diff options
Diffstat (limited to 'helix-tui/src/terminal.rs')
| -rw-r--r-- | helix-tui/src/terminal.rs | 216 |
1 files changed, 216 insertions, 0 deletions
diff --git a/helix-tui/src/terminal.rs b/helix-tui/src/terminal.rs new file mode 100644 index 00000000..7346d66d --- /dev/null +++ b/helix-tui/src/terminal.rs @@ -0,0 +1,216 @@ +use crate::{backend::Backend, buffer::Buffer, layout::Rect}; +use std::io; + +#[derive(Debug, Clone, PartialEq)] +/// UNSTABLE +enum ResizeBehavior { + Fixed, + Auto, +} + +#[derive(Debug, Clone, PartialEq)] +/// UNSTABLE +pub struct Viewport { + area: Rect, + resize_behavior: ResizeBehavior, +} + +impl Viewport { + /// UNSTABLE + pub fn fixed(area: Rect) -> Viewport { + Viewport { + area, + resize_behavior: ResizeBehavior::Fixed, + } + } +} + +#[derive(Debug, Clone, PartialEq)] +/// Options to pass to [`Terminal::with_options`] +pub struct TerminalOptions { + /// Viewport used to draw to the terminal + pub viewport: Viewport, +} + +/// Interface to the terminal backed by Termion +#[derive(Debug)] +pub struct Terminal<B> +where + B: Backend, +{ + backend: B, + /// Holds the results of the current and previous draw calls. The two are compared at the end + /// of each draw pass to output the necessary updates to the terminal + buffers: [Buffer; 2], + /// Index of the current buffer in the previous array + current: usize, + /// Whether the cursor is currently hidden + hidden_cursor: bool, + /// Viewport + viewport: Viewport, +} + +impl<B> Drop for Terminal<B> +where + B: Backend, +{ + fn drop(&mut self) { + // Attempt to restore the cursor state + if self.hidden_cursor { + if let Err(err) = self.show_cursor() { + eprintln!("Failed to show the cursor: {}", err); + } + } + } +} + +impl<B> Terminal<B> +where + B: Backend, +{ + /// Wrapper around Terminal initialization. Each buffer is initialized with a blank string and + /// default colors for the foreground and the background + pub fn new(backend: B) -> io::Result<Terminal<B>> { + let size = backend.size()?; + Terminal::with_options( + backend, + TerminalOptions { + viewport: Viewport { + area: size, + resize_behavior: ResizeBehavior::Auto, + }, + }, + ) + } + + /// UNSTABLE + pub fn with_options(backend: B, options: TerminalOptions) -> io::Result<Terminal<B>> { + Ok(Terminal { + backend, + buffers: [ + Buffer::empty(options.viewport.area), + Buffer::empty(options.viewport.area), + ], + current: 0, + hidden_cursor: false, + viewport: options.viewport, + }) + } + + // /// Get a Frame object which provides a consistent view into the terminal state for rendering. + // pub fn get_frame(&mut self) -> Frame<B> { + // Frame { + // terminal: self, + // cursor_position: None, + // } + // } + + pub fn current_buffer_mut(&mut self) -> &mut Buffer { + &mut self.buffers[self.current] + } + + pub fn backend(&self) -> &B { + &self.backend + } + + pub fn backend_mut(&mut self) -> &mut B { + &mut self.backend + } + + /// Obtains a difference between the previous and the current buffer and passes it to the + /// current backend for drawing. + pub fn flush(&mut self) -> io::Result<()> { + let previous_buffer = &self.buffers[1 - self.current]; + let current_buffer = &self.buffers[self.current]; + let updates = previous_buffer.diff(current_buffer); + self.backend.draw(updates.into_iter()) + } + + /// Updates the Terminal so that internal buffers match the requested size. Requested size will + /// be saved so the size can remain consistent when rendering. + /// This leads to a full clear of the screen. + pub fn resize(&mut self, area: Rect) -> io::Result<()> { + self.buffers[self.current].resize(area); + self.buffers[1 - self.current].resize(area); + self.viewport.area = area; + self.clear() + } + + /// Queries the backend for size and resizes if it doesn't match the previous size. + pub fn autoresize(&mut self) -> io::Result<()> { + if self.viewport.resize_behavior == ResizeBehavior::Auto { + let size = self.size()?; + if size != self.viewport.area { + self.resize(size)?; + } + }; + Ok(()) + } + + /// Synchronizes terminal size, calls the rendering closure, flushes the current internal state + /// and prepares for the next draw call. + pub fn draw(&mut self, cursor_position: Option<(u16, u16)>) -> io::Result<()> { + // // Autoresize - otherwise we get glitches if shrinking or potential desync between widgets + // // and the terminal (if growing), which may OOB. + // self.autoresize()?; + + // let mut frame = self.get_frame(); + // f(&mut frame); + // // We can't change the cursor position right away because we have to flush the frame to + // // stdout first. But we also can't keep the frame around, since it holds a &mut to + // // Terminal. Thus, we're taking the important data out of the Frame and dropping it. + // let cursor_position = frame.cursor_position; + + // Draw to stdout + self.flush()?; + + match cursor_position { + None => self.hide_cursor()?, + Some((x, y)) => { + self.show_cursor()?; + self.set_cursor(x, y)?; + } + } + + // Swap buffers + self.buffers[1 - self.current].reset(); + self.current = 1 - self.current; + + // Flush + self.backend.flush()?; + Ok(()) + } + + pub fn hide_cursor(&mut self) -> io::Result<()> { + self.backend.hide_cursor()?; + self.hidden_cursor = true; + Ok(()) + } + + pub fn show_cursor(&mut self) -> io::Result<()> { + self.backend.show_cursor()?; + self.hidden_cursor = false; + Ok(()) + } + + pub fn get_cursor(&mut self) -> io::Result<(u16, u16)> { + self.backend.get_cursor() + } + + pub fn set_cursor(&mut self, x: u16, y: u16) -> io::Result<()> { + self.backend.set_cursor(x, y) + } + + /// Clear the terminal and force a full redraw on the next draw call. + pub fn clear(&mut self) -> io::Result<()> { + self.backend.clear()?; + // Reset the back buffer to make sure the next update will redraw everything. + self.buffers[1 - self.current].reset(); + Ok(()) + } + + /// Queries the real size of the backend. + pub fn size(&self) -> io::Result<Rect> { + self.backend.size() + } +} |