From c87efb0dbc14e74708f3557567d49fb887addd48 Mon Sep 17 00:00:00 2001
From: Antonio Scandurra <me@as-cii.com>
Date: Wed, 13 Jul 2022 11:44:33 +0200
Subject: [PATCH] Show split button at the right edge of the tab bar

---
 crates/theme/src/theme.rs         |  1 +
 crates/workspace/src/pane.rs      | 40 ++++++++++++++++++++++++-------
 styles/src/styleTree/workspace.ts | 12 ++++++++++
 3 files changed, 45 insertions(+), 8 deletions(-)

diff --git a/crates/theme/src/theme.rs b/crates/theme/src/theme.rs
index 32ddb9c825..c609dcc829 100644
--- a/crates/theme/src/theme.rs
+++ b/crates/theme/src/theme.rs
@@ -40,6 +40,7 @@ pub struct Workspace {
     pub titlebar: Titlebar,
     pub tab: Tab,
     pub active_tab: Tab,
+    pub pane_button: Interactive<IconButton>,
     pub pane_divider: Border,
     pub leader_border_opacity: f32,
     pub leader_border_width: f32,
diff --git a/crates/workspace/src/pane.rs b/crates/workspace/src/pane.rs
index 391ddfc1f7..bbbaffc530 100644
--- a/crates/workspace/src/pane.rs
+++ b/crates/workspace/src/pane.rs
@@ -800,13 +800,13 @@ impl Pane {
         });
     }
 
-    fn render_tabs(&mut self, cx: &mut RenderContext<Self>) -> ElementBox {
+    fn render_tabs(&mut self, cx: &mut RenderContext<Self>) -> impl Element {
         let theme = cx.global::<Settings>().theme.clone();
 
         enum Tabs {}
         enum Tab {}
         let pane = cx.handle();
-        let tabs = MouseEventHandler::new::<Tabs, _, _>(0, cx, |mouse_state, cx| {
+        MouseEventHandler::new::<Tabs, _, _>(0, cx, |mouse_state, cx| {
             let autoscroll = if mem::take(&mut self.autoscroll) {
                 Some(self.active_item_index)
             } else {
@@ -941,11 +941,7 @@ impl Pane {
             );
 
             row.boxed()
-        });
-
-        ConstrainedBox::new(tabs.boxed())
-            .with_height(theme.workspace.tab.height)
-            .named("tabs")
+        })
     }
 }
 
@@ -959,11 +955,39 @@ impl View for Pane {
     }
 
     fn render(&mut self, cx: &mut RenderContext<Self>) -> ElementBox {
+        enum SplitIcon {}
+
         let this = cx.handle();
 
         EventHandler::new(if let Some(active_item) = self.active_item() {
             Flex::column()
-                .with_child(self.render_tabs(cx))
+                .with_child(
+                    Flex::row()
+                        .with_child(self.render_tabs(cx).flex(1., true).named("tabs"))
+                        .with_child(
+                            MouseEventHandler::new::<SplitIcon, _, _>(0, cx, |mouse_state, cx| {
+                                let theme = &cx.global::<Settings>().theme.workspace;
+                                let style = theme.pane_button.style_for(mouse_state, false);
+                                Svg::new("icons/split.svg")
+                                    .with_color(style.color)
+                                    .constrained()
+                                    .with_width(style.icon_width)
+                                    .aligned()
+                                    .contained()
+                                    .with_style(style.container)
+                                    .constrained()
+                                    .with_width(style.button_width)
+                                    .with_height(style.button_width)
+                                    .aligned()
+                                    .boxed()
+                            })
+                            .with_cursor_style(CursorStyle::PointingHand)
+                            .boxed(),
+                        )
+                        .constrained()
+                        .with_height(cx.global::<Settings>().theme.workspace.tab.height)
+                        .boxed(),
+                )
                 .with_child(ChildView::new(&self.toolbar).boxed())
                 .with_child(ChildView::new(active_item).flex(1., true).boxed())
                 .boxed()
diff --git a/styles/src/styleTree/workspace.ts b/styles/src/styleTree/workspace.ts
index fbd7b05a22..36d47bed92 100644
--- a/styles/src/styleTree/workspace.ts
+++ b/styles/src/styleTree/workspace.ts
@@ -55,6 +55,18 @@ export default function workspace(theme: Theme) {
     leaderBorderWidth: 2.0,
     tab,
     activeTab,
+    paneButton: {
+      color: iconColor(theme, "secondary"),
+      border: {
+        ...tab.border
+      },
+      iconWidth: 14,
+      buttonWidth: tab.height,
+      hover: {
+        color: iconColor(theme, "active"),
+        background: backgroundColor(theme, 300),
+      }
+    },
     modal: {
       margin: {
         bottom: 52,