Merge pull request #442 from hecrj/feature/pane-grid-titlebar

Title bar support for `PaneGrid`

4 files changed, 485 insertions, 44 deletions

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..1f5ce640 100644
--- a/native/src/widget/pane_grid/content.rs
+++ b/native/src/widget/pane_grid/content.rs
@@ -1,30 +1,197 @@
-use crate::pane_grid::Axis;
+use crate::container;
+use crate::layout;
+use crate::pane_grid::{self, TitleBar};
+use crate::{Clipboard, Element, Event, Hasher, Layout, Point, Size};
 
-/// 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
+#[allow(missing_debug_implementations)]
+pub struct Content<'a, Message, Renderer: pane_grid::Renderer> {
+    title_bar: Option<TitleBar<'a, Message, Renderer>>,
+    body: Element<'a, Message, Renderer>,
+    style: Renderer::Style,
+}
+
+impl<'a, Message, Renderer> Content<'a, Message, Renderer>
+where
+    Renderer: pane_grid::Renderer,
+{
+    /// Creates a new [`Content`] with the provided body.
+    ///
+    /// [`Content`]: struct.Content.html
+    pub fn new(body: impl Into<Element<'a, Message, Renderer>>) -> Self {
+        Self {
+            title_bar: None,
+            body: body.into(),
+            style: Renderer::Style::default(),
+        }
+    }
+
+    /// Sets the [`TitleBar`] of this [`Content`].
     ///
-    /// [`Pane`]: struct.Pane.html
-    Pane(T),
+    /// [`TitleBar`]: struct.TitleBar.html
+    /// [`Content`]: struct.Content.html
+    pub fn title_bar(
+        mut self,
+        title_bar: TitleBar<'a, Message, Renderer>,
+    ) -> Self {
+        self.title_bar = Some(title_bar);
+        self
+    }
+
+    /// Sets the style of the [`TitleBar`].
+    ///
+    /// [`TitleBar`]: struct.TitleBar.html
+    pub fn style(mut self, style: impl Into<Renderer::Style>) -> Self {
+        self.style = style.into();
+        self
+    }
+}
+
+impl<'a, Message, Renderer> Content<'a, Message, Renderer>
+where
+    Renderer: pane_grid::Renderer,
+{
+    /// Draws the [`Content`] with the provided [`Renderer`] and [`Layout`].
+    ///
+    /// [`Content`]: struct.Content.html
+    /// [`Renderer`]: trait.Renderer.html
+    /// [`Layout`]: ../layout/struct.Layout.html
+    pub fn draw(
+        &self,
+        renderer: &mut Renderer,
+        defaults: &Renderer::Defaults,
+        layout: Layout<'_>,
+        cursor_position: Point,
+    ) -> Renderer::Output {
+        if let Some(title_bar) = &self.title_bar {
+            let mut children = layout.children();
+            let title_bar_layout = children.next().unwrap();
+            let body_layout = children.next().unwrap();
+
+            renderer.draw_pane(
+                defaults,
+                layout.bounds(),
+                &self.style,
+                Some((title_bar, title_bar_layout)),
+                (&self.body, body_layout),
+                cursor_position,
+            )
+        } else {
+            renderer.draw_pane(
+                defaults,
+                layout.bounds(),
+                &self.style,
+                None,
+                (&self.body, layout),
+                cursor_position,
+            )
+        }
+    }
+
+    /// Returns whether the [`Content`] with the given [`Layout`] can be picked
+    /// at the provided cursor position.
+    ///
+    /// [`Content`]: struct.Content.html
+    /// [`Layout`]: ../layout/struct.Layout.html
+    pub fn can_be_picked_at(
+        &self,
+        layout: Layout<'_>,
+        cursor_position: Point,
+    ) -> bool {
+        if let Some(title_bar) = &self.title_bar {
+            let mut children = layout.children();
+            let title_bar_layout = children.next().unwrap();
+
+            title_bar.is_over_pick_area(title_bar_layout, cursor_position)
+        } else {
+            false
+        }
+    }
+
+    pub(crate) fn layout(
+        &self,
+        renderer: &Renderer,
+        limits: &layout::Limits,
+    ) -> layout::Node {
+        if let Some(title_bar) = &self.title_bar {
+            let max_size = limits.max();
+
+            let title_bar_layout = title_bar
+                .layout(renderer, &layout::Limits::new(Size::ZERO, max_size));
+
+            let title_bar_size = title_bar_layout.size();
+
+            let mut body_layout = self.body.layout(
+                renderer,
+                &layout::Limits::new(
+                    Size::ZERO,
+                    Size::new(
+                        max_size.width,
+                        max_size.height - title_bar_size.height,
+                    ),
+                ),
+            );
+
+            body_layout.move_to(Point::new(0.0, title_bar_size.height));
+
+            layout::Node::with_children(
+                max_size,
+                vec![title_bar_layout, body_layout],
+            )
+        } else {
+            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>,
+    ) {
+        let body_layout = if let Some(title_bar) = &mut self.title_bar {
+            let mut children = layout.children();
+
+            title_bar.on_event(
+                event.clone(),
+                children.next().unwrap(),
+                cursor_position,
+                messages,
+                renderer,
+                clipboard,
+            );
+
+            children.next().unwrap()
+        } else {
+            layout
+        };
+
+        self.body.on_event(
+            event,
+            body_layout,
+            cursor_position,
+            messages,
+            renderer,
+            clipboard,
+        );
+    }
+
+    pub(crate) fn hash_layout(&self, state: &mut Hasher) {
+        self.body.hash_layout(state);
+    }
+}
+
+impl<'a, T, Message, Renderer> From<T> for Content<'a, Message, Renderer>
+where
+    T: Into<Element<'a, Message, Renderer>>,
+    Renderer: pane_grid::Renderer + container::Renderer,
+{
+    fn from(element: T) -> Self {
+        Self::new(element)
+    }
 }
diff --git a/native/src/widget/pane_grid/state.rs b/native/src/widget/pane_grid/state.rs
index a4cfb6f6..e1585968 100644
--- a/native/src/widget/pane_grid/state.rs
+++ b/native/src/widget/pane_grid/state.rs
@@ -1,6 +1,5 @@
 use crate::{
-    keyboard,
-    pane_grid::{Axis, Content, Direction, Node, Pane, Split},
+    pane_grid::{Axis, Configuration, Direction, Node, Pane, Split},
     Hasher, Point, Rectangle, Size,
 };
 
@@ -25,7 +24,6 @@ use std::collections::HashMap;
 pub struct State<T> {
     pub(super) panes: HashMap<Pane, T>,
     pub(super) internal: Internal,
-    pub(super) modifiers: keyboard::ModifiersState,
 }
 
 /// The current focus of a [`Pane`].
@@ -53,18 +51,21 @@ 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,
@@ -73,7 +74,6 @@ impl<T> State<T> {
                 last_id,
                 action: Action::Idle { focus: None },
             },
-            modifiers: keyboard::ModifiersState::default(),
         }
     }
 
@@ -283,11 +283,11 @@ 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);
 
@@ -302,7 +302,7 @@ impl<T> State<T> {
                     next_id + 1,
                 )
             }
-            Content::Pane(state) => {
+            Configuration::Pane(state) => {
                 let id = Pane(next_id);
                 let _ = panes.insert(id, state);
 
@@ -319,13 +319,14 @@ pub struct Internal {
     action: Action,
 }
 
-#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+#[derive(Debug, Clone, Copy, PartialEq)]
 pub enum Action {
     Idle {
         focus: Option<Pane>,
     },
     Dragging {
         pane: Pane,
+        origin: Point,
     },
     Resizing {
         split: Split,
@@ -340,7 +341,7 @@ impl Action {
             Action::Idle { focus } | Action::Resizing { focus, .. } => {
                 focus.map(|pane| (pane, Focus::Idle))
             }
-            Action::Dragging { pane } => Some((*pane, Focus::Dragging)),
+            Action::Dragging { pane, .. } => Some((*pane, Focus::Dragging)),
         }
     }
 }
@@ -357,9 +358,9 @@ impl Internal {
         }
     }
 
-    pub fn picked_pane(&self) -> Option<Pane> {
+    pub fn picked_pane(&self) -> Option<(Pane, Point)> {
         match self.action {
-            Action::Dragging { pane } => Some(pane),
+            Action::Dragging { pane, origin } => Some((pane, origin)),
             _ => None,
         }
     }
@@ -391,8 +392,11 @@ impl Internal {
         self.action = Action::Idle { focus: Some(*pane) };
     }
 
-    pub fn pick_pane(&mut self, pane: &Pane) {
-        self.action = Action::Dragging { pane: *pane };
+    pub fn pick_pane(&mut self, pane: &Pane, origin: Point) {
+        self.action = Action::Dragging {
+            pane: *pane,
+            origin,
+        };
     }
 
     pub fn pick_split(&mut self, split: &Split, axis: Axis) {
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..c74c9e20
--- /dev/null
+++ b/native/src/widget/pane_grid/title_bar.rs
@@ -0,0 +1,240 @@
+use crate::layout;
+use crate::pane_grid;
+use crate::{Clipboard, Element, Event, Layout, Point, Rectangle, Size};
+
+/// The title bar of a [`Pane`].
+///
+/// [`Pane`]: struct.Pane.html
+#[allow(missing_debug_implementations)]
+pub struct TitleBar<'a, Message, Renderer: pane_grid::Renderer> {
+    title: String,
+    title_size: Option<u16>,
+    controls: Option<Element<'a, Message, Renderer>>,
+    padding: u16,
+    style: Renderer::Style,
+}
+
+impl<'a, Message, Renderer> TitleBar<'a, Message, Renderer>
+where
+    Renderer: pane_grid::Renderer,
+{
+    /// Cretes a new [`TitleBar`] with the given title.
+    ///
+    /// [`TitleBar`]: struct.TitleBar.html
+    pub fn new(title: impl Into<String>) -> Self {
+        Self {
+            title: title.into(),
+            title_size: None,
+            controls: None,
+            padding: 0,
+            style: Renderer::Style::default(),
+        }
+    }
+
+    /// Sets the size of the title of the [`TitleBar`].
+    ///
+    /// [`TitleBar`]: struct.TitleBar.html
+    pub fn title_size(mut self, size: u16) -> Self {
+        self.title_size = Some(size);
+        self
+    }
+
+    /// Sets the controls of the [`TitleBar`].
+    ///
+    /// [`TitleBar`]: struct.TitleBar.html
+    pub fn controls(
+        mut self,
+        controls: impl Into<Element<'a, Message, Renderer>>,
+    ) -> Self {
+        self.controls = Some(controls.into());
+        self
+    }
+
+    /// Sets the padding of the [`TitleBar`].
+    ///
+    /// [`TitleBar`]: struct.TitleBar.html
+    pub fn padding(mut self, units: u16) -> Self {
+        self.padding = units;
+        self
+    }
+
+    /// Sets the style of the [`TitleBar`].
+    ///
+    /// [`TitleBar`]: struct.TitleBar.html
+    pub fn style(mut self, style: impl Into<Renderer::Style>) -> Self {
+        self.style = style.into();
+        self
+    }
+}
+
+impl<'a, Message, Renderer> TitleBar<'a, Message, Renderer>
+where
+    Renderer: pane_grid::Renderer,
+{
+    /// Draws the [`TitleBar`] with the provided [`Renderer`] and [`Layout`].
+    ///
+    /// [`TitleBar`]: struct.TitleBar.html
+    /// [`Renderer`]: trait.Renderer.html
+    /// [`Layout`]: ../layout/struct.Layout.html
+    pub fn draw(
+        &self,
+        renderer: &mut Renderer,
+        defaults: &Renderer::Defaults,
+        layout: Layout<'_>,
+        cursor_position: Point,
+        show_controls: bool,
+    ) -> Renderer::Output {
+        let mut children = layout.children();
+        let padded = children.next().unwrap();
+
+        if let Some(controls) = &self.controls {
+            let mut children = padded.children();
+            let title_layout = children.next().unwrap();
+            let controls_layout = children.next().unwrap();
+
+            let (title_bounds, controls) = if show_controls {
+                (title_layout.bounds(), Some((controls, controls_layout)))
+            } else {
+                (
+                    Rectangle {
+                        width: padded.bounds().width,
+                        ..title_layout.bounds()
+                    },
+                    None,
+                )
+            };
+
+            renderer.draw_title_bar(
+                defaults,
+                layout.bounds(),
+                &self.style,
+                &self.title,
+                self.title_size.unwrap_or(renderer.default_size()),
+                Renderer::Font::default(),
+                title_bounds,
+                controls,
+                cursor_position,
+            )
+        } else {
+            renderer.draw_title_bar::<()>(
+                defaults,
+                layout.bounds(),
+                &self.style,
+                &self.title,
+                self.title_size.unwrap_or(renderer.default_size()),
+                Renderer::Font::default(),
+                padded.bounds(),
+                None,
+                cursor_position,
+            )
+        }
+    }
+
+    /// Returns whether the mouse cursor is over the pick area of the
+    /// [`TitleBar`] or not.
+    ///
+    /// The whole [`TitleBar`] is a pick area, except its controls.
+    ///
+    /// [`TitleBar`]: struct.TitleBar.html
+    pub fn is_over_pick_area(
+        &self,
+        layout: Layout<'_>,
+        cursor_position: Point,
+    ) -> bool {
+        if layout.bounds().contains(cursor_position) {
+            let mut children = layout.children();
+            let padded = children.next().unwrap();
+
+            if self.controls.is_some() {
+                let mut children = padded.children();
+                let _ = children.next().unwrap();
+                let controls_layout = children.next().unwrap();
+
+                !controls_layout.bounds().contains(cursor_position)
+            } else {
+                true
+            }
+        } else {
+            false
+        }
+    }
+
+    pub(crate) fn layout(
+        &self,
+        renderer: &Renderer,
+        limits: &layout::Limits,
+    ) -> layout::Node {
+        let padding = f32::from(self.padding);
+        let limits = limits.pad(padding);
+        let max_size = limits.max();
+
+        let title_size = self.title_size.unwrap_or(renderer.default_size());
+        let title_font = Renderer::Font::default();
+
+        let (title_width, title_height) = renderer.measure(
+            &self.title,
+            title_size,
+            title_font,
+            Size::new(f32::INFINITY, max_size.height),
+        );
+
+        let mut node = if let Some(controls) = &self.controls {
+            let mut controls_layout = controls
+                .layout(renderer, &layout::Limits::new(Size::ZERO, max_size));
+
+            let controls_size = controls_layout.size();
+            let space_before_controls = max_size.width - controls_size.width;
+
+            let mut title_layout = layout::Node::new(Size::new(
+                title_width.min(space_before_controls),
+                title_height,
+            ));
+
+            let title_size = title_layout.size();
+            let height = title_size.height.max(controls_size.height);
+
+            title_layout
+                .move_to(Point::new(0.0, (height - title_size.height) / 2.0));
+            controls_layout.move_to(Point::new(space_before_controls, 0.0));
+
+            layout::Node::with_children(
+                Size::new(max_size.width, height),
+                vec![title_layout, controls_layout],
+            )
+        } else {
+            layout::Node::new(Size::new(max_size.width, title_height))
+        };
+
+        node.move_to(Point::new(padding, padding));
+
+        layout::Node::with_children(node.size().pad(padding), vec![node])
+    }
+
+    pub(crate) fn on_event(
+        &mut self,
+        event: Event,
+        layout: Layout<'_>,
+        cursor_position: Point,
+        messages: &mut Vec<Message>,
+        renderer: &Renderer,
+        clipboard: Option<&dyn Clipboard>,
+    ) {
+        if let Some(controls) = &mut self.controls {
+            let mut children = layout.children();
+            let padded = children.next().unwrap();
+
+            let mut children = padded.children();
+            let _ = children.next();
+            let controls_layout = children.next().unwrap();
+
+            controls.on_event(
+                event,
+                controls_layout,
+                cursor_position,
+                messages,
+                renderer,
+                clipboard,
+            );
+        }
+    }
+}