Introduce a new BlockStyle field for blocks

This new field allows blocks to specify how they want to be laid out:

- If `Fixed` they can take up all the width they want and they will impact
the scroll width of the editor. This is useful for diagnostic messages and
allows scrolling the editor further to the right to visualize the entire message.
- If `Flex` they can extend all the way to the scroll width without impacting it
any further. This is useful for the rename editor that we insert as a block
decoration when hitting `F2`.
- If `Sticky`, they will be as wide as the editor element and won't participate
in the horizontal scrolling of the editor. This is useful for headers in general,
where we want e.g. the filename and the jump button to always be visible
independently of how much the user has scrolled to the right.

crates/diagnostics/src/diagnostics.rs

@@ -4,7 +4,7 @@ use anyhow::Result;
 use collections::{BTreeMap, HashSet};
 use editor::{
     diagnostic_block_renderer,
-    display_map::{BlockDisposition, BlockId, BlockProperties, RenderBlock},
+    display_map::{BlockDisposition, BlockId, BlockProperties, BlockStyle, RenderBlock},
     highlight_diagnostic_message, Autoscroll, Editor, ExcerptId, ExcerptRange, MultiBuffer,
     ToOffset,
 };
@@ -348,6 +348,7 @@ impl ProjectDiagnosticsEditor {
                                 blocks_to_add.push(BlockProperties {
                                     position: header_position,
                                     height: 2,
+                                    style: BlockStyle::Sticky,
                                     render: diagnostic_header_renderer(primary),
                                     disposition: BlockDisposition::Above,
                                 });
@@ -366,6 +367,7 @@ impl ProjectDiagnosticsEditor {
                                     blocks_to_add.push(BlockProperties {
                                         position: (excerpt_id.clone(), entry.range.start.clone()),
                                         height: diagnostic.message.matches('\n').count() as u8 + 1,
+                                        style: BlockStyle::Fixed,
                                         render: diagnostic_block_renderer(diagnostic, true),
                                         disposition: BlockDisposition::Below,
                                     });
@@ -402,6 +404,7 @@ impl ProjectDiagnosticsEditor {
                     BlockProperties {
                         position: excerpts_snapshot.anchor_in_excerpt(excerpt_id, text_anchor),
                         height: block.height,
+                        style: block.style,
                         render: block.render,
                         disposition: block.disposition,
                     }
@@ -621,7 +624,6 @@ fn diagnostic_header_renderer(diagnostic: Diagnostic) -> RenderBlock {
                 .with_color(theme.warning_diagnostic.message.text.color)
         };
 
-        let x_padding = cx.gutter_padding + cx.scroll_x * cx.em_width;
         Flex::row()
             .with_child(
                 icon.constrained()
@@ -651,8 +653,8 @@ fn diagnostic_header_renderer(diagnostic: Diagnostic) -> RenderBlock {
             }))
             .contained()
             .with_style(style.container)
-            .with_padding_left(x_padding)
+            .with_padding_left(cx.gutter_padding)
-            .with_padding_right(x_padding)
+            .with_padding_right(cx.gutter_padding)
             .expanded()
             .named("diagnostic header")
     })

crates/editor/src/display_map.rs

@@ -20,7 +20,7 @@ use wrap_map::WrapMap;
 
 pub use block_map::{
     BlockBufferRows as DisplayBufferRows, BlockChunks as DisplayChunks, BlockContext,
-    BlockDisposition, BlockId, BlockProperties, RenderBlock, TransformBlock,
+    BlockDisposition, BlockId, BlockProperties, BlockStyle, RenderBlock, TransformBlock,
 };
 
 pub trait ToDisplayPoint {
@@ -650,6 +650,7 @@ pub mod tests {
                                         height
                                     );
                                     BlockProperties {
+                                        style: BlockStyle::Fixed,
                                         position,
                                         height,
                                         disposition,

crates/editor/src/display_map/block_map.rs

@@ -56,6 +56,7 @@ pub struct Block {
     id: BlockId,
     position: Anchor,
     height: u8,
+    style: BlockStyle,
     render: Mutex<RenderBlock>,
     disposition: BlockDisposition,
 }
@@ -67,10 +68,18 @@ where
 {
     pub position: P,
     pub height: u8,
+    pub style: BlockStyle,
     pub render: Arc<dyn Fn(&mut BlockContext) -> ElementBox>,
     pub disposition: BlockDisposition,
 }
 
+#[derive(Copy, Clone, Eq, PartialEq, Ord, PartialOrd)]
+pub enum BlockStyle {
+    Fixed,
+    Flex,
+    Sticky,
+}
+
 pub struct BlockContext<'a, 'b> {
     pub cx: &'b mut RenderContext<'a, crate::Editor>,
     pub anchor_x: f32,
@@ -513,6 +522,7 @@ impl<'a> BlockMapWriter<'a> {
                     height: block.height,
                     render: Mutex::new(block.render),
                     disposition: block.disposition,
+                    style: block.style,
                 }),
             );
 
@@ -940,6 +950,10 @@ impl Block {
     pub fn position(&self) -> &Anchor {
         &self.position
     }
+
+    pub fn style(&self) -> BlockStyle {
+        self.style
+    }
 }
 
 impl Debug for Block {
@@ -1018,18 +1032,21 @@ mod tests {
         let mut writer = block_map.write(wraps_snapshot.clone(), Default::default());
         let block_ids = writer.insert(vec![
             BlockProperties {
+                style: BlockStyle::Fixed,
                 position: buffer_snapshot.anchor_after(Point::new(1, 0)),
                 height: 1,
                 disposition: BlockDisposition::Above,
                 render: Arc::new(|_| Empty::new().named("block 1")),
             },
             BlockProperties {
+                style: BlockStyle::Fixed,
                 position: buffer_snapshot.anchor_after(Point::new(1, 2)),
                 height: 2,
                 disposition: BlockDisposition::Above,
                 render: Arc::new(|_| Empty::new().named("block 2")),
             },
             BlockProperties {
+                style: BlockStyle::Fixed,
                 position: buffer_snapshot.anchor_after(Point::new(3, 3)),
                 height: 3,
                 disposition: BlockDisposition::Below,
@@ -1183,12 +1200,14 @@ mod tests {
         let mut writer = block_map.write(wraps_snapshot.clone(), Default::default());
         writer.insert(vec![
             BlockProperties {
+                style: BlockStyle::Fixed,
                 position: buffer_snapshot.anchor_after(Point::new(1, 12)),
                 disposition: BlockDisposition::Above,
                 render: Arc::new(|_| Empty::new().named("block 1")),
                 height: 1,
             },
             BlockProperties {
+                style: BlockStyle::Fixed,
                 position: buffer_snapshot.anchor_after(Point::new(1, 1)),
                 disposition: BlockDisposition::Below,
                 render: Arc::new(|_| Empty::new().named("block 2")),
@@ -1286,6 +1305,7 @@ mod tests {
                                 height
                             );
                             BlockProperties {
+                                style: BlockStyle::Fixed,
                                 position,
                                 height,
                                 disposition,

crates/editor/src/editor.rs

@@ -4801,6 +4801,7 @@ impl Editor {
                     cx.focus(&rename_editor);
                     let block_id = this.insert_blocks(
                         [BlockProperties {
+                            style: BlockStyle::Flex,
                             position: range.start.clone(),
                             height: 1,
                             render: Arc::new({
@@ -4985,6 +4986,7 @@ impl Editor {
                         let diagnostic = entry.diagnostic.clone();
                         let message_height = diagnostic.message.lines().count() as u8;
                         BlockProperties {
+                            style: BlockStyle::Fixed,
                             position: buffer.anchor_after(entry.range.start),
                             height: message_height,
                             render: diagnostic_block_renderer(diagnostic, true),
@@ -7932,6 +7934,7 @@ mod tests {
         editor.update(cx, |editor, cx| {
             editor.insert_blocks(
                 [BlockProperties {
+                    style: BlockStyle::Fixed,
                     position: snapshot.anchor_after(Point::new(2, 0)),
                     disposition: BlockDisposition::Below,
                     height: 1,

crates/editor/src/element.rs

@@ -3,9 +3,9 @@ use super::{
     Anchor, DisplayPoint, Editor, EditorMode, EditorSnapshot, Input, Scroll, Select, SelectPhase,
     SoftWrap, ToPoint, MAX_LINE_LEN,
 };
-use crate::hover_popover::HoverAt;
 use crate::{
-    display_map::{DisplaySnapshot, TransformBlock},
+    display_map::{BlockStyle, DisplaySnapshot, TransformBlock},
+    hover_popover::HoverAt,
     EditorStyle,
 };
 use clock::ReplicaId;
@@ -617,10 +617,13 @@ impl EditorElement {
         let scroll_left = scroll_position.x() * layout.em_width;
         let scroll_top = scroll_position.y() * layout.line_height;
 
-        for (row, element) in &mut layout.blocks {
+        for block in &mut layout.blocks {
-            let origin = bounds.origin()
+            let mut origin =
-                + vec2f(-scroll_left, *row as f32 * layout.line_height - scroll_top);
+                bounds.origin() + vec2f(0., block.row as f32 * layout.line_height - scroll_top);
-            element.paint(origin, visible_bounds, cx);
+            if !matches!(block.style, BlockStyle::Sticky) {
+                origin += vec2f(-scroll_left, 0.);
+            }
+            block.element.paint(origin, visible_bounds, cx);
         }
     }
 
@@ -789,6 +792,7 @@ impl EditorElement {
         rows: Range<u32>,
         snapshot: &EditorSnapshot,
         width: f32,
+        scroll_width: f32,
         gutter_padding: f32,
         gutter_width: f32,
         em_width: f32,
@@ -797,7 +801,7 @@ impl EditorElement {
         style: &EditorStyle,
         line_layouts: &[text_layout::Line],
         cx: &mut LayoutContext,
-    ) -> Vec<(u32, ElementBox)> {
+    ) -> (f32, Vec<BlockLayout>) {
         let editor = if let Some(editor) = self.view.upgrade(cx) {
             editor
         } else {
@@ -806,9 +810,13 @@ impl EditorElement {
 
         let tooltip_style = cx.global::<Settings>().theme.tooltip.clone();
         let scroll_x = snapshot.scroll_position.x();
-        snapshot
+        let (fixed_blocks, non_fixed_blocks) = snapshot
             .blocks_in_range(rows.clone())
-            .map(|(block_row, block)| {
+            .partition::<Vec<_>, _>(|(_, block)| match block {
+                TransformBlock::ExcerptHeader { .. } => false,
+                TransformBlock::Custom(block) => block.style() == BlockStyle::Fixed,
+            });
+        let mut render_block = |block: &TransformBlock, width: f32| {
             let mut element = match block {
                 TransformBlock::Custom(block) => {
                     let align_to = block
@@ -874,9 +882,7 @@ impl EditorElement {
                                     .boxed()
                             })
                             .with_cursor_style(CursorStyle::PointingHand)
-                                .on_click({
+                            .on_click(move |_, _, cx| cx.dispatch_action(jump_action.clone()))
-                                    move |_, _, cx| cx.dispatch_action(jump_action.clone())
-                                })
                             .with_tooltip(
                                 *key,
                                 "Jump to Buffer".to_string(),
@@ -890,7 +896,6 @@ impl EditorElement {
                         })
                     });
 
-                        let padding = gutter_padding + scroll_x * em_width;
                     if *starts_new_buffer {
                         let style = &self.style.diagnostic_path_header;
                         let font_size =
@@ -900,8 +905,7 @@ impl EditorElement {
                         let mut parent_path = None;
                         if let Some(file) = buffer.file() {
                             let path = file.path();
-                                filename =
+                            filename = path.file_name().map(|f| f.to_string_lossy().to_string());
-                                    path.file_name().map(|f| f.to_string_lossy().to_string());
                             parent_path =
                                 path.parent().map(|p| p.to_string_lossy().to_string() + "/");
                         }
@@ -918,10 +922,7 @@ impl EditorElement {
                                 .boxed(),
                             )
                             .with_children(parent_path.map(|path| {
-                                    Label::new(
+                                Label::new(path, style.path.text.clone().with_font_size(font_size))
-                                        path,
-                                        style.path.text.clone().with_font_size(font_size),
-                                    )
                                     .contained()
                                     .with_style(style.path.container)
                                     .aligned()
@@ -930,8 +931,8 @@ impl EditorElement {
                             .with_children(jump_icon)
                             .contained()
                             .with_style(style.container)
-                                .with_padding_left(padding)
+                            .with_padding_left(gutter_padding)
-                                .with_padding_right(padding)
+                            .with_padding_right(gutter_padding)
                             .expanded()
                             .named("path header block")
                     } else {
@@ -940,8 +941,8 @@ impl EditorElement {
                             .with_child(Label::new("…".to_string(), text_style).boxed())
                             .with_children(jump_icon)
                             .contained()
-                                .with_padding_left(padding)
+                            .with_padding_left(gutter_padding)
-                                .with_padding_right(padding)
+                            .with_padding_right(gutter_padding)
                             .expanded()
                             .named("collapsed context")
                     }
@@ -955,9 +956,38 @@ impl EditorElement {
                 },
                 cx,
             );
-                (block_row, element)
+            element
-            })
+        };
-            .collect()
+
+        let mut max_width = width.max(scroll_width);
+        let mut blocks = Vec::new();
+        for (row, block) in fixed_blocks {
+            let element = render_block(block, f32::INFINITY);
+            max_width = max_width.max(element.size().x() + em_width);
+            blocks.push(BlockLayout {
+                row,
+                element,
+                style: BlockStyle::Fixed,
+            });
+        }
+        for (row, block) in non_fixed_blocks {
+            let style = match block {
+                TransformBlock::Custom(block) => block.style(),
+                TransformBlock::ExcerptHeader { .. } => BlockStyle::Sticky,
+            };
+            let width = match style {
+                BlockStyle::Fixed => unreachable!(),
+                BlockStyle::Sticky => width,
+                BlockStyle::Flex => max_width,
+            };
+            let element = render_block(block, width);
+            blocks.push(BlockLayout {
+                row,
+                element,
+                style,
+            });
+        }
+        (max_width, blocks)
     }
 }
 
@@ -1146,8 +1176,24 @@ impl Element for EditorElement {
             cx.text_layout_cache,
         )
         .width();
-        let scroll_width = longest_line_width.max(max_visible_line_width) + overscroll.x();
+        let mut scroll_width = longest_line_width.max(max_visible_line_width) + overscroll.x();
         let em_width = style.text.em_width(cx.font_cache);
+        let (blocks_max_width, blocks) = self.layout_blocks(
+            start_row..end_row,
+            &snapshot,
+            size.x(),
+            scroll_width + gutter_width,
+            gutter_padding,
+            gutter_width,
+            em_width,
+            gutter_width + gutter_margin,
+            line_height,
+            &style,
+            &line_layouts,
+            cx,
+        );
+        scroll_width = scroll_width.max(blocks_max_width - gutter_width);
+
         let max_row = snapshot.max_point().row();
         let scroll_max = vec2f(
             ((scroll_width - text_size.x()) / em_width).max(0.0),
@@ -1246,20 +1292,6 @@ impl Element for EditorElement {
             );
         }
 
-        let blocks = self.layout_blocks(
-            start_row..end_row,
-            &snapshot,
-            size.x().max(scroll_width + gutter_width),
-            gutter_padding,
-            gutter_width,
-            em_width,
-            gutter_width + gutter_margin,
-            line_height,
-            &style,
-            &line_layouts,
-            cx,
-        );
-
         (
             size,
             LayoutState {
@@ -1353,8 +1385,8 @@ impl Element for EditorElement {
             }
         }
 
-        for (_, block) in &mut layout.blocks {
+        for block in &mut layout.blocks {
-            if block.dispatch_event(event, cx) {
+            if block.element.dispatch_event(event, cx) {
                 return true;
             }
         }
@@ -1440,7 +1472,7 @@ pub struct LayoutState {
     highlighted_rows: Option<Range<u32>>,
     line_layouts: Vec<text_layout::Line>,
     line_number_layouts: Vec<Option<text_layout::Line>>,
-    blocks: Vec<(u32, ElementBox)>,
+    blocks: Vec<BlockLayout>,
     line_height: f32,
     em_width: f32,
     em_advance: f32,
@@ -1451,6 +1483,12 @@ pub struct LayoutState {
     hover: Option<(DisplayPoint, ElementBox)>,
 }
 
+struct BlockLayout {
+    row: u32,
+    element: ElementBox,
+    style: BlockStyle,
+}
+
 fn layout_line(
     row: u32,
     snapshot: &EditorSnapshot,
@@ -1763,6 +1801,7 @@ mod tests {
             editor.set_placeholder_text("hello", cx);
             editor.insert_blocks(
                 [BlockProperties {
+                    style: BlockStyle::Fixed,
                     disposition: BlockDisposition::Above,
                     height: 3,
                     position: Anchor::min(),