Add WindowDecorations widget.

masonry/examples/custom_decorations.rs

@@ -0,0 +1,54 @@
+// Copyright 2024 the Xilem Authors and the Druid Authors
+// SPDX-License-Identifier: Apache-2.0
+
+// On Windows platform, don't show a console when opening the app.
+#![windows_subsystem = "windows"]
+
+use masonry::app_driver::{AppDriver, DriverCtx};
+use masonry::dpi::LogicalSize;
+use masonry::widget::{Button, CrossAxisAlignment, Flex, RootWidget, TitleBar, WindowDecorations};
+use masonry::{Action, WidgetId};
+use winit::window::Window;
+
+struct Driver;
+
+impl AppDriver for Driver {
+    fn on_action(&mut self, _ctx: &mut DriverCtx<'_>, _widget_id: WidgetId, action: Action) {
+        match action {
+            Action::ButtonPressed(_) => {
+                println!("Hello");
+            }
+            action => {
+                eprintln!("Unexpected action {action:?}");
+            }
+        }
+    }
+}
+
+pub fn main() {
+    let title_bar = TitleBar::new();
+
+    let button = Button::new("Say hello");
+
+    let content = Flex::column()
+        .cross_axis_alignment(CrossAxisAlignment::Fill)
+        .with_child(title_bar)
+        .with_flex_child(button, CrossAxisAlignment::Center);
+
+    let main_widget = WindowDecorations::new(content);
+
+    let window_size = LogicalSize::new(400.0, 400.0);
+    let window_attributes = Window::default_attributes()
+        .with_title("Hello World!")
+        .with_resizable(true)
+        .with_decorations(false)
+        .with_min_inner_size(window_size);
+
+    masonry::event_loop_runner::run(
+        masonry::event_loop_runner::EventLoop::with_user_event(),
+        window_attributes,
+        RootWidget::new(main_widget),
+        Driver,
+    )
+    .unwrap();
+}

masonry/src/widget/mod.rs

@@ -34,6 +34,7 @@ mod title_bar;
 mod variable_label;
 mod widget_arena;
 mod window_button;
+mod window_decorations;
 mod window_handle;
 
 pub use self::image::Image;
@@ -58,6 +59,7 @@ pub use widget_mut::WidgetMut;
 pub use widget_pod::WidgetPod;
 pub use widget_ref::WidgetRef;
 pub use widget_state::WidgetState;
+pub use window_decorations::WindowDecorations;
 pub use window_handle::WindowHandle;
 
 pub(crate) use widget_arena::WidgetArena;

masonry/src/widget/window_decorations.rs

@@ -0,0 +1,113 @@
+// Copyright 2024 the Xilem Authors
+// SPDX-License-Identifier: Apache-2.0
+
+//! A container to show window decorations.
+
+use accesskit::{NodeBuilder, Role};
+use cursor_icon::CursorIcon;
+use smallvec::{smallvec, SmallVec};
+use tracing::{trace_span, Span};
+use vello::kurbo::Insets;
+use vello::Scene;
+use winit::window::ResizeDirection;
+
+use crate::paint_scene_helpers::stroke;
+use crate::widget::WidgetPod;
+use crate::{
+    theme, AccessCtx, AccessEvent, BoxConstraints, EventCtx, LayoutCtx, LifeCycleCtx, PaintCtx,
+    PointerEvent, Size, StatusChange, TextEvent, Widget, WidgetId,
+};
+
+const BORDER_WIDTH: f64 = 2.0;
+const INSETS: Insets = Insets::uniform(BORDER_WIDTH);
+
+/// A container to show window decorations.
+pub struct WindowDecorations<W> {
+    pub(crate) child: WidgetPod<W>,
+}
+
+impl<W: Widget> WindowDecorations<W> {
+    pub fn new(widget: W) -> WindowDecorations<W> {
+        WindowDecorations {
+            child: WidgetPod::new(widget),
+        }
+    }
+}
+
+impl<W: Widget> Widget for WindowDecorations<W> {
+    fn on_pointer_event(&mut self, ctx: &mut EventCtx, event: &PointerEvent) {
+        match event {
+            PointerEvent::PointerMove(state) => {
+                if state.position.y <= BORDER_WIDTH {
+                    ctx.set_cursor(&CursorIcon::NResize);
+                } else if state.position.y >= ctx.size().height - BORDER_WIDTH {
+                    ctx.set_cursor(&CursorIcon::SResize);
+                } else if state.position.x <= BORDER_WIDTH {
+                    ctx.set_cursor(&CursorIcon::WResize);
+                } else if state.position.x >= ctx.size().width - BORDER_WIDTH {
+                    ctx.set_cursor(&CursorIcon::EResize);
+                }
+            }
+            PointerEvent::PointerLeave(_) => {
+                ctx.set_cursor(&CursorIcon::Default);
+            }
+            PointerEvent::PointerDown(_, state) => {
+                if state.position.y <= BORDER_WIDTH {
+                    ctx.drag_resize_window(ResizeDirection::North);
+                } else if state.position.y >= ctx.size().height - BORDER_WIDTH {
+                    ctx.drag_resize_window(ResizeDirection::South);
+                } else if state.position.x <= BORDER_WIDTH {
+                    ctx.drag_resize_window(ResizeDirection::West);
+                } else if state.position.x >= ctx.size().width - BORDER_WIDTH {
+                    ctx.drag_resize_window(ResizeDirection::East);
+                }
+            }
+            _ => {}
+        }
+    }
+
+    fn on_text_event(&mut self, _ctx: &mut EventCtx, _event: &TextEvent) {}
+    fn on_access_event(&mut self, _ctx: &mut EventCtx, _event: &AccessEvent) {}
+
+    fn on_status_change(&mut self, _: &mut LifeCycleCtx, _: &StatusChange) {}
+
+    fn register_children(&mut self, ctx: &mut crate::RegisterCtx) {
+        ctx.register_child(&mut self.child);
+    }
+
+    fn layout(&mut self, ctx: &mut LayoutCtx, bc: &BoxConstraints) -> Size {
+        let padding = Size::new(INSETS.x_value(), INSETS.y_value());
+        let child_bc = bc.shrink(padding);
+
+        let child_size = ctx.run_layout(&mut self.child, &child_bc);
+
+        let size = bc.constrain(Size::new(
+            child_size.width + padding.width,
+            child_size.height + padding.height,
+        ));
+
+        let child_offset = (size.to_vec2() - child_size.to_vec2()) / 2.0;
+        ctx.place_child(&mut self.child, child_offset.to_point());
+
+        size
+    }
+
+    fn paint(&mut self, ctx: &mut PaintCtx, scene: &mut Scene) {
+        let rect = ctx.size().to_rect().inset(-BORDER_WIDTH / 2.0);
+        stroke(scene, &rect, theme::BORDER_DARK, BORDER_WIDTH);
+    }
+
+    fn accessibility_role(&self) -> Role {
+        Role::GenericContainer
+    }
+
+    fn accessibility(&mut self, _ctx: &mut AccessCtx, _node: &mut NodeBuilder) {}
+
+    fn children_ids(&self) -> SmallVec<[WidgetId; 16]> {
+        smallvec![self.child.id()]
+    }
+
+    fn make_trace_span(&self) -> Span {
+        trace_span!("WindowDecorations")
+    }
+}