T04 window and shell: chrome, bars, rail, tabs, windows, dialogs, tray, badge, zoom

src/shell/frame.rs

@@ -0,0 +1,137 @@
+use gpui::{
+    AnyElement, App, Bounds, CursorStyle, Decorations, HitboxBehavior, IntoElement, MouseButton,
+    ParentElement, Pixels, Point, RenderOnce, ResizeEdge, Size, Styled, Window, canvas, div, point,
+    prelude::*,
+};
+use smallvec::SmallVec;
+
+use crate::theme::{ActiveTheme, Elevation, Radius};
+
+/// Which edge or corner `pos` grabs, within `inset` of the window's rim.
+fn resize_edge(pos: Point<Pixels>, inset: Pixels, size: Size<Pixels>) -> Option<ResizeEdge> {
+    let (top, bottom) = (pos.y < inset, pos.y > size.height - inset);
+    let (left, right) = (pos.x < inset, pos.x > size.width - inset);
+    Some(match (top, bottom, left, right) {
+        (true, _, true, _) => ResizeEdge::TopLeft,
+        (true, _, _, true) => ResizeEdge::TopRight,
+        (true, ..) => ResizeEdge::Top,
+        (_, true, true, _) => ResizeEdge::BottomLeft,
+        (_, true, _, true) => ResizeEdge::BottomRight,
+        (_, true, ..) => ResizeEdge::Bottom,
+        (.., true, _) => ResizeEdge::Left,
+        (.., true) => ResizeEdge::Right,
+        _ => return None,
+    })
+}
+
+fn cursor(edge: ResizeEdge) -> CursorStyle {
+    match edge {
+        ResizeEdge::Top | ResizeEdge::Bottom => CursorStyle::ResizeUpDown,
+        ResizeEdge::Left | ResizeEdge::Right => CursorStyle::ResizeLeftRight,
+        ResizeEdge::TopLeft | ResizeEdge::BottomRight => CursorStyle::ResizeUpLeftDownRight,
+        ResizeEdge::TopRight | ResizeEdge::BottomLeft => CursorStyle::ResizeUpRightDownLeft,
+    }
+}
+
+/// Resize margin, hairline and shadow for a client-drawn window; else a plain box.
+#[derive(IntoElement, Default)]
+pub struct ResizeBorder {
+    children: SmallVec<[AnyElement; 2]>,
+}
+
+impl ResizeBorder {
+    pub fn new() -> Self {
+        Self::default()
+    }
+}
+
+impl ParentElement for ResizeBorder {
+    fn extend(&mut self, elements: impl IntoIterator<Item = AnyElement>) {
+        self.children.extend(elements);
+    }
+}
+
+impl RenderOnce for ResizeBorder {
+    fn render(self, window: &mut Window, cx: &mut App) -> impl IntoElement {
+        let Decorations::Client { tiling } = window.window_decorations() else {
+            return div().size_full().children(self.children).into_any_element();
+        };
+        let theme = cx.theme();
+        let inset = theme.window_inset().to_pixels(window.rem_size());
+        window.set_client_inset(inset);
+        let radius = theme.radius(Radius::Lg);
+        let floating = !tiling.is_tiled();
+        div()
+            .id("resize-border")
+            .size_full()
+            .child(
+                canvas(
+                    |_, window, _| {
+                        let size = window.window_bounds().get_bounds().size;
+                        window.insert_hitbox(
+                            Bounds::new(point(Pixels::ZERO, Pixels::ZERO), size),
+                            HitboxBehavior::Normal,
+                        )
+                    },
+                    move |_, hitbox, window, _| {
+                        let size = window.window_bounds().get_bounds().size;
+                        if let Some(edge) = resize_edge(window.mouse_position(), inset, size) {
+                            window.set_cursor_style(cursor(edge), &hitbox);
+                        }
+                    },
+                )
+                .absolute()
+                .size_full(),
+            )
+            .when(!tiling.top, |edge| edge.pt(inset))
+            .when(!tiling.bottom, |edge| edge.pb(inset))
+            .when(!tiling.left, |edge| edge.pl(inset))
+            .when(!tiling.right, |edge| edge.pr(inset))
+            .on_mouse_move(|_, window, _| window.refresh())
+            .on_mouse_down(MouseButton::Left, move |event, window, _| {
+                let size = window.window_bounds().get_bounds().size;
+                if let Some(edge) = resize_edge(event.position, inset, size) {
+                    log::info!("window: resize from {edge:?}");
+                    window.start_window_resize(edge);
+                }
+            })
+            .child(
+                div()
+                    .size_full()
+                    .overflow_hidden()
+                    .cursor(CursorStyle::Arrow)
+                    .bg(theme.colors.bg)
+                    .when(floating, |pane| {
+                        pane.rounded(radius)
+                            .border_1()
+                            .border_color(theme.colors.border_strong)
+                            .shadow(theme.elevation(Elevation::Modal))
+                    })
+                    .on_mouse_move(|_, _, cx| cx.stop_propagation())
+                    .children(self.children),
+            )
+            .into_any_element()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use gpui::{ResizeEdge, point, px, size};
+
+    use super::resize_edge;
+
+    #[test]
+    fn corners_win_over_edges_and_the_middle_is_free() {
+        let window = size(px(400.0), px(300.0));
+        let at = |x: f32, y: f32| resize_edge(point(px(x), px(y)), px(10.0), window);
+        assert_eq!(at(2.0, 2.0), Some(ResizeEdge::TopLeft));
+        assert_eq!(at(398.0, 5.0), Some(ResizeEdge::TopRight));
+        assert_eq!(at(200.0, 3.0), Some(ResizeEdge::Top));
+        assert_eq!(at(1.0, 299.0), Some(ResizeEdge::BottomLeft));
+        assert_eq!(at(395.0, 295.0), Some(ResizeEdge::BottomRight));
+        assert_eq!(at(200.0, 295.0), Some(ResizeEdge::Bottom));
+        assert_eq!(at(4.0, 150.0), Some(ResizeEdge::Left));
+        assert_eq!(at(396.0, 150.0), Some(ResizeEdge::Right));
+        assert_eq!(at(200.0, 150.0), None);
+    }
+}