From 5e73f83efa406a6989fff6077b90dd77a7328b36 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bla=C5=BE=20Hrastnik?= <blaz@mxxn.io>
Date: Tue, 9 Feb 2021 15:59:42 +0900
Subject: [PATCH] Implement vertical split calculations.

---
 TODO.md                     |  3 ++-
 helix-term/src/ui/editor.rs | 14 +++++++-------
 helix-view/src/editor.rs    |  5 ++++-
 helix-view/src/tree.rs      | 26 +++++++++++++++++++++++++-
 helix-view/src/view.rs      |  2 +-
 5 files changed, 39 insertions(+), 11 deletions(-)

diff --git a/TODO.md b/TODO.md
index 60bd003a2..69f65a1f4 100644
--- a/TODO.md
+++ b/TODO.md
@@ -10,8 +10,9 @@
 1
 - [ ] selection mode
 - [x] % for whole doc selection
-- [ ] vertical splits
+- [x] vertical splits
 - [ ] input counts (30j)
+- [ ] respect view fullscreen flag
 - [ ] retain horiz when moving vertically
 - [ ] update lsp on redo/undo
 - [ ] Implement marks (superset of Selection/Range)
diff --git a/helix-term/src/ui/editor.rs b/helix-term/src/ui/editor.rs
index 773bc44d2..79e6ed93f 100644
--- a/helix-term/src/ui/editor.rs
+++ b/helix-term/src/ui/editor.rs
@@ -42,8 +42,8 @@ impl EditorView {
             viewport.x + OFFSET,
             viewport.y,
             viewport.width - OFFSET,
-            viewport.height - 2,
-        ); // - 2 for statusline and prompt
+            viewport.height - 1,
+        ); // - 1 for statusline
         self.render_buffer(view, area, surface, theme, is_focused);
 
         // clear with background color
@@ -52,7 +52,7 @@ impl EditorView {
 
         let area = Rect::new(
             viewport.x,
-            viewport.y + viewport.height - 2,
+            viewport.y + viewport.height - 1,
             viewport.width,
             1,
         );
@@ -301,9 +301,8 @@ impl Component for EditorView {
     fn handle_event(&mut self, event: Event, cx: &mut Context) -> EventResult {
         match event {
             Event::Resize(width, height) => {
-                // TODO: simplistic ensure cursor in view for now
-                // TODO: loop over views
-                cx.editor.tree.resize(Rect::new(0, 0, width, height));
+                // HAXX: offset the render area height by 1 to account for prompt/commandline
+                cx.editor.tree.resize(Rect::new(0, 0, width, height - 1));
                 // TODO: restore view.ensure_cursor_in_view();
                 EventResult::Consumed(None)
             }
@@ -353,10 +352,11 @@ impl Component for EditorView {
         }
     }
 
-    fn render(&self, area: Rect, surface: &mut Surface, cx: &mut Context) {
+    fn render(&self, mut area: Rect, surface: &mut Surface, cx: &mut Context) {
         // SAFETY: we cheat around the view_mut() borrow because it doesn't allow us to also borrow
         // theme. Theme is immutable mutating view won't disrupt theme_ref.
         let theme_ref = unsafe { &*(&cx.editor.theme as *const Theme) };
+
         for (view, is_focused) in cx.editor.tree.views() {
             // TODO: use parent area
             self.render_view(view, view.area, surface, theme_ref, is_focused);
diff --git a/helix-view/src/editor.rs b/helix-view/src/editor.rs
index 2942507d7..6b5b285db 100644
--- a/helix-view/src/editor.rs
+++ b/helix-view/src/editor.rs
@@ -15,10 +15,13 @@ pub struct Editor {
 }
 
 impl Editor {
-    pub fn new(area: tui::layout::Rect) -> Self {
+    pub fn new(mut area: tui::layout::Rect) -> Self {
         let theme = Theme::default();
         let language_servers = helix_lsp::Registry::new();
 
+        // HAXX: offset the render area height by 1 to account for prompt/commandline
+        area.height -= 1;
+
         Self {
             tree: Tree::new(area),
             should_close: false,
diff --git a/helix-view/src/tree.rs b/helix-view/src/tree.rs
index a5b59a79e..dd07d76d2 100644
--- a/helix-view/src/tree.rs
+++ b/helix-view/src/tree.rs
@@ -156,7 +156,31 @@ impl Tree {
                     container.area = area;
 
                     match container.layout {
-                        Layout::Vertical => unimplemented!(),
+                        Layout::Vertical => {
+                            let len = container.children.len();
+
+                            let height = area.height / len as u16;
+
+                            let mut child_y = area.y;
+
+                            for (i, child) in container.children.iter().enumerate() {
+                                let mut area = Rect::new(
+                                    container.area.x,
+                                    child_y,
+                                    container.area.width,
+                                    height,
+                                );
+                                child_y += height;
+
+                                // last child takes the remaining width because we can get uneven
+                                // space from rounding
+                                if i == len - 1 {
+                                    area.height = container.area.y + container.area.height - area.y;
+                                }
+
+                                self.stack.push((*child, area));
+                            }
+                        }
                         Layout::Horizontal => {
                             let len = container.children.len();
 
diff --git a/helix-view/src/view.rs b/helix-view/src/view.rs
index 02eda72fa..f1959ee34 100644
--- a/helix-view/src/view.rs
+++ b/helix-view/src/view.rs
@@ -51,7 +51,7 @@ impl View {
     /// Calculates the last visible line on screen
     #[inline]
     pub fn last_line(&self) -> usize {
-        let viewport = Rect::new(6, 0, self.area.width, self.area.height - 2); // - 2 for statusline and prompt
+        let viewport = Rect::new(6, 0, self.area.width, self.area.height - 1); // - 1 for statusline
         std::cmp::min(
             self.first_line + (viewport.height as usize),
             self.doc.text().len_lines() - 1,