From c70080dd686738ab6272dd0b3c421c6621e86e34 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bla=C5=BE=20Hrastnik?= <blaz@mxxn.io>
Date: Fri, 5 Feb 2021 14:42:56 +0900
Subject: [PATCH] Work around rendering errors for positions offscreen.

---
 helix-term/src/ui/editor.rs | 26 ++++++++++++++++++--------
 helix-view/src/tree.rs      | 19 +++++++++++++++----
 2 files changed, 33 insertions(+), 12 deletions(-)

diff --git a/helix-term/src/ui/editor.rs b/helix-term/src/ui/editor.rs
index 090f3d0bb..18e853f62 100644
--- a/helix-term/src/ui/editor.rs
+++ b/helix-term/src/ui/editor.rs
@@ -198,12 +198,16 @@ impl EditorView {
 
                             // TODO: paint cursor heads except primary
 
-                            surface.set_string(
-                                viewport.x + visual_x,
-                                viewport.y + line,
-                                grapheme,
-                                style,
-                            );
+                            // HAXX: we don't render the char if it's offscreen. This should be
+                            // skipped in a better way much earlier
+                            if visual_x < viewport.width {
+                                surface.set_string(
+                                    viewport.x + visual_x,
+                                    viewport.y + line,
+                                    grapheme,
+                                    style,
+                                );
+                            }
 
                             visual_x += width;
                         }
@@ -268,12 +272,18 @@ impl EditorView {
 
         if let Some(path) = doc.relative_path() {
             let path = path.to_string_lossy();
-            surface.set_string(viewport.x + 6, viewport.y, path, text_color);
+            surface.set_stringn(
+                viewport.x + 6,
+                viewport.y,
+                path,
+                viewport.width.saturating_sub(6) as usize,
+                text_color,
+            );
             // TODO: append [+] if modified
         }
 
         surface.set_string(
-            viewport.x + viewport.width - 10,
+            viewport.x + viewport.width.saturating_sub(10),
             viewport.y,
             format!("{}", doc.diagnostics.len()),
             text_color,
diff --git a/helix-view/src/tree.rs b/helix-view/src/tree.rs
index 100d8a549..784fea3f0 100644
--- a/helix-view/src/tree.rs
+++ b/helix-view/src/tree.rs
@@ -152,16 +152,27 @@ impl Tree {
                     match container.layout {
                         Layout::Vertical => unimplemented!(),
                         Layout::Horizontal => {
-                            let len = container.children.len() as u16;
+                            let len = container.children.len();
 
-                            let width = area.width / len;
+                            let width = area.width / len as u16;
 
                             let mut child_x = area.x;
 
-                            for (_i, child) in container.children.iter().enumerate() {
-                                let area = Rect::new(child_x, area.y, width, area.height);
+                            for (i, child) in container.children.iter().enumerate() {
+                                let mut area = Rect::new(
+                                    child_x,
+                                    container.area.y,
+                                    width,
+                                    container.area.height,
+                                );
                                 child_x += width;
 
+                                // last child takes the remaining width because we can get uneven
+                                // space from rounding
+                                if i == len - 1 {
+                                    area.width = container.area.x + container.area.width - area.x;
+                                }
+
                                 self.stack.push((*child, area));
                             }
                         }