feat(frame)!: Remove generic Backend parameter (#530)

This change simplifys UI code that uses the Frame type. E.g.:

```rust
fn draw<B: Backend>(frame: &mut Frame<B>) {
    // ...
}
```

Frame was generic over Backend because it stored a reference to the
terminal in the field. Instead it now directly stores the viewport area
and current buffer. These are provided at creation time and are valid
for the duration of the frame.

BREAKING CHANGE: Frame is no longer generic over Backend. Code that
accepted `Frame<Backend>` will now need to accept `Frame`. To migrate
existing code, remove any generic parameters from code that uses an
instance of a Frame. E.g. the above code becomes:

```rust
fn draw(frame: &mut Frame) {
    // ...
}
```

examples/barchart.rs

@@ -136,7 +136,7 @@ fn run_app<B: Backend>(
     }
 }
 
-fn ui<B: Backend>(f: &mut Frame<B>, app: &App) {
+fn ui(f: &mut Frame, app: &App) {
     let chunks = Layout::default()
         .direction(Direction::Vertical)
         .constraints([Constraint::Ratio(1, 3), Constraint::Ratio(2, 3)].as_ref())
@@ -198,10 +198,7 @@ fn create_groups<'a>(app: &'a App, combine_values_and_labels: bool) -> Vec<BarGr
         .collect()
 }
 
-fn draw_bar_with_group_labels<B>(f: &mut Frame<B>, app: &App, area: Rect)
-where
-    B: Backend,
-{
+fn draw_bar_with_group_labels(f: &mut Frame, app: &App, area: Rect) {
     let groups = create_groups(app, false);
 
     let mut barchart = BarChart::default()
@@ -228,10 +225,7 @@ where
     }
 }
 
-fn draw_horizontal_bars<B>(f: &mut Frame<B>, app: &App, area: Rect)
-where
-    B: Backend,
-{
+fn draw_horizontal_bars(f: &mut Frame, app: &App, area: Rect) {
     let groups = create_groups(app, true);
 
     let mut barchart = BarChart::default()
@@ -260,10 +254,7 @@ where
     }
 }
 
-fn draw_legend<B>(f: &mut Frame<B>, area: Rect)
-where
-    B: Backend,
-{
+fn draw_legend(f: &mut Frame, area: Rect) {
     let text = vec![
         Line::from(Span::styled(
             TOTAL_REVENUE,

examples/block.rs

@@ -21,7 +21,6 @@ use ratatui::{
 
 // These type aliases are used to make the code more readable by reducing repetition of the generic
 // types. They are not necessary for the functionality of the code.
-type Frame<'a> = ratatui::Frame<'a, CrosstermBackend<Stdout>>;
 type Terminal = ratatui::Terminal<CrosstermBackend<Stdout>>;
 type Result<T> = std::result::Result<T, Box<dyn Error>>;
 

examples/calendar.rs

@@ -16,7 +16,7 @@ fn main() -> Result<(), Box<dyn Error>> {
     let mut terminal = Terminal::new(backend)?;
 
     loop {
-        let _ = terminal.draw(|f| draw(f));
+        let _ = terminal.draw(draw);
 
         if let Event::Key(key) = event::read()? {
             #[allow(clippy::single_match)]
@@ -35,7 +35,7 @@ fn main() -> Result<(), Box<dyn Error>> {
     Ok(())
 }
 
-fn draw<B: Backend>(f: &mut Frame<B>) {
+fn draw(f: &mut Frame) {
     let app_area = f.size();
 
     let calarea = Rect {

examples/canvas.rs

@@ -156,7 +156,7 @@ fn run_app<B: Backend>(
     }
 }
 
-fn ui<B: Backend>(f: &mut Frame<B>, app: &App) {
+fn ui(f: &mut Frame, app: &App) {
     let chunks = Layout::default()
         .direction(Direction::Horizontal)
         .constraints([Constraint::Percentage(50), Constraint::Percentage(50)].as_ref())

examples/chart.rs

@@ -142,7 +142,7 @@ fn run_app<B: Backend>(
     }
 }
 
-fn ui<B: Backend>(f: &mut Frame<B>, app: &App) {
+fn ui(f: &mut Frame, app: &App) {
     let size = f.size();
     let chunks = Layout::default()
         .direction(Direction::Vertical)

examples/colors.rs

@@ -41,7 +41,7 @@ fn run_app<B: Backend>(terminal: &mut Terminal<B>) -> io::Result<()> {
     }
 }
 
-fn ui<B: Backend>(frame: &mut Frame<B>) {
+fn ui(frame: &mut Frame) {
     let layout = Layout::default()
         .direction(Direction::Vertical)
         .constraints(vec![
@@ -75,7 +75,7 @@ const NAMED_COLORS: [Color; 16] = [
     Color::White,
 ];
 
-fn render_named_colors<B: Backend>(frame: &mut Frame<B>, area: Rect) {
+fn render_named_colors(frame: &mut Frame, area: Rect) {
     let layout = Layout::default()
         .direction(Direction::Vertical)
         .constraints(vec![Constraint::Length(3); 10])
@@ -94,7 +94,7 @@ fn render_named_colors<B: Backend>(frame: &mut Frame<B>, area: Rect) {
     render_bg_named_colors(frame, Color::White, layout[9]);
 }
 
-fn render_fg_named_colors<B: Backend>(frame: &mut Frame<B>, bg: Color, area: Rect) {
+fn render_fg_named_colors(frame: &mut Frame, bg: Color, area: Rect) {
     let block = title_block(format!("Foreground colors on {bg} background"));
     let inner = block.inner(area);
     frame.render_widget(block, area);
@@ -119,7 +119,7 @@ fn render_fg_named_colors<B: Backend>(frame: &mut Frame<B>, bg: Color, area: Rec
     }
 }
 
-fn render_bg_named_colors<B: Backend>(frame: &mut Frame<B>, fg: Color, area: Rect) {
+fn render_bg_named_colors(frame: &mut Frame, fg: Color, area: Rect) {
     let block = title_block(format!("Background colors with {fg} foreground"));
     let inner = block.inner(area);
     frame.render_widget(block, area);
@@ -144,7 +144,7 @@ fn render_bg_named_colors<B: Backend>(frame: &mut Frame<B>, fg: Color, area: Rec
     }
 }
 
-fn render_indexed_colors<B: Backend>(frame: &mut Frame<B>, area: Rect) {
+fn render_indexed_colors(frame: &mut Frame, area: Rect) {
     let block = title_block("Indexed colors".into());
     let inner = block.inner(area);
     frame.render_widget(block, area);
@@ -243,7 +243,7 @@ fn title_block(title: String) -> Block<'static> {
         .title_style(Style::new().reset())
 }
 
-fn render_indexed_grayscale<B: Backend>(frame: &mut Frame<B>, area: Rect) {
+fn render_indexed_grayscale(frame: &mut Frame, area: Rect) {
     let layout = Layout::default()
         .direction(Direction::Vertical)
         .constraints(vec![

examples/custom_widget.rs

@@ -64,7 +64,7 @@ fn run_app<B: Backend>(terminal: &mut Terminal<B>) -> io::Result<()> {
     }
 }
 
-fn ui<B: Backend>(f: &mut Frame<B>) {
+fn ui(f: &mut Frame) {
     let size = f.size();
     let label = Label::default().text("Test");
     f.render_widget(label, size);

examples/demo/ui.rs

@@ -5,7 +5,7 @@ use ratatui::{
 
 use crate::app::App;
 
-pub fn draw<B: Backend>(f: &mut Frame<B>, app: &mut App) {
+pub fn draw(f: &mut Frame, app: &mut App) {
     let chunks = Layout::default()
         .constraints([Constraint::Length(3), Constraint::Min(0)].as_ref())
         .split(f.size());
@@ -28,10 +28,7 @@ pub fn draw<B: Backend>(f: &mut Frame<B>, app: &mut App) {
     };
 }
 
-fn draw_first_tab<B>(f: &mut Frame<B>, app: &mut App, area: Rect)
-where
-    B: Backend,
-{
+fn draw_first_tab(f: &mut Frame, app: &mut App, area: Rect) {
     let chunks = Layout::default()
         .constraints(
             [
@@ -47,10 +44,7 @@ where
     draw_text(f, chunks[2]);
 }
 
-fn draw_gauges<B>(f: &mut Frame<B>, app: &mut App, area: Rect)
-where
-    B: Backend,
-{
+fn draw_gauges(f: &mut Frame, app: &mut App, area: Rect) {
     let chunks = Layout::default()
         .constraints(
             [
@@ -102,10 +96,7 @@ where
     f.render_widget(line_gauge, chunks[2]);
 }
 
-fn draw_charts<B>(f: &mut Frame<B>, app: &mut App, area: Rect)
-where
-    B: Backend,
-{
+fn draw_charts(f: &mut Frame, app: &mut App, area: Rect) {
     let constraints = if app.show_chart {
         vec![Constraint::Percentage(50), Constraint::Percentage(50)]
     } else {
@@ -249,10 +240,7 @@ where
     }
 }
 
-fn draw_text<B>(f: &mut Frame<B>, area: Rect)
-where
-    B: Backend,
-{
+fn draw_text(f: &mut Frame, area: Rect) {
     let text = vec![
         text::Line::from("This is a paragraph with several lines. You can change style your text the way you want"),
         text::Line::from(""),
@@ -290,10 +278,7 @@ where
     f.render_widget(paragraph, area);
 }
 
-fn draw_second_tab<B>(f: &mut Frame<B>, app: &mut App, area: Rect)
-where
-    B: Backend,
-{
+fn draw_second_tab(f: &mut Frame, app: &mut App, area: Rect) {
     let chunks = Layout::default()
         .constraints([Constraint::Percentage(30), Constraint::Percentage(70)].as_ref())
         .direction(Direction::Horizontal)
@@ -379,10 +364,7 @@ where
     f.render_widget(map, chunks[1]);
 }
 
-fn draw_third_tab<B>(f: &mut Frame<B>, _app: &mut App, area: Rect)
-where
-    B: Backend,
-{
+fn draw_third_tab(f: &mut Frame, _app: &mut App, area: Rect) {
     let chunks = Layout::default()
         .direction(Direction::Horizontal)
         .constraints([Constraint::Ratio(1, 2), Constraint::Ratio(1, 2)])

examples/gauge.rs

@@ -103,7 +103,7 @@ fn run_app<B: Backend>(
     }
 }
 
-fn ui<B: Backend>(f: &mut Frame<B>, app: &App) {
+fn ui(f: &mut Frame, app: &App) {
     let chunks = Layout::default()
         .direction(Direction::Vertical)
         .constraints(

examples/hello_world.rs

@@ -61,7 +61,7 @@ fn run(terminal: &mut Terminal<CrosstermBackend<Stdout>>) -> Result<()> {
 
 /// Render the application. This is where you would draw the application UI. This example just
 /// draws a greeting.
-fn render_app(frame: &mut ratatui::Frame<CrosstermBackend<Stdout>>) {
+fn render_app(frame: &mut Frame) {
     let greeting = Paragraph::new("Hello World! (press 'q' to quit)");
     frame.render_widget(greeting, frame.size());
 }

examples/inline.rs

@@ -216,7 +216,7 @@ fn run_app<B: Backend>(
     Ok(())
 }
 
-fn ui<B: Backend>(f: &mut Frame<B>, downloads: &Downloads) {
+fn ui(f: &mut Frame, downloads: &Downloads) {
     let size = f.size();
 
     let block = Block::default().title(block::Title::from("Progress").alignment(Alignment::Center));

examples/layout.rs

@@ -37,7 +37,7 @@ fn main() -> Result<(), Box<dyn Error>> {
 
 fn run_app<B: Backend>(terminal: &mut Terminal<B>) -> io::Result<()> {
     loop {
-        terminal.draw(|f| ui(f))?;
+        terminal.draw(ui)?;
 
         if let Event::Key(key) = event::read()? {
             if let KeyCode::Char('q') = key.code {
@@ -47,7 +47,7 @@ fn run_app<B: Backend>(terminal: &mut Terminal<B>) -> io::Result<()> {
     }
 }
 
-fn ui<B: Backend>(frame: &mut Frame<B>) {
+fn ui(frame: &mut Frame) {
     let main_layout = Layout::default()
         .direction(Direction::Vertical)
         .constraints(vec![
@@ -169,8 +169,8 @@ fn ui<B: Backend>(frame: &mut Frame<B>) {
 }
 
 /// Renders a single example box
-fn render_example_combination<B: Backend>(
-    frame: &mut Frame<B>,
+fn render_example_combination(
+    frame: &mut Frame,
     area: Rect,
     title: &str,
     constraints: Vec<(Constraint, Constraint)>,
@@ -195,11 +195,7 @@ fn render_example_combination<B: Backend>(
 }
 
 /// Renders a single example line
-fn render_single_example<B: Backend>(
-    frame: &mut Frame<B>,
-    area: Rect,
-    constraints: Vec<Constraint>,
-) {
+fn render_single_example(frame: &mut Frame, area: Rect, constraints: Vec<Constraint>) {
     let red = Paragraph::new(constraint_label(constraints[0])).on_red();
     let blue = Paragraph::new(constraint_label(constraints[1])).on_blue();
     let green = Paragraph::new("·".repeat(12)).on_green();

examples/list.rs

@@ -198,7 +198,7 @@ fn run_app<B: Backend>(
     }
 }
 
-fn ui<B: Backend>(f: &mut Frame<B>, app: &mut App) {
+fn ui(f: &mut Frame, app: &mut App) {
     // Create two chunks with equal horizontal screen space
     let chunks = Layout::default()
         .direction(Direction::Horizontal)

examples/modifiers.rs

@@ -43,7 +43,7 @@ fn run_app<B: Backend>(terminal: &mut Terminal<B>) -> io::Result<()> {
     }
 }
 
-fn ui<B: Backend>(frame: &mut Frame<B>) {
+fn ui(frame: &mut Frame) {
     let layout = Layout::default()
         .direction(Direction::Vertical)
         .constraints(vec![Constraint::Length(1), Constraint::Min(0)])

examples/panic.rs

@@ -102,7 +102,7 @@ fn run_tui<B: Backend>(terminal: &mut Terminal<B>, app: &mut App) -> io::Result<
 }
 
 /// Render the TUI.
-fn ui<B: Backend>(f: &mut Frame<B>, app: &App) {
+fn ui(f: &mut Frame, app: &App) {
     let text = vec![
         if app.hook_enabled {
             Line::from("HOOK IS CURRENTLY **ENABLED**")

examples/paragraph.rs

@@ -81,7 +81,7 @@ fn run_app<B: Backend>(
     }
 }
 
-fn ui<B: Backend>(f: &mut Frame<B>, app: &App) {
+fn ui(f: &mut Frame, app: &App) {
     let size = f.size();
 
     // Words made "loooong" to demonstrate line breaking.

examples/popup.rs

@@ -61,7 +61,7 @@ fn run_app<B: Backend>(terminal: &mut Terminal<B>, mut app: App) -> io::Result<(
     }
 }
 
-fn ui<B: Backend>(f: &mut Frame<B>, app: &App) {
+fn ui(f: &mut Frame, app: &App) {
     let size = f.size();
 
     let chunks = Layout::default()

examples/scrollbar.rs

@@ -94,7 +94,7 @@ fn run_app<B: Backend>(
     }
 }
 
-fn ui<B: Backend>(f: &mut Frame<B>, app: &mut App) {
+fn ui(f: &mut Frame, app: &mut App) {
     let size = f.size();
 
     // Words made "loooong" to demonstrate line breaking.

examples/sparkline.rs

@@ -126,7 +126,7 @@ fn run_app<B: Backend>(
     }
 }
 
-fn ui<B: Backend>(f: &mut Frame<B>, app: &App) {
+fn ui(f: &mut Frame, app: &App) {
     let chunks = Layout::default()
         .direction(Direction::Vertical)
         .constraints(

examples/table.rs

@@ -113,7 +113,7 @@ fn run_app<B: Backend>(terminal: &mut Terminal<B>, mut app: App) -> io::Result<(
     }
 }
 
-fn ui<B: Backend>(f: &mut Frame<B>, app: &mut App) {
+fn ui(f: &mut Frame, app: &mut App) {
     let rects = Layout::default()
         .constraints([Constraint::Percentage(100)].as_ref())
         .split(f.size());

examples/tabs.rs

@@ -78,7 +78,7 @@ fn run_app<B: Backend>(terminal: &mut Terminal<B>, mut app: App) -> io::Result<(
     }
 }
 
-fn ui<B: Backend>(f: &mut Frame<B>, app: &App) {
+fn ui(f: &mut Frame, app: &App) {
     let size = f.size();
     let chunks = Layout::default()
         .direction(Direction::Vertical)

examples/user_input.rs

@@ -171,7 +171,7 @@ fn run_app<B: Backend>(terminal: &mut Terminal<B>, mut app: App) -> io::Result<(
     }
 }
 
-fn ui<B: Backend>(f: &mut Frame<B>, app: &App) {
+fn ui(f: &mut Frame, app: &App) {
     let chunks = Layout::default()
         .direction(Direction::Vertical)
         .constraints(