Notify `Highlighter` of topmost line change

3 files changed, 61 insertions, 31 deletions

diff --git a/core/src/text/editor.rs b/core/src/text/editor.rs
index 0f439c8d..2144715f 100644
--- a/core/src/text/editor.rs
+++ b/core/src/text/editor.rs
@@ -47,13 +47,18 @@ pub enum Action {
     Select(Motion),
     SelectWord,
     SelectLine,
+    Edit(Edit),
+    Click(Point),
+    Drag(Point),
+}
+
+#[derive(Debug, Clone, PartialEq)]
+pub enum Edit {
     Insert(char),
     Paste(Arc<String>),
     Enter,
     Backspace,
     Delete,
-    Click(Point),
-    Drag(Point),
 }
 
 #[derive(Debug, Clone, Copy, PartialEq)]
diff --git a/graphics/src/text/editor.rs b/graphics/src/text/editor.rs
index fbae287e..47c210bd 100644
--- a/graphics/src/text/editor.rs
+++ b/graphics/src/text/editor.rs
@@ -1,10 +1,12 @@
-use crate::core::text::editor::{self, Action, Cursor, Direction, Motion};
+use crate::core::text::editor::{
+    self, Action, Cursor, Direction, Edit, Motion,
+};
 use crate::core::text::highlighter::{self, Highlighter};
 use crate::core::text::LineHeight;
 use crate::core::{Font, Pixels, Point, Rectangle, Size};
 use crate::text;
 
-use cosmic_text::Edit;
+use cosmic_text::Edit as _;
 
 use std::fmt;
 use std::sync::{self, Arc};
@@ -370,22 +372,42 @@ impl editor::Editor for Editor {
             }
 
             // Editing events
-            Action::Insert(c) => {
-                editor
-                    .action(font_system.raw(), cosmic_text::Action::Insert(c));
-            }
-            Action::Paste(text) => {
-                editor.insert_string(&text, None);
-            }
-            Action::Enter => {
-                editor.action(font_system.raw(), cosmic_text::Action::Enter);
-            }
-            Action::Backspace => {
-                editor
-                    .action(font_system.raw(), cosmic_text::Action::Backspace);
-            }
-            Action::Delete => {
-                editor.action(font_system.raw(), cosmic_text::Action::Delete);
+            Action::Edit(edit) => {
+                match edit {
+                    Edit::Insert(c) => {
+                        editor.action(
+                            font_system.raw(),
+                            cosmic_text::Action::Insert(c),
+                        );
+                    }
+                    Edit::Paste(text) => {
+                        editor.insert_string(&text, None);
+                    }
+                    Edit::Enter => {
+                        editor.action(
+                            font_system.raw(),
+                            cosmic_text::Action::Enter,
+                        );
+                    }
+                    Edit::Backspace => {
+                        editor.action(
+                            font_system.raw(),
+                            cosmic_text::Action::Backspace,
+                        );
+                    }
+                    Edit::Delete => {
+                        editor.action(
+                            font_system.raw(),
+                            cosmic_text::Action::Delete,
+                        );
+                    }
+                }
+
+                let cursor = editor.cursor();
+                let selection = editor.select_opt().unwrap_or(cursor);
+
+                internal.topmost_line_changed =
+                    Some(cursor.min(selection).line);
             }
 
             // Mouse events
diff --git a/widget/src/text_editor.rs b/widget/src/text_editor.rs
index 03adbb59..c30e185f 100644
--- a/widget/src/text_editor.rs
+++ b/widget/src/text_editor.rs
@@ -17,7 +17,7 @@ use std::ops::DerefMut;
 use std::sync::Arc;
 
 pub use crate::style::text_editor::{Appearance, Highlight, StyleSheet};
-pub use text::editor::{Action, Motion};
+pub use text::editor::{Action, Edit, Motion};
 
 pub struct TextEditor<'a, Highlighter, Message, Renderer = crate::Renderer>
 where
@@ -301,7 +301,7 @@ where
             Update::Release => {
                 state.drag_click = None;
             }
-            Update::Edit(action) => {
+            Update::Action(action) => {
                 shell.publish(on_edit(action));
             }
             Update::Copy => {
@@ -311,7 +311,9 @@ where
             }
             Update::Paste => {
                 if let Some(contents) = clipboard.read() {
-                    shell.publish(on_edit(Action::Paste(Arc::new(contents))));
+                    shell.publish(on_edit(Action::Edit(Edit::Paste(
+                        Arc::new(contents),
+                    ))));
                 }
             }
         }
@@ -457,7 +459,7 @@ enum Update {
     Click(mouse::Click),
     Unfocus,
     Release,
-    Edit(Action),
+    Action(Action),
     Copy,
     Paste,
 }
@@ -470,7 +472,8 @@ impl Update {
         padding: Padding,
         cursor: mouse::Cursor,
     ) -> Option<Self> {
-        let edit = |action| Some(Update::Edit(action));
+        let action = |action| Some(Update::Action(action));
+        let edit = |edit| action(Action::Edit(edit));
 
         match event {
             Event::Mouse(event) => match event {
@@ -499,7 +502,7 @@ impl Update {
                         let cursor_position = cursor.position_in(bounds)?
                             - Vector::new(padding.top, padding.left);
 
-                        edit(Action::Drag(cursor_position))
+                        action(Action::Drag(cursor_position))
                     }
                     _ => None,
                 },
@@ -518,7 +521,7 @@ impl Update {
                                 motion
                             };
 
-                        return edit(if modifiers.shift() {
+                        return action(if modifiers.shift() {
                             Action::Select(motion)
                         } else {
                             Action::Move(motion)
@@ -526,9 +529,9 @@ impl Update {
                     }
 
                     match key_code {
-                        keyboard::KeyCode::Enter => edit(Action::Enter),
-                        keyboard::KeyCode::Backspace => edit(Action::Backspace),
-                        keyboard::KeyCode::Delete => edit(Action::Delete),
+                        keyboard::KeyCode::Enter => edit(Edit::Enter),
+                        keyboard::KeyCode::Backspace => edit(Edit::Backspace),
+                        keyboard::KeyCode::Delete => edit(Edit::Delete),
                         keyboard::KeyCode::Escape => Some(Self::Unfocus),
                         keyboard::KeyCode::C if modifiers.command() => {
                             Some(Self::Copy)
@@ -542,7 +545,7 @@ impl Update {
                     }
                 }
                 keyboard::Event::CharacterReceived(c) if state.is_focused => {
-                    edit(Action::Insert(c))
+                    edit(Edit::Insert(c))
                 }
                 _ => None,
             },