Draft draggable and graphics logic for `TitleBar`

2 files changed, 85 insertions, 26 deletions

diff --git a/graphics/src/widget/container.rs b/graphics/src/widget/container.rs
index 070cb48b..576062d4 100644
--- a/graphics/src/widget/container.rs
+++ b/graphics/src/widget/container.rs
@@ -39,20 +39,10 @@ where
         let (content, mouse_interaction) =
             content.draw(self, &defaults, content_layout, cursor_position);
 
-        if style.background.is_some() || style.border_width > 0 {
-            let quad = Primitive::Quad {
-                bounds,
-                background: style
-                    .background
-                    .unwrap_or(Background::Color(Color::TRANSPARENT)),
-                border_radius: style.border_radius,
-                border_width: style.border_width,
-                border_color: style.border_color,
-            };
-
+        if let Some(background) = background(bounds, &style) {
             (
                 Primitive::Group {
-                    primitives: vec![quad, content],
+                    primitives: vec![background, content],
                 },
                 mouse_interaction,
             )
@@ -61,3 +51,22 @@ where
         }
     }
 }
+
+pub(crate) fn background(
+    bounds: Rectangle,
+    style: &container::Style,
+) -> Option<Primitive> {
+    if style.background.is_none() && style.border_width > 0 {
+        return None;
+    }
+
+    Some(Primitive::Quad {
+        bounds,
+        background: style
+            .background
+            .unwrap_or(Background::Color(Color::TRANSPARENT)),
+        border_radius: style.border_radius,
+        border_width: style.border_width,
+        border_color: style.border_color,
+    })
+}
diff --git a/graphics/src/widget/pane_grid.rs b/graphics/src/widget/pane_grid.rs
index 71b1658a..27b4f211 100644
--- a/graphics/src/widget/pane_grid.rs
+++ b/graphics/src/widget/pane_grid.rs
@@ -35,7 +35,7 @@ where
         &mut self,
         defaults: &Self::Defaults,
         content: &[(Pane, Content<'_, Message, Self>)],
-        dragging: Option<Pane>,
+        dragging: Option<(Pane, Point)>,
         resizing: Option<Axis>,
         layout: Layout<'_>,
         cursor_position: Point,
@@ -63,32 +63,40 @@ where
                     mouse_interaction = new_mouse_interaction;
                 }
 
-                if Some(*id) == dragging {
-                    dragged_pane = Some((i, layout));
+                if let Some((dragging, origin)) = dragging {
+                    if *id == dragging {
+                        dragged_pane = Some((i, layout, origin));
+                    }
                 }
 
                 primitive
             })
             .collect();
 
-        let primitives = if let Some((index, layout)) = dragged_pane {
+        let primitives = if let Some((index, layout, origin)) = dragged_pane {
             let pane = panes.remove(index);
             let bounds = layout.bounds();
 
+            if let Primitive::Group { primitives } = &pane {
+                panes.push(
+                    primitives.first().cloned().unwrap_or(Primitive::None),
+                );
+            }
+
             // TODO: Fix once proper layering is implemented.
             // This is a pretty hacky way to achieve layering.
             let clip = Primitive::Clip {
                 bounds: Rectangle {
-                    x: cursor_position.x - bounds.width / 2.0,
-                    y: cursor_position.y - bounds.height / 2.0,
+                    x: cursor_position.x - origin.x,
+                    y: cursor_position.y - origin.y,
                     width: bounds.width + 0.5,
                     height: bounds.height + 0.5,
                 },
                 offset: Vector::new(0, 0),
                 content: Box::new(Primitive::Translate {
                     translation: Vector::new(
-                        cursor_position.x - bounds.x - bounds.width / 2.0,
-                        cursor_position.y - bounds.y - bounds.height / 2.0,
+                        cursor_position.x - bounds.x - origin.x,
+                        cursor_position.y - bounds.y - origin.y,
                     ),
                     content: Box::new(pane),
                 }),
@@ -119,48 +127,77 @@ where
     fn draw_pane<Message>(
         &mut self,
         defaults: &Self::Defaults,
+        bounds: Rectangle,
+        style_sheet: &Self::Style,
         title_bar: Option<(&TitleBar<'_, Message, Self>, Layout<'_>)>,
         body: (&Element<'_, Message, Self>, Layout<'_>),
         cursor_position: Point,
     ) -> Self::Output {
+        let style = style_sheet.style();
         let (body, body_layout) = body;
 
         let (body_primitive, body_interaction) =
             body.draw(self, defaults, body_layout, cursor_position);
 
+        let background = crate::widget::container::background(bounds, &style);
+
         if let Some((title_bar, title_bar_layout)) = title_bar {
+            let show_controls = bounds.contains(cursor_position);
+            let is_over_draggable =
+                title_bar.is_over_draggable(title_bar_layout, cursor_position);
+
             let (title_bar_primitive, title_bar_interaction) = title_bar.draw(
                 self,
                 defaults,
                 title_bar_layout,
                 cursor_position,
+                show_controls,
             );
 
             (
                 Primitive::Group {
-                    primitives: vec![title_bar_primitive, body_primitive],
+                    primitives: vec![
+                        background.unwrap_or(Primitive::None),
+                        title_bar_primitive,
+                        body_primitive,
+                    ],
                 },
-                if title_bar_interaction > body_interaction {
+                if is_over_draggable {
+                    mouse::Interaction::Grab
+                } else if title_bar_interaction > body_interaction {
                     title_bar_interaction
                 } else {
                     body_interaction
                 },
             )
         } else {
-            (body_primitive, body_interaction)
+            (
+                if let Some(background) = background {
+                    Primitive::Group {
+                        primitives: vec![background, body_primitive],
+                    }
+                } else {
+                    body_primitive
+                },
+                body_interaction,
+            )
         }
     }
 
     fn draw_title_bar<Message>(
         &mut self,
         defaults: &Self::Defaults,
-        style: &<Self as iced_native::container::Renderer>::Style,
+        bounds: Rectangle,
+        style_sheet: &Self::Style,
         title: (&Element<'_, Message, Self>, Layout<'_>),
         controls: Option<(&Element<'_, Message, Self>, Layout<'_>)>,
         cursor_position: Point,
     ) -> Self::Output {
+        let style = style_sheet.style();
         let (title, title_layout) = title;
 
+        let background = crate::widget::container::background(bounds, &style);
+
         let (title_primitive, _) =
             title.draw(self, defaults, title_layout, cursor_position);
 
@@ -170,12 +207,25 @@ where
 
             (
                 Primitive::Group {
-                    primitives: vec![title_primitive, controls_primitive],
+                    primitives: vec![
+                        background.unwrap_or(Primitive::None),
+                        title_primitive,
+                        controls_primitive,
+                    ],
                 },
                 controls_interaction,
             )
         } else {
-            (title_primitive, mouse::Interaction::default())
+            (
+                if let Some(background) = background {
+                    Primitive::Group {
+                        primitives: vec![background, title_primitive],
+                    }
+                } else {
+                    title_primitive
+                },
+                mouse::Interaction::default(),
+            )
         }
     }
 }