1use super::Padding;
2use crate::{
3 geometry::{
4 rect::RectF,
5 vector::{vec2f, Vector2F},
6 },
7 platform::CursorStyle,
8 platform::MouseButton,
9 scene::{
10 CursorRegion, HandlerSet, MouseClick, MouseDown, MouseDownOut, MouseDrag, MouseHover,
11 MouseMove, MouseMoveOut, MouseScrollWheel, MouseUp, MouseUpOut,
12 },
13 Element, ElementBox, MouseRegion, MouseState, SceneBuilder, SizeConstraint, View, ViewContext,
14};
15use serde_json::json;
16use std::{marker::PhantomData, ops::Range};
17
18pub struct MouseEventHandler<Tag: 'static, V: View> {
19 child: ElementBox<V>,
20 region_id: usize,
21 cursor_style: Option<CursorStyle>,
22 handlers: HandlerSet,
23 hoverable: bool,
24 notify_on_hover: bool,
25 notify_on_click: bool,
26 above: bool,
27 padding: Padding,
28 _tag: PhantomData<Tag>,
29}
30
31/// Element which provides a render_child callback with a MouseState and paints a mouse
32/// region under (or above) it for easy mouse event handling.
33impl<Tag, V: View> MouseEventHandler<Tag, V> {
34 pub fn new<F>(region_id: usize, view: &mut V, cx: &mut ViewContext<V>, render_child: F) -> Self
35 where
36 V: View,
37 F: FnOnce(&mut MouseState, &mut V, &mut ViewContext<V>) -> ElementBox<V>,
38 {
39 let mut mouse_state = cx.mouse_state::<Tag>(region_id);
40 let child = render_child(&mut mouse_state, view, cx);
41 let notify_on_hover = mouse_state.accessed_hovered();
42 let notify_on_click = mouse_state.accessed_clicked();
43 Self {
44 child,
45 region_id,
46 cursor_style: None,
47 handlers: Default::default(),
48 notify_on_hover,
49 notify_on_click,
50 hoverable: true,
51 above: false,
52 padding: Default::default(),
53 _tag: PhantomData,
54 }
55 }
56
57 /// Modifies the MouseEventHandler to render the MouseRegion above the child element. Useful
58 /// for drag and drop handling and similar events which should be captured before the child
59 /// gets the opportunity
60 pub fn above<F>(
61 region_id: usize,
62 view: &mut V,
63 cx: &mut ViewContext<V>,
64 render_child: F,
65 ) -> Self
66 where
67 V: View,
68 F: FnOnce(&mut MouseState, &mut V, &mut ViewContext<V>) -> ElementBox<V>,
69 {
70 let mut handler = Self::new(region_id, view, cx, render_child);
71 handler.above = true;
72 handler
73 }
74
75 pub fn with_cursor_style(mut self, cursor: CursorStyle) -> Self {
76 self.cursor_style = Some(cursor);
77 self
78 }
79
80 pub fn capture_all(mut self) -> Self {
81 self.handlers = HandlerSet::capture_all();
82 self
83 }
84
85 pub fn on_move(mut self, handler: impl Fn(MouseMove, &mut ViewContext<V>) + 'static) -> Self {
86 self.handlers = self.handlers.on_move(handler);
87 self
88 }
89
90 pub fn on_move_out(
91 mut self,
92 handler: impl Fn(MouseMoveOut, &mut ViewContext<V>) + 'static,
93 ) -> Self {
94 self.handlers = self.handlers.on_move_out(handler);
95 self
96 }
97
98 pub fn on_down(
99 mut self,
100 button: MouseButton,
101 handler: impl Fn(MouseDown, &mut ViewContext<V>) + 'static,
102 ) -> Self {
103 self.handlers = self.handlers.on_down(button, handler);
104 self
105 }
106
107 pub fn on_up(
108 mut self,
109 button: MouseButton,
110 handler: impl Fn(MouseUp, &mut ViewContext<V>) + 'static,
111 ) -> Self {
112 self.handlers = self.handlers.on_up(button, handler);
113 self
114 }
115
116 pub fn on_click(
117 mut self,
118 button: MouseButton,
119 handler: impl Fn(MouseClick, &mut ViewContext<V>) + 'static,
120 ) -> Self {
121 self.handlers = self.handlers.on_click(button, handler);
122 self
123 }
124
125 pub fn on_down_out(
126 mut self,
127 button: MouseButton,
128 handler: impl Fn(MouseDownOut, &mut ViewContext<V>) + 'static,
129 ) -> Self {
130 self.handlers = self.handlers.on_down_out(button, handler);
131 self
132 }
133
134 pub fn on_up_out(
135 mut self,
136 button: MouseButton,
137 handler: impl Fn(MouseUpOut, &mut ViewContext<V>) + 'static,
138 ) -> Self {
139 self.handlers = self.handlers.on_up_out(button, handler);
140 self
141 }
142
143 pub fn on_drag(
144 mut self,
145 button: MouseButton,
146 handler: impl Fn(MouseDrag, &mut ViewContext<V>) + 'static,
147 ) -> Self {
148 self.handlers = self.handlers.on_drag(button, handler);
149 self
150 }
151
152 pub fn on_hover(mut self, handler: impl Fn(MouseHover, &mut ViewContext<V>) + 'static) -> Self {
153 self.handlers = self.handlers.on_hover(handler);
154 self
155 }
156
157 pub fn on_scroll(
158 mut self,
159 handler: impl Fn(MouseScrollWheel, &mut ViewContext<V>) + 'static,
160 ) -> Self {
161 self.handlers = self.handlers.on_scroll(handler);
162 self
163 }
164
165 pub fn with_hoverable(mut self, is_hoverable: bool) -> Self {
166 self.hoverable = is_hoverable;
167 self
168 }
169
170 pub fn with_padding(mut self, padding: Padding) -> Self {
171 self.padding = padding;
172 self
173 }
174
175 fn hit_bounds(&self, bounds: RectF) -> RectF {
176 RectF::from_points(
177 bounds.origin() - vec2f(self.padding.left, self.padding.top),
178 bounds.lower_right() + vec2f(self.padding.right, self.padding.bottom),
179 )
180 .round_out()
181 }
182
183 fn paint_regions(
184 &self,
185 scene: &mut SceneBuilder,
186 bounds: RectF,
187 visible_bounds: RectF,
188 cx: &mut ViewContext<V>,
189 ) {
190 let visible_bounds = visible_bounds.intersection(bounds).unwrap_or_default();
191 let hit_bounds = self.hit_bounds(visible_bounds);
192
193 if let Some(style) = self.cursor_style {
194 cx.scene.push_cursor_region(CursorRegion {
195 bounds: hit_bounds,
196 style,
197 });
198 }
199 cx.scene.push_mouse_region(
200 MouseRegion::from_handlers::<Tag>(
201 cx.current_view_id(),
202 self.region_id,
203 hit_bounds,
204 self.handlers.clone(),
205 )
206 .with_hoverable(self.hoverable)
207 .with_notify_on_hover(self.notify_on_hover)
208 .with_notify_on_click(self.notify_on_click),
209 );
210 }
211}
212
213impl<Tag, V: View> Element<V> for MouseEventHandler<Tag, V> {
214 type LayoutState = ();
215 type PaintState = ();
216
217 fn layout(
218 &mut self,
219 constraint: SizeConstraint,
220 view: &mut V,
221 cx: &mut ViewContext<V>,
222 ) -> (Vector2F, Self::LayoutState) {
223 (self.child.layout(constraint, view, cx), ())
224 }
225
226 fn paint(
227 &mut self,
228 scene: &mut SceneBuilder,
229 bounds: RectF,
230 visible_bounds: RectF,
231 _: &mut Self::LayoutState,
232 view: &mut V,
233 cx: &mut ViewContext<V>,
234 ) -> Self::PaintState {
235 if self.above {
236 self.child
237 .paint(scene, bounds.origin(), visible_bounds, view, cx);
238
239 cx.paint_layer(None, |cx| {
240 self.paint_regions(scene, bounds, visible_bounds, cx);
241 });
242 } else {
243 self.paint_regions(scene, bounds, visible_bounds, cx);
244 self.child
245 .paint(scene, bounds.origin(), visible_bounds, view, cx);
246 }
247 }
248
249 fn rect_for_text_range(
250 &self,
251 range_utf16: Range<usize>,
252 _: RectF,
253 _: RectF,
254 _: &Self::LayoutState,
255 _: &Self::PaintState,
256 view: &V,
257 cx: &ViewContext<Self>,
258 ) -> Option<RectF> {
259 self.child.rect_for_text_range(range_utf16, view, cx)
260 }
261
262 fn debug(
263 &self,
264 _: RectF,
265 _: &Self::LayoutState,
266 _: &Self::PaintState,
267 view: &V,
268 cx: &ViewContext<V>,
269 ) -> serde_json::Value {
270 json!({
271 "type": "MouseEventHandler",
272 "child": self.child.debug(view, cx),
273 })
274 }
275}