add query context (#400)

examples/tui_colorpicker.rs

@@ -0,0 +1,27 @@
+use dioxus::prelude::*;
+use dioxus_tui::query::Query;
+use dioxus_tui::Size;
+
+fn main() {
+    dioxus::tui::launch(app);
+}
+
+fn app(cx: Scope) -> Element {
+    let hue = use_state(&cx, || 0.0);
+    let brightness = use_state(&cx, || 0.0);
+    let tui_query: Query = cx.consume_context().unwrap();
+    cx.render(rsx! {
+        div{
+            width: "100%",
+            background_color: "hsl({hue}, 70%, {brightness}%)",
+            onmousemove: move |evt| {
+                let node = tui_query.get(cx.root_node().mounted_id());
+                let Size{width, height} = node.size().unwrap();
+                let pos = evt.data.element_coordinates();
+                hue.set((pos.x as f32/width as f32)*255.0);
+                brightness.set((pos.y as f32/height as f32)*100.0);
+            },
+            "hsl({hue}, 70%, {brightness}%)",
+        }
+    })
+}

packages/tui/src/layout.rs

@@ -20,6 +20,12 @@ impl<T> PossiblyUninitalized<T> {
             _ => panic!(),
         }
     }
+    pub fn ok(self) -> Option<T> {
+        match self {
+            Self::Initialized(i) => Some(i),
+            _ => None,
+        }
+    }
 }
 impl<T> Default for PossiblyUninitalized<T> {
     fn default() -> Self {

packages/tui/src/lib.rs

@@ -13,10 +13,12 @@ use futures::{
     channel::mpsc::{UnboundedReceiver, UnboundedSender},
     pin_mut, StreamExt,
 };
+use query::Query;
 use std::cell::RefCell;
 use std::rc::Rc;
 use std::{io, time::Duration};
-use taffy::{geometry::Point, prelude::Size, Taffy};
+use taffy::Taffy;
+pub use taffy::{geometry::Point, prelude::Size};
 use tui::{backend::CrosstermBackend, layout::Rect, Terminal};
 
 mod config;
@@ -24,6 +26,7 @@ mod focus;
 mod hooks;
 mod layout;
 mod node;
+pub mod query;
 mod render;
 mod style;
 mod style_attributes;
@@ -76,16 +79,23 @@ pub fn launch_cfg(app: Component<()>, cfg: Config) {
     }
 
     let cx = dom.base_scope();
+    let rdom = Rc::new(RefCell::new(RealDom::new()));
+    let taffy = Rc::new(RefCell::new(Taffy::new()));
     cx.provide_root_context(state);
     cx.provide_root_context(TuiContext { tx: event_tx_clone });
+    cx.provide_root_context(Query {
+        rdom: rdom.clone(),
+        stretch: taffy.clone(),
+    });
 
-    let mut rdom: Dom = RealDom::new();
-    let mutations = dom.rebuild();
-    let to_update = rdom.apply_mutations(vec![mutations]);
-    let taffy = Rc::new(RefCell::new(Taffy::new()));
-    let mut any_map = AnyMap::new();
-    any_map.insert(taffy.clone());
-    let _to_rerender = rdom.update_state(&dom, to_update, any_map).unwrap();
+    {
+        let mut rdom = rdom.borrow_mut();
+        let mutations = dom.rebuild();
+        let to_update = rdom.apply_mutations(vec![mutations]);
+        let mut any_map = AnyMap::new();
+        any_map.insert(taffy.clone());
+        let _to_rerender = rdom.update_state(&dom, to_update, any_map).unwrap();
+    }
 
     render_vdom(
         &mut dom,
@@ -104,7 +114,7 @@ fn render_vdom(
     mut event_reciever: UnboundedReceiver<InputEvent>,
     handler: RinkInputHandler,
     cfg: Config,
-    mut rdom: Dom,
+    rdom: Rc<RefCell<Dom>>,
     taffy: Rc<RefCell<Taffy>>,
     mut register_event: impl FnMut(crossterm::event::Event),
 ) -> Result<()> {
@@ -157,6 +167,7 @@ fn render_vdom(
                     }
                     if let Some(terminal) = &mut terminal {
                         terminal.draw(|frame| {
+                            let rdom = rdom.borrow();
                             // size is guaranteed to not change when rendering
                             resize(frame.size(), &mut taffy.borrow_mut(), &rdom);
                             let root = &rdom[0];
@@ -170,6 +181,7 @@ fn render_vdom(
                             );
                         })?;
                     } else {
+                        let rdom = rdom.borrow();
                         resize(
                             Rect {
                                 x: 0,
@@ -217,13 +229,17 @@ fn render_vdom(
                 }
 
                 {
-                    let evts = handler.get_events(&taffy.borrow(), &mut rdom);
+                    let evts = {
+                        let mut rdom = rdom.borrow_mut();
+                        handler.get_events(&taffy.borrow(), &mut rdom)
+                    };
                     {
                         updated |= handler.state().focus_state.clean();
                     }
                     for e in evts {
                         vdom.handle_message(SchedulerMsg::Event(e));
                     }
+                    let mut rdom = rdom.borrow_mut();
                     let mutations = vdom.work_with_deadline(|| false);
                     for m in &mutations {
                         handler.prune(m, &rdom);

packages/tui/src/query.rs

@@ -0,0 +1,85 @@
+use std::{
+    cell::{Ref, RefCell},
+    rc::Rc,
+};
+
+use dioxus_core::ElementId;
+use taffy::{
+    geometry::Point,
+    prelude::{Layout, Size},
+    Taffy,
+};
+
+use crate::Dom;
+
+/// Allows querying the layout of nodes after rendering. It will only provide a correct value after a node is rendered.
+/// Provided as a root context for all tui applictions.
+/// # Example
+/// ```rust
+/// use dioxus::prelude::*;
+/// use dioxus::tui::query::Query;
+/// use dioxus::tui::Size;
+///
+/// fn main() {
+///     dioxus::tui::launch(app);
+/// }
+///
+/// fn app(cx: Scope) -> Element {
+///     let hue = use_state(&cx, || 0.0);
+///     let brightness = use_state(&cx, || 0.0);
+///     let tui_query: Query = cx.consume_context().unwrap();
+///     cx.render(rsx! {
+///         div{
+///             width: "100%",
+///             background_color: "hsl({hue}, 70%, {brightness}%)",
+///             onmousemove: move |evt| {
+///                 let node = tui_query.get(cx.root_node().mounted_id());
+///                 let Size{width, height} = node.size().unwrap();
+///                 hue.set((evt.data.offset_x as f32/width as f32)*255.0);
+///                 brightness.set((evt.data.offset_y as f32/height as f32)*100.0);
+///             },
+///             "hsl({hue}, 70%, {brightness}%)",
+///         }
+///     })
+/// }
+/// ```
+#[derive(Clone)]
+pub struct Query {
+    pub(crate) rdom: Rc<RefCell<Dom>>,
+    pub(crate) stretch: Rc<RefCell<Taffy>>,
+}
+
+impl Query {
+    pub fn get(&self, id: ElementId) -> ElementRef {
+        ElementRef::new(self.rdom.borrow(), self.stretch.borrow(), id)
+    }
+}
+
+pub struct ElementRef<'a> {
+    inner: Ref<'a, Dom>,
+    stretch: Ref<'a, Taffy>,
+    id: ElementId,
+}
+
+impl<'a> ElementRef<'a> {
+    fn new(inner: Ref<'a, Dom>, stretch: Ref<'a, Taffy>, id: ElementId) -> Self {
+        Self { inner, stretch, id }
+    }
+
+    pub fn size(&self) -> Option<Size<u32>> {
+        self.layout().map(|l| l.size.map(|v| v as u32))
+    }
+
+    pub fn pos(&self) -> Option<Point<u32>> {
+        self.layout().map(|l| Point {
+            x: l.location.x as u32,
+            y: l.location.y as u32,
+        })
+    }
+
+    pub fn layout(&self) -> Option<&Layout> {
+        self.stretch
+            .layout(self.inner[self.id].state.layout.node.ok()?)
+            .ok()
+    }
+}