This crate is a part of rat-salsa.

• Changes

Rat-Cursor

Why?

This crate defines the trait HasScreenCursor.

This aims to overcome the shortcomings of ratatui. ratatui can set the cursor with the Frame, but if you implement StatefulWidget all you get is the Buffer.

pub trait HasScreenCursor {
    fn screen_cursor(&self) -> Option<(u16, u16)>;
}

Usage

StatefulWidget

Implement the trait for the widget state struct.

It's implemented for the state struct because the widget might need to run the full layout process to know the cursor position. Which would approximately double the rendering process.

Instead of setting the cursor position during rendering somehow, the rendering process stores the cursor position in the state struct, where it can be retrieved later on.

The trait returns a screen-position, but only if it actually needs the cursor to be displayed:

• The cursor is not scrolled off-screen.
• The widget has some kind of input-focus.

Container widget

A container widget can cascade down to its components.

    fn screen_cursor(&self) -> Option<(u16, u16)> {
    self.widget1.screen_cursor()
        .or(self.widget2.screen_cursor())
        .or(self.widget3.screen_cursor())
}