feat!: remove title from Popup::new (#31)

BREAKING CHANGE: The `Popup::new` method no longer accepts a title
parameter. Instead, the title can be set using the `title` method on the
`Popup` instance.

```diff
- let popup = Popup::new("tui-popup demo", "Press any key to exit")
+ let popup = Popup::new("Press any key to exit")
+     .title("tui-popup demo")
      .style(Style::new().white().on_blue());
```

examples/demo.rs

@@ -25,8 +25,9 @@ fn main() -> Result<()> {
 fn render(frame: &mut Frame) {
     let area = frame.size();
     let background = background(area);
-    let popup =
-        Popup::new("tui-popup demo", "Press any key to exit").style(Style::new().white().on_blue());
+    let popup = Popup::new("Press any key to exit")
+        .title("tui-popup demo")
+        .style(Style::new().white().on_blue());
     frame.render_widget(background, area);
     frame.render_widget(&popup, area);
 }

examples/paragraph.rs

@@ -33,8 +33,9 @@ impl App {
         let background = background(area);
 
         let paragraph = paragraph(self.scroll);
-        let popup =
-            Popup::new("scroll: ↑/↓ quit: Esc", paragraph).style(Style::new().white().on_blue());
+        let popup = Popup::new(paragraph)
+            .title("scroll: ↑/↓ quit: Esc")
+            .style(Style::new().white().on_blue());
 
         frame.render_widget(background, area);
         frame.render_widget(&popup, area);

examples/state.rs

@@ -50,17 +50,15 @@ impl App {
     }
 
     fn popup_widget() -> Popup<'static, Text<'static>> {
-        Popup::new(
-            "Popup",
-            Text::from_iter([
-                "q: exit",
-                "r: reset",
-                "j: move down",
-                "k: move up",
-                "h: move left",
-                "l: move right",
-            ]),
-        )
+        Popup::new(Text::from_iter([
+            "q: exit",
+            "r: reset",
+            "j: move down",
+            "k: move up",
+            "h: move left",
+            "l: move right",
+        ]))
+        .title("Popup")
         .style(Style::new().white().on_blue())
     }
 

src/lib.rs

@@ -10,7 +10,8 @@
 //! use tui_popup::Popup;
 //!
 //! fn render_popup(frame: &mut Frame) {
-//!     let popup = Popup::new("tui-popup demo", "Press any key to exit")
+//!     let popup = Popup::new("Press any key to exit")
+//!         .title("tui-popup demo")
 //!        .style(Style::new().white().on_blue());
 //!     frame.render_widget(&popup, frame.size());
 //! }
@@ -23,7 +24,6 @@
 
 mod popup;
 mod state;
-mod widget;
 
 pub use popup::*;
 pub use state::*;

src/popup.rs

@@ -1,10 +1,12 @@
 use std::fmt::Debug;
 
+use crate::PopupState;
 use derive_setters::Setters;
 use ratatui::{
-    prelude::*,
-    widgets::{Borders, WidgetRef},
+    prelude::{Buffer, Line, Rect, Style, Text},
+    widgets::{Block, Borders, Clear, StatefulWidgetRef, Widget, WidgetRef},
 };
+use std::cmp::min;
 
 /// Configuration for a popup.
 ///
@@ -18,7 +20,8 @@ use ratatui::{
 /// use tui_popup::Popup;
 ///
 /// fn render_popup(frame: &mut Frame) {
-///     let popup = Popup::new("tui-popup demo", "Press any key to exit")
+///     let popup = Popup::new("Press any key to exit")
+///         .title("tui-popup demo")
 ///         .style(Style::new().white().on_blue());
 ///     frame.render_widget(&popup, frame.size());
 /// }
@@ -28,6 +31,7 @@ use ratatui::{
 #[non_exhaustive]
 pub struct Popup<'content, W: SizedWidgetRef> {
     /// The body of the popup.
+    #[setters(skip)]
     pub body: W,
     /// The title of the popup.
     pub title: Line<'content>,
@@ -53,8 +57,6 @@ impl<'content, W: SizedWidgetRef> Popup<'content, W> {
     ///
     /// # Parameters
     ///
-    /// - `title` - The title of the popup. This can be any type that can be converted into a
-    ///   [`Line`].
     /// - `body` - The body of the popup. This can be any type that can be converted into a
     ///   [`Text`].
     ///
@@ -63,17 +65,14 @@ impl<'content, W: SizedWidgetRef> Popup<'content, W> {
     /// ```rust
     /// use tui_popup::Popup;
     ///
-    /// let popup = Popup::new("tui-popup demo", "Press any key to exit");
+    /// let popup = Popup::new("Press any key to exit").title("tui-popup demo");
     /// ```
-    pub fn new<L>(title: L, body: W) -> Self
-    where
-        L: Into<Line<'content>>,
-    {
+    pub fn new(body: W) -> Self {
         Self {
             body,
-            title: title.into(),
-            style: Style::default(),
             borders: Borders::ALL,
+            title: Line::default(),
+            style: Style::default(),
         }
     }
 }
@@ -120,3 +119,65 @@ impl<W: WidgetRef + Debug> SizedWidgetRef for SizedWrapper<W> {
         self.height
     }
 }
+
+impl<W: SizedWidgetRef> WidgetRef for Popup<'_, W> {
+    fn render_ref(&self, area: Rect, buf: &mut Buffer) {
+        let mut state = PopupState::default();
+        StatefulWidgetRef::render_ref(self, area, buf, &mut state);
+    }
+}
+
+impl<W: SizedWidgetRef> StatefulWidgetRef for Popup<'_, W> {
+    type State = PopupState;
+
+    fn render_ref(&self, area: Rect, buf: &mut Buffer, state: &mut Self::State) {
+        let area = if let Some(next) = state.area.take() {
+            // ensure that the popup remains on screen
+            let width = min(next.width, area.width);
+            let height = min(next.height, area.height);
+            let x = next.x.clamp(buf.area.x, area.right() - width);
+            let y = next.y.clamp(buf.area.y, area.bottom() - height);
+
+            Rect::new(x, y, width, height)
+        } else {
+            let border_height = usize::from(self.borders.intersects(Borders::TOP))
+                + usize::from(self.borders.intersects(Borders::BOTTOM));
+            let border_width = usize::from(self.borders.intersects(Borders::LEFT))
+                + usize::from(self.borders.intersects(Borders::RIGHT));
+
+            let height = self
+                .body
+                .height()
+                .saturating_add(border_height)
+                .try_into()
+                .unwrap_or(area.height);
+            let width = self
+                .body
+                .width()
+                .saturating_add(border_width)
+                .try_into()
+                .unwrap_or(area.width);
+            centered_rect(width, height, area)
+        };
+
+        state.area.replace(area);
+
+        Clear.render(area, buf);
+        let block = Block::default()
+            .borders(self.borders)
+            .title(self.title.clone())
+            .style(self.style);
+        block.render_ref(area, buf);
+        self.body.render_ref(block.inner(area), buf);
+    }
+}
+
+/// Create a rectangle centered in the given area.
+fn centered_rect(width: u16, height: u16, area: Rect) -> Rect {
+    Rect {
+        x: area.width.saturating_sub(width) / 2,
+        y: area.height.saturating_sub(height) / 2,
+        width: min(width, area.width),
+        height: min(height, area.height),
+    }
+}