Draft first-class `TitleBar` in `pane_grid`

6 files changed, 171 insertions, 48 deletions

diff --git a/native/src/lib.rs b/native/src/lib.rs
index b67ff2a1..86046f63 100644
--- a/native/src/lib.rs
+++ b/native/src/lib.rs
@@ -30,8 +30,8 @@
 //! [`Widget`]: widget/trait.Widget.html
 //! [`UserInterface`]: struct.UserInterface.html
 //! [renderer]: renderer/index.html
-#![deny(missing_docs)]
-#![deny(missing_debug_implementations)]
+//#![deny(missing_docs)]
+//#![deny(missing_debug_implementations)]
 #![deny(unused_results)]
 #![forbid(unsafe_code)]
 #![forbid(rust_2018_idioms)]
diff --git a/native/src/widget/pane_grid.rs b/native/src/widget/pane_grid.rs
index 076ae76f..4c037ee9 100644
--- a/native/src/widget/pane_grid.rs
+++ b/native/src/widget/pane_grid.rs
@@ -9,20 +9,24 @@
 //! [`pane_grid` example]: https://github.com/hecrj/iced/tree/0.1/examples/pane_grid
 //! [`PaneGrid`]: struct.PaneGrid.html
 mod axis;
+mod configuration;
 mod content;
 mod direction;
 mod node;
 mod pane;
 mod split;
 mod state;
+mod title_bar;
 
 pub use axis::Axis;
+pub use configuration::Configuration;
 pub use content::Content;
 pub use direction::Direction;
 pub use node::Node;
 pub use pane::Pane;
 pub use split::Split;
 pub use state::{Focus, State};
+pub use title_bar::TitleBar;
 
 use crate::{
     keyboard, layout, mouse, Clipboard, Element, Event, Hasher, Layout, Length,
@@ -70,10 +74,10 @@ use crate::{
 ///
 /// let pane_grid =
 ///     PaneGrid::new(&mut state, |pane, state, focus| {
-///         match state {
+///         pane_grid::Content::new(match state {
 ///             PaneState::SomePane => Text::new("This is some pane"),
 ///             PaneState::AnotherKindOfPane => Text::new("This is another kind of pane"),
-///         }.into()
+///         })
 ///     })
 ///     .on_drag(Message::PaneDragged)
 ///     .on_resize(Message::PaneResized);
@@ -85,7 +89,7 @@ use crate::{
 pub struct PaneGrid<'a, Message, Renderer> {
     state: &'a mut state::Internal,
     pressed_modifiers: &'a mut keyboard::ModifiersState,
-    elements: Vec<(Pane, Element<'a, Message, Renderer>)>,
+    elements: Vec<(Pane, Content<'a, Message, Renderer>)>,
     width: Length,
     height: Length,
     spacing: u16,
@@ -110,7 +114,7 @@ impl<'a, Message, Renderer> PaneGrid<'a, Message, Renderer> {
             Pane,
             &'a mut T,
             Option<Focus>,
-        ) -> Element<'a, Message, Renderer>,
+        ) -> Content<'a, Message, Renderer>,
     ) -> Self {
         let elements = {
             let action = state.internal.action();
@@ -416,12 +420,15 @@ where
                             },
                         );
 
-                    if let Some(((pane, _), _)) = clicked_region.next() {
+                    if let Some(((pane, content), layout)) =
+                        clicked_region.next()
+                    {
                         match &self.on_drag {
                             Some(on_drag)
-                                if self
-                                    .pressed_modifiers
-                                    .matches(self.modifier_keys) =>
+                                if content.is_over_drag_target(
+                                    layout,
+                                    cursor_position,
+                                ) =>
                             {
                                 self.state.pick_pane(pane);
 
@@ -576,7 +583,7 @@ where
             {
                 self.elements.iter_mut().zip(layout.children()).for_each(
                     |((_, pane), layout)| {
-                        pane.widget.on_event(
+                        pane.on_event(
                             event.clone(),
                             layout,
                             cursor_position,
@@ -645,12 +652,31 @@ pub trait Renderer: crate::Renderer + Sized {
     fn draw<Message>(
         &mut self,
         defaults: &Self::Defaults,
-        content: &[(Pane, Element<'_, Message, Self>)],
+        content: &[(Pane, Content<'_, Message, Self>)],
         dragging: Option<Pane>,
         resizing: Option<Axis>,
         layout: Layout<'_>,
         cursor_position: Point,
     ) -> Self::Output;
+
+    /// Draws a [`Pane`].
+    ///
+    /// It receives:
+    /// - the [`TitleBar`] of the [`Pane`], if any
+    /// - the [`Content`] of the [`Pane`]
+    /// - the [`Layout`] of the [`Pane`] and its elements
+    /// - the cursor position
+    ///
+    /// [`Pane`]: struct.Pane.html
+    /// [`Layout`]: ../layout/struct.Layout.html
+    fn draw_pane<Message>(
+        &mut self,
+        defaults: &Self::Defaults,
+        title_bar: Option<&TitleBar<'_, Message, Self>>,
+        body: &Element<'_, Message, Self>,
+        layout: Layout<'_>,
+        cursor_position: Point,
+    ) -> Self::Output;
 }
 
 impl<'a, Message, Renderer> From<PaneGrid<'a, Message, Renderer>>
diff --git a/native/src/widget/pane_grid/configuration.rs b/native/src/widget/pane_grid/configuration.rs
new file mode 100644
index 00000000..1fed98b7
--- /dev/null
+++ b/native/src/widget/pane_grid/configuration.rs
@@ -0,0 +1,30 @@
+use crate::pane_grid::Axis;
+
+/// The arrangement of a [`PaneGrid`].
+///
+/// [`PaneGrid`]: struct.PaneGrid.html
+#[derive(Debug, Clone)]
+pub enum Configuration<T> {
+    /// A split of the available space.
+    Split {
+        /// The direction of the split.
+        axis: Axis,
+
+        /// The ratio of the split in [0.0, 1.0].
+        ratio: f32,
+
+        /// The left/top [`Content`] of the split.
+        ///
+        /// [`Configuration`]: enum.Node.html
+        a: Box<Configuration<T>>,
+
+        /// The right/bottom [`Content`] of the split.
+        ///
+        /// [`Configuration`]: enum.Node.html
+        b: Box<Configuration<T>>,
+    },
+    /// A [`Pane`].
+    ///
+    /// [`Pane`]: struct.Pane.html
+    Pane(T),
+}
diff --git a/native/src/widget/pane_grid/content.rs b/native/src/widget/pane_grid/content.rs
index 8822083e..e1374c82 100644
--- a/native/src/widget/pane_grid/content.rs
+++ b/native/src/widget/pane_grid/content.rs
@@ -1,30 +1,88 @@
-use crate::pane_grid::Axis;
+use crate::layout;
+use crate::pane_grid::{self, TitleBar};
+use crate::{Clipboard, Element, Event, Hasher, Layout, Point};
 
-/// The content of a [`PaneGrid`].
+/// The content of a [`Pane`].
 ///
-/// [`PaneGrid`]: struct.PaneGrid.html
-#[derive(Debug, Clone)]
-pub enum Content<T> {
-    /// A split of the available space.
-    Split {
-        /// The direction of the split.
-        axis: Axis,
-
-        /// The ratio of the split in [0.0, 1.0].
-        ratio: f32,
-
-        /// The left/top [`Content`] of the split.
-        ///
-        /// [`Content`]: enum.Node.html
-        a: Box<Content<T>>,
-
-        /// The right/bottom [`Content`] of the split.
-        ///
-        /// [`Content`]: enum.Node.html
-        b: Box<Content<T>>,
-    },
-    /// A [`Pane`].
-    ///
-    /// [`Pane`]: struct.Pane.html
-    Pane(T),
+/// [`Pane`]: struct.Pane.html
+pub struct Content<'a, Message, Renderer> {
+    title_bar: Option<TitleBar<'a, Message, Renderer>>,
+    body: Element<'a, Message, Renderer>,
+}
+
+impl<'a, Message, Renderer> Content<'a, Message, Renderer> {
+    pub fn new(body: impl Into<Element<'a, Message, Renderer>>) -> Self {
+        Self {
+            title_bar: None,
+            body: body.into(),
+        }
+    }
+
+    pub fn title_bar(
+        mut self,
+        title_bar: TitleBar<'a, Message, Renderer>,
+    ) -> Self {
+        self.title_bar = Some(title_bar);
+        self
+    }
+}
+
+impl<'a, Message, Renderer> Content<'a, Message, Renderer>
+where
+    Renderer: pane_grid::Renderer,
+{
+    pub fn draw(
+        &self,
+        renderer: &mut Renderer,
+        defaults: &Renderer::Defaults,
+        layout: Layout<'_>,
+        cursor_position: Point,
+    ) -> Renderer::Output {
+        renderer.draw_pane(
+            defaults,
+            self.title_bar.as_ref(),
+            &self.body,
+            layout,
+            cursor_position,
+        )
+    }
+
+    pub(crate) fn is_over_drag_target(
+        &self,
+        _layout: Layout<'_>,
+        _cursor_position: Point,
+    ) -> bool {
+        false
+    }
+
+    pub(crate) fn layout(
+        &self,
+        renderer: &Renderer,
+        limits: &layout::Limits,
+    ) -> layout::Node {
+        self.body.layout(renderer, limits)
+    }
+
+    pub(crate) fn on_event(
+        &mut self,
+        event: Event,
+        layout: Layout<'_>,
+        cursor_position: Point,
+        messages: &mut Vec<Message>,
+        renderer: &Renderer,
+        clipboard: Option<&dyn Clipboard>,
+    ) {
+        self.body.on_event(
+            event,
+            layout,
+            cursor_position,
+            messages,
+            renderer,
+            clipboard,
+        )
+    }
+
+    pub(crate) fn hash_layout(&self, state: &mut Hasher) {
+        self.body.hash_layout(state);
+    }
 }
diff --git a/native/src/widget/pane_grid/state.rs b/native/src/widget/pane_grid/state.rs
index 4b13fb8e..943120e3 100644
--- a/native/src/widget/pane_grid/state.rs
+++ b/native/src/widget/pane_grid/state.rs
@@ -1,6 +1,6 @@
 use crate::{
     keyboard,
-    pane_grid::{Axis, Content, Direction, Node, Pane, Split},
+    pane_grid::{Axis, Configuration, Direction, Node, Pane, Split},
     Hasher, Point, Rectangle, Size,
 };
 
@@ -53,18 +53,21 @@ impl<T> State<T> {
     /// [`State`]: struct.State.html
     /// [`Pane`]: struct.Pane.html
     pub fn new(first_pane_state: T) -> (Self, Pane) {
-        (Self::with_content(Content::Pane(first_pane_state)), Pane(0))
+        (
+            Self::with_configuration(Configuration::Pane(first_pane_state)),
+            Pane(0),
+        )
     }
 
-    /// Creates a new [`State`] with the given [`Content`].
+    /// Creates a new [`State`] with the given [`Configuration`].
     ///
     /// [`State`]: struct.State.html
-    /// [`Content`]: enum.Content.html
-    pub fn with_content(content: impl Into<Content<T>>) -> Self {
+    /// [`Configuration`]: enum.Configuration.html
+    pub fn with_configuration(config: impl Into<Configuration<T>>) -> Self {
         let mut panes = HashMap::new();
 
         let (layout, last_id) =
-            Self::distribute_content(&mut panes, content.into(), 0);
+            Self::distribute_content(&mut panes, config.into(), 0);
 
         State {
             panes,
@@ -274,11 +277,11 @@ impl<T> State<T> {
 
     fn distribute_content(
         panes: &mut HashMap<Pane, T>,
-        content: Content<T>,
+        content: Configuration<T>,
         next_id: usize,
     ) -> (Node, usize) {
         match content {
-            Content::Split { axis, ratio, a, b } => {
+            Configuration::Split { axis, ratio, a, b } => {
                 let (a, next_id) = Self::distribute_content(panes, *a, next_id);
                 let (b, next_id) = Self::distribute_content(panes, *b, next_id);
 
@@ -293,7 +296,7 @@ impl<T> State<T> {
                     next_id + 1,
                 )
             }
-            Content::Pane(state) => {
+            Configuration::Pane(state) => {
                 let id = Pane(next_id);
                 let _ = panes.insert(id, state);
 
diff --git a/native/src/widget/pane_grid/title_bar.rs b/native/src/widget/pane_grid/title_bar.rs
new file mode 100644
index 00000000..fa868a20
--- /dev/null
+++ b/native/src/widget/pane_grid/title_bar.rs
@@ -0,0 +1,6 @@
+use crate::Element;
+
+pub struct TitleBar<'a, Message, Renderer> {
+    title: String,
+    buttons: Option<Element<'a, Message, Renderer>>,
+}