Redesign for the v1 stable release (#3)

Only half done. Will continue in another PR.

Reviewed-on: #3

crates/dock/src/resizable/panel.rs

@@ -0,0 +1,405 @@
+use std::ops::{Deref, Range};
+use std::rc::Rc;
+
+use gpui::prelude::FluentBuilder;
+use gpui::{
+    div, Along, AnyElement, App, AppContext, Axis, Bounds, Context, Element, ElementId, Empty,
+    Entity, EventEmitter, InteractiveElement as _, IntoElement, IsZero as _, MouseMoveEvent,
+    MouseUpEvent, ParentElement, Pixels, Render, RenderOnce, Style, Styled, Window,
+};
+use ui::{h_flex, v_flex, AxisExt, ElementExt};
+
+use super::{resizable_panel, resize_handle, ResizableState};
+use crate::resizable::PANEL_MIN_SIZE;
+
+pub enum ResizablePanelEvent {
+    Resized,
+}
+
+#[derive(Clone)]
+pub(crate) struct DragPanel;
+impl Render for DragPanel {
+    fn render(&mut self, _: &mut Window, _: &mut Context<'_, Self>) -> impl IntoElement {
+        Empty
+    }
+}
+
+/// A group of resizable panels.
+#[allow(clippy::type_complexity)]
+#[derive(IntoElement)]
+pub struct ResizablePanelGroup {
+    id: ElementId,
+    state: Option<Entity<ResizableState>>,
+    axis: Axis,
+    size: Option<Pixels>,
+    children: Vec<ResizablePanel>,
+    on_resize: Rc<dyn Fn(&Entity<ResizableState>, &mut Window, &mut App)>,
+}
+
+impl ResizablePanelGroup {
+    /// Create a new resizable panel group.
+    pub fn new(id: impl Into<ElementId>) -> Self {
+        Self {
+            id: id.into(),
+            axis: Axis::Horizontal,
+            children: vec![],
+            state: None,
+            size: None,
+            on_resize: Rc::new(|_, _, _| {}),
+        }
+    }
+
+    /// Bind yourself to a resizable state entity.
+    ///
+    /// If not provided, it will handle its own state internally.
+    pub fn with_state(mut self, state: &Entity<ResizableState>) -> Self {
+        self.state = Some(state.clone());
+        self
+    }
+
+    /// Set the axis of the resizable panel group, default is horizontal.
+    pub fn axis(mut self, axis: Axis) -> Self {
+        self.axis = axis;
+        self
+    }
+
+    /// Add a panel to the group.
+    ///
+    /// - The `axis` will be set to the same axis as the group.
+    /// - The `initial_size` will be set to the average size of all panels if not provided.
+    /// - The `group` will be set to the group entity.
+    pub fn child(mut self, panel: impl Into<ResizablePanel>) -> Self {
+        self.children.push(panel.into());
+        self
+    }
+
+    /// Add multiple panels to the group.
+    pub fn children<I>(mut self, panels: impl IntoIterator<Item = I>) -> Self
+    where
+        I: Into<ResizablePanel>,
+    {
+        self.children = panels.into_iter().map(|panel| panel.into()).collect();
+        self
+    }
+
+    /// Set size of the resizable panel group
+    ///
+    /// - When the axis is horizontal, the size is the height of the group.
+    /// - When the axis is vertical, the size is the width of the group.
+    pub fn size(mut self, size: Pixels) -> Self {
+        self.size = Some(size);
+        self
+    }
+
+    /// Set the callback to be called when the panels are resized.
+    ///
+    /// ## Callback arguments
+    ///
+    /// - Entity<ResizableState>: The state of the ResizablePanelGroup.
+    pub fn on_resize(
+        mut self,
+        on_resize: impl Fn(&Entity<ResizableState>, &mut Window, &mut App) + 'static,
+    ) -> Self {
+        self.on_resize = Rc::new(on_resize);
+        self
+    }
+}
+
+impl<T> From<T> for ResizablePanel
+where
+    T: Into<AnyElement>,
+{
+    fn from(value: T) -> Self {
+        resizable_panel().child(value.into())
+    }
+}
+
+impl From<ResizablePanelGroup> for ResizablePanel {
+    fn from(value: ResizablePanelGroup) -> Self {
+        resizable_panel().child(value)
+    }
+}
+
+impl EventEmitter<ResizablePanelEvent> for ResizablePanelGroup {}
+
+impl RenderOnce for ResizablePanelGroup {
+    fn render(self, window: &mut Window, cx: &mut App) -> impl IntoElement {
+        let state = self.state.unwrap_or(
+            window.use_keyed_state(self.id.clone(), cx, |_, _| ResizableState::default()),
+        );
+        let container = if self.axis.is_horizontal() {
+            h_flex()
+        } else {
+            v_flex()
+        };
+
+        // Sync panels to the state
+        let panels_count = self.children.len();
+        state.update(cx, |state, cx| {
+            state.sync_panels_count(self.axis, panels_count, cx);
+        });
+
+        container
+            .id(self.id)
+            .size_full()
+            .children(
+                self.children
+                    .into_iter()
+                    .enumerate()
+                    .map(|(ix, mut panel)| {
+                        panel.panel_ix = ix;
+                        panel.axis = self.axis;
+                        panel.state = Some(state.clone());
+                        panel
+                    }),
+            )
+            .on_prepaint({
+                let state = state.clone();
+                move |bounds, _, cx| {
+                    state.update(cx, |state, cx| {
+                        let size_changed =
+                            state.bounds.size.along(self.axis) != bounds.size.along(self.axis);
+
+                        state.bounds = bounds;
+
+                        if size_changed {
+                            state.adjust_to_container_size(cx);
+                        }
+                    })
+                }
+            })
+            .child(ResizePanelGroupElement {
+                state: state.clone(),
+                axis: self.axis,
+                on_resize: self.on_resize.clone(),
+            })
+    }
+}
+
+/// A resizable panel inside a [`ResizablePanelGroup`].
+#[derive(IntoElement)]
+pub struct ResizablePanel {
+    axis: Axis,
+    panel_ix: usize,
+    state: Option<Entity<ResizableState>>,
+    /// Initial size is the size that the panel has when it is created.
+    initial_size: Option<Pixels>,
+    /// size range limit of this panel.
+    size_range: Range<Pixels>,
+    children: Vec<AnyElement>,
+    visible: bool,
+}
+
+impl ResizablePanel {
+    /// Create a new resizable panel.
+    pub(super) fn new() -> Self {
+        Self {
+            panel_ix: 0,
+            initial_size: None,
+            state: None,
+            size_range: (PANEL_MIN_SIZE..Pixels::MAX),
+            axis: Axis::Horizontal,
+            children: vec![],
+            visible: true,
+        }
+    }
+
+    /// Set the visibility of the panel, default is true.
+    pub fn visible(mut self, visible: bool) -> Self {
+        self.visible = visible;
+        self
+    }
+
+    /// Set the initial size of the panel.
+    pub fn size(mut self, size: impl Into<Pixels>) -> Self {
+        self.initial_size = Some(size.into());
+        self
+    }
+
+    /// Set the size range to limit panel resize.
+    ///
+    /// Default is [`PANEL_MIN_SIZE`] to [`Pixels::MAX`].
+    pub fn size_range(mut self, range: impl Into<Range<Pixels>>) -> Self {
+        self.size_range = range.into();
+        self
+    }
+}
+
+impl ParentElement for ResizablePanel {
+    fn extend(&mut self, elements: impl IntoIterator<Item = AnyElement>) {
+        self.children.extend(elements);
+    }
+}
+
+impl RenderOnce for ResizablePanel {
+    fn render(self, _: &mut Window, cx: &mut App) -> impl IntoElement {
+        if !self.visible {
+            return div().id(("resizable-panel", self.panel_ix));
+        }
+
+        let state = self
+            .state
+            .expect("BUG: The `state` in ResizablePanel should be present.");
+        let panel_state = state
+            .read(cx)
+            .panels
+            .get(self.panel_ix)
+            .expect("BUG: The `index` of ResizablePanel should be one of in `state`.");
+        let size_range = self.size_range.clone();
+
+        div()
+            .id(("resizable-panel", self.panel_ix))
+            .flex()
+            .flex_grow()
+            .size_full()
+            .relative()
+            .when(self.axis.is_vertical(), |this| {
+                this.min_h(size_range.start).max_h(size_range.end)
+            })
+            .when(self.axis.is_horizontal(), |this| {
+                this.min_w(size_range.start).max_w(size_range.end)
+            })
+            // 1. initial_size is None, to use auto size.
+            // 2. initial_size is Some and size is none, to use the initial size of the panel for first time render.
+            // 3. initial_size is Some and size is Some, use `size`.
+            .when(self.initial_size.is_none(), |this| this.flex_shrink())
+            .when_some(self.initial_size, |this, initial_size| {
+                // The `self.size` is None, that mean the initial size for the panel,
+                // so we need set `flex_shrink_0` To let it keep the initial size.
+                this.when(
+                    panel_state.size.is_none() && !initial_size.is_zero(),
+                    |this| this.flex_none(),
+                )
+                .flex_basis(initial_size)
+            })
+            .map(|this| match panel_state.size {
+                Some(size) => this.flex_basis(size.min(size_range.end).max(size_range.start)),
+                None => this,
+            })
+            .on_prepaint({
+                let state = state.clone();
+                move |bounds, _, cx| {
+                    state.update(cx, |state, cx| {
+                        state.update_panel_size(self.panel_ix, bounds, self.size_range, cx)
+                    })
+                }
+            })
+            .children(self.children)
+            .when(self.panel_ix > 0, |this| {
+                let ix = self.panel_ix - 1;
+                this.child(resize_handle(("resizable-handle", ix), self.axis).on_drag(
+                    DragPanel,
+                    move |drag_panel, _, _, cx| {
+                        cx.stop_propagation();
+                        // Set current resizing panel ix
+                        state.update(cx, |state, _| {
+                            state.resizing_panel_ix = Some(ix);
+                        });
+                        cx.new(|_| drag_panel.deref().clone())
+                    },
+                ))
+            })
+    }
+}
+
+#[allow(clippy::type_complexity)]
+struct ResizePanelGroupElement {
+    state: Entity<ResizableState>,
+    on_resize: Rc<dyn Fn(&Entity<ResizableState>, &mut Window, &mut App)>,
+    axis: Axis,
+}
+
+impl IntoElement for ResizePanelGroupElement {
+    type Element = Self;
+
+    fn into_element(self) -> Self::Element {
+        self
+    }
+}
+
+impl Element for ResizePanelGroupElement {
+    type PrepaintState = ();
+    type RequestLayoutState = ();
+
+    fn id(&self) -> Option<gpui::ElementId> {
+        None
+    }
+
+    fn source_location(&self) -> Option<&'static std::panic::Location<'static>> {
+        None
+    }
+
+    fn request_layout(
+        &mut self,
+        _: Option<&gpui::GlobalElementId>,
+        _: Option<&gpui::InspectorElementId>,
+        window: &mut Window,
+        cx: &mut App,
+    ) -> (gpui::LayoutId, Self::RequestLayoutState) {
+        (window.request_layout(Style::default(), None, cx), ())
+    }
+
+    fn prepaint(
+        &mut self,
+        _: Option<&gpui::GlobalElementId>,
+        _: Option<&gpui::InspectorElementId>,
+        _: Bounds<Pixels>,
+        _: &mut Self::RequestLayoutState,
+        _window: &mut Window,
+        _cx: &mut App,
+    ) -> Self::PrepaintState {
+    }
+
+    fn paint(
+        &mut self,
+        _: Option<&gpui::GlobalElementId>,
+        _: Option<&gpui::InspectorElementId>,
+        _: Bounds<Pixels>,
+        _: &mut Self::RequestLayoutState,
+        _: &mut Self::PrepaintState,
+        window: &mut Window,
+        cx: &mut App,
+    ) {
+        window.on_mouse_event({
+            let state = self.state.clone();
+            let axis = self.axis;
+            let current_ix = state.read(cx).resizing_panel_ix;
+            move |e: &MouseMoveEvent, phase, window, cx| {
+                if !phase.bubble() {
+                    return;
+                }
+                let Some(ix) = current_ix else { return };
+
+                state.update(cx, |state, cx| {
+                    let panel = state.panels.get(ix).expect("BUG: invalid panel index");
+
+                    match axis {
+                        Axis::Horizontal => {
+                            state.resize_panel(ix, e.position.x - panel.bounds.left(), window, cx)
+                        }
+                        Axis::Vertical => {
+                            state.resize_panel(ix, e.position.y - panel.bounds.top(), window, cx);
+                        }
+                    }
+                    cx.notify();
+                })
+            }
+        });
+
+        // When any mouse up, stop dragging
+        window.on_mouse_event({
+            let state = self.state.clone();
+            let current_ix = state.read(cx).resizing_panel_ix;
+            let on_resize = self.on_resize.clone();
+            move |_: &MouseUpEvent, phase, window, cx| {
+                if current_ix.is_none() {
+                    return;
+                }
+                if phase.bubble() {
+                    state.update(cx, |state, cx| state.done_resizing(cx));
+                    on_resize(&state, window, cx);
+                }
+            }
+        })
+    }
+}