editor: Scale minimap width to editor width (#32317)

assets/settings/default.json

@@ -435,7 +435,9 @@
     // 1. `null` to inherit the editor `current_line_highlight` setting (default)
     // 2. "line" or "all" to highlight the current line in the minimap.
     // 3. "gutter" or "none" to not highlight the current line in the minimap.
-    "current_line_highlight": null
+    "current_line_highlight": null,
+    // Maximum number of columns to display in the minimap.
+    "max_width_columns": 80
   },
   // Enable middle-click paste on Linux.
   "middle_click_paste": true,

crates/editor/src/editor_settings.rs

@@ -1,3 +1,6 @@
+use core::num;
+use std::num::NonZeroU32;
+
 use gpui::App;
 use language::CursorShape;
 use project::project_settings::DiagnosticSeverity;
@@ -150,6 +153,7 @@ pub struct Minimap {
     pub thumb: MinimapThumb,
     pub thumb_border: MinimapThumbBorder,
     pub current_line_highlight: Option<CurrentLineHighlight>,
+    pub max_width_columns: num::NonZeroU32,
 }
 
 impl Minimap {
@@ -632,6 +636,11 @@ pub struct MinimapContent {
     ///
     /// Default: inherits editor line highlights setting
     pub current_line_highlight: Option<Option<CurrentLineHighlight>>,
+
+    /// Maximum number of columns to display in the minimap.
+    ///
+    /// Default: 80
+    pub max_width_columns: Option<num::NonZeroU32>,
 }
 
 /// Forcefully enable or disable the scrollbar for each axis
@@ -854,6 +863,8 @@ impl Settings for EditorSettings {
         let mut minimap = MinimapContent::default();
         let minimap_enabled = vscode.read_bool("editor.minimap.enabled").unwrap_or(true);
         let autohide = vscode.read_bool("editor.minimap.autohide");
+        let mut max_width_columns: Option<u32> = None;
+        vscode.u32_setting("editor.minimap.maxColumn", &mut max_width_columns);
         if minimap_enabled {
             if let Some(false) = autohide {
                 minimap.show = Some(ShowMinimap::Always);
@@ -863,6 +874,9 @@ impl Settings for EditorSettings {
         } else {
             minimap.show = Some(ShowMinimap::Never);
         }
+        if let Some(max_width_columns) = max_width_columns {
+            minimap.max_width_columns = NonZeroU32::new(max_width_columns);
+        }
 
         vscode.enum_setting(
             "editor.minimap.showSlider",

crates/editor/src/element.rs

@@ -16,9 +16,9 @@ use crate::{
         HighlightedChunk, ToDisplayPoint,
     },
     editor_settings::{
-        CurrentLineHighlight, DocumentColorsRenderMode, DoubleClickInMultibuffer, MinimapThumb,
+        CurrentLineHighlight, DocumentColorsRenderMode, DoubleClickInMultibuffer, Minimap,
-        MinimapThumbBorder, ScrollBeyondLastLine, ScrollbarAxes, ScrollbarDiagnostics, ShowMinimap,
+        MinimapThumb, MinimapThumbBorder, ScrollBeyondLastLine, ScrollbarAxes,
-        ShowScrollbar,
+        ScrollbarDiagnostics, ShowMinimap, ShowScrollbar,
     },
     git::blame::{BlameRenderer, GitBlame, GlobalBlameRenderer},
     hover_popover::{
@@ -1908,6 +1908,40 @@ impl EditorElement {
         text_style.line_height_in_pixels(rem_size)
     }
 
+    fn get_minimap_width(
+        &self,
+        minimap_settings: &Minimap,
+        scrollbars_shown: bool,
+        text_width: Pixels,
+        em_width: Pixels,
+        font_size: Pixels,
+        rem_size: Pixels,
+        cx: &App,
+    ) -> Option<Pixels> {
+        if minimap_settings.show == ShowMinimap::Auto && !scrollbars_shown {
+            return None;
+        }
+
+        let minimap_font_size = self.editor.read_with(cx, |editor, cx| {
+            editor.minimap().map(|minimap_editor| {
+                minimap_editor
+                    .read(cx)
+                    .text_style_refinement
+                    .as_ref()
+                    .and_then(|refinement| refinement.font_size)
+                    .unwrap_or(MINIMAP_FONT_SIZE)
+            })
+        })?;
+
+        let minimap_em_width = em_width * (minimap_font_size.to_pixels(rem_size) / font_size);
+
+        let minimap_width = (text_width * MinimapLayout::MINIMAP_WIDTH_PCT)
+            .min(minimap_em_width * minimap_settings.max_width_columns.get() as f32);
+
+        (minimap_width >= minimap_em_width * MinimapLayout::MINIMAP_MIN_WIDTH_COLUMNS)
+            .then_some(minimap_width)
+    }
+
     fn prepaint_crease_toggles(
         &self,
         crease_toggles: &mut [Option<AnyElement>],
@@ -7829,9 +7863,10 @@ impl Element for EditorElement {
                     });
                     let style = self.style.clone();
 
+                    let rem_size = window.rem_size();
                     let font_id = window.text_system().resolve_font(&style.text.font());
-                    let font_size = style.text.font_size.to_pixels(window.rem_size());
+                    let font_size = style.text.font_size.to_pixels(rem_size);
-                    let line_height = style.text.line_height_in_pixels(window.rem_size());
+                    let line_height = style.text.line_height_in_pixels(rem_size);
                     let em_width = window.text_system().em_width(font_id, font_size).unwrap();
                     let em_advance = window.text_system().em_advance(font_id, font_size).unwrap();
                     let glyph_grid_cell = size(em_advance, line_height);
@@ -7859,27 +7894,21 @@ impl Element for EditorElement {
                         .then_some(style.scrollbar_width)
                         .unwrap_or_default();
                     let minimap_width = self
-                        .editor
+                        .get_minimap_width(
-                        .read(cx)
+                            &settings.minimap,
-                        .minimap()
+                            scrollbars_shown,
-                        .is_some()
+                            text_width,
-                        .then(|| match settings.minimap.show {
+                            em_width,
-                            ShowMinimap::Auto => {
+                            font_size,
-                                scrollbars_shown.then_some(MinimapLayout::MINIMAP_WIDTH)
+                            rem_size,
-                            }
+                            cx,
-                            _ => Some(MinimapLayout::MINIMAP_WIDTH),
+                        )
-                        })
-                        .flatten()
-                        .filter(|minimap_width| {
-                            text_width - vertical_scrollbar_width - *minimap_width > *minimap_width
-                        })
                         .unwrap_or_default();
 
                     let right_margin = minimap_width + vertical_scrollbar_width;
 
                     let editor_width =
                         text_width - gutter_dimensions.margin - 2 * em_width - right_margin;
-
                     let editor_margins = EditorMargins {
                         gutter: gutter_dimensions,
                         right: right_margin,
@@ -9474,7 +9503,10 @@ struct MinimapLayout {
 }
 
 impl MinimapLayout {
-    const MINIMAP_WIDTH: Pixels = px(100.);
+    /// The minimum width of the minimap in columns. If the minimap is smaller than this, it will be hidden.
+    const MINIMAP_MIN_WIDTH_COLUMNS: f32 = 20.;
+    /// The minimap width as a percentage of the editor width.
+    const MINIMAP_WIDTH_PCT: f32 = 0.15;
     /// Calculates the scroll top offset the minimap editor has to have based on the
     /// current scroll progress.
     fn calculate_minimap_top_offset(