ui: Move terminal into compositor, redo required_size hints.

7 files changed, 85 insertions, 76 deletions

diff --git a/helix-term/src/application.rs b/helix-term/src/application.rs
index c63e6e57..afbf1f6b 100644
--- a/helix-term/src/application.rs
+++ b/helix-term/src/application.rs
@@ -23,23 +23,19 @@ use crossterm::{
     execute, terminal,
 };
 
-use tui::{backend::CrosstermBackend, layout::Rect};
-
-type Terminal = crate::terminal::Terminal<CrosstermBackend<std::io::Stdout>>;
+use tui::layout::Rect;
 
 pub struct Application {
     compositor: Compositor,
     editor: Editor,
-    terminal: Terminal,
 
     executor: &'static smol::Executor<'static>,
 }
 
 impl Application {
     pub fn new(mut args: Args, executor: &'static smol::Executor<'static>) -> Result<Self, Error> {
-        let backend = CrosstermBackend::new(stdout());
-        let mut terminal = Terminal::new(backend)?;
-        let size = terminal.size()?;
+        let mut compositor = Compositor::new()?;
+        let size = compositor.size();
         let mut editor = Editor::new(size);
 
         let files = args.values_of_t::<PathBuf>("files").unwrap();
@@ -47,12 +43,10 @@ impl Application {
             editor.open(file, executor)?;
         }
 
-        let mut compositor = Compositor::new();
         compositor.push(Box::new(ui::EditorView::new()));
 
         let mut app = Self {
             editor,
-            terminal,
             compositor,
 
             executor,
@@ -64,17 +58,11 @@ impl Application {
     fn render(&mut self) {
         let executor = &self.executor;
         let editor = &mut self.editor;
-        let compositor = &self.compositor;
+        let compositor = &mut self.compositor;
 
         let mut cx = crate::compositor::Context { editor, executor };
-        let area = self.terminal.size().unwrap();
-
-        compositor.render(area, self.terminal.current_buffer_mut(), &mut cx);
-        let pos = compositor
-            .cursor_position(area, &editor)
-            .map(|pos| (pos.col as u16, pos.row as u16));
 
-        self.terminal.draw(pos);
+        compositor.render(&mut cx);
     }
 
     pub async fn event_loop(&mut self) {
@@ -107,7 +95,7 @@ impl Application {
         // Handle key events
         let should_redraw = match event {
             Some(Ok(Event::Resize(width, height))) => {
-                self.terminal.resize(Rect::new(0, 0, width, height));
+                self.compositor.resize(width, height);
 
                 self.compositor
                     .handle_event(Event::Resize(width, height), &mut cx)
diff --git a/helix-term/src/commands.rs b/helix-term/src/commands.rs
index 4a5f1007..47a61b7f 100644
--- a/helix-term/src/commands.rs
+++ b/helix-term/src/commands.rs
@@ -39,9 +39,12 @@ impl<'a> Context<'a> {
     }
 
     /// Push a new component onto the compositor.
-    pub fn push_layer(&mut self, component: Box<dyn crate::compositor::Component>) {
+    pub fn push_layer(&mut self, mut component: Box<dyn crate::compositor::Component>) {
         self.callback = Some(Box::new(
             |compositor: &mut Compositor, editor: &mut Editor| {
+                let size = compositor.size();
+                // trigger required_size on init
+                component.required_size((size.width, size.height));
                 compositor.push(component);
             },
         ));
diff --git a/helix-term/src/compositor.rs b/helix-term/src/compositor.rs
index 3c90b76a..0a08a0d1 100644
--- a/helix-term/src/compositor.rs
+++ b/helix-term/src/compositor.rs
@@ -1,14 +1,3 @@
-// Features:
-// Tracks currently focused component which receives all input
-// Event loop is external as opposed to cursive-rs
-// Calls render on the component and translates screen coords to local component coords
-//
-// TODO:
-// Q: where is the Application state stored? do we store it into an external static var?
-// A: probably makes sense to initialize the editor into a `static Lazy<>` global var.
-//
-// Q: how do we composit nested structures? There should be sub-components/views
-//
 // Each component declares it's own size constraints and gets fitted based on it's parent.
 // Q: how does this work with popups?
 // cursive does compositor.screen_mut().add_layer_at(pos::absolute(x, y), <component>)
@@ -36,7 +25,7 @@ pub enum EventResult {
 }
 
 use helix_view::{Editor, View};
-// shared with commands.rs
+
 pub struct Context<'a> {
     pub editor: &'a mut Editor,
     pub executor: &'static smol::Executor<'static>,
@@ -54,46 +43,53 @@ pub trait Component {
         true
     }
 
+    /// Render the component onto the provided surface.
     fn render(&self, area: Rect, frame: &mut Surface, ctx: &mut Context);
 
     fn cursor_position(&self, area: Rect, ctx: &Editor) -> Option<Position> {
         None
     }
 
-    fn size_hint(&self, area: Rect) -> Option<(usize, usize)> {
+    /// May be used by the parent component to compute the child area.
+    /// viewport is the maximum allowed area, and the child should stay within those bounds.
+    fn required_size(&mut self, viewport: (u16, u16)) -> Option<(u16, u16)> {
+        // TODO: the compositor should trigger this on push_layer too so that we can use it as an
+        // initializer there too.
+        //
+        // TODO: for scrolling, the scroll wrapper should place a size + offset on the Context
+        // that way render can use it
         None
     }
 }
 
-// For v1:
-// Child views are something each view needs to handle on it's own for now, positioning and sizing
-// options, focus tracking. In practice this is simple: we only will need special solving for
-// splits etc
-
-// impl Editor {
-//     fn render(&mut self, surface: &mut Surface, args: ()) {
-//         // compute x, y, w, h rects for sub-views!
-//         // get surface area
-//         // get constraints for textarea, statusbar
-//         // -> cassowary-rs
-
-//         // first render textarea
-//         // then render statusbar
-//     }
-// }
-
-// usecases to consider:
-// - a single view with subviews (textarea + statusbar)
-// - a popup panel / dialog with it's own interactions
-// - an autocomplete popup that doesn't change focus
+use anyhow::Error;
+use std::io::stdout;
+use tui::backend::CrosstermBackend;
+type Terminal = crate::terminal::Terminal<CrosstermBackend<std::io::Stdout>>;
 
 pub struct Compositor {
     layers: Vec<Box<dyn Component>>,
+    terminal: Terminal,
 }
 
 impl Compositor {
-    pub fn new() -> Self {
-        Self { layers: Vec::new() }
+    pub fn new() -> Result<Self, Error> {
+        let backend = CrosstermBackend::new(stdout());
+        let mut terminal = Terminal::new(backend)?;
+        Ok(Self {
+            layers: Vec::new(),
+            terminal,
+        })
+    }
+
+    pub fn size(&self) -> Rect {
+        self.terminal.size().expect("couldn't get terminal size")
+    }
+
+    pub fn resize(&mut self, width: u16, height: u16) {
+        self.terminal
+            .resize(Rect::new(0, 0, width, height))
+            .expect("Unable to resize terminal")
     }
 
     pub fn push(&mut self, layer: Box<dyn Component>) {
@@ -120,10 +116,19 @@ impl Compositor {
         false
     }
 
-    pub fn render(&self, area: Rect, surface: &mut Surface, cx: &mut Context) {
+    pub fn render(&mut self, cx: &mut Context) {
+        let area = self.size();
+        let surface = self.terminal.current_buffer_mut();
+
         for layer in &self.layers {
             layer.render(area, surface, cx)
         }
+
+        let pos = self
+            .cursor_position(area, cx.editor)
+            .map(|pos| (pos.col as u16, pos.row as u16));
+
+        self.terminal.draw(pos);
     }
 
     pub fn cursor_position(&self, area: Rect, editor: &Editor) -> Option<Position> {
diff --git a/helix-term/src/ui/markdown.rs b/helix-term/src/ui/markdown.rs
index 8456ef74..976d00fa 100644
--- a/helix-term/src/ui/markdown.rs
+++ b/helix-term/src/ui/markdown.rs
@@ -59,16 +59,14 @@ impl Component for Markdown {
                 Event::End(tag) => {
                     tags.pop();
                     match tag {
-                        Tag::Heading(_) | Tag::Paragraph => {
-                            // whenever paragraph closes, new line
+                        Tag::Heading(_)
+                        | Tag::Paragraph
+                        | Tag::CodeBlock(CodeBlockKind::Fenced(_)) => {
+                            // whenever code block or paragraph closes, new line
                             let spans = std::mem::replace(&mut spans, Vec::new());
                             lines.push(Spans::from(spans));
                             lines.push(Spans::default());
                         }
-                        Tag::CodeBlock(CodeBlockKind::Fenced(_)) => {
-                            let spans = std::mem::replace(&mut spans, Vec::new());
-                            lines.push(Spans::from(spans));
-                        }
                         _ => (),
                     }
                 }
@@ -117,14 +115,15 @@ impl Component for Markdown {
         let par = Paragraph::new(contents).wrap(Wrap { trim: false });
         // .scroll(x, y) offsets
 
-        // padding on all sides
         let area = Rect::new(area.x + 1, area.y + 1, area.width - 2, area.height - 2);
         par.render(area, surface);
     }
 
-    fn size_hint(&self, area: Rect) -> Option<(usize, usize)> {
+    fn required_size(&mut self, viewport: (u16, u16)) -> Option<(u16, u16)> {
         let contents = tui::text::Text::from(self.contents.clone());
-        Some((contents.width(), contents.height()))
+        let width = std::cmp::min(contents.width() as u16, viewport.0);
+        let height = std::cmp::min(contents.height() as u16, viewport.1);
+        Some((width, height))
     }
 }
 
diff --git a/helix-term/src/ui/menu.rs b/helix-term/src/ui/menu.rs
index 9f0e79be..c129420d 100644
--- a/helix-term/src/ui/menu.rs
+++ b/helix-term/src/ui/menu.rs
@@ -149,16 +149,21 @@ impl<T> Component for Menu<T> {
         EventResult::Ignored
     }
 
-    fn size_hint(&self, area: Rect) -> Option<(usize, usize)> {
+    fn required_size(&mut self, viewport: (u16, u16)) -> Option<(u16, u16)> {
+        let width = std::cmp::min(30, viewport.0);
+
         const MAX: usize = 5;
         let height = std::cmp::min(self.options.len(), MAX);
-        Some((30, height))
+        let height = std::cmp::min(height, viewport.1 as usize);
+
+        Some((width as u16, height as u16))
     }
 
     fn render(&self, area: Rect, surface: &mut Surface, cx: &mut Context) {
         let style = Style::default().fg(Color::Rgb(164, 160, 232)); // lavender
         let selected = Style::default().fg(Color::Rgb(255, 255, 255));
 
+        // TODO: instead of a cell, all these numbers should be precomputed in handle_event + init
         let mut scroll = self.scroll.get();
         let len = self.options.len();
 
diff --git a/helix-term/src/ui/popup.rs b/helix-term/src/ui/popup.rs
index 625ee2b3..4ca70c50 100644
--- a/helix-term/src/ui/popup.rs
+++ b/helix-term/src/ui/popup.rs
@@ -18,6 +18,7 @@ use helix_view::Editor;
 pub struct Popup {
     contents: Box<dyn Component>,
     position: Option<Position>,
+    size: (u16, u16),
 }
 
 impl Popup {
@@ -27,6 +28,7 @@ impl Popup {
         Self {
             contents,
             position: None,
+            size: (0, 0),
         }
     }
 
@@ -68,6 +70,17 @@ impl Component for Popup {
         // tab/enter/ctrl-k or whatever will confirm the selection/ ctrl-n/ctrl-p for scroll.
     }
 
+    fn required_size(&mut self, viewport: (u16, u16)) -> Option<(u16, u16)> {
+        let (width, height) = self
+            .contents
+            .required_size((120, 26)) // max width, max height
+            .expect("Component needs required_size implemented in order to be embedded in a popup");
+
+        self.size = (width, height);
+
+        Some(self.size)
+    }
+
     fn render(&self, viewport: Rect, surface: &mut Surface, cx: &mut Context) {
         use tui::text::Text;
         use tui::widgets::{Paragraph, Widget, Wrap};
@@ -77,13 +90,7 @@ impl Component for Popup {
             .or_else(|| cx.editor.cursor_position())
             .unwrap_or_default();
 
-        let (width, height) = self
-            .contents
-            .size_hint(viewport)
-            .expect("Component needs size_hint implemented in order to be embedded in a popup");
-
-        let width = width.min(120) as u16;
-        let height = height.min(26) as u16;
+        let (width, height) = self.size;
 
         // -- make sure frame doesn't stick out of bounds
         let mut rel_x = position.col as u16;
diff --git a/helix-term/src/ui/text.rs b/helix-term/src/ui/text.rs
index 133cdd25..9db4d3bc 100644
--- a/helix-term/src/ui/text.rs
+++ b/helix-term/src/ui/text.rs
@@ -33,8 +33,10 @@ impl Component for Text {
         par.render(area, surface);
     }
 
-    fn size_hint(&self, area: Rect) -> Option<(usize, usize)> {
+    fn required_size(&mut self, viewport: (u16, u16)) -> Option<(u16, u16)> {
         let contents = tui::text::Text::from(self.contents.clone());
-        Some((contents.width(), contents.height()))
+        let width = std::cmp::min(contents.width() as u16, viewport.0);
+        let height = std::cmp::min(contents.height() as u16, viewport.1);
+        Some((width, height))
     }
 }