feat: implement double-click + drag by-word selection

4 files changed, 106 insertions, 19 deletions

diff --git a/README.md b/README.md
index 0321630..d69df0b 100644
--- a/README.md
+++ b/README.md
@@ -38,7 +38,7 @@ iced_selection = { git = "https://git.sr.ht/~pml68/iced_selection" }
 
 - [ ] allow out-of-bounds selection dragging
 - [X] custom markdown `Viewer`
-- [ ] double-click + drag for by-word selection
+- [X] double-click + drag for by-word selection
 - [X] triple-click + drag for by-line selection
 - [ ] support wrapped lines
 
diff --git a/src/selection.rs b/src/selection.rs
index 9be01dd..375072c 100644
--- a/src/selection.rs
+++ b/src/selection.rs
@@ -213,6 +213,78 @@ impl Selection {
         self.select_range(start, end);
     }
 
+    /// Updates the current selection by setting a new end point, either to the start of the
+    /// previous word, or to the next one's end.
+    pub fn change_selection_by_word(
+        &mut self,
+        new_end: SelectionEnd,
+        paragraph: &Paragraph,
+    ) {
+        let (base_word_start, base_word_end) = {
+            if self.direction == Direction::Right {
+                let value = Value::new(
+                    paragraph.buffer().lines[self.start.line].text(),
+                );
+
+                let end = SelectionEnd::new(
+                    self.start.line,
+                    value.next_end_of_word(self.start.index),
+                );
+
+                (self.start, end)
+            } else {
+                let value =
+                    Value::new(paragraph.buffer().lines[self.end.line].text());
+
+                let start = SelectionEnd::new(
+                    self.end.line,
+                    value.previous_start_of_word(self.end.index),
+                );
+
+                (start, self.end)
+            }
+        };
+
+        let value = Value::new(paragraph.buffer().lines[new_end.line].text());
+
+        let (start, end) = if new_end < self.start {
+            self.direction = Direction::Left;
+
+            let start = SelectionEnd::new(
+                new_end.line,
+                value.previous_start_of_word(new_end.index),
+            );
+
+            (start, base_word_end)
+        } else if new_end > self.end {
+            self.direction = Direction::Right;
+
+            let end = SelectionEnd::new(
+                new_end.line,
+                value.next_end_of_word(new_end.index),
+            );
+
+            (base_word_start, end)
+        } else if self.direction == Direction::Right {
+            let end = SelectionEnd::new(
+                new_end.line,
+                value.next_end_of_word(new_end.index),
+            );
+
+            (base_word_start, end.max(base_word_end))
+        } else {
+            let start = SelectionEnd::new(
+                new_end.line,
+                value.previous_start_of_word(new_end.index),
+            );
+
+            (start.min(base_word_start), base_word_end)
+        };
+
+        self.moving_line_index = None;
+        self.select_range(start, end);
+    }
+
     /// Updates the current selection by setting a new end point, either to the end of a following
     /// line, or the beginning of a previous one.
     pub fn change_selection_by_line(
@@ -246,6 +318,7 @@ impl Selection {
             (start, end)
         } else {
             let start = SelectionEnd::new(new_line, 0);
+
             let end = if self.direction == old_direction {
                 self.end
             } else {
diff --git a/src/text.rs b/src/text.rs
index ad5c350..ff5d5a4 100644
--- a/src/text.rs
+++ b/src/text.rs
@@ -388,7 +388,7 @@ where
         let click_position = cursor.position_in(bounds);
 
         if viewport.intersection(&bounds).is_none()
-            && state.selection == Selection::default()
+            && state.selection.is_empty()
             && state.dragging.is_none()
         {
             return;
@@ -466,7 +466,14 @@ where
 
                             state.selection.change_selection(new_end);
                         }
-                        Dragging::Word => {}
+                        Dragging::Word => {
+                            let new_end = SelectionEnd { line, index };
+
+                            state.selection.change_selection_by_word(
+                                new_end,
+                                &state.paragraph,
+                            );
+                        }
                         Dragging::Line => {
                             state.selection.change_selection_by_line(
                                 line,
@@ -491,7 +498,7 @@ where
                     }
                     keyboard::Key::Character("a")
                         if state.keyboard_modifiers.command()
-                            && state.selection != Selection::default() =>
+                            && !state.selection.is_empty() =>
                     {
                         state.selection.select_all(&state.paragraph);
 
@@ -499,7 +506,7 @@ where
                     }
                     keyboard::Key::Named(key::Named::Home)
                         if state.keyboard_modifiers.shift()
-                            && state.selection != Selection::default() =>
+                            && !state.selection.is_empty() =>
                     {
                         if state.keyboard_modifiers.jump() {
                             state.selection.select_beginning();
@@ -511,7 +518,7 @@ where
                     }
                     keyboard::Key::Named(key::Named::End)
                         if state.keyboard_modifiers.shift()
-                            && state.selection != Selection::default() =>
+                            && !state.selection.is_empty() =>
                     {
                         if state.keyboard_modifiers.jump() {
                             state.selection.select_end(&state.paragraph);
@@ -523,7 +530,7 @@ where
                     }
                     keyboard::Key::Named(key::Named::ArrowLeft)
                         if state.keyboard_modifiers.shift()
-                            && state.selection != Selection::default() =>
+                            && !state.selection.is_empty() =>
                     {
                         if state.keyboard_modifiers.macos_command() {
                             state.selection.select_line_beginning();
@@ -539,7 +546,7 @@ where
                     }
                     keyboard::Key::Named(key::Named::ArrowRight)
                         if state.keyboard_modifiers.shift()
-                            && state.selection != Selection::default() =>
+                            && !state.selection.is_empty() =>
                     {
                         if state.keyboard_modifiers.macos_command() {
                             state.selection.select_line_end(&state.paragraph);
@@ -555,7 +562,7 @@ where
                     }
                     keyboard::Key::Named(key::Named::ArrowUp)
                         if state.keyboard_modifiers.shift()
-                            && state.selection != Selection::default() =>
+                            && !state.selection.is_empty() =>
                     {
                         if state.keyboard_modifiers.macos_command() {
                             state.selection.select_beginning();
@@ -569,7 +576,7 @@ where
                     }
                     keyboard::Key::Named(key::Named::ArrowDown)
                         if state.keyboard_modifiers.shift()
-                            && state.selection != Selection::default() =>
+                            && !state.selection.is_empty() =>
                     {
                         if state.keyboard_modifiers.macos_command() {
                             state.selection.select_end(&state.paragraph);
diff --git a/src/text/rich.rs b/src/text/rich.rs
index a30663b..5ca3051 100644
--- a/src/text/rich.rs
+++ b/src/text/rich.rs
@@ -600,7 +600,7 @@ where
         let click_position = cursor.position_in(bounds);
 
         if viewport.intersection(&bounds).is_none()
-            && state.selection == Selection::default()
+            && state.selection.is_empty()
             && state.dragging.is_none()
         {
             return;
@@ -720,7 +720,14 @@ where
 
                             state.selection.change_selection(new_end);
                         }
-                        Dragging::Word => {}
+                        Dragging::Word => {
+                            let new_end = SelectionEnd { line, index };
+
+                            state.selection.change_selection_by_word(
+                                new_end,
+                                &state.paragraph,
+                            );
+                        }
                         Dragging::Line => {
                             state.selection.change_selection_by_line(
                                 line,
@@ -745,7 +752,7 @@ where
                     }
                     keyboard::Key::Character("a")
                         if state.keyboard_modifiers.command()
-                            && state.selection != Selection::default() =>
+                            && !state.selection.is_empty() =>
                     {
                         state.selection.select_all(&state.paragraph);
 
@@ -753,7 +760,7 @@ where
                     }
                     keyboard::Key::Named(key::Named::Home)
                         if state.keyboard_modifiers.shift()
-                            && state.selection != Selection::default() =>
+                            && !state.selection.is_empty() =>
                     {
                         if state.keyboard_modifiers.jump() {
                             state.selection.select_beginning();
@@ -765,7 +772,7 @@ where
                     }
                     keyboard::Key::Named(key::Named::End)
                         if state.keyboard_modifiers.shift()
-                            && state.selection != Selection::default() =>
+                            && !state.selection.is_empty() =>
                     {
                         if state.keyboard_modifiers.jump() {
                             state.selection.select_end(&state.paragraph);
@@ -777,7 +784,7 @@ where
                     }
                     keyboard::Key::Named(key::Named::ArrowLeft)
                         if state.keyboard_modifiers.shift()
-                            && state.selection != Selection::default() =>
+                            && !state.selection.is_empty() =>
                     {
                         if state.keyboard_modifiers.macos_command() {
                             state.selection.select_line_beginning();
@@ -793,7 +800,7 @@ where
                     }
                     keyboard::Key::Named(key::Named::ArrowRight)
                         if state.keyboard_modifiers.shift()
-                            && state.selection != Selection::default() =>
+                            && !state.selection.is_empty() =>
                     {
                         if state.keyboard_modifiers.macos_command() {
                             state.selection.select_line_end(&state.paragraph);
@@ -809,7 +816,7 @@ where
                     }
                     keyboard::Key::Named(key::Named::ArrowUp)
                         if state.keyboard_modifiers.shift()
-                            && state.selection != Selection::default() =>
+                            && !state.selection.is_empty() =>
                     {
                         if state.keyboard_modifiers.macos_command() {
                             state.selection.select_beginning();
@@ -823,7 +830,7 @@ where
                     }
                     keyboard::Key::Named(key::Named::ArrowDown)
                         if state.keyboard_modifiers.shift()
-                            && state.selection != Selection::default() =>
+                            && !state.selection.is_empty() =>
                     {
                         if state.keyboard_modifiers.macos_command() {
                             state.selection.select_end(&state.paragraph);