Add color_column option

book/src/configuration.md

@@ -42,6 +42,7 @@ hidden = false
 | `completion-trigger-len` | The min-length of word under cursor to trigger autocompletion | `2` |
 | `auto-info` | Whether to display infoboxes | `true` |
 | `true-color` | Set to `true` to override automatic detection of terminal truecolor support in the event of a false negative. | `false` |
+| `color-column` | List of column positions at which to display the color columns. | `[]` |
 
 ### `[editor.lsp]` Section
 

book/src/themes.md

@@ -228,6 +228,7 @@ These scopes are used for theming the editor interface.
 | `ui.menu.selected`       |                                     |
 | `ui.selection`           | For selections in the editing area  |
 | `ui.selection.primary`   |                                     |
+| `ui.colorcolumn`         |                                     |
 | `warning`                | Diagnostics warning (gutter)        |
 | `error`                  | Diagnostics error (gutter)          |
 | `info`                   | Diagnostics info (gutter)           |

helix-term/src/ui/editor.rs

@@ -127,6 +127,24 @@ impl EditorView {
         Self::render_text_highlights(doc, view.offset, inner, surface, theme, highlights);
         Self::render_gutter(editor, doc, view, view.area, surface, theme, is_focused);
 
+        // Render color columns
+        editor
+            .config()
+            .color_column
+            .iter()
+            .filter_map(|column| {
+                column
+                    .checked_sub(1 + view.offset.col as u16)
+                    .map(|x| {
+                        inner
+                            .with_height((view.last_line(doc) - view.offset.row + 1) as u16)
+                            .clip_left(x)
+                            .with_width(1)
+                    })
+                    .filter(|area| area.left() < inner.right())
+            })
+            .for_each(|area| surface.set_style(area, theme.get("ui.colorcolumn")));
+
         if is_focused {
             Self::render_focused_view_elements(view, doc, inner, theme, surface);
         }

helix-view/src/editor.rs

@@ -144,6 +144,8 @@ pub struct Config {
     #[serde(default)]
     pub search: SearchConfig,
     pub lsp: LspConfig,
+    /// Column numbers at which to draw the color columns. Default to `[]`, meaning no color column.
+    pub color_column: Vec<u16>,
 }
 
 #[derive(Debug, Default, Clone, PartialEq, Serialize, Deserialize)]
@@ -261,6 +263,7 @@ impl Default for Config {
             true_color: false,
             search: SearchConfig::default(),
             lsp: LspConfig::default(),
+            color_column: Vec::new(),
         }
     }
 }

theme.toml

@@ -62,6 +62,7 @@ label = "honey"
 "ui.cursor.match" = { fg = "#212121", bg = "#6C6999" }
 "ui.cursor" = { modifiers = ["reversed"] }
 "ui.highlight" = { bg = "bossanova" }
+"ui.colorcolumn" = { bg = "gray" }
 
 "ui.menu.selected" = { fg = "revolver", bg = "white" }