fix(readline): align IME cursor and place output after prompt

Author: ynqa

examples/readline/src/readline_loop.rs

@@ -1,21 +1,10 @@
-use promkit::{
-    core::crossterm::{cursor, terminal},
-    preset::readline::Readline,
-    Prompt,
-};
+use promkit::{preset::readline::Readline, Prompt};
 
 #[tokio::main]
 async fn main() -> anyhow::Result<()> {
     loop {
         match Readline::default().run().await {
             Ok(cmd) => {
-                // If the prompt is finalized on the last line, print one line-feed
-                // first so the result does not overwrite the prompt line.
-                let (_, y) = cursor::position()?;
-                let (_, h) = terminal::size()?;
-                if y >= h.saturating_sub(1) {
-                    println!();
-                }
                 println!("result: {:?}", cmd);
             }
             Err(e) => {

promkit-core/src/render.rs

@@ -54,6 +54,7 @@ impl<K: Ord + Clone + Send + 'static> Renderer<K> {
             terminal: Mutex::new(Terminal {
                 origin,
                 position: origin,
+                after_frame_position: origin,
             }),
             views: SkipMap::new(),
             last_frame_for_hit_test: Mutex::new(Frame::default()),
@@ -137,6 +138,10 @@ impl<K: Ord + Clone + Send + 'static> Renderer<K> {
         })
     }
 
+    pub async fn move_to_after_frame(&self) -> anyhow::Result<()> {
+        self.terminal.lock().await.move_to_after_frame()
+    }
+
     fn build_frame(&self, width: u16, origin_col: u16) -> Frame<K> {
         let mut frame = Frame::default();
         let mut current_row = 0u16;

promkit-core/src/terminal.rs

@@ -10,6 +10,8 @@ pub struct Terminal {
     pub origin: (u16, u16),
     /// The current cursor position within the terminal.
     pub position: (u16, u16),
+    /// The cursor position immediately after the rendered frame.
+    pub after_frame_position: (u16, u16),
 }
 
 impl Terminal {
@@ -83,11 +85,12 @@ impl Terminal {
         }
 
         io::stdout().flush()?;
-        self.position = if is_first_line {
+        self.after_frame_position = if is_first_line {
             self.origin
         } else {
             (0, current_row)
         };
+        self.position = self.after_frame_position;
         Ok(())
     }
 
@@ -105,4 +108,24 @@ impl Terminal {
         self.position = (x, y);
         Ok(true)
     }
+
+    pub(crate) fn move_to_after_frame(&mut self) -> anyhow::Result<()> {
+        let (_, height) = self.size()?;
+        if height == 0 {
+            return Ok(());
+        }
+
+        let mut y = self.after_frame_position.1;
+        if y >= height {
+            let extra = y - height + 1;
+            crossterm::queue!(io::stdout(), terminal::ScrollUp(extra))?;
+            self.origin.1 = self.origin.1.saturating_sub(extra);
+            y = height - 1;
+        }
+
+        crossterm::queue!(io::stdout(), cursor::MoveTo(0, y))?;
+        io::stdout().flush()?;
+        self.position = (0, y);
+        Ok(())
+    }
 }

promkit/src/lib.rs

@@ -86,7 +86,7 @@ pub trait Prompt {
     ///
     /// Returns a `Result` containing the final result of the prompt. The type of the result
     /// is defined by the `Return` associated type.
-    fn finalize(&mut self) -> anyhow::Result<Self::Return>;
+    async fn finalize(&mut self) -> anyhow::Result<Self::Return>;
 
     /// Runs the prompt, handling events and producing a result.
     ///
@@ -133,6 +133,6 @@ pub trait Prompt {
             }
         }
 
-        self.finalize()
+        self.finalize().await
     }
 }

promkit/src/preset/checkbox.rs

@@ -68,7 +68,7 @@ impl crate::Prompt for Checkbox {
 
     type Return = Vec<String>;
 
-    fn finalize(&mut self) -> anyhow::Result<Self::Return> {
+    async fn finalize(&mut self) -> anyhow::Result<Self::Return> {
         Ok(self
             .checkbox
             .checkbox

promkit/src/preset/form.rs

@@ -76,7 +76,7 @@ impl crate::Prompt for Form {
 
     type Return = Vec<String>;
 
-    fn finalize(&mut self) -> anyhow::Result<Self::Return> {
+    async fn finalize(&mut self) -> anyhow::Result<Self::Return> {
         Ok(self
             .readlines
             .contents()

promkit/src/preset/json.rs

@@ -69,7 +69,7 @@ impl crate::Prompt for Json {
 
     type Return = ();
 
-    fn finalize(&mut self) -> anyhow::Result<Self::Return> {
+    async fn finalize(&mut self) -> anyhow::Result<Self::Return> {
         Ok(())
     }
 }

promkit/src/preset/listbox.rs

@@ -67,7 +67,7 @@ impl crate::Prompt for Listbox {
 
     type Return = String;
 
-    fn finalize(&mut self) -> anyhow::Result<Self::Return> {
+    async fn finalize(&mut self) -> anyhow::Result<Self::Return> {
         Ok(self.listbox.listbox.get().to_string())
     }
 }

promkit/src/preset/query_selector.rs

@@ -106,7 +106,7 @@ impl crate::Prompt for QuerySelector {
 
     type Return = String;
 
-    fn finalize(&mut self) -> anyhow::Result<Self::Return> {
+    async fn finalize(&mut self) -> anyhow::Result<Self::Return> {
         Ok(self.list.listbox.get().to_string())
     }
 }

promkit/src/preset/readline.rs

@@ -170,7 +170,10 @@ impl crate::Prompt for Readline {
 
     type Return = String;
 
-    fn finalize(&mut self) -> anyhow::Result<Self::Return> {
+    async fn finalize(&mut self) -> anyhow::Result<Self::Return> {
+        if let Some(renderer) = self.renderer.as_ref() {
+            renderer.move_to_after_frame().await?;
+        }
         let ret = self.readline.texteditor.text_without_cursor().to_string();
 
         // Reset the text editor state for the next prompt.