feat(rich): add `on_link_hover` and `on_hover_lost`

2 files changed, 104 insertions, 21 deletions

diff --git a/examples/rich/src/main.rs b/examples/rich/src/main.rs
index f8f7414..095651a 100644
--- a/examples/rich/src/main.rs
+++ b/examples/rich/src/main.rs
@@ -1,5 +1,5 @@
-use iced::widget::{center, column, responsive};
-use iced::{Center, Element, color};
+use iced::widget::{column, container, responsive};
+use iced::{Center, Element, Fill, Font, color, font, padding};
 use iced_selection::{rich_text, span};
 
 fn main() -> iced::Result {
@@ -8,12 +8,15 @@ fn main() -> iced::Result {
 
 #[derive(Default)]
 struct State {
-    link: Option<String>,
+    clicked: Option<String>,
+    hovered: Option<String>,
 }
 
 #[derive(Debug, Clone)]
 enum Message {
     LinkClicked(String),
+    LinkHovered(String),
+    HoverLost,
 }
 
 impl State {
@@ -21,14 +24,18 @@ impl State {
         match message {
             Message::LinkClicked(link) => {
                 let _ = open::that_in_background(&link);
-                self.link = Some(link);
+                self.clicked = Some(link);
             }
+            Message::LinkHovered(link) => {
+                self.hovered = Some(link);
+            }
+            Message::HoverLost => self.hovered = None,
         };
     }
 
     fn view(&self) -> Element<'_, Message> {
         responsive(|size| {
-            center(
+            container(
                 column![
                     rich_text![
                         span("iced")
@@ -42,19 +49,44 @@ impl State {
                         span("Elm")
                             .color(color!(0x2b79a2))
                             .link("https://elm-lang.org"),
-                        "."
+                        ", a delightful functional language for building web applications."
+                    ]
+                    .on_link_click(Message::LinkClicked)
+                    .on_link_hover(Message::LinkHovered)
+                    .on_hover_lost(Message::HoverLost),
+                    rich_text![
+                        "As a GUI library, iced helps you build ",
+                        span("graphical user interfaces")
+                            .color(color!(0x2b79a2))
+                            .link("https://en.wikipedia.org/wiki/Graphical_user_interface")
+                            .font(Font {
+                                style:font::Style::Italic,
+                                ..Font::DEFAULT
+                            }),
+                        " for your Rust applications."
+                    ]
+                    .on_link_click(Message::LinkClicked)
+                    .on_link_hover(Message::LinkHovered)
+                    .on_hover_lost(Message::HoverLost),
+                    self.hovered.as_deref().map(|link| rich_text![
+                        "Currently hovered link: ",
+                        span(link).color(color!(0x2b79a2)).link(link)
                     ]
-                    .on_link_click(Message::LinkClicked),
-                    self.link.as_deref().map(|link| rich_text![
+                    .on_link_click(Message::LinkClicked)),
+                    self.clicked.as_deref().map(|link| rich_text![
                         "Last clicked link: ",
                         span(link).color(color!(0x2b79a2)).link(link)
                     ]
-                    .on_link_click(Message::LinkClicked))
+                    .on_link_click(Message::LinkClicked)
+                    .on_link_hover(Message::LinkHovered)
+                    .on_hover_lost(Message::HoverLost))
                 ]
                 .spacing(10)
                 .align_x(Center)
                 .max_width(size.width * 0.8),
             )
+            .padding(padding::top(size.height * 0.4))
+            .center_x(Fill)
             .into()
         })
         .into()
diff --git a/src/text/rich.rs b/src/text/rich.rs
index 3268160..a30663b 100644
--- a/src/text/rich.rs
+++ b/src/text/rich.rs
@@ -40,8 +40,9 @@ pub struct Rich<
     align_y: alignment::Vertical,
     wrapping: Wrapping,
     class: Theme::Class<'a>,
-    hovered_link: Option<usize>,
     on_link_click: Option<Box<dyn Fn(Link) -> Message + 'a>>,
+    on_link_hover: Option<Box<dyn Fn(Link) -> Message + 'a>>,
+    on_hover_lost: Option<Box<dyn Fn() -> Message + 'a>>,
 }
 
 impl<'a, Link, Message, Theme, Renderer>
@@ -65,8 +66,9 @@ where
             align_y: alignment::Vertical::Top,
             wrapping: Wrapping::default(),
             class: Theme::default(),
-            hovered_link: None,
             on_link_click: None,
+            on_link_hover: None,
+            on_hover_lost: None,
         }
     }
 
@@ -147,6 +149,36 @@ where
         self
     }
 
+    /// Sets the message that will be produced when a link of the [`Rich`] text
+    /// is hovered.
+    pub fn on_link_hover(
+        mut self,
+        on_link_hovered: impl Fn(Link) -> Message + 'a,
+    ) -> Self {
+        self.on_link_hover = Some(Box::new(on_link_hovered));
+        self
+    }
+
+    /// Sets the message that will be produced when a link of the [`Rich`] text
+    /// is no longer hovered.
+    pub fn on_hover_lost(mut self, on_hover_lost: Message) -> Self
+    where
+        Message: Clone + 'a,
+    {
+        self.on_hover_lost = Some(Box::new(move || on_hover_lost.clone()));
+        self
+    }
+
+    /// Sets the message that will be produced when a link of the [`Rich`] text
+    /// is no longer hovered.
+    pub fn on_hover_lost_with(
+        mut self,
+        on_hover_lost: impl Fn() -> Message + 'a,
+    ) -> Self {
+        self.on_hover_lost = Some(Box::new(on_hover_lost));
+        self
+    }
+
     /// Sets the default style of the [`Rich`] text.
     #[must_use]
     pub fn style(mut self, style: impl Fn(&Theme) -> Style + 'a) -> Self
@@ -181,6 +213,7 @@ where
 struct State<Link> {
     spans: Vec<Span<'static, Link, Font>>,
     span_pressed: Option<usize>,
+    hovered_link: Option<usize>,
     paragraph: Paragraph,
     is_hovered: bool,
     selection: Selection,
@@ -335,6 +368,7 @@ where
         tree::State::new(State::<Link> {
             spans: Vec::new(),
             span_pressed: None,
+            hovered_link: None,
             paragraph: Paragraph::default(),
             is_hovered: false,
             selection: Selection::default(),
@@ -393,7 +427,7 @@ where
 
         for (index, span) in self.spans.as_ref().as_ref().iter().enumerate() {
             let is_hovered_link = self.on_link_click.is_some()
-                && Some(index) == self.hovered_link;
+                && Some(index) == state.hovered_link;
 
             if span.highlight.is_some()
                 || span.underline
@@ -572,14 +606,14 @@ where
             return;
         }
 
-        let link_was_hovered = self.hovered_link.is_some();
         let was_hovered = state.is_hovered;
+        let hovered_link_before = state.hovered_link;
         let selection_before = state.selection;
 
         state.is_hovered = click_position.is_some();
 
         if let Some(position) = click_position {
-            self.hovered_link =
+            state.hovered_link =
                 state.paragraph.hit_span(position).and_then(|span| {
                     if self.spans.as_ref().as_ref().get(span)?.link.is_some() {
                         Some(span)
@@ -588,14 +622,14 @@ where
                     }
                 });
         } else {
-            self.hovered_link = None;
+            state.hovered_link = None;
         }
 
         match event {
             Event::Mouse(mouse::Event::ButtonPressed(mouse::Button::Left))
             | Event::Touch(touch::Event::FingerPressed { .. }) => {
-                if self.hovered_link.is_some() {
-                    state.span_pressed = self.hovered_link;
+                if state.hovered_link.is_some() {
+                    state.span_pressed = state.hovered_link;
                     shell.capture_event();
                 }
 
@@ -653,7 +687,7 @@ where
                 ) && state.selection.is_empty()
                 {
                     match state.span_pressed {
-                        Some(span) if Some(span) == self.hovered_link => {
+                        Some(span) if Some(span) == state.hovered_link => {
                             if let Some((link, on_link_clicked)) = self
                                 .spans
                                 .as_ref()
@@ -823,21 +857,38 @@ where
 
         if state.is_hovered != was_hovered
             || state.selection != selection_before
-            || self.hovered_link.is_some() != link_was_hovered
+            || state.hovered_link != hovered_link_before
         {
+            if let Some(span) = state.hovered_link {
+                if let Some((link, on_link_hovered)) = self
+                    .spans
+                    .as_ref()
+                    .as_ref()
+                    .get(span)
+                    .and_then(|span| span.link.clone())
+                    .zip(self.on_link_hover.as_deref())
+                {
+                    shell.publish(on_link_hovered(link));
+                }
+            } else if let Some(on_hover_lost) = self.on_hover_lost.as_deref() {
+                shell.publish(on_hover_lost());
+            }
+
             shell.request_redraw();
         }
     }
 
     fn mouse_interaction(
         &self,
-        _tree: &Tree,
+        tree: &Tree,
         layout: Layout<'_>,
         cursor: mouse::Cursor,
         _viewport: &Rectangle,
         _renderer: &Renderer,
     ) -> mouse::Interaction {
-        if self.hovered_link.is_some() {
+        let state = tree.state.downcast_ref::<State<Link>>();
+
+        if state.hovered_link.is_some() {
             mouse::Interaction::Pointer
         } else if cursor.is_over(layout.bounds()) {
             mouse::Interaction::Text