Q: How to avoid overlapping content in the MainScreen mode?

[Araz Abishov]

Description

Use case

First of all, thanks for the awesome crate!

I'm building a simple application that grabs data from a server and dumps it onto a screen. The idea was to render the content inline within the MainScreen right after the invocation. You can think of it as of cat, which dumps some data onto the screen and exists immediately.

I've followed the "getting started" guide to get something up and running (see the snippet in the "To Reproduce" section). As the result, the snippet is overlapping with the existing content in the terminal:

What I'm trying to achieve is to render the block right after the cargo run command logs (without overlapping). I understand that the current behaviour might be the expected one, as tui might not care if there is existing content and treats the terminal window as canvas. But I was curious, if anyone has come across the same use case / problem before, and what would be the right solution?

To Reproduce

Here is the snippet:

let stdout = io::stdout();
let backend = CrosstermBackend::new(stdout);
let mut terminal = Terminal::new(backend)?;

terminal.draw(|f| {
    let chunks = Layout::default()
        .direction(Direction::Vertical)
        .margin(1)
        .constraints(
            [
                Constraint::Percentage(10),
                Constraint::Percentage(80),
                Constraint::Percentage(10),
            ]
            .as_ref(),
        )
        .split(f.size());

    let block = Block::default().title("Test").borders(Borders::ALL);
    f.render_widget(block, chunks[2]);
})?;

Expected behavior

A mode or a way to instruct "tui" to append rendered contents to the existing content in terminal.

Environment

• OS: macOS Big Sur v11.6.1
• Terminal Emulator: Terminal.app
• Font: San Francisco
• Crate version: v0.16.0
• Backend: crossterm v0.22.1

[Florian Dehau]

Hey 👋, so this is a bit related to #518. This is not currently supported by tui-rs that assumes you are running your application in an alternate screen or fullscreen.

The good news is that I've started working on this topic in #552 as I also think that it could be really valuable to be able to use tui widgets in cli outputs. This is still very much in progress but you can see a preview by running cargo run --example inline.

[Araz Abishov]

Thanks a bunch! I will try out the preview and let you know how it goes :)