Render edit mode line by line

basalt/CHANGELOG.md

@@ -1,6 +1,32 @@
 # Changelog
 
-## [0.12.6](https://github.com/erikjuhani/basalt/releases/tag/basalt/0.12.6) (Unreleased)
+## [0.12.6](https://github.com/erikjuhani/basalt/releases/tag/basalt/0.12.6) (Jun, 07 2026)
+
+### Changed
+
+- [0545dc4](https://github.com/erikjuhani/basalt/commit/0545dc4d35d276036ef4fd2c46e27250b43c4a16) Render edit mode line by line (#486)
+
+> Editing used to flip the whole block to raw on entry, and rendering it
+> from the AST during edits drifted from the source, so nested lists and
+> structural edits were unreliable.
+>
+> Render the active block with a line decorator that maps 1:1 to source
+> place. This keeps indentation, blank lines and code blocks faithful to
+> the source and makes editing predictable.
+>
+> Read mode and non-active blocks keep the AST renderer; unifying the two
+> is tracked in #533.
+
+### Fixed
+
+- [f40bc77](https://github.com/erikjuhani/basalt/commit/f40bc77e49fc7e27aca04cd0936d8f4cd746ad17) Preserve source blank lines in Edit mode by @erikjuhani
+
+> In Edit mode the visual rendering now mirrors the source's blank-line
+> structure. Empty lines between loose list items render as empty rows,
+> and block spacing matches the source byte gap instead of a fixed "one
+> empty line per block". Adjacent blocks with no source empty lines now
+> render with no visual gap, so deleting at a block's start merges into
+> the previous block without a misleading empty row in between.
 
 ### Added
 
@@ -25,7 +51,6 @@
 > The watcher is rebuilt when the active vault changes and avoids stealing
 > focus from the editor.
 
-
 ### Fixed
 
 - [f40bc77](https://github.com/erikjuhani/basalt/commit/f40bc77e49fc7e27aca04cd0936d8f4cd746ad17) Preserve source blank lines in Edit mode by @erikjuhani

basalt/src/note_editor/cursor.rs

@@ -41,6 +41,17 @@ pub struct Cursor {
     pub virtual_column: usize,
 }
 
+/// Display width of a source character. Tabs are one byte but rendered as two
+/// columns (see the draw-time expansion), so they must count as two here to
+/// keep cursor columns aligned with the displayed text.
+fn char_display_width(c: char) -> usize {
+    if c == '\t' {
+        2
+    } else {
+        c.width().unwrap_or(0)
+    }
+}
+
 pub fn virtual_position_to_source_offset<'a>(
     (row, col): (usize, usize),
     lines: &'a [VirtualLine<'a>],
@@ -59,7 +70,7 @@ pub fn virtual_position_to_source_offset<'a>(
                         return Some(range.start + byte_idx);
                     }
 
-                    let char_width = ch.width().unwrap_or(0);
+                    let char_width = char_display_width(ch);
                     cur_col += char_width;
                     content_col += char_width;
                 }
@@ -116,7 +127,7 @@ pub fn source_offset_to_virtual_column<'a>(offset: usize, line: &VirtualLine<'a>
                 let n = span
                     .char_indices()
                     .map_while(|(byte_idx, c)| {
-                        (byte_idx < byte_offset).then(|| c.width().unwrap_or(0))
+                        (byte_idx < byte_offset).then(|| char_display_width(c))
                     })
                     .sum::<usize>();
 

basalt/src/note_editor/editor.rs

@@ -427,6 +427,32 @@ mod tests {
                     state
                 }),
             ),
+            (
+                // Only the list item under the cursor should render raw; the
+                // surrounding items stay rendered. Ref: issue #486.
+                "edit_mode_list_line_by_line_raw",
+                Box::new(|area| {
+                    let content = indoc! { r#"## Shopping
+
+                    - apples
+                    - bananas
+                    - cherries
+                    "#};
+                    let mut state = NoteEditorState::new(
+                        content,
+                        "Test",
+                        Path::new("test.md"),
+                        &Symbols::unicode(),
+                    );
+                    state.resize_viewport(area.as_size());
+                    state.set_view(View::Edit(EditMode::Source));
+                    // Enter the list (lands on the first item), then step down to
+                    // the "bananas" item.
+                    state.cursor_down(1);
+                    state.cursor_down(1);
+                    state
+                }),
+            ),
         ];
 
         let mut terminal = Terminal::new(TestBackend::new(80, 20)).unwrap();