36 files changed, 292 insertions, 51 deletions
diff --git a/core/Cargo.toml b/core/Cargo.toml
index 7ccb7b7a..9edc20f6 100644
--- a/core/Cargo.toml
+++ b/core/Cargo.toml
@@ -10,6 +10,7 @@ repository = "https://github.com/iced-rs/iced"
 [dependencies]
 bitflags = "1.2"
 thiserror = "1"
+twox-hash = { version = "1.5", default-features = false }
 
 [dependencies.palette]
 version = "0.6"
diff --git a/core/src/clipboard.rs b/core/src/clipboard.rs
new file mode 100644
index 00000000..081b4004
--- /dev/null
+++ b/core/src/clipboard.rs
@@ -0,0 +1,23 @@
+//! Access the clipboard.
+
+/// A buffer for short-term storage and transfer within and between
+/// applications.
+pub trait Clipboard {
+    /// Reads the current content of the [`Clipboard`] as text.
+    fn read(&self) -> Option<String>;
+
+    /// Writes the given text contents to the [`Clipboard`].
+    fn write(&mut self, contents: String);
+}
+
+/// A null implementation of the [`Clipboard`] trait.
+#[derive(Debug, Clone, Copy)]
+pub struct Null;
+
+impl Clipboard for Null {
+    fn read(&self) -> Option<String> {
+        None
+    }
+
+    fn write(&mut self, _contents: String) {}
+}
diff --git a/native/src/element.rs b/core/src/element.rs
index 0a677d20..98c53737 100644
--- a/native/src/element.rs
+++ b/core/src/element.rs
@@ -90,41 +90,65 @@ impl<'a, Message, Renderer> Element<'a, Message, Renderer> {
     /// We compose the previous __messages__ with the index of the counter
     /// producing them. Let's implement our __view logic__ now:
     ///
-    /// ```
+    /// ```no_run
     /// # mod counter {
-    /// #     type Text<'a> = iced_native::widget::Text<'a, iced_native::renderer::Null>;
-    /// #
     /// #     #[derive(Debug, Clone, Copy)]
     /// #     pub enum Message {}
     /// #     pub struct Counter;
     /// #
     /// #     impl Counter {
-    /// #         pub fn view(&mut self) -> Text {
-    /// #             Text::new("")
+    /// #         pub fn view(
+    /// #             &self,
+    /// #         ) -> iced_core::Element<Message, iced_core::renderer::Null> {
+    /// #             unimplemented!()
     /// #         }
     /// #     }
     /// # }
     /// #
-    /// # mod iced_wgpu {
-    /// #     pub use iced_native::renderer::Null as Renderer;
-    /// # }
+    /// # mod iced {
+    /// #     pub use iced_core::renderer::Null as Renderer;
+    /// #     pub use iced_core::Element;
     /// #
-    /// # use counter::Counter;
+    /// #     pub mod widget {
+    /// #         pub struct Row<Message> {
+    /// #             _t: std::marker::PhantomData<Message>,
+    /// #         }
     /// #
-    /// # struct ManyCounters {
-    /// #     counters: Vec<Counter>,
-    /// # }
+    /// #         impl<Message> Row<Message> {
+    /// #             pub fn new() -> Self {
+    /// #                 unimplemented!()
+    /// #             }
     /// #
-    /// # #[derive(Debug, Clone, Copy)]
-    /// # pub enum Message {
-    /// #    Counter(usize, counter::Message)
+    /// #             pub fn spacing(mut self, _: u32) -> Self {
+    /// #                 unimplemented!()
+    /// #             }
+    /// #
+    /// #             pub fn push(
+    /// #                 mut self,
+    /// #                 _: iced_core::Element<Message, iced_core::renderer::Null>,
+    /// #             ) -> Self {
+    /// #                 unimplemented!()
+    /// #             }
+    /// #         }
+    /// #     }
     /// # }
-    /// use iced_native::Element;
-    /// use iced_native::widget::Row;
-    /// use iced_wgpu::Renderer;
+    /// #
+    /// use counter::Counter;
+    ///
+    /// use iced::widget::Row;
+    /// use iced::{Element, Renderer};
+    ///
+    /// struct ManyCounters {
+    ///     counters: Vec<Counter>,
+    /// }
+    ///
+    /// #[derive(Debug, Clone, Copy)]
+    /// pub enum Message {
+    ///     Counter(usize, counter::Message),
+    /// }
     ///
     /// impl ManyCounters {
-    ///     pub fn view(&mut self) -> Row<Message, Renderer> {
+    ///     pub fn view(&mut self) -> Row<Message> {
     ///         // We can quickly populate a `Row` by folding over our counters
     ///         self.counters.iter_mut().enumerate().fold(
     ///             Row::new().spacing(20),
@@ -137,9 +161,10 @@ impl<'a, Message, Renderer> Element<'a, Message, Renderer> {
     ///                     // Here we turn our `Element<counter::Message>` into
     ///                     // an `Element<Message>` by combining the `index` and the
     ///                     // message of the `element`.
-    ///                     element.map(move |message| Message::Counter(index, message))
+    ///                     element
+    ///                         .map(move |message| Message::Counter(index, message)),
     ///                 )
-    ///             }
+    ///             },
     ///         )
     ///     }
     /// }
diff --git a/native/src/event.rs b/core/src/event.rs
index bcfaf891..953cd73f 100644
--- a/native/src/event.rs
+++ b/core/src/event.rs
@@ -62,7 +62,7 @@ impl Status {
     /// `Captured` takes precedence over `Ignored`:
     ///
     /// ```
-    /// use iced_native::event::Status;
+    /// use iced_core::event::Status;
     ///
     /// assert_eq!(Status::Ignored.merge(Status::Ignored), Status::Ignored);
     /// assert_eq!(Status::Ignored.merge(Status::Captured), Status::Captured);
diff --git a/native/src/hasher.rs b/core/src/hasher.rs
index fa52f16d..fa52f16d 100644
--- a/native/src/hasher.rs
+++ b/core/src/hasher.rs
diff --git a/native/src/image.rs b/core/src/image.rs
index 70fbade0..70fbade0 100644
--- a/native/src/image.rs
+++ b/core/src/image.rs
diff --git a/native/src/layout.rs b/core/src/layout.rs
index 04954fb9..04954fb9 100644
--- a/native/src/layout.rs
+++ b/core/src/layout.rs
diff --git a/native/src/layout/DRUID_LICENSE b/core/src/layout/DRUID_LICENSE
index d6456956..d6456956 100644
--- a/native/src/layout/DRUID_LICENSE
+++ b/core/src/layout/DRUID_LICENSE
diff --git a/native/src/layout/flex.rs b/core/src/layout/flex.rs
index 5d70c2fc..5d70c2fc 100644
--- a/native/src/layout/flex.rs
+++ b/core/src/layout/flex.rs
diff --git a/native/src/layout/limits.rs b/core/src/layout/limits.rs
index 5d3c1556..5d3c1556 100644
--- a/native/src/layout/limits.rs
+++ b/core/src/layout/limits.rs
diff --git a/native/src/layout/node.rs b/core/src/layout/node.rs
index e0c7dcb2..e0c7dcb2 100644
--- a/native/src/layout/node.rs
+++ b/core/src/layout/node.rs
diff --git a/core/src/lib.rs b/core/src/lib.rs
index 1e4f0411..5bdcee6a 100644
--- a/core/src/lib.rs
+++ b/core/src/lib.rs
@@ -25,33 +25,57 @@
 #![forbid(unsafe_code, rust_2018_idioms)]
 #![allow(clippy::inherent_to_string, clippy::type_complexity)]
 pub mod alignment;
+pub mod clipboard;
+pub mod event;
 pub mod font;
 pub mod gradient;
+pub mod image;
 pub mod keyboard;
+pub mod layout;
 pub mod mouse;
+pub mod overlay;
+pub mod renderer;
+pub mod svg;
+pub mod text;
 pub mod time;
+pub mod touch;
+pub mod widget;
+pub mod window;
 
 mod background;
 mod color;
 mod content_fit;
+mod element;
+mod hasher;
 mod length;
 mod padding;
 mod pixels;
 mod point;
 mod rectangle;
+mod shell;
 mod size;
 mod vector;
 
 pub use alignment::Alignment;
 pub use background::Background;
+pub use clipboard::Clipboard;
 pub use color::Color;
 pub use content_fit::ContentFit;
+pub use element::Element;
+pub use event::Event;
 pub use font::Font;
 pub use gradient::Gradient;
+pub use hasher::Hasher;
+pub use layout::Layout;
 pub use length::Length;
+pub use overlay::Overlay;
 pub use padding::Padding;
 pub use pixels::Pixels;
 pub use point::Point;
 pub use rectangle::Rectangle;
+pub use renderer::Renderer;
+pub use shell::Shell;
 pub use size::Size;
+pub use text::Text;
 pub use vector::Vector;
+pub use widget::Widget;
diff --git a/core/src/mouse.rs b/core/src/mouse.rs
index 48214f65..0c405ce6 100644
--- a/core/src/mouse.rs
+++ b/core/src/mouse.rs
@@ -1,8 +1,11 @@
 //! Handle mouse events.
+pub mod click;
+
 mod button;
 mod event;
 mod interaction;
 
 pub use button::Button;
+pub use click::Click;
 pub use event::{Event, ScrollDelta};
 pub use interaction::Interaction;
diff --git a/native/src/mouse/click.rs b/core/src/mouse/click.rs
index 4a7d796c..4a7d796c 100644
--- a/native/src/mouse/click.rs
+++ b/core/src/mouse/click.rs
diff --git a/native/src/overlay.rs b/core/src/overlay.rs
index 6cada416..b9f3c735 100644
--- a/native/src/overlay.rs
+++ b/core/src/overlay.rs
@@ -2,11 +2,8 @@
 mod element;
 mod group;
 
-pub mod menu;
-
 pub use element::Element;
 pub use group::Group;
-pub use menu::Menu;
 
 use crate::event::{self, Event};
 use crate::layout;
diff --git a/native/src/overlay/element.rs b/core/src/overlay/element.rs
index 237d25d1..237d25d1 100644
--- a/native/src/overlay/element.rs
+++ b/core/src/overlay/element.rs
diff --git a/native/src/overlay/group.rs b/core/src/overlay/group.rs
index 1126f0cf..0c48df34 100644
--- a/native/src/overlay/group.rs
+++ b/core/src/overlay/group.rs
@@ -1,12 +1,10 @@
-use iced_core::{Point, Rectangle, Size};
-
 use crate::event;
 use crate::layout;
 use crate::mouse;
 use crate::overlay;
 use crate::renderer;
 use crate::widget;
-use crate::{Clipboard, Event, Layout, Overlay, Shell};
+use crate::{Clipboard, Event, Layout, Overlay, Point, Rectangle, Shell, Size};
 
 /// An [`Overlay`] container that displays multiple overlay [`overlay::Element`]
 /// children.
diff --git a/native/src/renderer.rs b/core/src/renderer.rs
index 2ac78982..d6247e39 100644
--- a/native/src/renderer.rs
+++ b/core/src/renderer.rs
@@ -1,6 +1,7 @@
 //! Write your own renderer.
 #[cfg(debug_assertions)]
 mod null;
+
 #[cfg(debug_assertions)]
 pub use null::Null;
 
diff --git a/native/src/renderer/null.rs b/core/src/renderer/null.rs
index 150ee786..d93338ae 100644
--- a/native/src/renderer/null.rs
+++ b/core/src/renderer/null.rs
@@ -1,6 +1,6 @@
 use crate::renderer::{self, Renderer};
 use crate::text::{self, Text};
-use crate::{Background, Font, Point, Rectangle, Size, Theme, Vector};
+use crate::{Background, Font, Point, Rectangle, Size, Vector};
 
 use std::borrow::Cow;
 
@@ -18,7 +18,7 @@ impl Null {
 }
 
 impl Renderer for Null {
-    type Theme = Theme;
+    type Theme = ();
 
     fn with_layer(&mut self, _bounds: Rectangle, _f: impl FnOnce(&mut Self)) {}
 
diff --git a/native/src/shell.rs b/core/src/shell.rs
index 74a5c616..74a5c616 100644
--- a/native/src/shell.rs
+++ b/core/src/shell.rs
diff --git a/native/src/svg.rs b/core/src/svg.rs
index 9b98877a..9b98877a 100644
--- a/native/src/svg.rs
+++ b/core/src/svg.rs
diff --git a/native/src/text.rs b/core/src/text.rs
index 4c72abc3..4c72abc3 100644
--- a/native/src/text.rs
+++ b/core/src/text.rs
diff --git a/native/src/touch.rs b/core/src/touch.rs
index 18120644..18120644 100644
--- a/native/src/touch.rs
+++ b/core/src/touch.rs
diff --git a/core/src/widget.rs b/core/src/widget.rs
new file mode 100644
index 00000000..70e2c2d9
--- /dev/null
+++ b/core/src/widget.rs
@@ -0,0 +1,145 @@
+//! Create custom widgets and operate on them.
+pub mod operation;
+pub mod text;
+pub mod tree;
+
+mod id;
+
+pub use id::Id;
+pub use operation::Operation;
+pub use text::Text;
+pub use tree::Tree;
+
+use crate::event::{self, Event};
+use crate::layout::{self, Layout};
+use crate::mouse;
+use crate::overlay;
+use crate::renderer;
+use crate::{Clipboard, Length, Point, Rectangle, Shell};
+
+/// A component that displays information and allows interaction.
+///
+/// If you want to build your own widgets, you will need to implement this
+/// trait.
+///
+/// # Examples
+/// The repository has some [examples] showcasing how to implement a custom
+/// widget:
+///
+/// - [`bezier_tool`], a Paint-like tool for drawing Bézier curves using
+/// [`lyon`].
+/// - [`custom_widget`], a demonstration of how to build a custom widget that
+/// draws a circle.
+/// - [`geometry`], a custom widget showcasing how to draw geometry with the
+/// `Mesh2D` primitive in [`iced_wgpu`].
+///
+/// [examples]: https://github.com/iced-rs/iced/tree/0.8/examples
+/// [`bezier_tool`]: https://github.com/iced-rs/iced/tree/0.8/examples/bezier_tool
+/// [`custom_widget`]: https://github.com/iced-rs/iced/tree/0.8/examples/custom_widget
+/// [`geometry`]: https://github.com/iced-rs/iced/tree/0.8/examples/geometry
+/// [`lyon`]: https://github.com/nical/lyon
+/// [`iced_wgpu`]: https://github.com/iced-rs/iced/tree/0.8/wgpu
+pub trait Widget<Message, Renderer>
+where
+    Renderer: crate::Renderer,
+{
+    /// Returns the width of the [`Widget`].
+    fn width(&self) -> Length;
+
+    /// Returns the height of the [`Widget`].
+    fn height(&self) -> Length;
+
+    /// Returns the [`layout::Node`] of the [`Widget`].
+    ///
+    /// This [`layout::Node`] is used by the runtime to compute the [`Layout`] of the
+    /// user interface.
+    fn layout(
+        &self,
+        renderer: &Renderer,
+        limits: &layout::Limits,
+    ) -> layout::Node;
+
+    /// Draws the [`Widget`] using the associated `Renderer`.
+    fn draw(
+        &self,
+        state: &Tree,
+        renderer: &mut Renderer,
+        theme: &Renderer::Theme,
+        style: &renderer::Style,
+        layout: Layout<'_>,
+        cursor_position: Point,
+        viewport: &Rectangle,
+    );
+
+    /// Returns the [`Tag`] of the [`Widget`].
+    ///
+    /// [`Tag`]: tree::Tag
+    fn tag(&self) -> tree::Tag {
+        tree::Tag::stateless()
+    }
+
+    /// Returns the [`State`] of the [`Widget`].
+    ///
+    /// [`State`]: tree::State
+    fn state(&self) -> tree::State {
+        tree::State::None
+    }
+
+    /// Returns the state [`Tree`] of the children of the [`Widget`].
+    fn children(&self) -> Vec<Tree> {
+        Vec::new()
+    }
+
+    /// Reconciliates the [`Widget`] with the provided [`Tree`].
+    fn diff(&self, _tree: &mut Tree) {}
+
+    /// Applies an [`Operation`] to the [`Widget`].
+    fn operate(
+        &self,
+        _state: &mut Tree,
+        _layout: Layout<'_>,
+        _renderer: &Renderer,
+        _operation: &mut dyn Operation<Message>,
+    ) {
+    }
+
+    /// Processes a runtime [`Event`].
+    ///
+    /// By default, it does nothing.
+    fn on_event(
+        &mut self,
+        _state: &mut Tree,
+        _event: Event,
+        _layout: Layout<'_>,
+        _cursor_position: Point,
+        _renderer: &Renderer,
+        _clipboard: &mut dyn Clipboard,
+        _shell: &mut Shell<'_, Message>,
+    ) -> event::Status {
+        event::Status::Ignored
+    }
+
+    /// Returns the current [`mouse::Interaction`] of the [`Widget`].
+    ///
+    /// By default, it returns [`mouse::Interaction::Idle`].
+    fn mouse_interaction(
+        &self,
+        _state: &Tree,
+        _layout: Layout<'_>,
+        _cursor_position: Point,
+        _viewport: &Rectangle,
+        _renderer: &Renderer,
+    ) -> mouse::Interaction {
+        mouse::Interaction::Idle
+    }
+
+    /// Returns the overlay of the [`Widget`], if there is any.
+    fn overlay<'a>(
+        &'a mut self,
+        _state: &'a mut Tree,
+        _layout: Layout<'_>,
+        _renderer: &Renderer,
+    ) -> Option<overlay::Element<'a, Message, Renderer>> {
+        None
+    }
+}
diff --git a/native/src/widget/id.rs b/core/src/widget/id.rs
index 4b8fedf1..ae739bb7 100644
--- a/native/src/widget/id.rs
+++ b/core/src/widget/id.rs
@@ -24,7 +24,7 @@ impl Id {
 }
 
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
-pub enum Internal {
+enum Internal {
     Unique(usize),
     Custom(borrow::Cow<'static, str>),
 }
diff --git a/native/src/widget/operation.rs b/core/src/widget/operation.rs
index 53688a21..53688a21 100644
--- a/native/src/widget/operation.rs
+++ b/core/src/widget/operation.rs
diff --git a/native/src/widget/operation/focusable.rs b/core/src/widget/operation/focusable.rs
index 312e4894..312e4894 100644
--- a/native/src/widget/operation/focusable.rs
+++ b/core/src/widget/operation/focusable.rs
diff --git a/native/src/widget/operation/scrollable.rs b/core/src/widget/operation/scrollable.rs
index 3b20631f..3b20631f 100644
--- a/native/src/widget/operation/scrollable.rs
+++ b/core/src/widget/operation/scrollable.rs
diff --git a/native/src/widget/operation/text_input.rs b/core/src/widget/operation/text_input.rs
index 4c773e99..4c773e99 100644
--- a/native/src/widget/operation/text_input.rs
+++ b/core/src/widget/operation/text_input.rs
diff --git a/native/src/widget/text.rs b/core/src/widget/text.rs
index aede754a..485bb542 100644
--- a/native/src/widget/text.rs
+++ b/core/src/widget/text.rs
@@ -4,27 +4,13 @@ use crate::layout;
 use crate::renderer;
 use crate::text;
 use crate::widget::Tree;
-use crate::{Element, Layout, Length, Pixels, Point, Rectangle, Size, Widget};
+use crate::{
+    Color, Element, Layout, Length, Pixels, Point, Rectangle, Size, Widget,
+};
 
 use std::borrow::Cow;
 
-pub use iced_style::text::{Appearance, StyleSheet};
-
 /// A paragraph of text.
-///
-/// # Example
-///
-/// ```
-/// # use iced_native::Color;
-/// #
-/// # type Text<'a> = iced_native::widget::Text<'a, iced_native::renderer::Null>;
-/// #
-/// Text::new("I <3 iced!")
-///     .size(40)
-///     .style(Color::from([0.0, 0.0, 1.0]));
-/// ```
-///
-/// ![Text drawn by `iced_wgpu`](https://github.com/iced-rs/iced/blob/7760618fb112074bc40b148944521f312152012a/docs/images/text.png?raw=true)
 #[allow(missing_debug_implementations)]
 pub struct Text<'a, Renderer>
 where
@@ -211,7 +197,7 @@ pub fn draw<Renderer>(
         alignment::Vertical::Bottom => bounds.y + bounds.height,
     };
 
-    renderer.fill_text(crate::text::Text {
+    renderer.fill_text(crate::Text {
         content,
         size: size.unwrap_or_else(|| renderer.default_size()),
         bounds: Rectangle { x, y, ..bounds },
@@ -252,12 +238,40 @@ where
     }
 }
 
+impl<'a, Renderer> From<&'a str> for Text<'a, Renderer>
+where
+    Renderer: text::Renderer,
+    Renderer::Theme: StyleSheet,
+{
+    fn from(content: &'a str) -> Self {
+        Self::new(content)
+    }
+}
+
 impl<'a, Message, Renderer> From<&'a str> for Element<'a, Message, Renderer>
 where
     Renderer: text::Renderer + 'a,
     Renderer::Theme: StyleSheet,
 {
-    fn from(contents: &'a str) -> Self {
-        Text::new(contents).into()
+    fn from(content: &'a str) -> Self {
+        Text::from(content).into()
     }
 }
+
+/// The style sheet of some text.
+pub trait StyleSheet {
+    /// The supported style of the [`StyleSheet`].
+    type Style: Default + Copy;
+
+    /// Produces the [`Appearance`] of some text.
+    fn appearance(&self, style: Self::Style) -> Appearance;
+}
+
+/// The apperance of some text.
+#[derive(Debug, Clone, Copy, Default)]
+pub struct Appearance {
+    /// The [`Color`] of the text.
+    ///
+    /// The default, `None`, means using the inherited color.
+    pub color: Option<Color>,
+}
diff --git a/native/src/widget/tree.rs b/core/src/widget/tree.rs
index 0af40c33..0af40c33 100644
--- a/native/src/widget/tree.rs
+++ b/core/src/widget/tree.rs
diff --git a/core/src/window.rs b/core/src/window.rs
new file mode 100644
index 00000000..d829a4b4
--- /dev/null
+++ b/core/src/window.rs
@@ -0,0 +1,10 @@
+//! Build window-based GUI applications.
+mod event;
+mod mode;
+mod redraw_request;
+mod user_attention;
+
+pub use event::Event;
+pub use mode::Mode;
+pub use redraw_request::RedrawRequest;
+pub use user_attention::UserAttention;
diff --git a/native/src/window/event.rs b/core/src/window/event.rs
index e2fb5e66..e2fb5e66 100644
--- a/native/src/window/event.rs
+++ b/core/src/window/event.rs
diff --git a/native/src/window/mode.rs b/core/src/window/mode.rs
index fdce8e23..fdce8e23 100644
--- a/native/src/window/mode.rs
+++ b/core/src/window/mode.rs
diff --git a/native/src/window/redraw_request.rs b/core/src/window/redraw_request.rs
index 3b4f0fd3..3b4f0fd3 100644
--- a/native/src/window/redraw_request.rs
+++ b/core/src/window/redraw_request.rs
diff --git a/native/src/window/user_attention.rs b/core/src/window/user_attention.rs
index b03dfeef..b03dfeef 100644
--- a/native/src/window/user_attention.rs
+++ b/core/src/window/user_attention.rs