Draft drawing logic for Content and TitleBar

native/src/widget/pane_grid/title_bar.rs

@@ -1,6 +1,119 @@
-use crate::Element;
+use crate::container;
+use crate::layout;
+use crate::pane_grid;
+use crate::{Element, Layout, Point, Size};
 
-pub struct TitleBar<'a, Message, Renderer> {
-    title: String,
-    buttons: Option<Element<'a, Message, Renderer>>,
+pub struct TitleBar<'a, Message, Renderer: container::Renderer> {
+    title: Element<'a, Message, Renderer>,
+    controls: Option<Element<'a, Message, Renderer>>,
+    padding: u16,
+    style: Renderer::Style,
+}
+
+impl<'a, Message, Renderer> TitleBar<'a, Message, Renderer>
+where
+    Renderer: container::Renderer,
+{
+    pub fn new(title: impl Into<Element<'a, Message, Renderer>>) -> Self {
+        Self {
+            title: title.into(),
+            controls: None,
+            padding: 0,
+            style: Renderer::Style::default(),
+        }
+    }
+
+    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
+    }
+}
+
+impl<'a, Message, Renderer> TitleBar<'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 {
+        if let Some(controls) = &self.controls {
+            let mut children = layout.children();
+            let title_layout = children.next().unwrap();
+            let controls_layout = children.next().unwrap();
+
+            renderer.draw_title_bar(
+                defaults,
+                &self.style,
+                (&self.title, title_layout),
+                Some((controls, controls_layout)),
+                cursor_position,
+            )
+        } else {
+            renderer.draw_title_bar(
+                defaults,
+                &self.style,
+                (&self.title, layout),
+                None,
+                cursor_position,
+            )
+        }
+    }
+
+    pub(crate) fn layout(
+        &self,
+        renderer: &Renderer,
+        limits: &layout::Limits,
+    ) -> layout::Node {
+        let padding = f32::from(self.padding);
+        let limits = limits.pad(padding);
+
+        let mut node = if let Some(controls) = &self.controls {
+            let max_size = limits.max();
+
+            let title_layout = self
+                .title
+                .layout(renderer, &layout::Limits::new(Size::ZERO, max_size));
+
+            let title_size = title_layout.size();
+
+            let mut controls_layout = controls.layout(
+                renderer,
+                &layout::Limits::new(
+                    Size::ZERO,
+                    Size::new(
+                        max_size.width - title_size.width,
+                        max_size.height,
+                    ),
+                ),
+            );
+
+            controls_layout.move_to(Point::new(title_size.width, 0.0));
+
+            layout::Node::with_children(
+                max_size,
+                vec![title_layout, controls_layout],
+            )
+        } else {
+            self.title.layout(renderer, &limits)
+        };
+
+        node.move_to(Point::new(padding, padding));
+
+        node
+    }
 }