From 6ae04aacea30f714b78d88b214e57a5a684f1290 Mon Sep 17 00:00:00 2001
From: Denis Gruzdev <codingjerk@gmail.com>
Date: Sun, 29 Sep 2024 18:04:10 +0000
Subject: [PATCH] Allow to use character to draw rulers

---
 book/src/editor.md          |  1 +
 book/src/themes.md          |  1 +
 helix-term/src/ui/editor.rs | 23 ++++++++++++++++++++---
 helix-view/src/editor.rs    |  3 +++
 4 files changed, 25 insertions(+), 3 deletions(-)

diff --git a/book/src/editor.md b/book/src/editor.md
index 82d5f8461..9abeacef3 100644
--- a/book/src/editor.md
+++ b/book/src/editor.md
@@ -42,6 +42,7 @@ ### `[editor]` Section
 | `true-color` | Set to `true` to override automatic detection of terminal truecolor support in the event of a false negative | `false` |
 | `undercurl` | Set to `true` to override automatic detection of terminal undercurl support in the event of a false negative | `false` |
 | `rulers` | List of column positions at which to display the rulers. Can be overridden by language specific `rulers` in `languages.toml` file | `[]` |
+| `ruler-char` | Specifies the character used to display the rulers. When unset, the rulers will be indicated by a subtle background or style change, depending on the theme in use | `none` |
 | `bufferline` | Renders a line at the top of the editor displaying open buffers. Can be `always`, `never` or `multiple` (only shown if more than one buffer is in use) | `never` |
 | `color-modes` | Whether to color the mode indicator with different colors depending on the mode itself | `false` |
 | `text-width` | Maximum line length. Used for the `:reflow` command and soft-wrapping if `soft-wrap.wrap-at-text-width` is set | `80` |
diff --git a/book/src/themes.md b/book/src/themes.md
index 1bc2627dd..0dab4463a 100644
--- a/book/src/themes.md
+++ b/book/src/themes.md
@@ -307,6 +307,7 @@ #### Interface
 | `ui.text.inactive`                | Same as `ui.text` but when the text is inactive (e.g. suggestions)                             |
 | `ui.text.info`                    | The key: command text in `ui.popup.info` boxes                                                 |
 | `ui.virtual.ruler`                | Ruler columns (see the [`editor.rulers` config][editor-section])                               |
+| `ui.virtual.ruler.char`           | Ruler columns, ([only if `editor.ruler-char` is set][editor-section]                           |
 | `ui.virtual.whitespace`           | Visible whitespace characters                                                                  |
 | `ui.virtual.indent-guide`         | Vertical indent width guides                                                                   |
 | `ui.virtual.inlay-hint`           | Default style for inlay hints of all kinds                                                     |
diff --git a/helix-term/src/ui/editor.rs b/helix-term/src/ui/editor.rs
index f7541fe25..44a8b7acc 100644
--- a/helix-term/src/ui/editor.rs
+++ b/helix-term/src/ui/editor.rs
@@ -201,6 +201,9 @@ pub fn render_view(
             inline_diagnostic_config,
             config.end_of_line_diagnostics,
         ));
+
+        Self::render_rulers(editor, doc, view, inner, surface, theme);
+
         render_document(
             surface,
             inner,
@@ -212,7 +215,6 @@ pub fn render_view(
             theme,
             decorations,
         );
-        Self::render_rulers(editor, doc, view, inner, surface, theme);
 
         // if we're not at the edge of the screen, draw a right border
         if viewport.right() != view.area.right() {
@@ -252,8 +254,15 @@ pub fn render_rulers(
         theme: &Theme,
     ) {
         let editor_rulers = &editor.config().rulers;
+        let editor_ruler_char = editor.config().ruler_char.map(|c| c.to_string());
+
+        let theme_key = match &editor_ruler_char {
+            None => "ui.virtual.ruler",
+            Some(_) => "ui.virtual.ruler.char",
+        };
+
         let ruler_theme = theme
-            .try_get("ui.virtual.ruler")
+            .try_get(theme_key)
             .unwrap_or_else(|| Style::default().bg(Color::Red));
 
         let rulers = doc
@@ -270,7 +279,15 @@ pub fn render_rulers(
             .filter_map(|ruler| ruler.checked_sub(1 + view_offset.horizontal_offset as u16))
             .filter(|ruler| ruler < &viewport.width)
             .map(|ruler| viewport.clip_left(ruler).with_width(1))
-            .for_each(|area| surface.set_style(area, ruler_theme))
+            .for_each(|area| {
+                if let Some(ruler_char) = &editor_ruler_char {
+                    for y in area.y..area.height {
+                        surface.set_string(area.x, y, ruler_char, ruler_theme)
+                    }
+                } else {
+                    surface.set_style(area, ruler_theme)
+                }
+            })
     }
 
     fn viewport_byte_range(
diff --git a/helix-view/src/editor.rs b/helix-view/src/editor.rs
index 26dea3a21..fe39af965 100644
--- a/helix-view/src/editor.rs
+++ b/helix-view/src/editor.rs
@@ -314,6 +314,8 @@ pub struct Config {
     pub terminal: Option<TerminalConfig>,
     /// Column numbers at which to draw the rulers. Defaults to `[]`, meaning no rulers.
     pub rulers: Vec<u16>,
+    /// Character used to draw the rulers when specified. If `None`, rulers are drawn using style only.
+    pub ruler_char: Option<char>,
     #[serde(default)]
     pub whitespace: WhitespaceConfig,
     /// Persistently display open buffers along the top
@@ -963,6 +965,7 @@ fn default() -> Self {
             lsp: LspConfig::default(),
             terminal: get_terminal_provider(),
             rulers: Vec::new(),
+            ruler_char: None,
             whitespace: WhitespaceConfig::default(),
             bufferline: BufferLine::default(),
             indent_guides: IndentGuidesConfig::default(),