Vendor ratatui temporarily (#835)

* Vendor ratatui temporarily

Once https://github.com/tui-rs-revival/ratatui/pull/114 has been merged,
we can undo this! But otherwise we can't publish to crates.io with a git
dependency.

* make tests pass

* Shush.

* these literally just fail in nix, nowhere else

idk how to work with nix properly, and they're also not our tests

1 files changed, 37 insertions, 0 deletions

diff --git a/src/ratatui/widgets/clear.rs b/src/ratatui/widgets/clear.rs
new file mode 100644
index 00000000..a7c8d34b
--- /dev/null
+++ b/src/ratatui/widgets/clear.rs
@@ -0,0 +1,37 @@
+use crate::ratatui::{buffer::Buffer, layout::Rect, widgets::Widget};
+
+/// A widget to clear/reset a certain area to allow overdrawing (e.g. for popups).
+///
+/// This widget **cannot be used to clear the terminal on the first render** as `ratatui` assumes the
+/// render area is empty. Use [`crate::Terminal::clear`] instead.
+///
+/// # Examples
+///
+/// ```
+/// # use ratatui::widgets::{Clear, Block, Borders};
+/// # use ratatui::layout::Rect;
+/// # use ratatui::Frame;
+/// # use ratatui::backend::Backend;
+/// fn draw_on_clear<B: Backend>(f: &mut Frame<B>, area: Rect) {
+///     let block = Block::default().title("Block").borders(Borders::ALL);
+///     f.render_widget(Clear, area); // <- this will clear/reset the area first
+///     f.render_widget(block, area); // now render the block widget
+/// }
+/// ```
+///
+/// # Popup Example
+///
+/// For a more complete example how to utilize `Clear` to realize popups see
+/// the example `examples/popup.rs`
+#[derive(Debug, Clone)]
+pub struct Clear;
+
+impl Widget for Clear {
+    fn render(self, area: Rect, buf: &mut Buffer) {
+        for x in area.left()..area.right() {
+            for y in area.top()..area.bottom() {
+                buf.get_mut(x, y).reset();
+            }
+        }
+    }
+}