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