Draft combo_box example to test overlay logic

Cargo.toml

@@ -56,6 +56,7 @@ members = [
     "examples/bezier_tool",
     "examples/clock",
     "examples/color_palette",
+    "examples/combo_box",
     "examples/counter",
     "examples/custom_widget",
     "examples/download_progress",

examples/combo_box/Cargo.toml

@@ -0,0 +1,11 @@
+[package]
+name = "combo_box"
+version = "0.1.0"
+authors = ["Héctor Ramón Jiménez <hector0193@gmail.com>"]
+edition = "2018"
+publish = false
+
+[dependencies]
+iced = { path = "../..", features = ["debug"] }
+iced_native = { path = "../../native" }
+iced_wgpu = { path = "../../wgpu" }

examples/combo_box/README.md

@@ -0,0 +1,18 @@
+## Counter
+
+The classic counter example explained in the [`README`](../../README.md).
+
+The __[`main`]__ file contains all the code of the example.
+
+<div align="center">
+  <a href="https://gfycat.com/fairdeadcatbird">
+    <img src="https://thumbs.gfycat.com/FairDeadCatbird-small.gif">
+  </a>
+</div>
+
+You can run it with `cargo run`:
+```
+cargo run --package counter
+```
+
+[`main`]: src/main.rs

examples/combo_box/src/main.rs

@@ -0,0 +1,163 @@
+mod combo_box {
+    use iced_native::{
+        layout, mouse, Background, Color, Element, Hasher, Layer, Layout,
+        Length, Overlay, Point, Size, Vector, Widget,
+    };
+    use iced_wgpu::{Defaults, Primitive, Renderer};
+
+    pub struct ComboBox;
+
+    impl ComboBox {
+        pub fn new() -> Self {
+            Self
+        }
+    }
+
+    impl<'a, Message> Widget<'a, Message, Renderer> for ComboBox {
+        fn width(&self) -> Length {
+            Length::Shrink
+        }
+
+        fn height(&self) -> Length {
+            Length::Shrink
+        }
+
+        fn layout(
+            &self,
+            _renderer: &Renderer,
+            _limits: &layout::Limits,
+        ) -> layout::Node {
+            layout::Node::new(Size::new(50.0, 50.0))
+        }
+
+        fn hash_layout(&self, _state: &mut Hasher) {}
+
+        fn draw(
+            &self,
+            _renderer: &mut Renderer,
+            _defaults: &Defaults,
+            layout: Layout<'_>,
+            _cursor_position: Point,
+        ) -> (Primitive, mouse::Interaction) {
+            let primitive = Primitive::Quad {
+                bounds: layout.bounds(),
+                background: Background::Color(Color::BLACK),
+                border_width: 0,
+                border_radius: 0,
+                border_color: Color::TRANSPARENT,
+            };
+
+            (primitive, mouse::Interaction::default())
+        }
+
+        fn overlay(
+            &mut self,
+            layout: Layout<'_>,
+        ) -> Option<Overlay<'a, Message, Renderer>> {
+            Some(Overlay::new(layout.position(), Box::new(Menu)))
+        }
+    }
+
+    impl<'a, Message> Into<Element<'a, Message, Renderer>> for ComboBox {
+        fn into(self) -> Element<'a, Message, Renderer> {
+            Element::new(self)
+        }
+    }
+
+    pub struct Menu;
+
+    impl<Message> Layer<Message, Renderer> for Menu {
+        fn layout(
+            &self,
+            _renderer: &Renderer,
+            _bounds: Size,
+            position: Point,
+        ) -> layout::Node {
+            let mut node = layout::Node::new(Size::new(100.0, 100.0));
+
+            node.move_to(position + Vector::new(25.0, 25.0));
+
+            node
+        }
+
+        fn hash_layout(&self, state: &mut Hasher, position: Point) {
+            use std::hash::Hash;
+
+            (position.x as u32).hash(state);
+            (position.y as u32).hash(state);
+        }
+
+        fn draw(
+            &self,
+            _renderer: &mut Renderer,
+            _defaults: &Defaults,
+            layout: Layout<'_>,
+            _cursor_position: Point,
+        ) -> (Primitive, mouse::Interaction) {
+            let primitive = Primitive::Quad {
+                bounds: layout.bounds(),
+                background: Background::Color(Color {
+                    r: 0.0,
+                    g: 0.0,
+                    b: 1.0,
+                    a: 0.5,
+                }),
+                border_width: 0,
+                border_radius: 0,
+                border_color: Color::TRANSPARENT,
+            };
+
+            (primitive, mouse::Interaction::default())
+        }
+    }
+}
+
+pub use combo_box::ComboBox;
+
+use iced::{
+    button, Button, Column, Container, Element, Length, Sandbox, Settings, Text,
+};
+
+pub fn main() {
+    Example::run(Settings::default())
+}
+
+#[derive(Default)]
+struct Example {
+    button: button::State,
+}
+
+#[derive(Debug, Clone, Copy)]
+enum Message {
+    ButtonPressed,
+}
+
+impl Sandbox for Example {
+    type Message = Message;
+
+    fn new() -> Self {
+        Self::default()
+    }
+
+    fn title(&self) -> String {
+        String::from("Combo box - Iced")
+    }
+
+    fn update(&mut self, _message: Message) {}
+
+    fn view(&mut self) -> Element<Message> {
+        let combo_box = ComboBox::new();
+
+        let button = Button::new(&mut self.button, Text::new("Press me!"))
+            .on_press(Message::ButtonPressed);
+
+        let content = Column::new().spacing(10).push(combo_box).push(button);
+
+        Container::new(content)
+            .width(Length::Fill)
+            .height(Length::Fill)
+            .center_x()
+            .center_y()
+            .into()
+    }
+}