feat: implement triple-click + drag by-line selection

4 files changed, 81 insertions, 24 deletions

diff --git a/TODO.md b/TODO.md
index 867dbb4..fe881aa 100644
--- a/TODO.md
+++ b/TODO.md
@@ -1,4 +1,4 @@
 - [ ] allow out-of-bounds selection dragging
 - [X] custom markdown `Viewer`
 - [ ] double-click + drag for by-word selection
-- [ ] triple-click + drag for by-line selection
+- [X] triple-click + drag for by-line selection
diff --git a/src/selection.rs b/src/selection.rs
index b98a113..2c1e43d 100644
--- a/src/selection.rs
+++ b/src/selection.rs
@@ -208,6 +208,31 @@ impl Selection {
         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(
+        &mut self,
+        new_line: usize,
+        paragraph: &Paragraph,
+    ) {
+        if new_line < self.start.line {
+            self.direction = Direction::Left;
+        } else if new_line > self.end.line {
+            self.direction = Direction::Right;
+        }
+
+        let (start, end) = if self.direction == Direction::Right {
+            let value = Value::new(paragraph.buffer().lines[new_line].text());
+
+            (self.start, SelectionEnd::new(new_line, value.len()))
+        } else {
+            (SelectionEnd::new(new_line, 0), self.end)
+        };
+
+        self.moving_line_index = None;
+        self.select_range(start, end);
+    }
+
     /// Selects the word around the given grapheme position.
     pub fn select_word(
         &mut self,
diff --git a/src/text.rs b/src/text.rs
index b407cd5..484456a 100644
--- a/src/text.rs
+++ b/src/text.rs
@@ -159,11 +159,20 @@ pub struct State {
     content: String,
     is_hovered: bool,
     selection: Selection,
-    is_dragging: bool,
+    dragging: Option<Dragging>,
     last_click: Option<mouse::Click>,
     keyboard_modifiers: keyboard::Modifiers,
 }
 
+/// The type of dragging selection.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+#[allow(missing_docs)]
+pub enum Dragging {
+    Grapheme,
+    Word,
+    Line,
+}
+
 impl State {
     fn grapheme_line_and_index(&self, point: Point) -> Option<(usize, usize)> {
         let cursor = self.paragraph.buffer().hit(point.x, point.y)?;
@@ -266,7 +275,7 @@ where
 
         if viewport.intersection(&bounds).is_none()
             && state.selection == Selection::default()
-            && !state.is_dragging
+            && state.dragging.is_none()
         {
             return;
         }
@@ -299,7 +308,7 @@ where
                                 state.selection.select_range(new_end, new_end);
                             }
 
-                            state.is_dragging = true;
+                            state.dragging = Some(Dragging::Grapheme);
                         }
                         click::Kind::Double => {
                             let (line, index) = state
@@ -311,7 +320,8 @@ where
                                 index,
                                 &state.paragraph,
                             );
-                            state.is_dragging = false;
+
+                            state.dragging = None;
                         }
                         click::Kind::Triple => {
                             let (line, _) = state
@@ -319,7 +329,7 @@ where
                                 .unwrap_or((0, 0));
 
                             state.selection.select_line(line, &state.paragraph);
-                            state.is_dragging = false;
+                            state.dragging = Some(Dragging::Line);
                         }
                     }
 
@@ -333,20 +343,31 @@ where
             Event::Mouse(mouse::Event::ButtonReleased(mouse::Button::Left))
             | Event::Touch(touch::Event::FingerLifted { .. })
             | Event::Touch(touch::Event::FingerLost { .. }) => {
-                state.is_dragging = false;
+                state.dragging = None;
             }
             Event::Mouse(mouse::Event::CursorMoved { .. })
             | Event::Touch(touch::Event::FingerMoved { .. }) => {
                 if let Some(position) = click_position
-                    && state.is_dragging
+                    && let Some(dragging) = state.dragging
                 {
                     let (line, index) = state
                         .grapheme_line_and_index(position)
                         .unwrap_or((0, 0));
 
-                    let new_end = SelectionEnd { line, index };
+                    match dragging {
+                        Dragging::Grapheme => {
+                            let new_end = SelectionEnd { line, index };
 
-                    state.selection.change_selection(new_end);
+                            state.selection.change_selection(new_end);
+                        }
+                        Dragging::Word => {}
+                        Dragging::Line => {
+                            state.selection.change_selection_by_line(
+                                line,
+                                &state.paragraph,
+                            );
+                        }
+                    };
                 }
             }
             Event::Keyboard(keyboard::Event::KeyPressed { key, .. }) => {
@@ -455,7 +476,7 @@ where
                         shell.capture_event();
                     }
                     keyboard::Key::Named(key::Named::Escape) => {
-                        state.is_dragging = false;
+                        state.dragging = None;
                         state.selection = Selection::default();
 
                         state.keyboard_modifiers =
diff --git a/src/text/rich.rs b/src/text/rich.rs
index ae8bbab..93cefa2 100644
--- a/src/text/rich.rs
+++ b/src/text/rich.rs
@@ -16,7 +16,7 @@ use crate::core::{
     Rectangle, Shell, Size, Vector, Widget,
 };
 use crate::selection::{Selection, SelectionEnd};
-use crate::text::{Catalog, Style, StyleFn};
+use crate::text::{Catalog, Dragging, Style, StyleFn};
 
 /// A bunch of [`Rich`] text.
 pub struct Rich<
@@ -184,7 +184,7 @@ struct State<Link> {
     paragraph: Paragraph,
     is_hovered: bool,
     selection: Selection,
-    is_dragging: bool,
+    dragging: Option<Dragging>,
     last_click: Option<mouse::Click>,
     keyboard_modifiers: keyboard::Modifiers,
 }
@@ -239,7 +239,7 @@ where
             paragraph: Paragraph::default(),
             is_hovered: false,
             selection: Selection::default(),
-            is_dragging: false,
+            dragging: None,
             last_click: None,
             keyboard_modifiers: keyboard::Modifiers::default(),
         })
@@ -475,7 +475,7 @@ where
 
         if viewport.intersection(&bounds).is_none()
             && state.selection == Selection::default()
-            && !state.is_dragging
+            && state.dragging.is_none()
         {
             return;
         }
@@ -524,10 +524,10 @@ where
 
                             if state.keyboard_modifiers.shift() {
                                 state.selection.change_selection(new_end);
-                                state.is_dragging = true;
+                                state.dragging = Some(Dragging::Grapheme);
                             } else if state.span_pressed.is_none() {
                                 state.selection.select_range(new_end, new_end);
-                                state.is_dragging = true;
+                                state.dragging = Some(Dragging::Grapheme);
                             }
                         }
                         mouse::click::Kind::Double => {
@@ -536,11 +536,11 @@ where
                                 index,
                                 &state.paragraph,
                             );
-                            state.is_dragging = false;
+                            state.dragging = None;
                         }
                         mouse::click::Kind::Triple => {
                             state.selection.select_line(line, &state.paragraph);
-                            state.is_dragging = false;
+                            state.dragging = Some(Dragging::Line);
                         }
                     }
                 } else {
@@ -550,7 +550,7 @@ where
             Event::Mouse(mouse::Event::ButtonReleased(mouse::Button::Left))
             | Event::Touch(touch::Event::FingerLifted { .. })
             | Event::Touch(touch::Event::FingerLost { .. }) => {
-                state.is_dragging = false;
+                state.dragging = None;
                 if !matches!(
                     event,
                     Event::Touch(touch::Event::FingerLost { .. })
@@ -578,15 +578,26 @@ where
             Event::Mouse(mouse::Event::CursorMoved { .. })
             | Event::Touch(touch::Event::FingerMoved { .. }) => {
                 if let Some(position) = click_position
-                    && state.is_dragging
+                    && let Some(dragging) = state.dragging
                 {
                     let (line, index) = state
                         .grapheme_line_and_index(position)
                         .unwrap_or((0, 0));
 
-                    let new_end = SelectionEnd { line, index };
+                    match dragging {
+                        Dragging::Grapheme => {
+                            let new_end = SelectionEnd { line, index };
 
-                    state.selection.change_selection(new_end);
+                            state.selection.change_selection(new_end);
+                        }
+                        Dragging::Word => {}
+                        Dragging::Line => {
+                            state.selection.change_selection_by_line(
+                                line,
+                                &state.paragraph,
+                            );
+                        }
+                    };
                 }
             }
             Event::Keyboard(keyboard::Event::KeyPressed { key, .. }) => {
@@ -695,7 +706,7 @@ where
                         shell.capture_event();
                     }
                     keyboard::Key::Named(key::Named::Escape) => {
-                        state.is_dragging = false;
+                        state.dragging = None;
                         state.selection = Selection::default();
 
                         state.keyboard_modifiers =