1use crate::{
  2    element::{AnyElement, Element, IntoElement, Layout, ParentElement},
  3    interactive::{InteractionHandlers, Interactive},
  4    style::{Style, StyleHelpers, Styleable},
  5    ViewContext,
  6};
  7use anyhow::Result;
  8use gpui::{geometry::vector::Vector2F, platform::MouseButtonEvent, LayoutId};
  9use refineable::{CascadeSlot, Refineable, RefinementCascade};
 10use smallvec::SmallVec;
 11use std::{cell::Cell, rc::Rc};
 12
 13pub struct Pressable<E: Styleable> {
 14    pressed: Rc<Cell<bool>>,
 15    pressed_style: <E::Style as Refineable>::Refinement,
 16    cascade_slot: CascadeSlot,
 17    child: E,
 18}
 19
 20pub fn pressable<E: Styleable>(mut child: E) -> Pressable<E> {
 21    Pressable {
 22        pressed: Rc::new(Cell::new(false)),
 23        pressed_style: Default::default(),
 24        cascade_slot: child.style_cascade().reserve(),
 25        child,
 26    }
 27}
 28
 29impl<E: Styleable> Styleable for Pressable<E> {
 30    type Style = E::Style;
 31
 32    fn declared_style(&mut self) -> &mut <Self::Style as Refineable>::Refinement {
 33        &mut self.pressed_style
 34    }
 35
 36    fn style_cascade(&mut self) -> &mut RefinementCascade<E::Style> {
 37        self.child.style_cascade()
 38    }
 39}
 40
 41impl<V: 'static, E: Element<V> + Styleable> Element<V> for Pressable<E> {
 42    type PaintState = E::PaintState;
 43
 44    fn layout(
 45        &mut self,
 46        view: &mut V,
 47        cx: &mut ViewContext<V>,
 48    ) -> Result<(LayoutId, Self::PaintState)>
 49    where
 50        Self: Sized,
 51    {
 52        self.child.layout(view, cx)
 53    }
 54
 55    fn paint(
 56        &mut self,
 57        view: &mut V,
 58        parent_origin: Vector2F,
 59        layout: &Layout,
 60        paint_state: &mut Self::PaintState,
 61        cx: &mut ViewContext<V>,
 62    ) where
 63        Self: Sized,
 64    {
 65        let slot = self.cascade_slot;
 66        let style = self.pressed.get().then_some(self.pressed_style.clone());
 67        self.style_cascade().set(slot, style);
 68
 69        let pressed = self.pressed.clone();
 70        let bounds = layout.bounds + parent_origin;
 71        cx.on_event(layout.order, move |_view, event: &MouseButtonEvent, cx| {
 72            if event.is_down {
 73                if bounds.contains_point(event.position) {
 74                    pressed.set(true);
 75                    cx.repaint();
 76                } else {
 77                    cx.bubble_event();
 78                }
 79            } else {
 80                if pressed.get() {
 81                    pressed.set(false);
 82                    cx.repaint();
 83                }
 84                cx.bubble_event();
 85            }
 86        });
 87
 88        self.child
 89            .paint(view, parent_origin, layout, paint_state, cx);
 90    }
 91}
 92
 93impl<E: Styleable<Style = Style>> StyleHelpers for Pressable<E> {}
 94
 95impl<V: 'static, E: Interactive<V> + Styleable> Interactive<V> for Pressable<E> {
 96    fn interaction_handlers(&mut self) -> &mut InteractionHandlers<V> {
 97        self.child.interaction_handlers()
 98    }
 99}
100
101impl<V: 'static, E: ParentElement<V> + Styleable> ParentElement<V> for Pressable<E> {
102    fn children_mut(&mut self) -> &mut SmallVec<[AnyElement<V>; 2]> {
103        self.child.children_mut()
104    }
105}
106
107impl<V: 'static, E: Element<V> + Styleable> IntoElement<V> for Pressable<E> {
108    type Element = Self;
109
110    fn into_element(self) -> Self::Element {
111        self
112    }
113}