WIP: start on tooltips

crates/gpui/src/elements/tooltip.rs

@@ -0,0 +1,87 @@
+use super::{ContainerStyle, Element, ElementBox};
+use crate::{
+    geometry::{rect::RectF, vector::Vector2F},
+    json::{json, ToJson},
+    ElementStateHandle, LayoutContext, PaintContext, RenderContext, SizeConstraint, View,
+};
+
+pub struct Tooltip {
+    state: ElementStateHandle<TooltipState>,
+    child: ElementBox,
+    style: ContainerStyle,
+    text: String,
+}
+
+#[derive(Default)]
+struct TooltipState {}
+
+impl Tooltip {
+    pub fn new<T: View>(
+        id: usize,
+        child: ElementBox,
+        text: String,
+        cx: &mut RenderContext<T>,
+    ) -> Self {
+        Self {
+            state: cx.element_state::<Self, _>(id),
+            child,
+            text,
+            style: Default::default(),
+        }
+    }
+
+    pub fn with_style(mut self, style: ContainerStyle) -> Self {
+        self.style = style;
+        self
+    }
+}
+
+impl Element for Tooltip {
+    type LayoutState = ();
+    type PaintState = ();
+
+    fn layout(
+        &mut self,
+        constraint: SizeConstraint,
+        cx: &mut LayoutContext,
+    ) -> (Vector2F, Self::LayoutState) {
+        let size = self.child.layout(constraint, cx);
+        (size, ())
+    }
+
+    fn paint(
+        &mut self,
+        bounds: RectF,
+        visible_bounds: RectF,
+        _: &mut Self::LayoutState,
+        cx: &mut PaintContext,
+    ) {
+        self.child.paint(bounds.origin(), visible_bounds, cx);
+    }
+
+    fn dispatch_event(
+        &mut self,
+        event: &crate::Event,
+        _: RectF,
+        _: RectF,
+        _: &mut Self::LayoutState,
+        _: &mut Self::PaintState,
+        cx: &mut crate::EventContext,
+    ) -> bool {
+        self.child.dispatch_event(event, cx)
+    }
+
+    fn debug(
+        &self,
+        _: RectF,
+        _: &Self::LayoutState,
+        _: &Self::PaintState,
+        cx: &crate::DebugContext,
+    ) -> serde_json::Value {
+        json!({
+            "child": self.child.debug(cx),
+            "style": self.style.to_json(),
+            "text": &self.text,
+        })
+    }
+}