((idx_in_layer, widget_rect));
135                layer_widgets.push(widget_rect);
136            }
137            std::collections::hash_map::Entry::Occupied(mut entry) => {
138                // This is a known widget, but we might need to update it!
139                // e.g. calling `response.interact(…)` to add more interaction.
140                let (idx_in_layer, existing) = entry.get_mut();
141
142                debug_assert!(
143                    existing.layer_id == widget_rect.layer_id,
144                    "Widget changed layer_id during the frame"
145                );
146
147                // Update it:
148                existing.rect = widget_rect.rect; // last wins
149                existing.interact_rect = widget_rect.interact_rect; // last wins
150                existing.sense |= widget_rect.sense;
151                existing.enabled |= widget_rect.enabled;
152
153                if existing.layer_id == widget_rect.layer_id {
154                    layer_widgets[*idx_in_layer] = *existing;
155                }
156            }
157        }
158    }
159
160    pub fn set_info(&mut self, id: Id, info: WidgetInfo) {
161        self.infos.insert(id, info);
162    }
163
164    pub fn info(&self, id: Id) -> Option<&WidgetInfo> {
165        self.infos.get(&id)
166    }
167}
egui/widget_rect.rs

egui/
widget_rect.rs
