add redraw command (#6949)

Co-authored-by: Roberto Vidal <vidal.roberto.j@gmail.com>

book/src/generated/typable-cmd.md

@@ -83,3 +83,4 @@
 | `:run-shell-command`, `:sh` | Run a shell command |
 | `:reset-diff-change`, `:diffget`, `:diffg` | Reset the diff change at the cursor position. |
 | `:clear-register` | Clear given register. If no argument is provided, clear all registers. |
+| `:redraw` | Clear and re-render the whole UI |

helix-term/src/application.rs

@@ -251,6 +251,11 @@ pub fn new(
     }
 
     async fn render(&mut self) {
+        if self.compositor.full_redraw {
+            self.terminal.clear().expect("Cannot clear the terminal");
+            self.compositor.full_redraw = false;
+        }
+
         let mut cx = crate::compositor::Context {
             editor: &mut self.editor,
             jobs: &mut self.jobs,

helix-term/src/commands/typed.rs

@@ -2291,6 +2291,29 @@ fn clear_register(
     Ok(())
 }
 
+fn redraw(
+    cx: &mut compositor::Context,
+    _args: &[Cow<str>],
+    event: PromptEvent,
+) -> anyhow::Result<()> {
+    if event != PromptEvent::Validate {
+        return Ok(());
+    }
+
+    let callback = Box::pin(async move {
+        let call: job::Callback =
+            job::Callback::EditorCompositor(Box::new(|_editor, compositor| {
+                compositor.need_full_redraw();
+            }));
+
+        Ok(call)
+    });
+
+    cx.jobs.callback(callback);
+
+    Ok(())
+}
+
 pub const TYPABLE_COMMAND_LIST: &[TypableCommand] = &[
     TypableCommand {
         name: "quit",
@@ -2877,6 +2900,13 @@ fn clear_register(
         fun: clear_register,
         signature: CommandSignature::none(),
     },
+    TypableCommand {
+        name: "redraw",
+        aliases: &[],
+        doc: "Clear and re-render the whole UI",
+        fun: redraw,
+        signature: CommandSignature::none(),
+    },
 ];
 
 pub static TYPABLE_COMMAND_MAP: Lazy<HashMap<&'static str, &'static TypableCommand>> =

helix-term/src/compositor.rs

@@ -80,6 +80,7 @@ pub struct Compositor {
     area: Rect,
 
     pub(crate) last_picker: Option<Box<dyn Component>>,
+    pub(crate) full_redraw: bool,
 }
 
 impl Compositor {
@@ -88,6 +89,7 @@ pub fn new(area: Rect) -> Self {
             layers: Vec::new(),
             area,
             last_picker: None,
+            full_redraw: false,
         }
     }
 
@@ -206,6 +208,10 @@ pub fn find_id<T: 'static>(&mut self, id: &'static str) -> Option<&mut T> {
             .find(|component| component.id() == Some(id))
             .and_then(|component| component.as_any_mut().downcast_mut())
     }
+
+    pub fn need_full_redraw(&mut self) {
+        self.full_redraw = true;
+    }
 }
 
 // View casting, taken straight from Cursive