Quite a failed attempt to move cursor back up for overdrawing…

crosstermion/src/cursor.rs

@@ -0,0 +1,25 @@
+#[cfg(feature = "crossterm")]
+mod _impl {
+    // pub use crossterm::cursor::MoveToPreviousLine;
+    pub use crossterm::cursor::MoveUp as MoveToPreviousLine;
+}
+#[cfg(feature = "crossterm")]
+pub use _impl::*;
+
+#[cfg(feature = "crossterm")]
+#[macro_export]
+macro_rules! execute {
+    ($writer:expr $(, $command:expr)* $(,)? ) => {
+        // Queue each command, then flush
+        $crate::crossterm::queue!($writer $(, $command)*).and_then(|()| {
+            $writer.flush().map_err($crate::crossterm::ErrorKind::IoError)
+        }).map_err($crate::crossterm_utils::into_io_error)
+    }
+}
+
+#[cfg(all(feature = "termion", not(feature = "crossterm")))]
+mod _impl {
+    compile_error!("not implemented");
+}
+#[cfg(all(feature = "termion", not(feature = "crossterm")))]
+pub use _impl::*;

crosstermion/src/lib.rs

@@ -6,10 +6,13 @@ pub mod input;
 #[cfg(any(feature = "termion", feature = "crossterm"))]
 pub mod terminal;
 
+#[cfg(any(feature = "termion", feature = "crossterm"))]
+pub mod cursor;
+
 pub mod color;
 
 #[cfg(feature = "crossterm")]
-mod crossterm_utils;
+pub mod crossterm_utils;
 
 // Reexports
 #[cfg(feature = "ansi_term")]

examples/dashboard.rs

@@ -84,7 +84,7 @@ fn launch_ambient_gui(
         "line" => smol::Task::blocking(async move {
             let output_is_terminal = atty::is(atty::Stream::Stdout);
             let mut handle = line::render(
-                std::io::stdout(),
+                std::io::stderr(),
                 progress,
                 line::Options {
                     output_is_terminal,

src/line/draw.rs

@@ -66,20 +66,25 @@ fn messages(out: &mut impl io::Write, state: &mut State, colored: bool, timestam
     Ok(())
 }
 
-pub fn lines(out: &mut impl io::Write, progress: &tree::Root, state: &mut State, config: &Options) -> io::Result<()> {
+pub fn all(out: &mut impl io::Write, progress: &tree::Root, state: &mut State, config: &Options) -> io::Result<()> {
     progress.sorted_snapshot(&mut state.tree);
     if !config.keep_running_if_progress_is_empty && state.tree.is_empty() {
         return Err(io::Error::new(io::ErrorKind::Other, "stop as progress is empty"));
     }
     state.from_copying = Some(progress.copy_new_messages(&mut state.messages, state.from_copying.take()));
     messages(out, state, config.colored, config.timestamp)?;
+
     if config.output_is_terminal {
         let level_range = config
             .level_filter
             .clone()
             .unwrap_or(RangeInclusive::new(0, tree::Level::max_value()));
         if state.blocks_per_line.len() > 0 {
             // Move the cursor back all the way so we can start overwriting the screen
+            crosstermion::execute!(
+                out,
+                crosstermion::cursor::MoveToPreviousLine(state.blocks_per_line.len() as u16)
+            )?;
         }
         if state.blocks_per_line.len() < state.tree.len() {
             state.blocks_per_line.resize(state.tree.len(), 0);
@@ -100,7 +105,7 @@ pub fn lines(out: &mut impl io::Write, progress: &tree::Root, state: &mut State,
                 // fill to the end of line to overwrite what was previously there
                 writeln!(
                     out,
-                    "{:width$}",
+                    "{:>width$}",
                     "",
                     width = (**blocks_in_last_iteration - current_block_count) as usize
                 )?;
@@ -112,8 +117,13 @@ pub fn lines(out: &mut impl io::Write, progress: &tree::Root, state: &mut State,
         // overwrite remaining lines that we didn't touch naturally
         if state.blocks_per_line.len() > state.tree.len() {
             for blocks_in_last_iteration in &state.blocks_per_line[state.tree.len()..] {
-                writeln!(out, "{:width$}", width = *blocks_in_last_iteration as usize)?;
+                writeln!(out, "{:>width$}", "", width = *blocks_in_last_iteration as usize)?;
             }
+            // Move cursor back to end of the portion we have actually drawn
+            crosstermion::execute!(
+                out,
+                crosstermion::cursor::MoveToPreviousLine((state.blocks_per_line.len() - state.tree.len()) as u16)
+            )?;
             state.blocks_per_line.resize(state.tree.len(), 0);
         }
     }

src/line/engine.rs

@@ -155,7 +155,7 @@ pub fn render(mut out: impl io::Write + Send + 'static, progress: tree::Root, co
                 if let Ok(Event::Quit) = quit_recv.try_recv() {
                     break;
                 }
-                draw::lines(&mut out, &progress, &mut state, &config)?;
+                draw::all(&mut out, &progress, &mut state, &config)?;
                 std::thread::sleep(Duration::from_secs_f32(1.0 / frames_per_second));
             }
         } else {
@@ -178,7 +178,7 @@ pub fn render(mut out: impl io::Write + Send + 'static, progress: tree::Root, co
                 })
                 .recv(&tick_recv, |_res| Event::Tick);
             while let Event::Tick = selector.wait() {
-                draw::lines(&mut out, &progress, &mut state, &config)?;
+                draw::all(&mut out, &progress, &mut state, &config)?;
             }
         }
         Ok(())